diff --git a/src/syntax/expr.rs b/src/syntax/expr.rs
index b5bce2cd1..3f5357290 100644
--- a/src/syntax/expr.rs
+++ b/src/syntax/expr.rs
@@ -2,6 +2,9 @@
 
 use std::fmt::{self, Write, Debug, Formatter};
 use std::iter::FromIterator;
+use std::ops::Deref;
+use std::str::FromStr;
+use std::u8;
 
 use crate::error::Errors;
 use crate::size::Size;
@@ -23,8 +26,12 @@ pub enum Expr {
     Size(Size),
     /// A bool: `true, false`.
     Bool(bool),
+    /// A color value, including the alpha channel: `#f79143ff`
+    Color(RgbaColor),
     /// A tuple: `(false, 12cm, "hi")`.
     Tuple(Tuple),
+    /// A named tuple: `cmyk(37.7, 0, 3.9, 1.1)`.
+    NamedTuple(NamedTuple),
     /// An object: `{ fit: false, size: 12pt }`.
     Object(Object),
 }
@@ -39,7 +46,9 @@ impl Expr {
             Number(_) => "number",
             Size(_) => "size",
             Bool(_) => "bool",
+            Color(_) => "color",
             Tuple(_) => "tuple",
+            NamedTuple(_) => "named tuple",
             Object(_) => "object",
         }
     }
@@ -54,7 +63,9 @@ impl Debug for Expr {
             Number(n) => n.fmt(f),
             Size(s) => s.fmt(f),
             Bool(b) => b.fmt(f),
+            Color(c) => c.fmt(f),
             Tuple(t) => t.fmt(f),
+            NamedTuple(t) => t.fmt(f),
             Object(o) => o.fmt(f),
         }
     }
@@ -97,6 +108,116 @@ impl Debug for Ident {
     }
 }
 
+/// An 8-bit RGBA color.
+///
+/// # Example
+/// ```typst
+/// [box: background=#423abaff]
+///                   ^^^^^^^^
+/// ```
+#[derive(Clone, Eq, PartialEq, Hash)]
+pub struct RgbaColor {
+    /// Red channel.
+    pub r: u8,
+    /// Green channel.
+    pub g: u8,
+    /// Blue channel.
+    pub b: u8,
+    /// Alpha channel.
+    pub a: u8,
+    /// Indicates whether this is a user-provided value or a
+    /// default value provided as a fail-over by the parser.
+    /// This color may be overwritten if this property is true.
+    pub healed: bool,
+}
+
+impl RgbaColor {
+    /// Constructs a new color.
+    pub fn new(r: u8, g: u8, b: u8, a: u8) -> RgbaColor {
+        RgbaColor { r, g, b, a, healed: false }
+    }
+
+    /// Constructs a new color with the healed property set to true.
+    pub fn new_healed(r: u8, g: u8, b: u8, a: u8) -> RgbaColor {
+        RgbaColor { r, g, b, a, healed: true }
+    }
+
+}
+
+impl FromStr for RgbaColor {
+    type Err = ParseColorError;
+
+    /// Constructs a new color from a hex string like `7a03c2`.
+    /// Do not specify a leading `#`.
+    fn from_str(hex_str: &str) -> Result<RgbaColor, Self::Err> {
+        if !hex_str.is_ascii() {
+            return Err(ParseColorError);
+        }
+
+        let len = hex_str.len();
+        let long =  len == 6 || len == 8;
+        let short = len == 3 || len == 4;
+        let alpha = len == 4 || len == 8;
+
+        if !long && !short {
+            return Err(ParseColorError);
+        }
+
+        let mut values: [u8; 4] = [255; 4];
+
+        for elem in if alpha { 0..4 } else { 0..3 } {
+            let item_len = if long { 2 } else { 1 };
+            let pos = elem * item_len;
+
+            let item = &hex_str[pos..(pos+item_len)];
+            values[elem] = u8::from_str_radix(item, 16)
+                .map_err(|_| ParseColorError)?;
+
+            if short {
+                // Duplicate number for shorthand notation, i.e. `a` -> `aa`
+                values[elem] += values[elem] * 16;
+            }
+        }
+
+        Ok(RgbaColor::new(values[0], values[1], values[2], values[3]))
+    }
+}
+
+impl Debug for RgbaColor {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        if f.alternate() {
+            f.write_str("rgba(")?;
+            write!(f, "r: {:02}, ", self.r)?;
+            write!(f, "g: {:02}, ", self.g)?;
+            write!(f, "b: {:02}, ", self.b)?;
+            write!(f, "a: {:02}",   self.a)?;
+            f.write_char(')')?;
+        } else {
+            f.write_char('#')?;
+            write!(f, "{:02x}", self.r)?;
+            write!(f, "{:02x}", self.g)?;
+            write!(f, "{:02x}", self.b)?;
+            write!(f, "{:02x}", self.a)?;
+        }
+        if self.healed {
+            f.write_fmt(format_args!(" [healed]"))?;
+        }
+        Ok(())
+    }
+}
+
+/// The error returned when parsing a [`RgbaColor`] from a string fails.
+#[derive(Debug, Copy, Clone, Eq, PartialEq)]
+pub struct ParseColorError;
+
+impl std::error::Error for ParseColorError {}
+
+impl fmt::Display for ParseColorError {
+    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
+        f.write_str("invalid color")
+    }
+}
+
 /// An untyped sequence of expressions.
 ///
 /// # Example
@@ -185,6 +306,35 @@ impl Debug for Tuple {
     }
 }
 
+/// A named, untyped sequence of expressions.
+///
+/// # Example
+/// ```typst
+/// hsl(93, 10, 19.4)
+/// ```
+#[derive(Debug, Clone, PartialEq)]
+pub struct NamedTuple {
+    /// The name of the tuple and where it is in the user source.
+    pub name: Spanned<Ident>,
+    /// The elements of the tuple.
+    pub tuple: Spanned<Tuple>,
+}
+
+impl NamedTuple {
+    /// Create a named tuple from a tuple.
+    pub fn new(name: Spanned<Ident>, tuple: Spanned<Tuple>) -> NamedTuple {
+        NamedTuple { name, tuple }
+    }
+}
+
+impl Deref for NamedTuple {
+    type Target = Tuple;
+
+    fn deref(&self) -> &Self::Target {
+        &self.tuple.v
+    }
+}
+
 /// A key-value collection of identifiers and associated expressions.
 ///
 /// The pairs themselves are not spanned, but the combined spans can easily be
diff --git a/src/syntax/parsing.rs b/src/syntax/parsing.rs
index 2fb8b58ac..cfbf2bf3f 100644
--- a/src/syntax/parsing.rs
+++ b/src/syntax/parsing.rs
@@ -1,6 +1,7 @@
 //! Parsing of source code into syntax models.
 
 use std::iter::FromIterator;
+use std::str::FromStr;
 
 use crate::{Pass, Feedback};
 use super::func::{FuncHeader, FuncArgs, FuncArg};
@@ -187,6 +188,14 @@ impl<'s> FuncParser<'s> {
             // If we have an identifier we might have a keyword argument,
             // otherwise its for sure a postional argument.
             if let Some(ident) = p.parse_ident() {
+                // This could still be a named tuple
+                if let Some(Token::LeftParen) = p.peekv() {
+                    return Ok(FuncArg::Pos(
+                        p.parse_named_tuple(ident)
+                            .map(|t| Expr::NamedTuple(t))
+                    ));
+                }
+
                 p.skip_whitespace();
 
                 if let Some(Token::Equals) = p.peekv() {
@@ -223,7 +232,16 @@ impl<'s> FuncParser<'s> {
         }
 
         Some(match first.v {
-            Token::ExprIdent(i) => take!((Expr::Ident(Ident(i.to_string())))),
+            Token::ExprIdent(i) => {
+                let name = take!(Ident(i.to_string()));
+
+                // This could be a named tuple or an identifier
+                if let Some(Token::LeftParen) = self.peekv() {
+                    self.parse_named_tuple(name).map(|t| Expr::NamedTuple(t))
+                } else {
+                    name.map(|i| Expr::Ident(i))
+                }
+            },
             Token::ExprStr { string, terminated } => {
                 if !terminated {
                     self.expected_at("quote", first.span.end);
@@ -235,16 +253,25 @@ impl<'s> FuncParser<'s> {
             Token::ExprNumber(n) => take!(Expr::Number(n)),
             Token::ExprSize(s) => take!(Expr::Size(s)),
             Token::ExprBool(b) => take!(Expr::Bool(b)),
+            Token::ExprHex(s) => {
+                if let Ok(color) = RgbaColor::from_str(s) {
+                    take!(Expr::Color(color))
+                } else {
+                    // Heal color by assuming black
+                    self.feedback.errors.push(err!(first.span; "invalid color"));
+                    take!(Expr::Color(RgbaColor::new_healed(0, 0, 0, 255)))
+                }
+            },
 
-            Token::LeftParen => self.parse_tuple(),
-            Token::LeftBrace => self.parse_object(),
+            Token::LeftParen => self.parse_tuple().map(|t| Expr::Tuple(t)),
+            Token::LeftBrace => self.parse_object().map(|o| Expr::Object(o)),
 
             _ => return None,
         })
     }
 
     /// Parse a tuple expression: `(<expr>, ...)`.
-    fn parse_tuple(&mut self) -> Spanned<Expr> {
+    fn parse_tuple(&mut self) -> Spanned<Tuple> {
         let token = self.eat();
         debug_assert_eq!(token.map(Spanned::value), Some(Token::LeftParen));
 
@@ -252,11 +279,17 @@ impl<'s> FuncParser<'s> {
         // missing a `value` when an invalid token is encoutered.
         self.parse_collection(Some(Token::RightParen),
             |p| p.parse_expr().ok_or(("value", None)))
-            .map(|tuple| Expr::Tuple(tuple))
+    }
+
+    /// Parse a tuple expression: `name(<expr>, ...)` with a given identifier.
+    fn parse_named_tuple(&mut self, name: Spanned<Ident>) -> Spanned<NamedTuple> {
+        let tuple = self.parse_tuple();
+        let span = Span::merge(name.span, tuple.span);
+        Spanned::new(NamedTuple::new(name, tuple), span)
     }
 
     /// Parse an object expression: `{ <key>: <value>, ... }`.
-    fn parse_object(&mut self) -> Spanned<Expr> {
+    fn parse_object(&mut self) -> Spanned<Object> {
         let token = self.eat();
         debug_assert_eq!(token.map(Spanned::value), Some(Token::LeftBrace));
 
@@ -282,7 +315,7 @@ impl<'s> FuncParser<'s> {
             let value = p.parse_expr().ok_or(("value", None))?;
 
             Ok(Pair { key, value })
-        }).map(|object| Expr::Object(object))
+        })
     }
 
     /// Parse a comma-separated collection where each item is parsed through
@@ -513,6 +546,19 @@ mod tests {
     fn Id(text: &str) -> Expr { Expr::Ident(Ident(text.to_string())) }
     fn Str(text: &str) -> Expr { Expr::Str(text.to_string()) }
     fn Pt(points: f32) -> Expr { Expr::Size(Size::pt(points)) }
+
+    fn Clr(r: u8, g: u8, b: u8, a: u8) -> Expr {
+        Expr::Color(RgbaColor::new(r, g, b, a))
+    }
+    fn ClrStr(color: &str) -> Expr {
+        Expr::Color(RgbaColor::from_str(color).expect("invalid test color"))
+    }
+    fn ClrStrHealed() -> Expr {
+        let mut c = RgbaColor::from_str("000f").expect("invalid test color");
+        c.healed = true;
+        Expr::Color(c)
+    }
+
     fn T(text: &str) -> Node { Node::Text(text.to_string()) }
 
     /// Create a raw text node.
@@ -529,6 +575,16 @@ mod tests {
         };
     }
 
+    /// Create a named tuple expression.
+    macro_rules! named_tuple {
+        ($name:expr $(, $items:expr)* $(,)?) => {
+            Expr::NamedTuple(NamedTuple::new(
+                zspan(Ident($name.to_string())),
+                zspan(Tuple { items: spanned![vec $($items),*].0 })
+            ))
+        };
+    }
+
     /// Create an object expression.
     macro_rules! object {
         ($($key:expr => $value:expr),* $(,)?) => {
@@ -603,6 +659,15 @@ mod tests {
         (@body) => (None);
     }
 
+    #[test]
+    fn parse_color_strings() {
+        assert_eq!(Clr(0xf6, 0x12, 0x43, 0xff), ClrStr("f61243ff"));
+        assert_eq!(Clr(0xb3, 0xd8, 0xb3, 0xff), ClrStr("b3d8b3"));
+        assert_eq!(Clr(0xfc, 0xd2, 0xa9, 0xad), ClrStr("fCd2a9AD"));
+        assert_eq!(Clr(0x22, 0x33, 0x33, 0xff), ClrStr("233"));
+        assert_eq!(Clr(0x11, 0x11, 0x11, 0xbb), ClrStr("111b"));
+    }
+
     #[test]
     fn unescape_strings() {
         fn test(string: &str, expected: &str) {
@@ -747,43 +812,96 @@ mod tests {
         p!("[val: 3.14]"   => [func!("val": (Num(3.14)), {})]);
         p!("[val: 4.5cm]"  => [func!("val": (Sz(Size::cm(4.5))), {})]);
         p!("[val: 12e1pt]" => [func!("val": (Pt(12e1)), {})]);
+        p!("[val: #f7a20500]" => [func!("val": (ClrStr("f7a20500")), {})]);
 
         // Unclosed string.
         p!("[val: \"hello]" => [func!("val": (Str("hello]")), {})], [
             (0:13, 0:13, "expected quote"),
             (0:13, 0:13, "expected closing bracket"),
         ]);
+
+        //Invalid colors
+        p!("[val: #12345]" => [func!("val": (ClrStrHealed()), {})], [
+            (0:6, 0:12, "invalid color"),
+        ]);
+        p!("[val: #a5]" => [func!("val": (ClrStrHealed()), {})], [
+            (0:6, 0:9, "invalid color"),
+        ]);
+        p!("[val: #14b2ah]" => [func!("val": (ClrStrHealed()), {})], [
+            (0:6, 0:13, "invalid color"),
+        ]);
+        p!("[val: #f075ff011]" => [func!("val": (ClrStrHealed()), {})], [
+            (0:6, 0:16, "invalid color"),
+        ]);
     }
 
     #[test]
     fn parse_tuples() {
         // Empty tuple
         p!("[val: ()]" => [func!("val": (tuple!()), {})]);
+        p!("[val: empty()]" => [func!("val": (named_tuple!("empty")), {})]);
 
         // Invalid value
         p!("[val: (🌎)]" =>
             [func!("val": (tuple!()), {})],
             [(0:7, 0:8, "expected value, found invalid token")],
         );
+        p!("[val: sound(\x07)]" =>
+            [func!("val": (named_tuple!("sound")), {})],
+            [(0:12, 0:13, "expected value, found invalid token")],
+        );
+
+        // Invalid tuple name
+        p!("[val: 👠(\"abc\", 13e-5)]" =>
+            [func!("val": (tuple!(Str("abc"), Num(13.0e-5))), {})],
+            [(0:6, 0:7, "expected argument, found invalid token")],
+        );
 
         // Unclosed tuple
         p!("[val: (hello]" =>
             [func!("val": (tuple!(Id("hello"))), {})],
             [(0:12, 0:12, "expected closing paren")],
         );
+        p!("[val: lang(中文]" =>
+            [func!("val": (named_tuple!("lang", Id("中文"))), {})],
+            [(0:13, 0:13, "expected closing paren")],
+        );
 
         // Valid values
         p!("[val: (1, 2)]" => [func!("val": (tuple!(Num(1.0), Num(2.0))), {})]);
         p!("[val: (\"s\",)]" => [func!("val": (tuple!(Str("s"))), {})]);
+        p!("[val: cmyk(1, 46, 0, 0)]" =>
+            [func!("val": (named_tuple!(
+                "cmyk", Num(1.0), Num(46.0), Num(0.0), Num(0.0)
+            )), {})]
+        );
+        p!("[val: items(\"fire\", #f93a6d)]" =>
+            [func!("val": (named_tuple!(
+                "items", Str("fire"), ClrStr("f93a6d")
+            )), {})]
+        );
 
         // Nested tuples
-        p!("[val: (1, (2))]" => [func!("val": (tuple!(Num(1.0), tuple!(Num(2.0)))), {})]);
+        p!("[val: (1, (2))]" =>
+            [func!("val": (tuple!(Num(1.0), tuple!(Num(2.0)))), {})]
+        );
+        p!("[val: css(1pt, rgb(90, 102, 254), \"solid\")]" =>
+            [func!("val": (named_tuple!(
+                "css", Pt(1.0), named_tuple!(
+                    "rgb", Num(90.0), Num(102.0), Num(254.0)
+                ), Str("solid")
+            )), {})]
+        );
 
         // Invalid commas
         p!("[val: (,)]" =>
             [func!("val": (tuple!()), {})],
             [(0:7, 0:8, "expected value, found comma")],
         );
+        p!("[val: nose(,)]" =>
+            [func!("val": (named_tuple!("nose")), {})],
+            [(0:11, 0:12, "expected value, found comma")],
+        );
         p!("[val: (true false)]" =>
             [func!("val": (tuple!(Bool(true), Bool(false))), {})],
             [(0:11, 0:11, "expected comma")],
diff --git a/src/syntax/test.rs b/src/syntax/test.rs
index 22ce45e50..ca47c0c55 100644
--- a/src/syntax/test.rs
+++ b/src/syntax/test.rs
@@ -1,7 +1,7 @@
 use std::fmt::Debug;
 
 use super::func::FuncHeader;
-use super::expr::{Expr, Tuple, Object};
+use super::expr::{Expr, Tuple, NamedTuple, Object};
 use super::span::{Span, Spanned};
 use super::tokens::Token;
 use super::*;
@@ -127,6 +127,7 @@ impl SpanlessEq for DebugFn {
 impl SpanlessEq for Expr {
     fn spanless_eq(&self, other: &Expr) -> bool {
         match (self, other) {
+            (Expr::NamedTuple(a), Expr::NamedTuple(b)) => a.spanless_eq(b),
             (Expr::Tuple(a), Expr::Tuple(b)) => a.spanless_eq(b),
             (Expr::Object(a), Expr::Object(b)) => a.spanless_eq(b),
             (a, b) => a == b,
@@ -142,6 +143,13 @@ impl SpanlessEq for Tuple {
     }
 }
 
+impl SpanlessEq for NamedTuple {
+    fn spanless_eq(&self, other: &NamedTuple) -> bool {
+        self.name.v == other.name.v
+        && self.tuple.v.spanless_eq(&other.tuple.v)
+    }
+}
+
 impl SpanlessEq for Object {
     fn spanless_eq(&self, other: &Object) -> bool {
         self.pairs.len() == other.pairs.len()
diff --git a/src/syntax/tokens.rs b/src/syntax/tokens.rs
index cc65d9937..adf29de23 100644
--- a/src/syntax/tokens.rs
+++ b/src/syntax/tokens.rs
@@ -78,6 +78,8 @@ pub enum Token<'s> {
     ExprSize(Size),
     /// A boolean in a function header: `true | false`.
     ExprBool(bool),
+    /// A hex value in a function header: `#20d82a`
+    ExprHex(&'s str),
 
     /// A star in body-text.
     Star,
@@ -122,6 +124,7 @@ impl<'s> Token<'s> {
             ExprNumber(_)   => "number",
             ExprSize(_)     => "size",
             ExprBool(_)     => "bool",
+            ExprHex(_)      => "hex value",
             Star            => "star",
             Underscore      => "underscore",
             Backslash       => "backslash",
@@ -221,9 +224,13 @@ impl<'s> Iterator for Tokens<'s> {
             // An escaped thing.
             '\\' if self.mode == Body => self.parse_escaped(),
 
+            // A hex expression.
+            '#' if self.mode == Header => self.parse_hex_value(),
+
             // Expressions or just strings.
             c => {
                 let body = self.mode == Body;
+
                 let text = self.read_string_until(|n| {
                     match n {
                         c if c.is_whitespace() => true,
@@ -379,6 +386,15 @@ impl<'s> Tokens<'s> {
         }
     }
 
+    fn parse_hex_value(&mut self) -> Token<'s> {
+        // This will parse more than the permissable 0-9, a-f, A-F character
+        // ranges to provide nicer error messages later.
+        ExprHex(self.read_string_until(
+            |n| !n.is_ascii_alphanumeric(),
+            false, 0, 0
+        ).0)
+    }
+
     fn parse_expr(&mut self, text: &'s str) -> Token<'s> {
         if let Ok(b) = text.parse::<bool>() {
             ExprBool(b)
@@ -499,6 +515,7 @@ mod tests {
         ExprNumber as Num,
         ExprSize as Sz,
         ExprBool as Bool,
+        ExprHex as Hex,
         Text as T,
     };
 
@@ -587,6 +604,8 @@ mod tests {
         t!(Body, "c=d, "               => [T("c=d,"), S(0)]);
         t!(Header, "(){}:=,"           => [LP, RP, LB, RB, Colon, Equals, Comma]);
         t!(Header, "a:b"               => [Id("a"), Colon, Id("b")]);
+        t!(Header, "#6ae6dd"           => [Hex("6ae6dd")]);
+        t!(Header, "#8A083c"           => [Hex("8A083c")]);
         t!(Header, "a: true, x=1"      => [Id("a"), Colon, S(0), Bool(true), Comma, S(0), Id("x"), Equals, Num(1.0)]);
         t!(Header, "=3.14"             => [Equals, Num(3.14)]);
         t!(Header, "12.3e5"            => [Num(12.3e5)]);