diff --git a/servo/Cargo.lock b/servo/Cargo.lock
index ad3a4b6be035..6934a50ac52b 100644
--- a/servo/Cargo.lock
+++ b/servo/Cargo.lock
@@ -312,7 +312,7 @@ version = "0.0.1"
 dependencies = [
  "azure 0.19.0 (git+https://github.com/servo/rust-azure)",
  "canvas_traits 0.0.1",
- "cssparser 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.16.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "gleam 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "ipc-channel 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -327,7 +327,7 @@ dependencies = [
 name = "canvas_traits"
 version = "0.0.1"
 dependencies = [
- "cssparser 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.16.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "heapsize 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "heapsize_derive 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -572,7 +572,7 @@ dependencies = [
 
 [[package]]
 name = "cssparser"
-version = "0.15.0"
+version = "0.16.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cssparser-macros 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -999,7 +999,7 @@ name = "geckoservo"
 version = "0.0.1"
 dependencies = [
  "atomic_refcell 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "cssparser 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.16.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "env_logger 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.23 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1065,7 +1065,7 @@ dependencies = [
 name = "gfx_tests"
 version = "0.0.1"
 dependencies = [
- "cssparser 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.16.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "gfx 0.0.1",
  "ipc-channel 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "style 0.0.1",
@@ -2361,7 +2361,7 @@ dependencies = [
  "caseless 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "cmake 0.1.22 (registry+https://github.com/rust-lang/crates.io-index)",
  "cookie 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "cssparser 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.16.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "deny_public_fields 0.0.1",
  "devtools_traits 0.0.1",
  "dom_struct 0.0.1",
@@ -2434,7 +2434,7 @@ dependencies = [
  "app_units 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "atomic_refcell 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "canvas_traits 0.0.1",
- "cssparser 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.16.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "gfx_traits 0.0.1",
  "heapsize 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2505,7 +2505,7 @@ name = "selectors"
 version = "0.19.0"
 dependencies = [
  "bitflags 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "cssparser 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.16.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "fnv 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "matches 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2897,7 +2897,7 @@ dependencies = [
  "bitflags 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "byteorder 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "cfg-if 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "cssparser 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.16.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "encoding 0.2.33 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "fnv 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2950,7 +2950,7 @@ version = "0.0.1"
 dependencies = [
  "app_units 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "byteorder 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "cssparser 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.16.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "html5ever 0.18.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2971,7 +2971,7 @@ version = "0.0.1"
 dependencies = [
  "app_units 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "bitflags 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "cssparser 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.16.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "heapsize 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "heapsize_derive 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2984,7 +2984,7 @@ name = "stylo_tests"
 version = "0.0.1"
 dependencies = [
  "atomic_refcell 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "cssparser 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.16.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "env_logger 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "geckoservo 0.0.1",
@@ -3564,7 +3564,7 @@ dependencies = [
 "checksum core-foundation-sys 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "41115a6aa5d3e1e5ef98148373f25971d1fad53818553f216495f9e67e90a624"
 "checksum core-graphics 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)" = "a9f841e9637adec70838c537cae52cb4c751cc6514ad05669b51d107c2021c79"
 "checksum core-text 5.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "74ba2a7abdccb94fb6c00822addef48504182b285aa45a30e78286487888fcb4"
-"checksum cssparser 0.15.0 (registry+https://github.com/rust-lang/crates.io-index)" = "dd54cdee668d71d20e9f8b9676e2e969968d186ab20a101af59c28398393a2b0"
+"checksum cssparser 0.16.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3c711c0c610b1e5fc2bf96e325b2d9f85839a8e71f6279a77c194af5dcafa502"
 "checksum cssparser-macros 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "079adec4af52bb5275eadd004292028c79eb3c5f5b4ee8086a36d4197032f6df"
 "checksum dbghelp-sys 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "97590ba53bcb8ac28279161ca943a924d1fd4a8fb3fa63302591647c4fc5b850"
 "checksum dbus 0.5.3 (registry+https://github.com/rust-lang/crates.io-index)" = "4aee01fb76ada3e5e7ca642ea6664ebf7308a810739ca2aca44909a1191ac254"
diff --git a/servo/components/canvas/Cargo.toml b/servo/components/canvas/Cargo.toml
index d14b88c20442..5fb7776fefc9 100644
--- a/servo/components/canvas/Cargo.toml
+++ b/servo/components/canvas/Cargo.toml
@@ -12,7 +12,7 @@ path = "lib.rs"
 [dependencies]
 azure = {git = "https://github.com/servo/rust-azure"}
 canvas_traits = {path = "../canvas_traits"}
-cssparser = "0.15"
+cssparser = "0.16"
 euclid = "0.15"
 gleam = "0.4"
 ipc-channel = "0.8"
diff --git a/servo/components/canvas_traits/Cargo.toml b/servo/components/canvas_traits/Cargo.toml
index a6d9f792955e..94465e168099 100644
--- a/servo/components/canvas_traits/Cargo.toml
+++ b/servo/components/canvas_traits/Cargo.toml
@@ -10,7 +10,7 @@ name = "canvas_traits"
 path = "lib.rs"
 
 [dependencies]
-cssparser = "0.15"
+cssparser = "0.16"
 euclid = "0.15"
 heapsize = "0.4"
 heapsize_derive = "0.1"
diff --git a/servo/components/script/Cargo.toml b/servo/components/script/Cargo.toml
index 31d876318f7b..b9d8a0b1304a 100644
--- a/servo/components/script/Cargo.toml
+++ b/servo/components/script/Cargo.toml
@@ -35,7 +35,7 @@ byteorder = "1.0"
 canvas_traits = {path = "../canvas_traits"}
 caseless = "0.1.0"
 cookie = "0.6"
-cssparser = "0.15"
+cssparser = "0.16"
 deny_public_fields = {path = "../deny_public_fields"}
 devtools_traits = {path = "../devtools_traits"}
 dom_struct = {path = "../dom_struct"}
diff --git a/servo/components/script/dom/bindings/str.rs b/servo/components/script/dom/bindings/str.rs
index 4e579044491b..33f4f1bc57f4 100644
--- a/servo/components/script/dom/bindings/str.rs
+++ b/servo/components/script/dom/bindings/str.rs
@@ -4,6 +4,7 @@
 
 //! The `ByteString` struct.
 
+use cssparser::CompactCowStr;
 use html5ever::{LocalName, Namespace};
 use servo_atoms::Atom;
 use std::ascii::AsciiExt;
@@ -298,6 +299,12 @@ impl<'a> Into<Cow<'a, str>> for DOMString {
     }
 }
 
+impl<'a> Into<CompactCowStr<'a>> for DOMString {
+    fn into(self) -> CompactCowStr<'a> {
+        self.0.into()
+    }
+}
+
 impl Extend<char> for DOMString {
     fn extend<I>(&mut self, iterable: I) where I: IntoIterator<Item=char> {
         self.0.extend(iterable)
diff --git a/servo/components/script_layout_interface/Cargo.toml b/servo/components/script_layout_interface/Cargo.toml
index b14e9395b21e..fa861a91e6b9 100644
--- a/servo/components/script_layout_interface/Cargo.toml
+++ b/servo/components/script_layout_interface/Cargo.toml
@@ -13,7 +13,7 @@ path = "lib.rs"
 app_units = "0.5"
 atomic_refcell = "0.1"
 canvas_traits = {path = "../canvas_traits"}
-cssparser = "0.15"
+cssparser = "0.16"
 euclid = "0.15"
 gfx_traits = {path = "../gfx_traits"}
 heapsize = "0.4"
diff --git a/servo/components/selectors/Cargo.toml b/servo/components/selectors/Cargo.toml
index 291ff4649bcf..3894e3e21ad0 100644
--- a/servo/components/selectors/Cargo.toml
+++ b/servo/components/selectors/Cargo.toml
@@ -24,7 +24,7 @@ gecko_like_types = []
 [dependencies]
 bitflags = "0.7"
 matches = "0.1"
-cssparser = "0.15"
+cssparser = "0.16"
 log = "0.3"
 fnv = "1.0"
 phf = "0.7.18"
diff --git a/servo/components/selectors/parser.rs b/servo/components/selectors/parser.rs
index 0899858bd7d9..783ba0cafbc1 100644
--- a/servo/components/selectors/parser.rs
+++ b/servo/components/selectors/parser.rs
@@ -5,7 +5,7 @@
 use attr::{AttrSelectorWithNamespace, ParsedAttrSelectorOperation, AttrSelectorOperator};
 use attr::{ParsedCaseSensitivity, SELECTOR_WHITESPACE, NamespaceConstraint};
 use bloom::BLOOM_HASH_MASK;
-use cssparser::{ParseError, BasicParseError};
+use cssparser::{ParseError, BasicParseError, CompactCowStr};
 use cssparser::{Token, Parser as CssParser, parse_nth, ToCss, serialize_identifier, CssStringWriter};
 use precomputed_hash::PrecomputedHash;
 use servo_arc::{Arc, HeaderWithLength, ThinArc};
@@ -58,7 +58,7 @@ pub enum SelectorParseError<'i, T> {
     PseudoElementExpectedColon,
     PseudoElementExpectedIdent,
     UnsupportedPseudoClass,
-    UnexpectedIdent(Cow<'i, str>),
+    UnexpectedIdent(CompactCowStr<'i>),
     ExpectedNamespace,
     Custom(T),
 }
@@ -133,21 +133,21 @@ pub trait Parser<'i> {
 
     /// This function can return an "Err" pseudo-element in order to support CSS2.1
     /// pseudo-elements.
-    fn parse_non_ts_pseudo_class(&self, name: Cow<'i, str>)
+    fn parse_non_ts_pseudo_class(&self, name: CompactCowStr<'i>)
                                  -> Result<<Self::Impl as SelectorImpl>::NonTSPseudoClass,
                                            ParseError<'i, SelectorParseError<'i, Self::Error>>> {
         Err(ParseError::Custom(SelectorParseError::UnexpectedIdent(name)))
     }
 
     fn parse_non_ts_functional_pseudo_class<'t>
-        (&self, name: Cow<'i, str>, _arguments: &mut CssParser<'i, 't>)
+        (&self, name: CompactCowStr<'i>, _arguments: &mut CssParser<'i, 't>)
          -> Result<<Self::Impl as SelectorImpl>::NonTSPseudoClass,
                    ParseError<'i, SelectorParseError<'i, Self::Error>>>
     {
         Err(ParseError::Custom(SelectorParseError::UnexpectedIdent(name)))
     }
 
-    fn parse_pseudo_element(&self, name: Cow<'i, str>)
+    fn parse_pseudo_element(&self, name: CompactCowStr<'i>)
                             -> Result<<Self::Impl as SelectorImpl>::PseudoElement,
                                       ParseError<'i, SelectorParseError<'i, Self::Error>>> {
         Err(ParseError::Custom(SelectorParseError::UnexpectedIdent(name)))
@@ -1152,7 +1152,7 @@ fn parse_type_selector<'i, 't, P, E, Impl>(parser: &P, input: &mut CssParser<'i,
                 Some(name) => {
                     sequence.push(Component::LocalName(LocalName {
                         lower_name: from_cow_str(to_ascii_lowercase(&name)),
-                        name: from_cow_str(name),
+                        name: from_cow_str(name.into()),
                     }))
                 }
                 None => {
@@ -1186,7 +1186,7 @@ enum QNamePrefix<Impl: SelectorImpl> {
 fn parse_qualified_name<'i, 't, P, E, Impl>
                        (parser: &P, input: &mut CssParser<'i, 't>,
                         in_attr_selector: bool)
-                        -> Result<Option<(QNamePrefix<Impl>, Option<Cow<'i, str>>)>,
+                        -> Result<Option<(QNamePrefix<Impl>, Option<CompactCowStr<'i>>)>,
                                   ParseError<'i, SelectorParseError<'i, E>>>
     where P: Parser<'i, Impl=Impl, Error=E>, Impl: SelectorImpl
 {
@@ -1217,7 +1217,7 @@ fn parse_qualified_name<'i, 't, P, E, Impl>
             let position = input.position();
             match input.next_including_whitespace() {
                 Ok(Token::Delim('|')) => {
-                    let prefix = from_cow_str(value);
+                    let prefix = from_cow_str(value.into());
                     let result = parser.namespace_for_prefix(&prefix);
                     let url = result.ok_or(ParseError::Custom(SelectorParseError::ExpectedNamespace))?;
                     explicit_namespace(input, QNamePrefix::ExplicitNamespace(prefix, url))
@@ -1300,7 +1300,7 @@ fn parse_attribute_selector<'i, 't, P, E, Impl>(parser: &P, input: &mut CssParse
         // [foo]
         Err(_) => {
             let local_name_lower = from_cow_str(to_ascii_lowercase(&local_name));
-            let local_name = from_cow_str(local_name);
+            let local_name = from_cow_str(local_name.into());
             if let Some(namespace) = namespace {
                 return Ok(Component::AttributeOther(Box::new(AttrSelectorWithNamespace {
                     namespace: namespace,
@@ -1358,7 +1358,7 @@ fn parse_attribute_selector<'i, 't, P, E, Impl>(parser: &P, input: &mut CssParse
 
     let mut case_sensitivity = parse_attribute_flags(input)?;
 
-    let value = from_cow_str(value);
+    let value = from_cow_str(value.into());
     let local_name_lower;
     {
         let local_name_lower_cow = to_ascii_lowercase(&local_name);
@@ -1371,9 +1371,9 @@ fn parse_attribute_selector<'i, 't, P, E, Impl>(parser: &P, input: &mut CssParse
                     ParsedCaseSensitivity::AsciiCaseInsensitiveIfInHtmlElementInHtmlDocument
             }
         }
-        local_name_lower = from_cow_str(local_name_lower_cow);
+        local_name_lower = from_cow_str(local_name_lower_cow.into());
     }
-    let local_name = from_cow_str(local_name);
+    let local_name = from_cow_str(local_name.into());
     if let Some(namespace) = namespace {
         Ok(Component::AttributeOther(Box::new(AttrSelectorWithNamespace {
             namespace: namespace,
@@ -1551,7 +1551,7 @@ fn parse_compound_selector<'i, 't, P, E, Impl>(
 
 fn parse_functional_pseudo_class<'i, 't, P, E, Impl>(parser: &P,
                                                      input: &mut CssParser<'i, 't>,
-                                                     name: Cow<'i, str>,
+                                                     name: CompactCowStr<'i>,
                                                      inside_negation: bool)
                                                      -> Result<Component<Impl>,
                                                                ParseError<'i, SelectorParseError<'i, E>>>
@@ -1599,13 +1599,13 @@ fn parse_one_simple_selector<'i, 't, P, E, Impl>(parser: &P,
     let start_position = input.position();
     match input.next_including_whitespace() {
         Ok(Token::IDHash(id)) => {
-            let id = Component::ID(from_cow_str(id));
+            let id = Component::ID(from_cow_str(id.into()));
             Ok(Some(SimpleSelectorParseResult::SimpleSelector(id)))
         }
         Ok(Token::Delim('.')) => {
             match input.next_including_whitespace() {
                 Ok(Token::Ident(class)) => {
-                    let class = Component::Class(from_cow_str(class));
+                    let class = Component::Class(from_cow_str(class.into()));
                     Ok(Some(SimpleSelectorParseResult::SimpleSelector(class)))
                 }
                 Ok(t) => Err(ParseError::Basic(BasicParseError::UnexpectedToken(t))),
@@ -1659,7 +1659,7 @@ fn parse_one_simple_selector<'i, 't, P, E, Impl>(parser: &P,
     }
 }
 
-fn parse_simple_pseudo_class<'i, P, E, Impl>(parser: &P, name: Cow<'i, str>)
+fn parse_simple_pseudo_class<'i, P, E, Impl>(parser: &P, name: CompactCowStr<'i>)
                                              -> Result<Component<Impl>,
                                                        ParseError<'i, SelectorParseError<'i, E>>>
     where P: Parser<'i, Impl=Impl, Error=E>, Impl: SelectorImpl
@@ -1804,7 +1804,7 @@ pub mod tests {
         type Impl = DummySelectorImpl;
         type Error = ();
 
-        fn parse_non_ts_pseudo_class(&self, name: Cow<'i, str>)
+        fn parse_non_ts_pseudo_class(&self, name: CompactCowStr<'i>)
                                      -> Result<PseudoClass,
                                                ParseError<'i, SelectorParseError<'i, ()>>> {
             match_ignore_ascii_case! { &name,
@@ -1814,7 +1814,7 @@ pub mod tests {
             }
         }
 
-        fn parse_non_ts_functional_pseudo_class<'t>(&self, name: Cow<'i, str>,
+        fn parse_non_ts_functional_pseudo_class<'t>(&self, name: CompactCowStr<'i>,
                                                     parser: &mut CssParser<'i, 't>)
                                                     -> Result<PseudoClass,
                                                               ParseError<'i, SelectorParseError<'i, ()>>> {
@@ -1824,7 +1824,7 @@ pub mod tests {
             }
         }
 
-        fn parse_pseudo_element(&self, name: Cow<'i, str>)
+        fn parse_pseudo_element(&self, name: CompactCowStr<'i>)
                                 -> Result<PseudoElement,
                                           ParseError<'i, SelectorParseError<'i, ()>>> {
             match_ignore_ascii_case! { &name,
diff --git a/servo/components/style/Cargo.toml b/servo/components/style/Cargo.toml
index f0f7b28deed4..edaf5d6ea3ad 100644
--- a/servo/components/style/Cargo.toml
+++ b/servo/components/style/Cargo.toml
@@ -38,7 +38,7 @@ bitflags = "0.7"
 bit-vec = "0.4.3"
 byteorder = "1.0"
 cfg-if = "0.1.0"
-cssparser = "0.15"
+cssparser = "0.16"
 encoding = {version = "0.2", optional = true}
 euclid = "0.15"
 fnv = "1.0"
diff --git a/servo/components/style/counter_style/mod.rs b/servo/components/style/counter_style/mod.rs
index 27d0c02950b6..c189429fb909 100644
--- a/servo/components/style/counter_style/mod.rs
+++ b/servo/components/style/counter_style/mod.rs
@@ -8,7 +8,7 @@
 
 use Atom;
 use cssparser::{AtRuleParser, DeclarationListParser, DeclarationParser};
-use cssparser::{Parser, Token, serialize_identifier, BasicParseError};
+use cssparser::{Parser, Token, serialize_identifier, BasicParseError, CompactCowStr};
 use error_reporting::ContextualParseError;
 #[cfg(feature = "gecko")] use gecko::rules::CounterStyleDescriptors;
 #[cfg(feature = "gecko")] use gecko_bindings::structs::nsCSSCounterDesc;
@@ -184,7 +184,7 @@ macro_rules! counter_style_descriptors {
             type Declaration = ();
             type Error = SelectorParseError<'i, StyleParseError<'i>>;
 
-            fn parse_value<'t>(&mut self, name: Cow<'i, str>, input: &mut Parser<'i, 't>)
+            fn parse_value<'t>(&mut self, name: CompactCowStr<'i>, input: &mut Parser<'i, 't>)
                                -> Result<(), ParseError<'i>> {
                 match_ignore_ascii_case! { &*name,
                     $(
@@ -430,7 +430,7 @@ impl Parse for Ranges {
 
 fn parse_bound<'i, 't>(input: &mut Parser<'i, 't>) -> Result<Option<i32>, ParseError<'i>> {
     match input.next() {
-        Ok(Token::Number(ref v)) if v.int_value.is_some() => Ok(Some(v.int_value.unwrap())),
+        Ok(Token::Number { int_value: Some(v), .. }) => Ok(Some(v)),
         Ok(Token::Ident(ref ident)) if ident.eq_ignore_ascii_case("infinite") => Ok(None),
         Ok(t) => Err(BasicParseError::UnexpectedToken(t).into()),
         Err(e) => Err(e.into()),
diff --git a/servo/components/style/custom_properties.rs b/servo/components/style/custom_properties.rs
index 810382acd647..f0528e24fc60 100644
--- a/servo/components/style/custom_properties.rs
+++ b/servo/components/style/custom_properties.rs
@@ -281,7 +281,7 @@ fn parse_declaration_value_block<'i, 't>
             Token::Hash(ref value) |
             Token::IDHash(ref value) |
             Token::UnquotedUrl(ref value) |
-            Token::Dimension(_, ref value) => {
+            Token::Dimension { unit: ref value, .. } => {
                 if value.ends_with("�") && input.slice_from(token_start).ends_with("\\") {
                     // Unescaped backslash at EOF in these contexts is interpreted as U+FFFD
                     // Check the value in case the final backslash was itself escaped.
diff --git a/servo/components/style/error_reporting.rs b/servo/components/style/error_reporting.rs
index d995bec0ba63..e2a28ea0f914 100644
--- a/servo/components/style/error_reporting.rs
+++ b/servo/components/style/error_reporting.rs
@@ -6,7 +6,7 @@
 
 #![deny(missing_docs)]
 
-use cssparser::{Parser, SourcePosition, BasicParseError, Token, NumericValue, PercentageValue};
+use cssparser::{Parser, SourcePosition, BasicParseError, Token};
 use cssparser::ParseError as CssParseError;
 use log;
 use style_traits::ParseError;
@@ -54,11 +54,11 @@ impl<'a> ContextualParseError<'a> {
                 Token::QuotedString(ref s) => format!("quoted string \"{}\"", s),
                 Token::UnquotedUrl(ref u) => format!("url {}", u),
                 Token::Delim(ref d) => format!("delimiter {}", d),
-                Token::Number(NumericValue { int_value: Some(i), .. }) => format!("number {}", i),
-                Token::Number(ref n) => format!("number {}", n.value),
-                Token::Percentage(PercentageValue { int_value: Some(i), .. }) => format!("percentage {}", i),
-                Token::Percentage(ref p) => format!("percentage {}", p.unit_value),
-                Token::Dimension(_, ref d) => format!("dimension {}", d),
+                Token::Number { int_value: Some(i), .. } => format!("number {}", i),
+                Token::Number { value, .. } => format!("number {}", value),
+                Token::Percentage { int_value: Some(i), .. } => format!("percentage {}", i),
+                Token::Percentage { unit_value, .. } => format!("percentage {}", unit_value * 100.),
+                Token::Dimension { value, ref unit, .. } => format!("dimension {}{}", value, unit),
                 Token::WhiteSpace(_) => format!("whitespace"),
                 Token::Comment(_) => format!("comment"),
                 Token::Colon => format!("colon (:)"),
diff --git a/servo/components/style/font_face.rs b/servo/components/style/font_face.rs
index 8346c801d8d6..fe010cf106d5 100644
--- a/servo/components/style/font_face.rs
+++ b/servo/components/style/font_face.rs
@@ -12,14 +12,13 @@
 use computed_values::{font_feature_settings, font_stretch, font_style, font_weight};
 use computed_values::font_family::FamilyName;
 use cssparser::{AtRuleParser, DeclarationListParser, DeclarationParser, Parser};
-use cssparser::SourceLocation;
+use cssparser::{SourceLocation, CompactCowStr};
 use error_reporting::ContextualParseError;
 #[cfg(feature = "gecko")] use gecko_bindings::structs::CSSFontFaceDescriptors;
 #[cfg(feature = "gecko")] use cssparser::UnicodeRange;
 use parser::{ParserContext, log_css_error, Parse};
 use selectors::parser::SelectorParseError;
 use shared_lock::{SharedRwLockReadGuard, ToCssWithGuard};
-use std::borrow::Cow;
 use std::fmt;
 use style_traits::{ToCss, OneOrMoreCommaSeparated, ParseError, StyleParseError};
 use values::specified::url::SpecifiedUrl;
@@ -256,7 +255,7 @@ macro_rules! font_face_descriptors_common {
            type Declaration = ();
            type Error = SelectorParseError<'i, StyleParseError<'i>>;
 
-           fn parse_value<'t>(&mut self, name: Cow<'i, str>, input: &mut Parser<'i, 't>)
+           fn parse_value<'t>(&mut self, name: CompactCowStr<'i>, input: &mut Parser<'i, 't>)
                               -> Result<(), ParseError<'i>> {
                 match_ignore_ascii_case! { &*name,
                     $(
diff --git a/servo/components/style/gecko/media_queries.rs b/servo/components/style/gecko/media_queries.rs
index 6edd5436adb1..e0af1fb1dbe0 100644
--- a/servo/components/style/gecko/media_queries.rs
+++ b/servo/components/style/gecko/media_queries.rs
@@ -231,21 +231,20 @@ impl Resolution {
 
     fn parse<'i, 't>(input: &mut Parser<'i, 't>) -> Result<Self, ParseError<'i>> {
         let (value, unit) = match try!(input.next()) {
-            Token::Dimension(value, unit) => {
+            Token::Dimension { value, unit, .. } => {
                 (value, unit)
             },
             t => return Err(BasicParseError::UnexpectedToken(t).into()),
         };
 
-        let inner_value = value.value;
-        if inner_value <= 0. {
+        if value <= 0. {
             return Err(StyleParseError::UnspecifiedError.into())
         }
 
         (match_ignore_ascii_case! { &unit,
-            "dpi" => Ok(Resolution::Dpi(inner_value)),
-            "dppx" => Ok(Resolution::Dppx(inner_value)),
-            "dpcm" => Ok(Resolution::Dpcm(inner_value)),
+            "dpi" => Ok(Resolution::Dpi(value)),
+            "dppx" => Ok(Resolution::Dppx(value)),
+            "dpcm" => Ok(Resolution::Dpcm(value)),
             _ => Err(())
         }).map_err(|()| StyleParseError::UnexpectedDimension(unit).into())
     }
diff --git a/servo/components/style/gecko/selector_parser.rs b/servo/components/style/gecko/selector_parser.rs
index 9729672a1c74..334ba15197ff 100644
--- a/servo/components/style/gecko/selector_parser.rs
+++ b/servo/components/style/gecko/selector_parser.rs
@@ -4,13 +4,12 @@
 
 //! Gecko-specific bits for selector-parsing.
 
-use cssparser::{Parser, ToCss};
+use cssparser::{Parser, ToCss, CompactCowStr};
 use element_state::ElementState;
 use gecko_bindings::structs::CSSPseudoClassType;
 use selector_parser::{SelectorParser, PseudoElementCascadeType};
 use selectors::parser::{Selector, SelectorMethods, SelectorParseError};
 use selectors::visitor::SelectorVisitor;
-use std::borrow::Cow;
 use std::fmt;
 use string_cache::{Atom, Namespace, WeakAtom, WeakNamespace};
 use style_traits::{ParseError, StyleParseError};
@@ -249,7 +248,7 @@ impl<'a, 'i> ::selectors::Parser<'i> for SelectorParser<'a> {
     type Impl = SelectorImpl;
     type Error = StyleParseError<'i>;
 
-    fn parse_non_ts_pseudo_class(&self, name: Cow<'i, str>)
+    fn parse_non_ts_pseudo_class(&self, name: CompactCowStr<'i>)
                                  -> Result<NonTSPseudoClass, ParseError<'i>> {
         macro_rules! pseudo_class_parse {
             (bare: [$(($css:expr, $name:ident, $gecko_type:tt, $state:tt, $flags:tt),)*],
@@ -271,7 +270,7 @@ impl<'a, 'i> ::selectors::Parser<'i> for SelectorParser<'a> {
     }
 
     fn parse_non_ts_functional_pseudo_class<'t>(&self,
-                                                name: Cow<'i, str>,
+                                                name: CompactCowStr<'i>,
                                                 parser: &mut Parser<'i, 't>)
                                                 -> Result<NonTSPseudoClass, ParseError<'i>> {
         macro_rules! pseudo_class_string_parse {
@@ -315,7 +314,7 @@ impl<'a, 'i> ::selectors::Parser<'i> for SelectorParser<'a> {
         }
     }
 
-    fn parse_pseudo_element(&self, name: Cow<'i, str>) -> Result<PseudoElement, ParseError<'i>> {
+    fn parse_pseudo_element(&self, name: CompactCowStr<'i>) -> Result<PseudoElement, ParseError<'i>> {
         PseudoElement::from_slice(&name, self.in_user_agent_stylesheet())
             .ok_or(SelectorParseError::UnexpectedIdent(name.clone()).into())
     }
diff --git a/servo/components/style/gecko/url.rs b/servo/components/style/gecko/url.rs
index d083aa9c3daa..28359fba6cdb 100644
--- a/servo/components/style/gecko/url.rs
+++ b/servo/components/style/gecko/url.rs
@@ -9,7 +9,6 @@ use gecko_bindings::structs::{ServoBundledURI, URLExtraData};
 use gecko_bindings::structs::root::mozilla::css::ImageValue;
 use gecko_bindings::sugar::refptr::RefPtr;
 use parser::ParserContext;
-use std::borrow::Cow;
 use std::fmt::{self, Write};
 use style_traits::{ToCss, ParseError};
 use stylearc::Arc;
@@ -36,11 +35,11 @@ impl SpecifiedUrl {
     /// URL.
     ///
     /// Returns `Err` in the case that extra_data is incomplete.
-    pub fn parse_from_string<'a>(url: Cow<'a, str>,
+    pub fn parse_from_string<'a>(url: String,
                                  context: &ParserContext)
                                  -> Result<Self, ParseError<'a>> {
         Ok(SpecifiedUrl {
-            serialization: Arc::new(url.into_owned()),
+            serialization: Arc::new(url),
             extra_data: context.url_data.clone(),
             image_value: None,
         })
diff --git a/servo/components/style/properties/declaration_block.rs b/servo/components/style/properties/declaration_block.rs
index bcbb26771a9e..248bc0bd0357 100644
--- a/servo/components/style/properties/declaration_block.rs
+++ b/servo/components/style/properties/declaration_block.rs
@@ -7,7 +7,7 @@
 #![deny(missing_docs)]
 
 use context::QuirksMode;
-use cssparser::{DeclarationListParser, parse_important, ParserInput};
+use cssparser::{DeclarationListParser, parse_important, ParserInput, CompactCowStr};
 use cssparser::{Parser, AtRuleParser, DeclarationParser, Delimiter};
 use error_reporting::{ParseErrorReporter, ContextualParseError};
 use parser::{ParserContext, log_css_error};
@@ -932,7 +932,7 @@ impl<'a, 'b, 'i> DeclarationParser<'i> for PropertyDeclarationParser<'a, 'b> {
     type Declaration = Importance;
     type Error = SelectorParseError<'i, StyleParseError<'i>>;
 
-    fn parse_value<'t>(&mut self, name: Cow<'i, str>, input: &mut Parser<'i, 't>)
+    fn parse_value<'t>(&mut self, name: CompactCowStr<'i>, input: &mut Parser<'i, 't>)
                        -> Result<Importance, ParseError<'i>> {
         let id = try!(PropertyId::parse(name));
         input.parse_until_before(Delimiter::Bang, |input| {
diff --git a/servo/components/style/properties/longhand/effects.mako.rs b/servo/components/style/properties/longhand/effects.mako.rs
index ffafde7f0ed0..c79b3ec5b38b 100644
--- a/servo/components/style/properties/longhand/effects.mako.rs
+++ b/servo/components/style/properties/longhand/effects.mako.rs
@@ -306,8 +306,8 @@ ${helpers.predefined_type("clip",
     fn parse_factor<'i, 't>(input: &mut Parser<'i, 't>) -> Result<::values::CSSFloat, ParseError<'i>> {
         use cssparser::Token;
         match input.next() {
-            Ok(Token::Number(value)) if value.value.is_sign_positive() => Ok(value.value),
-            Ok(Token::Percentage(value)) if value.unit_value.is_sign_positive() => Ok(value.unit_value),
+            Ok(Token::Number { value, .. }) if value.is_sign_positive() => Ok(value),
+            Ok(Token::Percentage { unit_value, .. }) if unit_value.is_sign_positive() => Ok(unit_value),
             Ok(t) => Err(BasicParseError::UnexpectedToken(t).into()),
             Err(e) => Err(e.into())
         }
diff --git a/servo/components/style/properties/longhand/list.mako.rs b/servo/components/style/properties/longhand/list.mako.rs
index 7b5b2879dd92..a578b619c0fa 100644
--- a/servo/components/style/properties/longhand/list.mako.rs
+++ b/servo/components/style/properties/longhand/list.mako.rs
@@ -144,7 +144,7 @@ ${helpers.single_keyword("list-style-position", "outside inside", animation_valu
 
 <%helpers:longhand name="quotes" animation_value_type="none"
                    spec="https://drafts.csswg.org/css-content/#propdef-quotes">
-    use std::borrow::Cow;
+    use cssparser::serialize_string;
     use std::fmt;
     use style_traits::ToCss;
     use values::computed::ComputedValueAsSpecified;
@@ -169,12 +169,12 @@ ${helpers.single_keyword("list-style-position", "outside inside", animation_valu
             let mut first = true;
             for pair in &self.0 {
                 if !first {
-                    try!(dest.write_str(" "));
+                    dest.write_str(" ")?;
                 }
                 first = false;
-                try!(Token::QuotedString(Cow::from(&*pair.0)).to_css(dest));
-                try!(dest.write_str(" "));
-                try!(Token::QuotedString(Cow::from(&*pair.1)).to_css(dest));
+                serialize_string(&*pair.0, dest)?;
+                dest.write_str(" ")?;
+                serialize_string(&*pair.1, dest)?;
             }
             Ok(())
         }
diff --git a/servo/components/style/properties/properties.mako.rs b/servo/components/style/properties/properties.mako.rs
index 0ba5e29314eb..0cab5745d7c3 100644
--- a/servo/components/style/properties/properties.mako.rs
+++ b/servo/components/style/properties/properties.mako.rs
@@ -20,7 +20,7 @@ use stylearc::{Arc, UniqueArc};
 use app_units::Au;
 #[cfg(feature = "servo")] use cssparser::RGBA;
 use cssparser::{Parser, TokenSerializationType, serialize_identifier};
-use cssparser::ParserInput;
+use cssparser::{ParserInput, CompactCowStr};
 use error_reporting::ParseErrorReporter;
 #[cfg(feature = "servo")] use euclid::SideOffsets2D;
 use computed_values;
@@ -491,7 +491,7 @@ impl CSSWideKeyword {
 
     /// Takes the result of cssparser::Parser::expect_ident() and converts it
     /// to a CSSWideKeyword.
-    pub fn from_ident<'i>(ident: &Cow<'i, str>) -> Option<Self> {
+    pub fn from_ident<'i>(ident: &str) -> Option<Self> {
         match_ignore_ascii_case! { ident,
             // If modifying this set of keyword, also update values::CustomIdent::from_ident
             "initial" => Some(CSSWideKeyword::Initial),
@@ -986,7 +986,7 @@ impl PropertyId {
     /// Returns a given property from the string `s`.
     ///
     /// Returns Err(()) for unknown non-custom properties
-    pub fn parse<'i>(property_name: Cow<'i, str>) -> Result<Self, ParseError<'i>> {
+    pub fn parse<'i>(property_name: CompactCowStr<'i>) -> Result<Self, ParseError<'i>> {
         if let Ok(name) = ::custom_properties::parse_name(&property_name) {
             return Ok(PropertyId::Custom(::custom_properties::Name::from(name)))
         }
diff --git a/servo/components/style/servo/selector_parser.rs b/servo/components/style/servo/selector_parser.rs
index 652daa5417c4..235f5fc0f805 100644
--- a/servo/components/style/servo/selector_parser.rs
+++ b/servo/components/style/servo/selector_parser.rs
@@ -8,7 +8,7 @@
 
 use {Atom, Prefix, Namespace, LocalName, CaseSensitivityExt};
 use attr::{AttrIdentifier, AttrValue};
-use cssparser::{Parser as CssParser, ToCss, serialize_identifier};
+use cssparser::{Parser as CssParser, ToCss, serialize_identifier, CompactCowStr};
 use dom::{OpaqueNode, TElement, TNode};
 use element_state::ElementState;
 use fnv::FnvHashMap;
@@ -311,7 +311,7 @@ impl<'a, 'i> ::selectors::Parser<'i> for SelectorParser<'a> {
     type Impl = SelectorImpl;
     type Error = StyleParseError<'i>;
 
-    fn parse_non_ts_pseudo_class(&self, name: Cow<'i, str>)
+    fn parse_non_ts_pseudo_class(&self, name: CompactCowStr<'i>)
                                  -> Result<NonTSPseudoClass, ParseError<'i>> {
         use self::NonTSPseudoClass::*;
         let pseudo_class = match_ignore_ascii_case! { &name,
@@ -344,7 +344,7 @@ impl<'a, 'i> ::selectors::Parser<'i> for SelectorParser<'a> {
     }
 
     fn parse_non_ts_functional_pseudo_class<'t>(&self,
-                                                name: Cow<'i, str>,
+                                                name: CompactCowStr<'i>,
                                                 parser: &mut CssParser<'i, 't>)
                                                 -> Result<NonTSPseudoClass, ParseError<'i>> {
         use self::NonTSPseudoClass::*;
@@ -356,7 +356,7 @@ impl<'a, 'i> ::selectors::Parser<'i> for SelectorParser<'a> {
                 if !self.in_user_agent_stylesheet() {
                     return Err(SelectorParseError::UnexpectedIdent(name.clone()).into());
                 }
-                ServoCaseSensitiveTypeAttr(Atom::from(parser.expect_ident()?))
+                ServoCaseSensitiveTypeAttr(Atom::from(Cow::from(parser.expect_ident()?)))
             }
             _ => return Err(SelectorParseError::UnexpectedIdent(name.clone()).into())
         };
@@ -364,7 +364,7 @@ impl<'a, 'i> ::selectors::Parser<'i> for SelectorParser<'a> {
         Ok(pseudo_class)
     }
 
-    fn parse_pseudo_element(&self, name: Cow<'i, str>) -> Result<PseudoElement, ParseError<'i>> {
+    fn parse_pseudo_element(&self, name: CompactCowStr<'i>) -> Result<PseudoElement, ParseError<'i>> {
         use self::PseudoElement::*;
         let pseudo_element = match_ignore_ascii_case! { &name,
             "before" => Before,
diff --git a/servo/components/style/servo/url.rs b/servo/components/style/servo/url.rs
index 4cf791e55121..fa019d581e69 100644
--- a/servo/components/style/servo/url.rs
+++ b/servo/components/style/servo/url.rs
@@ -7,7 +7,6 @@
 use cssparser::CssStringWriter;
 use parser::ParserContext;
 use servo_url::ServoUrl;
-use std::borrow::Cow;
 use std::fmt::{self, Write};
 // Note: We use std::sync::Arc rather than stylearc::Arc here because the
 // nonzero optimization is important in keeping the size of SpecifiedUrl below
@@ -41,10 +40,10 @@ impl SpecifiedUrl {
     /// Try to parse a URL from a string value that is a valid CSS token for a
     /// URL. Never fails - the API is only fallible to be compatible with the
     /// gecko version.
-    pub fn parse_from_string<'a>(url: Cow<'a, str>,
+    pub fn parse_from_string<'a>(url: String,
                                  context: &ParserContext)
                                  -> Result<Self, ParseError<'a>> {
-        let serialization = Arc::new(url.into_owned());
+        let serialization = Arc::new(url);
         let resolved = context.url_data.join(&serialization).ok();
         Ok(SpecifiedUrl {
             original: Some(serialization),
diff --git a/servo/components/style/stylesheets/keyframes_rule.rs b/servo/components/style/stylesheets/keyframes_rule.rs
index da5311f3da70..d182cdcb39c5 100644
--- a/servo/components/style/stylesheets/keyframes_rule.rs
+++ b/servo/components/style/stylesheets/keyframes_rule.rs
@@ -4,7 +4,7 @@
 
 //! Keyframes: https://drafts.csswg.org/css-animations/#keyframes
 
-use cssparser::{AtRuleParser, Parser, QualifiedRuleParser, RuleListParser, ParserInput};
+use cssparser::{AtRuleParser, Parser, QualifiedRuleParser, RuleListParser, ParserInput, CompactCowStr};
 use cssparser::{DeclarationListParser, DeclarationParser, parse_one_rule, SourceLocation};
 use error_reporting::{NullReporter, ContextualParseError};
 use parser::{ParserContext, log_css_error};
@@ -15,7 +15,6 @@ use properties::animated_properties::AnimatableLonghand;
 use properties::longhands::transition_timing_function::single_value::SpecifiedValue as SpecifiedTimingFunction;
 use selectors::parser::SelectorParseError;
 use shared_lock::{DeepCloneWithLock, SharedRwLock, SharedRwLockReadGuard, Locked, ToCssWithGuard};
-use std::borrow::Cow;
 use std::fmt;
 use style_traits::{PARSING_MODE_DEFAULT, ToCss, ParseError, StyleParseError};
 use stylearc::Arc;
@@ -523,7 +522,7 @@ impl<'a, 'b, 'i> DeclarationParser<'i> for KeyframeDeclarationParser<'a, 'b> {
     type Declaration = ();
     type Error = SelectorParseError<'i, StyleParseError<'i>>;
 
-    fn parse_value<'t>(&mut self, name: Cow<'i, str>, input: &mut Parser<'i, 't>)
+    fn parse_value<'t>(&mut self, name: CompactCowStr<'i>, input: &mut Parser<'i, 't>)
                        -> Result<(), ParseError<'i>> {
         let id = try!(PropertyId::parse(name.into()));
         match PropertyDeclaration::parse_into(self.declarations, id, self.context, input) {
diff --git a/servo/components/style/stylesheets/rule_parser.rs b/servo/components/style/stylesheets/rule_parser.rs
index 4da562e7dcb1..6892de64fa29 100644
--- a/servo/components/style/stylesheets/rule_parser.rs
+++ b/servo/components/style/stylesheets/rule_parser.rs
@@ -6,7 +6,8 @@
 
 use {Namespace, Prefix};
 use counter_style::{parse_counter_style_body, parse_counter_style_name};
-use cssparser::{AtRuleParser, AtRuleType, Parser, QualifiedRuleParser, RuleListParser, SourceLocation};
+use cssparser::{AtRuleParser, AtRuleType, Parser, QualifiedRuleParser, RuleListParser};
+use cssparser::{CompactCowStr, SourceLocation};
 use error_reporting::ContextualParseError;
 use font_face::parse_font_face_block;
 use media_queries::{parse_media_query_list, MediaList};
@@ -144,7 +145,7 @@ impl<'a, 'i> AtRuleParser<'i> for TopLevelRuleParser<'a> {
 
     fn parse_prelude<'t>(
         &mut self,
-        name: Cow<'i, str>,
+        name: CompactCowStr<'i>,
         input: &mut Parser<'i, 't>
     ) -> Result<AtRuleType<AtRulePrelude, CssRule>, ParseError<'i>> {
         let location = get_location_with_offset(input.current_source_location(),
@@ -158,7 +159,7 @@ impl<'a, 'i> AtRuleParser<'i> for TopLevelRuleParser<'a> {
                 }
 
                 self.state = State::Imports;
-                let url_string = input.expect_url_or_string()?;
+                let url_string = input.expect_url_or_string()?.into_owned();
                 let specified_url = SpecifiedUrl::parse_from_string(url_string, &self.context)?;
 
                 let media = parse_media_query_list(&self.context, input);
@@ -203,7 +204,7 @@ impl<'a, 'i> AtRuleParser<'i> for TopLevelRuleParser<'a> {
                 self.state = State::Namespaces;
 
                 let prefix_result = input.try(|input| input.expect_ident());
-                let url = Namespace::from(try!(input.expect_url_or_string()));
+                let url = Namespace::from(Cow::from(input.expect_url_or_string()?));
 
                 let id = register_namespace(&url)
                     .map_err(|()| StyleParseError::UnspecifiedError)?;
@@ -211,7 +212,7 @@ impl<'a, 'i> AtRuleParser<'i> for TopLevelRuleParser<'a> {
                 let mut namespaces = self.namespaces.as_mut().unwrap();
 
                 let opt_prefix = if let Ok(prefix) = prefix_result {
-                    let prefix = Prefix::from(prefix);
+                    let prefix = Prefix::from(Cow::from(prefix));
                     namespaces
                         .prefixes
                         .insert(prefix.clone(), (url.clone(), id));
@@ -337,7 +338,7 @@ impl<'a, 'b, 'i> AtRuleParser<'i> for NestedRuleParser<'a, 'b> {
 
     fn parse_prelude<'t>(
         &mut self,
-        name: Cow<'i, str>,
+        name: CompactCowStr<'i>,
         input: &mut Parser<'i, 't>
     ) -> Result<AtRuleType<AtRulePrelude, CssRule>, ParseError<'i>> {
         let location =
diff --git a/servo/components/style/stylesheets/viewport_rule.rs b/servo/components/style/stylesheets/viewport_rule.rs
index 8f48ac15bb57..6e5ae31d6e48 100644
--- a/servo/components/style/stylesheets/viewport_rule.rs
+++ b/servo/components/style/stylesheets/viewport_rule.rs
@@ -10,7 +10,7 @@
 use app_units::Au;
 use context::QuirksMode;
 use cssparser::{AtRuleParser, DeclarationListParser, DeclarationParser, Parser, parse_important};
-use cssparser::ToCss as ParserToCss;
+use cssparser::{CompactCowStr, ToCss as ParserToCss};
 use error_reporting::ContextualParseError;
 use euclid::TypedSize2D;
 use font_metrics::get_metrics_provider_for_product;
@@ -281,7 +281,7 @@ impl<'a, 'b, 'i> DeclarationParser<'i> for ViewportRuleParser<'a, 'b> {
     type Declaration = Vec<ViewportDescriptorDeclaration>;
     type Error = SelectorParseError<'i, StyleParseError<'i>>;
 
-    fn parse_value<'t>(&mut self, name: Cow<'i, str>, input: &mut Parser<'i, 't>)
+    fn parse_value<'t>(&mut self, name: CompactCowStr<'i>, input: &mut Parser<'i, 't>)
                        -> Result<Vec<ViewportDescriptorDeclaration>, ParseError<'i>> {
         macro_rules! declaration {
             ($declaration:ident($parse:expr)) => {
diff --git a/servo/components/style/values/mod.rs b/servo/components/style/values/mod.rs
index 962f8ecc0eb2..84cc853f2fb8 100644
--- a/servo/components/style/values/mod.rs
+++ b/servo/components/style/values/mod.rs
@@ -9,7 +9,7 @@
 #![deny(missing_docs)]
 
 use Atom;
-pub use cssparser::{RGBA, Token, Parser, serialize_identifier, BasicParseError};
+pub use cssparser::{RGBA, Token, Parser, serialize_identifier, BasicParseError, CompactCowStr};
 use parser::{Parse, ParserContext};
 use selectors::parser::SelectorParseError;
 use std::ascii::AsciiExt;
@@ -93,7 +93,7 @@ pub struct CustomIdent(pub Atom);
 
 impl CustomIdent {
     /// Parse an already-tokenizer identifier
-    pub fn from_ident<'i>(ident: Cow<'i, str>, excluding: &[&str]) -> Result<Self, ParseError<'i>> {
+    pub fn from_ident<'i>(ident: CompactCowStr<'i>, excluding: &[&str]) -> Result<Self, ParseError<'i>> {
         let valid = match_ignore_ascii_case! { &ident,
             "initial" | "inherit" | "unset" | "default" => false,
             _ => true
@@ -104,7 +104,7 @@ impl CustomIdent {
         if excluding.iter().any(|s| ident.eq_ignore_ascii_case(s)) {
             Err(StyleParseError::UnspecifiedError.into())
         } else {
-            Ok(CustomIdent(ident.into()))
+            Ok(CustomIdent(Atom::from(Cow::from(ident))))
         }
     }
 }
@@ -128,9 +128,10 @@ pub enum KeyframesName {
 impl KeyframesName {
     /// https://drafts.csswg.org/css-animations/#dom-csskeyframesrule-name
     pub fn from_ident(value: String) -> Self {
-        match CustomIdent::from_ident((&*value).into(), &["none"]) {
-            Ok(ident) => KeyframesName::Ident(ident),
-            Err(_) => KeyframesName::QuotedString(value.into()),
+        let custom_ident = CustomIdent::from_ident((&*value).into(), &["none"]).ok();
+        match custom_ident {
+            Some(ident) => KeyframesName::Ident(ident),
+            None => KeyframesName::QuotedString(value.into()),
         }
     }
 
@@ -161,7 +162,7 @@ impl Parse for KeyframesName {
     fn parse<'i, 't>(_context: &ParserContext, input: &mut Parser<'i, 't>) -> Result<Self, ParseError<'i>> {
         match input.next() {
             Ok(Token::Ident(s)) => Ok(KeyframesName::Ident(CustomIdent::from_ident(s, &["none"])?)),
-            Ok(Token::QuotedString(s)) => Ok(KeyframesName::QuotedString(s.into())),
+            Ok(Token::QuotedString(s)) => Ok(KeyframesName::QuotedString(Atom::from(Cow::from(s)))),
             Ok(t) => Err(BasicParseError::UnexpectedToken(t).into()),
             Err(e) => Err(e.into()),
         }
diff --git a/servo/components/style/values/specified/calc.rs b/servo/components/style/values/specified/calc.rs
index c4a2bae3f078..365bad098ed2 100644
--- a/servo/components/style/values/specified/calc.rs
+++ b/servo/components/style/values/specified/calc.rs
@@ -150,29 +150,25 @@ impl CalcNode {
         -> Result<Self, ParseError<'i>>
     {
         match (try!(input.next()), expected_unit) {
-            (Token::Number(ref value), _) => Ok(CalcNode::Number(value.value)),
-            (Token::Dimension(ref value, ref unit), CalcUnit::Length) |
-            (Token::Dimension(ref value, ref unit), CalcUnit::LengthOrPercentage) => {
-                NoCalcLength::parse_dimension(context, value.value, unit)
+            (Token::Number { value, .. }, _) => Ok(CalcNode::Number(value)),
+            (Token::Dimension { value, ref unit, .. }, CalcUnit::Length) |
+            (Token::Dimension { value, ref unit, .. }, CalcUnit::LengthOrPercentage) => {
+                NoCalcLength::parse_dimension(context, value, unit)
                     .map(CalcNode::Length)
                     .map_err(|()| StyleParseError::UnspecifiedError.into())
             }
-            (Token::Dimension(ref value, ref unit), CalcUnit::Angle) => {
-                Angle::parse_dimension(value.value,
-                                       unit,
-                                       /* from_calc = */ true)
+            (Token::Dimension { value, ref unit, .. }, CalcUnit::Angle) => {
+                Angle::parse_dimension(value, unit, /* from_calc = */ true)
                     .map(CalcNode::Angle)
                     .map_err(|()| StyleParseError::UnspecifiedError.into())
             }
-            (Token::Dimension(ref value, ref unit), CalcUnit::Time) => {
-                Time::parse_dimension(value.value,
-                                      unit,
-                                      /* from_calc = */ true)
+            (Token::Dimension { value, ref unit, .. }, CalcUnit::Time) => {
+                Time::parse_dimension(value, unit, /* from_calc = */ true)
                     .map(CalcNode::Time)
                     .map_err(|()| StyleParseError::UnspecifiedError.into())
             }
-            (Token::Percentage(ref value), CalcUnit::LengthOrPercentage) => {
-                Ok(CalcNode::Percentage(value.unit_value))
+            (Token::Percentage { unit_value, .. }, CalcUnit::LengthOrPercentage) => {
+                Ok(CalcNode::Percentage(unit_value))
             }
             (Token::ParenthesisBlock, _) => {
                 input.parse_nested_block(|i| {
diff --git a/servo/components/style/values/specified/color.rs b/servo/components/style/values/specified/color.rs
index 7969106c8d83..fdf6212151f2 100644
--- a/servo/components/style/values/specified/color.rs
+++ b/servo/components/style/values/specified/color.rs
@@ -173,12 +173,12 @@ impl Color {
     ///
     /// https://quirks.spec.whatwg.org/#the-hashless-hex-color-quirk
     fn parse_quirky_color<'i, 't>(input: &mut Parser<'i, 't>) -> Result<RGBA, ParseError<'i>> {
-        let (number, dimension) = match input.next()? {
-            Token::Number(number) => {
-                (number, None)
+        let (value, unit) = match input.next()? {
+            Token::Number { int_value: Some(integer), .. } => {
+                (integer, None)
             },
-            Token::Dimension(number, dimension) => {
-                (number, Some(dimension))
+            Token::Dimension { int_value: Some(integer), unit, .. } => {
+                (integer, Some(unit))
             },
             Token::Ident(ident) => {
                 if ident.len() != 3 && ident.len() != 6 {
@@ -191,7 +191,6 @@ impl Color {
                 return Err(BasicParseError::UnexpectedToken(t).into());
             },
         };
-        let value = number.int_value.ok_or(StyleParseError::UnspecifiedError)?;
         if value < 0 {
             return Err(StyleParseError::UnspecifiedError.into());
         }
@@ -210,7 +209,7 @@ impl Color {
         } else {
             return Err(StyleParseError::UnspecifiedError.into())
         };
-        let total = length + dimension.as_ref().map_or(0, |d| d.len());
+        let total = length + unit.as_ref().map_or(0, |d| d.len());
         if total > 6 {
             return Err(StyleParseError::UnspecifiedError.into());
         }
@@ -218,8 +217,8 @@ impl Color {
         let space_padding = 6 - total;
         let mut written = space_padding;
         written += itoa::write(&mut serialization[written..], value).unwrap();
-        if let Some(dimension) = dimension {
-            written += (&mut serialization[written..]).write(dimension.as_bytes()).unwrap();
+        if let Some(unit) = unit {
+            written += (&mut serialization[written..]).write(unit.as_bytes()).unwrap();
         }
         debug_assert!(written == 6);
         parse_hash_color(&serialization).map_err(|()| StyleParseError::UnspecifiedError.into())
diff --git a/servo/components/style/values/specified/grid.rs b/servo/components/style/values/specified/grid.rs
index 501d2ee6d2ab..d19ab3703c3c 100644
--- a/servo/components/style/values/specified/grid.rs
+++ b/servo/components/style/values/specified/grid.rs
@@ -19,8 +19,8 @@ use values::specified::LengthOrPercentage;
 /// Parse a single flexible length.
 pub fn parse_flex<'i, 't>(input: &mut Parser<'i, 't>) -> Result<CSSFloat, ParseError<'i>> {
     match input.next()? {
-        Token::Dimension(ref value, ref unit) if unit.eq_ignore_ascii_case("fr") && value.value.is_sign_positive()
-            => Ok(value.value),
+        Token::Dimension { value, ref unit, .. } if unit.eq_ignore_ascii_case("fr") && value.is_sign_positive()
+            => Ok(value),
         t => Err(BasicParseError::UnexpectedToken(t).into()),
     }
 }
diff --git a/servo/components/style/values/specified/image.rs b/servo/components/style/values/specified/image.rs
index 6b091d6aea95..a02d14207540 100644
--- a/servo/components/style/values/specified/image.rs
+++ b/servo/components/style/values/specified/image.rs
@@ -13,6 +13,7 @@ use parser::{Parse, ParserContext};
 use selectors::parser::SelectorParseError;
 #[cfg(feature = "servo")]
 use servo_url::ServoUrl;
+use std::borrow::Cow;
 use std::cmp::Ordering;
 use std::f32::consts::PI;
 use std::fmt;
@@ -137,7 +138,7 @@ impl Image {
         input.try(|i| i.expect_function_matching("-moz-element"))?;
         input.parse_nested_block(|i| {
             match i.next()? {
-                Token::IDHash(id) => Ok(Atom::from(id)),
+                Token::IDHash(id) => Ok(Atom::from(Cow::from(id))),
                 t => Err(BasicParseError::UnexpectedToken(t).into()),
             }
         })
@@ -699,7 +700,7 @@ impl Parse for PaintWorklet {
         input.parse_nested_block(|i| {
             let name = i.expect_ident()?;
             Ok(PaintWorklet {
-                name: Atom::from(name),
+                name: Atom::from(Cow::from(name)),
             })
         })
     }
@@ -710,7 +711,7 @@ impl Parse for ImageRect {
         input.try(|i| i.expect_function_matching("-moz-image-rect"))?;
         input.parse_nested_block(|i| {
             let string = i.expect_url_or_string()?;
-            let url = SpecifiedUrl::parse_from_string(string, context)?;
+            let url = SpecifiedUrl::parse_from_string(string.into_owned(), context)?;
             i.expect_comma()?;
             let top = NumberOrPercentage::parse_non_negative(context, i)?;
             i.expect_comma()?;
diff --git a/servo/components/style/values/specified/length.rs b/servo/components/style/values/specified/length.rs
index cc1655ce33e6..04543f7723dd 100644
--- a/servo/components/style/values/specified/length.rs
+++ b/servo/components/style/values/specified/length.rs
@@ -611,20 +611,22 @@ impl Length {
                               -> Result<Length, ParseError<'i>> {
         let token = try!(input.next());
         match token {
-            Token::Dimension(ref value, ref unit) if num_context.is_ok(context.parsing_mode, value.value) =>
-                Length::parse_dimension(context, value.value, unit),
-            Token::Number(ref value) if num_context.is_ok(context.parsing_mode, value.value) => {
-                if value.value != 0. &&
+            Token::Dimension { value, ref unit, .. } if num_context.is_ok(context.parsing_mode, value) => {
+                Length::parse_dimension(context, value, unit)
+            }
+            Token::Number { value, .. } if num_context.is_ok(context.parsing_mode, value) => {
+                if value != 0. &&
                    !context.parsing_mode.allows_unitless_lengths() &&
                    !allow_quirks.allowed(context.quirks_mode) {
                     return Err(StyleParseError::UnspecifiedError.into())
                 }
-                Ok(Length::NoCalc(NoCalcLength::Absolute(AbsoluteLength::Px(value.value))))
+                Ok(Length::NoCalc(NoCalcLength::Absolute(AbsoluteLength::Px(value))))
             },
-            Token::Function(ref name) if name.eq_ignore_ascii_case("calc") =>
+            Token::Function(ref name) if name.eq_ignore_ascii_case("calc") => {
                 return input.parse_nested_block(|input| {
                     CalcNode::parse_length(context, input, num_context).map(|calc| Length::Calc(Box::new(calc)))
-                }),
+                })
+            }
             _ => Err(())
         }.map_err(|()| BasicParseError::UnexpectedToken(token).into())
     }
@@ -720,8 +722,8 @@ impl Percentage {
                                             num_context: AllowedNumericType)
                                             -> Result<Self, ParseError<'i>> {
         match try!(input.next()) {
-            Token::Percentage(ref value) if num_context.is_ok(context.parsing_mode, value.unit_value) => {
-                Ok(Percentage(value.unit_value))
+            Token::Percentage { unit_value, .. } if num_context.is_ok(context.parsing_mode, unit_value) => {
+                Ok(Percentage(unit_value))
             }
             t => Err(BasicParseError::UnexpectedToken(t).into())
         }
@@ -804,17 +806,19 @@ impl LengthOrPercentage {
     {
         let token = try!(input.next());
         match token {
-            Token::Dimension(ref value, ref unit) if num_context.is_ok(context.parsing_mode, value.value) =>
-                NoCalcLength::parse_dimension(context, value.value, unit).map(LengthOrPercentage::Length),
-            Token::Percentage(ref value) if num_context.is_ok(context.parsing_mode, value.unit_value) =>
-                return Ok(LengthOrPercentage::Percentage(Percentage(value.unit_value))),
-            Token::Number(value) if num_context.is_ok(context.parsing_mode, value.value) => {
-                if value.value != 0. &&
+            Token::Dimension { value, ref unit, .. } if num_context.is_ok(context.parsing_mode, value) => {
+                NoCalcLength::parse_dimension(context, value, unit).map(LengthOrPercentage::Length)
+            }
+            Token::Percentage { unit_value, .. } if num_context.is_ok(context.parsing_mode, unit_value) => {
+                return Ok(LengthOrPercentage::Percentage(Percentage(unit_value)))
+            }
+            Token::Number { value, .. } if num_context.is_ok(context.parsing_mode, value) => {
+                if value != 0. &&
                    !context.parsing_mode.allows_unitless_lengths() &&
                    !allow_quirks.allowed(context.quirks_mode) {
                     Err(())
                 } else {
-                    return Ok(LengthOrPercentage::Length(NoCalcLength::from_px(value.value)))
+                    return Ok(LengthOrPercentage::Length(NoCalcLength::from_px(value)))
                 }
             }
             Token::Function(ref name) if name.eq_ignore_ascii_case("calc") => {
@@ -822,7 +826,7 @@ impl LengthOrPercentage {
                     CalcNode::parse_length_or_percentage(context, i, num_context)
                 }));
                 return Ok(LengthOrPercentage::Calc(Box::new(calc)))
-            },
+            }
             _ => Err(())
         }.map_err(|()| BasicParseError::UnexpectedToken(token).into())
     }
@@ -938,28 +942,31 @@ impl LengthOrPercentageOrAuto {
                               -> Result<Self, ParseError<'i>> {
         let token = try!(input.next());
         match token {
-            Token::Dimension(ref value, ref unit) if num_context.is_ok(context.parsing_mode, value.value) =>
-                NoCalcLength::parse_dimension(context, value.value, unit).map(LengthOrPercentageOrAuto::Length),
-            Token::Percentage(ref value) if num_context.is_ok(context.parsing_mode, value.unit_value) =>
-                Ok(LengthOrPercentageOrAuto::Percentage(Percentage(value.unit_value))),
-            Token::Number(ref value) if num_context.is_ok(context.parsing_mode, value.value) => {
-                if value.value != 0. &&
+            Token::Dimension { value, ref unit, .. } if num_context.is_ok(context.parsing_mode, value) => {
+                NoCalcLength::parse_dimension(context, value, unit).map(LengthOrPercentageOrAuto::Length)
+            }
+            Token::Percentage { unit_value, .. } if num_context.is_ok(context.parsing_mode, unit_value) => {
+                Ok(LengthOrPercentageOrAuto::Percentage(Percentage(unit_value)))
+            }
+            Token::Number { value, .. } if num_context.is_ok(context.parsing_mode, value) => {
+                if value != 0. &&
                    !context.parsing_mode.allows_unitless_lengths() &&
                    !allow_quirks.allowed(context.quirks_mode) {
                     return Err(StyleParseError::UnspecifiedError.into())
                 }
                 Ok(LengthOrPercentageOrAuto::Length(
-                    NoCalcLength::Absolute(AbsoluteLength::Px(value.value))
+                    NoCalcLength::Absolute(AbsoluteLength::Px(value))
                 ))
             }
-            Token::Ident(ref value) if value.eq_ignore_ascii_case("auto") =>
-                Ok(LengthOrPercentageOrAuto::Auto),
+            Token::Ident(ref value) if value.eq_ignore_ascii_case("auto") => {
+                Ok(LengthOrPercentageOrAuto::Auto)
+            }
             Token::Function(ref name) if name.eq_ignore_ascii_case("calc") => {
                 let calc = try!(input.parse_nested_block(|i| {
                     CalcNode::parse_length_or_percentage(context, i, num_context)
                 }));
                 Ok(LengthOrPercentageOrAuto::Calc(Box::new(calc)))
-            },
+            }
             _ => Err(())
         }.map_err(|()| BasicParseError::UnexpectedToken(token).into())
     }
@@ -1034,17 +1041,19 @@ impl LengthOrPercentageOrNone {
     {
         let token = try!(input.next());
         match token {
-            Token::Dimension(ref value, ref unit) if num_context.is_ok(context.parsing_mode, value.value) =>
-                NoCalcLength::parse_dimension(context, value.value, unit).map(LengthOrPercentageOrNone::Length),
-            Token::Percentage(ref value) if num_context.is_ok(context.parsing_mode, value.unit_value) =>
-                Ok(LengthOrPercentageOrNone::Percentage(Percentage(value.unit_value))),
-            Token::Number(value) if num_context.is_ok(context.parsing_mode, value.value) => {
-                if value.value != 0. && !context.parsing_mode.allows_unitless_lengths() &&
+            Token::Dimension { value, ref unit, .. } if num_context.is_ok(context.parsing_mode, value) => {
+                NoCalcLength::parse_dimension(context, value, unit).map(LengthOrPercentageOrNone::Length)
+            }
+            Token::Percentage { unit_value, .. } if num_context.is_ok(context.parsing_mode, unit_value) => {
+                Ok(LengthOrPercentageOrNone::Percentage(Percentage(unit_value)))
+            }
+            Token::Number { value, .. } if num_context.is_ok(context.parsing_mode, value) => {
+                if value != 0. && !context.parsing_mode.allows_unitless_lengths() &&
                    !allow_quirks.allowed(context.quirks_mode) {
                     return Err(StyleParseError::UnspecifiedError.into())
                 }
                 Ok(LengthOrPercentageOrNone::Length(
-                    NoCalcLength::Absolute(AbsoluteLength::Px(value.value))
+                    NoCalcLength::Absolute(AbsoluteLength::Px(value))
                 ))
             }
             Token::Function(ref name) if name.eq_ignore_ascii_case("calc") => {
@@ -1052,7 +1061,7 @@ impl LengthOrPercentageOrNone {
                     CalcNode::parse_length_or_percentage(context, i, num_context)
                 }));
                 Ok(LengthOrPercentageOrNone::Calc(Box::new(calc)))
-            },
+            }
             Token::Ident(ref value) if value.eq_ignore_ascii_case("none") =>
                 Ok(LengthOrPercentageOrNone::None),
             _ => Err(())
@@ -1116,23 +1125,28 @@ impl LengthOrPercentageOrAutoOrContent {
         let num_context = AllowedLengthType::NonNegative;
         let token = try!(input.next());
         match token {
-            Token::Dimension(ref value, ref unit) if num_context.is_ok(context.parsing_mode, value.value) =>
-                NoCalcLength::parse_dimension(context, value.value, unit)
-                             .map(LengthOrPercentageOrAutoOrContent::Length),
-            Token::Percentage(ref value) if num_context.is_ok(context.parsing_mode, value.unit_value) =>
-                Ok(LengthOrPercentageOrAutoOrContent::Percentage(Percentage(value.unit_value))),
-            Token::Number(ref value) if value.value == 0. =>
-                Ok(Self::zero()),
-            Token::Ident(ref value) if value.eq_ignore_ascii_case("auto") =>
-                Ok(LengthOrPercentageOrAutoOrContent::Auto),
-            Token::Ident(ref value) if value.eq_ignore_ascii_case("content") =>
-                Ok(LengthOrPercentageOrAutoOrContent::Content),
+            Token::Dimension { value, ref unit, .. } if num_context.is_ok(context.parsing_mode, value) => {
+                NoCalcLength::parse_dimension(context, value, unit)
+                             .map(LengthOrPercentageOrAutoOrContent::Length)
+            }
+            Token::Percentage { unit_value, .. } if num_context.is_ok(context.parsing_mode, unit_value) => {
+                Ok(LengthOrPercentageOrAutoOrContent::Percentage(Percentage(unit_value)))
+            }
+            Token::Number { value, .. } if value == 0. => {
+                Ok(Self::zero())
+            }
+            Token::Ident(ref value) if value.eq_ignore_ascii_case("auto") => {
+                Ok(LengthOrPercentageOrAutoOrContent::Auto)
+            }
+            Token::Ident(ref value) if value.eq_ignore_ascii_case("content") => {
+                Ok(LengthOrPercentageOrAutoOrContent::Content)
+            }
             Token::Function(ref name) if name.eq_ignore_ascii_case("calc") => {
                 let calc = try!(input.parse_nested_block(|i| {
                     CalcNode::parse_length_or_percentage(context, i, num_context)
                 }));
                 Ok(LengthOrPercentageOrAutoOrContent::Calc(Box::new(calc)))
-            },
+            }
             _ => Err(())
         }.map_err(|()| BasicParseError::UnexpectedToken(token).into())
     }
diff --git a/servo/components/style/values/specified/mod.rs b/servo/components/style/values/specified/mod.rs
index 112a3c38bc65..a1f3692d4f52 100644
--- a/servo/components/style/values/specified/mod.rs
+++ b/servo/components/style/values/specified/mod.rs
@@ -13,6 +13,7 @@ use parser::{ParserContext, Parse};
 use self::grid::TrackSizeOrRepeat;
 use self::url::SpecifiedUrl;
 use std::ascii::AsciiExt;
+use std::borrow::Cow;
 use std::f32;
 use std::fmt;
 use style_traits::{ToCss, ParseError, StyleParseError};
@@ -79,7 +80,7 @@ pub use ::gecko::url::*;
 impl Parse for SpecifiedUrl {
     fn parse<'i, 't>(context: &ParserContext, input: &mut Parser<'i, 't>) -> Result<Self, ParseError<'i>> {
         let url = try!(input.expect_url());
-        Self::parse_from_string(url, context)
+        Self::parse_from_string(url.into_owned(), context)
     }
 }
 
@@ -95,7 +96,7 @@ no_viewport_percentage!(SpecifiedUrl);
 pub fn parse_integer<'i, 't>(context: &ParserContext, input: &mut Parser<'i, 't>)
                              -> Result<Integer, ParseError<'i>> {
     match try!(input.next()) {
-        Token::Number(ref value) => value.int_value.ok_or(StyleParseError::UnspecifiedError.into()).map(Integer::new),
+        Token::Number { int_value: Some(v), .. } => Ok(Integer::new(v)),
         Token::Function(ref name) if name.eq_ignore_ascii_case("calc") => {
             let result = try!(input.parse_nested_block(|i| {
                 CalcNode::parse_integer(context, i)
@@ -120,9 +121,9 @@ pub fn parse_number_with_clamping_mode<'i, 't>(context: &ParserContext,
                                                clamping_mode: AllowedNumericType)
                                                -> Result<Number, ParseError<'i>> {
     match try!(input.next()) {
-        Token::Number(ref value) if clamping_mode.is_ok(context.parsing_mode, value.value) => {
+        Token::Number { value, .. } if clamping_mode.is_ok(context.parsing_mode, value) => {
             Ok(Number {
-                value: value.value.min(f32::MAX).max(f32::MIN),
+                value: value.min(f32::MAX).max(f32::MIN),
                 calc_clamping_mode: None,
             })
         },
@@ -226,10 +227,8 @@ impl Parse for Angle {
     fn parse<'i, 't>(context: &ParserContext, input: &mut Parser<'i, 't>) -> Result<Self, ParseError<'i>> {
         let token = try!(input.next());
         match token {
-            Token::Dimension(ref value, ref unit) => {
-                Angle::parse_dimension(value.value,
-                                       unit,
-                                       /* from_calc = */ false)
+            Token::Dimension { value, ref unit, .. } => {
+                Angle::parse_dimension(value, unit, /* from_calc = */ false)
             }
             Token::Function(ref name) if name.eq_ignore_ascii_case("calc") => {
                 return input.parse_nested_block(|i| CalcNode::parse_angle(context, i))
@@ -268,12 +267,10 @@ impl Angle {
                                        -> Result<Self, ParseError<'i>> {
         let token = try!(input.next());
         match token {
-            Token::Dimension(ref value, ref unit) => {
-                Angle::parse_dimension(value.value,
-                                       unit,
-                                       /* from_calc = */ false)
+            Token::Dimension { value, ref unit, .. } => {
+                Angle::parse_dimension(value, unit, /* from_calc = */ false)
             }
-            Token::Number(ref value) if value.value == 0. => Ok(Angle::zero()),
+            Token::Number { value, .. } if value == 0. => Ok(Angle::zero()),
             Token::Function(ref name) if name.eq_ignore_ascii_case("calc") => {
                 return input.parse_nested_block(|i| CalcNode::parse_angle(context, i))
             }
@@ -372,8 +369,8 @@ impl Time {
             // values for SMIL regardless of clamping_mode, but in this Time
             // value case, the value does not animate for SMIL at all, so we use
             // PARSING_MODE_DEFAULT directly.
-            Ok(Token::Dimension(ref value, ref unit)) if clamping_mode.is_ok(PARSING_MODE_DEFAULT, value.value) => {
-                Time::parse_dimension(value.value, &unit, /* from_calc = */ false)
+            Ok(Token::Dimension { value, ref unit, .. }) if clamping_mode.is_ok(PARSING_MODE_DEFAULT, value) => {
+                Time::parse_dimension(value, unit, /* from_calc = */ false)
                     .map_err(|()| StyleParseError::UnspecifiedError.into())
             }
             Ok(Token::Function(ref name)) if name.eq_ignore_ascii_case("calc") => {
@@ -1106,7 +1103,7 @@ impl Attr {
             };
 
             let ns_with_id = if let Some(ns) = first {
-                let ns: Namespace = ns.into();
+                let ns = Namespace::from(Cow::from(ns));
                 let id: Result<_, ParseError> =
                     get_id_for_namespace(&ns, context)
                     .map_err(|()| StyleParseError::UnspecifiedError.into());
diff --git a/servo/components/style_traits/Cargo.toml b/servo/components/style_traits/Cargo.toml
index 84089411781a..3be76bbfdbb7 100644
--- a/servo/components/style_traits/Cargo.toml
+++ b/servo/components/style_traits/Cargo.toml
@@ -16,7 +16,7 @@ gecko = []
 [dependencies]
 app_units = "0.5"
 bitflags = "0.7"
-cssparser = "0.15"
+cssparser = "0.16"
 euclid = "0.15"
 heapsize = {version = "0.4", optional = true}
 heapsize_derive = {version = "0.1", optional = true}
diff --git a/servo/components/style_traits/lib.rs b/servo/components/style_traits/lib.rs
index 41a8fe224fc5..a9934e5b56f8 100644
--- a/servo/components/style_traits/lib.rs
+++ b/servo/components/style_traits/lib.rs
@@ -22,8 +22,8 @@ extern crate euclid;
 extern crate selectors;
 #[cfg(feature = "servo")] #[macro_use] extern crate serde;
 
+use cssparser::CompactCowStr;
 use selectors::parser::SelectorParseError;
-use std::borrow::Cow;
 
 /// Opaque type stored in type-unsafe work queues for parallel layout.
 /// Must be transmutable to and from `TNode`.
@@ -95,11 +95,11 @@ pub enum StyleParseError<'i> {
     /// A property declaration value had input remaining after successfully parsing.
     PropertyDeclarationValueNotExhausted,
     /// An unexpected dimension token was encountered.
-    UnexpectedDimension(Cow<'i, str>),
+    UnexpectedDimension(CompactCowStr<'i>),
     /// A media query using a ranged expression with no value was encountered.
     RangedExpressionWithNoValue,
     /// A function was encountered that was not expected.
-    UnexpectedFunction(Cow<'i, str>),
+    UnexpectedFunction(CompactCowStr<'i>),
     /// @namespace must be before any rule but @charset and @import
     UnexpectedNamespaceRule,
     /// @import must be before any rule but @charset
@@ -107,7 +107,7 @@ pub enum StyleParseError<'i> {
     /// Unexpected @charset rule encountered.
     UnexpectedCharsetRule,
     /// Unsupported @ rule
-    UnsupportedAtRule(Cow<'i, str>),
+    UnsupportedAtRule(CompactCowStr<'i>),
     /// A placeholder for many sources of errors that require more specific variants.
     UnspecifiedError,
 }
diff --git a/servo/components/style_traits/viewport.rs b/servo/components/style_traits/viewport.rs
index c3061a30d222..23802789c7c5 100644
--- a/servo/components/style_traits/viewport.rs
+++ b/servo/components/style_traits/viewport.rs
@@ -149,12 +149,15 @@ impl Zoom {
             // argument, and pass ParsingMode owned by the ParserContext to
             // is_ok() instead of using PARSING_MODE_DEFAULT directly.
             // In order to do so, we might want to move these stuff into style::stylesheets::viewport_rule.
-            Token::Percentage(ref value) if NonNegative.is_ok(PARSING_MODE_DEFAULT, value.unit_value) =>
-                Ok(Zoom::Percentage(value.unit_value)),
-            Token::Number(ref value) if NonNegative.is_ok(PARSING_MODE_DEFAULT, value.value) =>
-                Ok(Zoom::Number(value.value)),
-            Token::Ident(ref value) if value.eq_ignore_ascii_case("auto") =>
-                Ok(Zoom::Auto),
+            Token::Percentage { unit_value, .. } if NonNegative.is_ok(PARSING_MODE_DEFAULT, unit_value) => {
+                Ok(Zoom::Percentage(unit_value))
+            }
+            Token::Number { value, .. } if NonNegative.is_ok(PARSING_MODE_DEFAULT, value) => {
+                Ok(Zoom::Number(value))
+            }
+            Token::Ident(ref value) if value.eq_ignore_ascii_case("auto") => {
+                Ok(Zoom::Auto)
+            }
             t => Err(CssParseError::Basic(BasicParseError::UnexpectedToken(t)))
         }
     }
diff --git a/servo/ports/geckolib/Cargo.toml b/servo/ports/geckolib/Cargo.toml
index ded378c5b836..8827d1dba7de 100644
--- a/servo/ports/geckolib/Cargo.toml
+++ b/servo/ports/geckolib/Cargo.toml
@@ -16,7 +16,7 @@ gecko_debug = ["style/gecko_debug"]
 
 [dependencies]
 atomic_refcell = "0.1"
-cssparser = "0.15"
+cssparser = "0.16"
 env_logger = {version = "0.4", default-features = false} # disable `regex` to reduce code size
 libc = "0.2"
 log = {version = "0.3.5", features = ["release_max_level_info"]}
diff --git a/servo/ports/geckolib/glue.rs b/servo/ports/geckolib/glue.rs
index 9d8f068be355..2b973124977c 100644
--- a/servo/ports/geckolib/glue.rs
+++ b/servo/ports/geckolib/glue.rs
@@ -7,7 +7,6 @@ use cssparser::{Parser, ParserInput};
 use cssparser::ToCss as ParserToCss;
 use env_logger::LogBuilder;
 use selectors::Element;
-use std::borrow::Cow;
 use std::env;
 use std::fmt::Write;
 use std::ptr;
@@ -1652,7 +1651,9 @@ pub extern "C" fn Servo_ParseEasing(easing: *const nsAString,
                                      QuirksMode::NoQuirks);
     let easing = unsafe { (*easing).to_string() };
     let mut input = ParserInput::new(&easing);
-    match transition_timing_function::single_value::parse(&context, &mut Parser::new(&mut input)) {
+    let mut parser = Parser::new(&mut input);
+    let result = transition_timing_function::single_value::parse(&context, &mut parser);
+    match result {
         Ok(parsed_easing) => {
             *output = parsed_easing.into();
             true
@@ -1826,7 +1827,7 @@ pub extern "C" fn Servo_DeclarationBlock_GetNthProperty(declarations: RawServoDe
 macro_rules! get_property_id_from_property {
     ($property: ident, $ret: expr) => {{
         let property = unsafe { $property.as_ref().unwrap().as_str_unchecked() };
-        match PropertyId::parse(Cow::Borrowed(property)) {
+        match PropertyId::parse(property.into()) {
             Ok(property_id) => property_id,
             Err(_) => { return $ret; }
         }
@@ -2351,7 +2352,8 @@ pub extern "C" fn Servo_DeclarationBlock_SetFontFamily(declarations:
     let string = unsafe { (*value).to_string() };
     let mut input = ParserInput::new(&string);
     let mut parser = Parser::new(&mut input);
-    if let Ok(family) = FontFamily::parse(&mut parser) {
+    let result = FontFamily::parse(&mut parser);
+    if let Ok(family) = result {
         if parser.is_exhausted() {
             let decl = PropertyDeclaration::FontFamily(Box::new(family));
             write_locked_arc(declarations, |decls: &mut PropertyDeclarationBlock| {
diff --git a/servo/tests/unit/gfx/Cargo.toml b/servo/tests/unit/gfx/Cargo.toml
index a2c4b9d4b496..b75bd6718fc4 100644
--- a/servo/tests/unit/gfx/Cargo.toml
+++ b/servo/tests/unit/gfx/Cargo.toml
@@ -10,7 +10,7 @@ path = "lib.rs"
 doctest = false
 
 [dependencies]
-cssparser = "0.15"
+cssparser = "0.16"
 gfx = {path = "../../../components/gfx"}
 ipc-channel = "0.8"
 style = {path = "../../../components/style"}
diff --git a/servo/tests/unit/style/Cargo.toml b/servo/tests/unit/style/Cargo.toml
index 70bab52c50f7..45bb6b3e608e 100644
--- a/servo/tests/unit/style/Cargo.toml
+++ b/servo/tests/unit/style/Cargo.toml
@@ -15,7 +15,7 @@ testing = ["style/testing"]
 [dependencies]
 byteorder = "1.0"
 app_units = "0.5"
-cssparser = "0.15"
+cssparser = "0.16"
 euclid = "0.15"
 html5ever = "0.18"
 parking_lot = "0.3"
diff --git a/servo/tests/unit/style/parsing/mod.rs b/servo/tests/unit/style/parsing/mod.rs
index 12cfe611992a..13998022ed53 100644
--- a/servo/tests/unit/style/parsing/mod.rs
+++ b/servo/tests/unit/style/parsing/mod.rs
@@ -87,13 +87,14 @@ macro_rules! assert_roundtrip_with_context {
         }, &mut input).unwrap();
 
         let mut input = ::cssparser::ParserInput::new(&serialized);
-        super::parse_input(|context, i| {
+        let unwrapped = super::parse_input(|context, i| {
             let re_parsed = $fun(context, i)
                             .expect(&format!("Failed to parse serialization {}", $input));
             let re_serialized = ToCss::to_css_string(&re_parsed);
             assert_eq!(serialized, re_serialized);
             Ok(())
-        }, &mut input).unwrap()
+        }, &mut input).unwrap();
+        unwrapped
     }}
 }
 
diff --git a/servo/tests/unit/style/properties/mod.rs b/servo/tests/unit/style/properties/mod.rs
index 96d66655f56c..241352741e24 100644
--- a/servo/tests/unit/style/properties/mod.rs
+++ b/servo/tests/unit/style/properties/mod.rs
@@ -40,13 +40,14 @@ macro_rules! assert_roundtrip_with_context {
         }, $input).unwrap();
 
         let mut input = ::cssparser::ParserInput::new(&serialized);
-        parse_input(|context, i| {
+        let unwrapped = parse_input(|context, i| {
             let re_parsed = $fun(context, i)
                             .expect(&format!("Failed to parse serialization {}", $input));
             let re_serialized = ToCss::to_css_string(&re_parsed);
             assert_eq!(serialized, re_serialized);
             Ok(())
-        }, &mut input).unwrap()
+        }, &mut input).unwrap();
+        unwrapped
     }}
 }
 
diff --git a/servo/tests/unit/stylo/Cargo.toml b/servo/tests/unit/stylo/Cargo.toml
index 9e4b41479e44..7427a60f3a8f 100644
--- a/servo/tests/unit/stylo/Cargo.toml
+++ b/servo/tests/unit/stylo/Cargo.toml
@@ -16,7 +16,7 @@ testing = ["style/testing"]
 
 [dependencies]
 atomic_refcell = "0.1"
-cssparser = "0.15"
+cssparser = "0.16"
 env_logger = "0.4"
 euclid = "0.15"
 geckoservo = {path = "../../../ports/geckolib"}