diff --git a/css/ast/src/lib.rs b/css/ast/src/lib.rs
index e3571bb7f265f..f88dfb35f4c15 100644
--- a/css/ast/src/lib.rs
+++ b/css/ast/src/lib.rs
@@ -10,18 +10,29 @@ pub struct Text {
 #[ast_node]
 pub struct Stylesheet {
     pub span: Span,
-    pub rules: Vec<Rule>,
+    pub rules: Vec<StyleRule>,
 }
 
 #[ast_node]
-pub struct Rule {
+pub struct StyleRule {
     pub span: Span,
     pub selectors: Vec<Selector>,
     pub properties: Vec<Property>,
 }
 
 #[ast_node]
-pub enum Selector {}
+pub struct Selector {
+    pub span: Span,
+    pub base: BaseSelector,
+    pub pseudo_class: Option<Text>,
+    pub pseudo_element: Option<Text>,
+}
+
+#[ast_node]
+pub enum BaseSelector {
+    #[tag("Id")]
+    Id(Text),
+}
 
 #[ast_node]
 pub struct Property {
diff --git a/css/parser/Cargo.toml b/css/parser/Cargo.toml
index e32d1f3f4c1bb..a19279f723fee 100644
--- a/css/parser/Cargo.toml
+++ b/css/parser/Cargo.toml
@@ -7,3 +7,8 @@ edition = "2018"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+swc_atoms = { version = "0.2", path = "../../atoms" }
+swc_common = { version = "0.9.0", path = "../../common" }
+swc_css_ast = { version = "0.1.0", path = "../ast" }
+nom = "5.1.2"
+serde = { version = "1", features = ["derive"] }
\ No newline at end of file
diff --git a/css/parser/src/input.rs b/css/parser/src/input.rs
new file mode 100644
index 0000000000000..2e532771d9edf
--- /dev/null
+++ b/css/parser/src/input.rs
@@ -0,0 +1,115 @@
+use nom::{Compare, CompareResult, InputIter, InputLength, InputTake, Slice, UnspecializedInput};
+use std::{
+    ops::{Deref, Range, RangeFrom, RangeTo},
+    str::{CharIndices, Chars},
+};
+use swc_common::{BytePos, Span};
+use swc_css_ast::Text;
+
+#[derive(Debug, Clone, Copy)]
+pub struct Input<'i> {
+    start: BytePos,
+    end: BytePos,
+    src: &'i str,
+}
+
+impl<'i> Input<'i> {
+    pub const fn empty() -> Self {
+        Self::new(BytePos(0), BytePos(0), "")
+    }
+
+    pub const fn new(start: BytePos, end: BytePos, src: &'i str) -> Self {
+        Self { start, end, src }
+    }
+
+    #[inline(always)]
+    pub fn span(self) -> Span {
+        Span::new(self.start, self.end, Default::default())
+    }
+}
+
+macro_rules! impl_slice {
+    ($T:ident) => {
+        impl Slice<$T<usize>> for Input<'_> {
+            fn slice(&self, range: $T<usize>) -> Self {
+                let s = self.src.slice(range);
+
+                Self::new(self.start, self.start + BytePos(s.as_bytes().len() as _), s)
+            }
+        }
+    };
+}
+
+impl_slice!(Range);
+impl_slice!(RangeFrom);
+impl_slice!(RangeTo);
+
+impl<'i> From<Input<'i>> for Text {
+    fn from(i: Input) -> Self {
+        Self {
+            span: Span::new(i.start, i.end, Default::default()),
+            sym: i.src.into(),
+        }
+    }
+}
+
+impl InputTake for Input<'_> {
+    fn take(&self, count: usize) -> Self {
+        self.slice(..count)
+    }
+
+    fn take_split(&self, count: usize) -> (Self, Self) {
+        (self.slice(..count), self.slice(count..))
+    }
+}
+
+impl<'a> Compare<&'a str> for Input<'_> {
+    fn compare(&self, t: &'a str) -> CompareResult {
+        self.src.compare(t)
+    }
+
+    fn compare_no_case(&self, t: &'a str) -> CompareResult {
+        self.src.compare_no_case(t)
+    }
+}
+
+impl InputLength for Input<'_> {
+    fn input_len(&self) -> usize {
+        self.src.as_bytes().len()
+    }
+}
+
+impl UnspecializedInput for Input<'_> {}
+
+impl<'a> InputIter for Input<'a> {
+    type Item = char;
+    type Iter = CharIndices<'a>;
+    type IterElem = Chars<'a>;
+
+    fn iter_indices(&self) -> Self::Iter {
+        self.src.iter_indices()
+    }
+
+    fn iter_elements(&self) -> Self::IterElem {
+        self.src.iter_elements()
+    }
+
+    fn position<P>(&self, predicate: P) -> Option<usize>
+    where
+        P: Fn(Self::Item) -> bool,
+    {
+        self.src.position(predicate)
+    }
+
+    fn slice_index(&self, count: usize) -> Option<usize> {
+        self.src.slice_index(count)
+    }
+}
+
+impl Deref for Input<'_> {
+    type Target = str;
+
+    fn deref(&self) -> &Self::Target {
+        self.src
+    }
+}
diff --git a/css/parser/src/lib.rs b/css/parser/src/lib.rs
index 8b137891791fe..8623b82ad265e 100644
--- a/css/parser/src/lib.rs
+++ b/css/parser/src/lib.rs
@@ -1 +1,9 @@
+pub use self::input::Input;
+use nom::IResult;
+use swc_css_ast::Stylesheet;
 
+pub type PResult<'a, T> = IResult<T, Input<'a>>;
+
+mod input;
+
+pub fn parse(s: Input) -> PResult<Stylesheet> {}