From 1334dd534bd5d4e320244d4fc71230145bb21ede Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Donny/=EA=B0=95=EB=8F=99=EC=9C=A4?= <kdy1997.dev@gmail.com>
Date: Mon, 12 Dec 2022 14:59:40 +0900
Subject: [PATCH 1/9] Compiler

---
 crates/swc_css_compat/src/compiler/mod.rs | 2 ++
 crates/swc_css_compat/src/lib.rs          | 2 ++
 2 files changed, 4 insertions(+)
 create mode 100644 crates/swc_css_compat/src/compiler/mod.rs

diff --git a/crates/swc_css_compat/src/compiler/mod.rs b/crates/swc_css_compat/src/compiler/mod.rs
new file mode 100644
index 000000000000..67c41541e5c0
--- /dev/null
+++ b/crates/swc_css_compat/src/compiler/mod.rs
@@ -0,0 +1,2 @@
+/// Compiles a modern CSS file to a legacy CSS file.
+pub struct Compiler {}
diff --git a/crates/swc_css_compat/src/lib.rs b/crates/swc_css_compat/src/lib.rs
index 485214058c30..b8def98eb856 100644
--- a/crates/swc_css_compat/src/lib.rs
+++ b/crates/swc_css_compat/src/lib.rs
@@ -1,4 +1,6 @@
 #![feature(box_patterns)]
 #![allow(clippy::vec_box)]
 
+pub mod compiler;
+pub mod custom_media_query;
 pub mod nesting;

From a46a611c5f9791f24dd304e4b204486786c700c1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Donny/=EA=B0=95=EB=8F=99=EC=9C=A4?= <kdy1997.dev@gmail.com>
Date: Mon, 12 Dec 2022 15:00:06 +0900
Subject: [PATCH 2/9] target

---
 crates/swc_css_compat/src/lib.rs    | 1 +
 crates/swc_css_compat/src/target.rs | 1 +
 2 files changed, 2 insertions(+)
 create mode 100644 crates/swc_css_compat/src/target.rs

diff --git a/crates/swc_css_compat/src/lib.rs b/crates/swc_css_compat/src/lib.rs
index b8def98eb856..978ffdd54682 100644
--- a/crates/swc_css_compat/src/lib.rs
+++ b/crates/swc_css_compat/src/lib.rs
@@ -4,3 +4,4 @@
 pub mod compiler;
 pub mod custom_media_query;
 pub mod nesting;
+pub mod target;
diff --git a/crates/swc_css_compat/src/target.rs b/crates/swc_css_compat/src/target.rs
new file mode 100644
index 000000000000..8b137891791f
--- /dev/null
+++ b/crates/swc_css_compat/src/target.rs
@@ -0,0 +1 @@
+

From f3730e23bfcd17b823933a228c00972869fddaa9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Donny/=EA=B0=95=EB=8F=99=EC=9C=A4?= <kdy1997.dev@gmail.com>
Date: Mon, 12 Dec 2022 15:01:12 +0900
Subject: [PATCH 3/9] custom_media

---
 crates/swc_css_compat/src/compiler/custom_media.rs | 1 +
 crates/swc_css_compat/src/compiler/mod.rs          | 2 ++
 2 files changed, 3 insertions(+)
 create mode 100644 crates/swc_css_compat/src/compiler/custom_media.rs

diff --git a/crates/swc_css_compat/src/compiler/custom_media.rs b/crates/swc_css_compat/src/compiler/custom_media.rs
new file mode 100644
index 000000000000..8b137891791f
--- /dev/null
+++ b/crates/swc_css_compat/src/compiler/custom_media.rs
@@ -0,0 +1 @@
+
diff --git a/crates/swc_css_compat/src/compiler/mod.rs b/crates/swc_css_compat/src/compiler/mod.rs
index 67c41541e5c0..8886dbe42262 100644
--- a/crates/swc_css_compat/src/compiler/mod.rs
+++ b/crates/swc_css_compat/src/compiler/mod.rs
@@ -1,2 +1,4 @@
+mod custom_media;
+
 /// Compiles a modern CSS file to a legacy CSS file.
 pub struct Compiler {}

From fc7a00db82f46eeaa44c3983d8b7c45038965971 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Donny/=EA=B0=95=EB=8F=99=EC=9C=A4?= <kdy1997.dev@gmail.com>
Date: Mon, 12 Dec 2022 15:02:09 +0900
Subject: [PATCH 4/9] Config

---
 crates/swc_css_compat/src/compiler/mod.rs | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/crates/swc_css_compat/src/compiler/mod.rs b/crates/swc_css_compat/src/compiler/mod.rs
index 8886dbe42262..52b37f1337b2 100644
--- a/crates/swc_css_compat/src/compiler/mod.rs
+++ b/crates/swc_css_compat/src/compiler/mod.rs
@@ -1,4 +1,20 @@
+use swc_css_visit::VisitMut;
+
 mod custom_media;
 
 /// Compiles a modern CSS file to a legacy CSS file.
-pub struct Compiler {}
+#[derive(Debug)]
+pub struct Compiler {
+    c: Config,
+}
+
+#[derive(Debug, Default)]
+pub struct Config {}
+
+impl Compiler {
+    pub fn new(config: Config) -> Self {
+        Self { c: config }
+    }
+}
+
+impl VisitMut for Compiler {}

From 5132549ae418a3c406ede7af46a118dafcdea602 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Donny/=EA=B0=95=EB=8F=99=EC=9C=A4?= <kdy1997.dev@gmail.com>
Date: Mon, 12 Dec 2022 15:07:55 +0900
Subject: [PATCH 5/9] feat

---
 crates/swc_css_compat/src/target.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crates/swc_css_compat/src/target.rs b/crates/swc_css_compat/src/target.rs
index 8b137891791f..c5c39935f55f 100644
--- a/crates/swc_css_compat/src/target.rs
+++ b/crates/swc_css_compat/src/target.rs
@@ -1 +1 @@
-
+pub struct SupportedFeatures {}

From fae7dd47fa1126a9c471e597d8037e35f44fdfdf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Donny/=EA=B0=95=EB=8F=99=EC=9C=A4?= <kdy1997.dev@gmail.com>
Date: Mon, 12 Dec 2022 15:08:49 +0900
Subject: [PATCH 6/9] compiler

---
 crates/swc_css_compat/src/lib.rs | 1 -
 1 file changed, 1 deletion(-)

diff --git a/crates/swc_css_compat/src/lib.rs b/crates/swc_css_compat/src/lib.rs
index 978ffdd54682..2473a39a8ccf 100644
--- a/crates/swc_css_compat/src/lib.rs
+++ b/crates/swc_css_compat/src/lib.rs
@@ -2,6 +2,5 @@
 #![allow(clippy::vec_box)]
 
 pub mod compiler;
-pub mod custom_media_query;
 pub mod nesting;
 pub mod target;

From bbb630a0447b6097f7bae63bc9599ec8efab009b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Donny/=EA=B0=95=EB=8F=99=EC=9C=A4?= <kdy1997.dev@gmail.com>
Date: Mon, 12 Dec 2022 15:09:59 +0900
Subject: [PATCH 7/9] dep

---
 Cargo.lock                       | 1 +
 crates/swc_css_compat/Cargo.toml | 1 +
 2 files changed, 2 insertions(+)

diff --git a/Cargo.lock b/Cargo.lock
index eaab1cd4bf5a..f3aca0a54539 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3372,6 +3372,7 @@ dependencies = [
 name = "swc_css_compat"
 version = "0.16.0"
 dependencies = [
+ "bitflags",
  "once_cell",
  "serde",
  "serde_json",
diff --git a/crates/swc_css_compat/Cargo.toml b/crates/swc_css_compat/Cargo.toml
index 3f77dd721d87..1fe0b755d070 100644
--- a/crates/swc_css_compat/Cargo.toml
+++ b/crates/swc_css_compat/Cargo.toml
@@ -13,6 +13,7 @@ version = "0.16.0"
 bench = false
 
 [dependencies]
+bitflags = "1.3.2"
 once_cell = "1.10.0"
 serde = {version = "1.0.118", features = ["derive"]}
 serde_json = "1.0.61"

From 9c072863a276f40285b7ed27dfe76b68ef93aeb1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Donny/=EA=B0=95=EB=8F=99=EC=9C=A4?= <kdy1997.dev@gmail.com>
Date: Mon, 12 Dec 2022 15:12:07 +0900
Subject: [PATCH 8/9] Features

---
 crates/swc_css_compat/src/compiler/mod.rs | 10 ++++++++--
 crates/swc_css_compat/src/feature.rs      |  7 +++++++
 crates/swc_css_compat/src/lib.rs          |  2 +-
 crates/swc_css_compat/src/target.rs       |  1 -
 4 files changed, 16 insertions(+), 4 deletions(-)
 create mode 100644 crates/swc_css_compat/src/feature.rs
 delete mode 100644 crates/swc_css_compat/src/target.rs

diff --git a/crates/swc_css_compat/src/compiler/mod.rs b/crates/swc_css_compat/src/compiler/mod.rs
index 52b37f1337b2..9d44be51ce6e 100644
--- a/crates/swc_css_compat/src/compiler/mod.rs
+++ b/crates/swc_css_compat/src/compiler/mod.rs
@@ -1,15 +1,21 @@
 use swc_css_visit::VisitMut;
 
+use crate::feature::Features;
+
 mod custom_media;
 
 /// Compiles a modern CSS file to a legacy CSS file.
 #[derive(Debug)]
 pub struct Compiler {
+    #[allow(unused)]
     c: Config,
 }
 
-#[derive(Debug, Default)]
-pub struct Config {}
+#[derive(Debug)]
+pub struct Config {
+    /// The list of features to **process**.
+    pub process: Features,
+}
 
 impl Compiler {
     pub fn new(config: Config) -> Self {
diff --git a/crates/swc_css_compat/src/feature.rs b/crates/swc_css_compat/src/feature.rs
new file mode 100644
index 000000000000..0d108a34f2b2
--- /dev/null
+++ b/crates/swc_css_compat/src/feature.rs
@@ -0,0 +1,7 @@
+use bitflags::bitflags;
+
+bitflags! {
+    pub struct Features: u64 {
+        const NESTING = 0b00000001;
+    }
+}
diff --git a/crates/swc_css_compat/src/lib.rs b/crates/swc_css_compat/src/lib.rs
index 2473a39a8ccf..d990d98d57af 100644
--- a/crates/swc_css_compat/src/lib.rs
+++ b/crates/swc_css_compat/src/lib.rs
@@ -2,5 +2,5 @@
 #![allow(clippy::vec_box)]
 
 pub mod compiler;
+pub mod feature;
 pub mod nesting;
-pub mod target;
diff --git a/crates/swc_css_compat/src/target.rs b/crates/swc_css_compat/src/target.rs
deleted file mode 100644
index c5c39935f55f..000000000000
--- a/crates/swc_css_compat/src/target.rs
+++ /dev/null
@@ -1 +0,0 @@
-pub struct SupportedFeatures {}

From 07628c56827f2b3302441a18de9add26b9acdf21 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Donny/=EA=B0=95=EB=8F=99=EC=9C=A4?= <kdy1997.dev@gmail.com>
Date: Mon, 12 Dec 2022 15:14:23 +0900
Subject: [PATCH 9/9] Doc

---
 crates/swc_css_compat/src/compiler/mod.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/crates/swc_css_compat/src/compiler/mod.rs b/crates/swc_css_compat/src/compiler/mod.rs
index 9d44be51ce6e..407da9976532 100644
--- a/crates/swc_css_compat/src/compiler/mod.rs
+++ b/crates/swc_css_compat/src/compiler/mod.rs
@@ -4,7 +4,7 @@ use crate::feature::Features;
 
 mod custom_media;
 
-/// Compiles a modern CSS file to a legacy CSS file.
+/// Compiles a modern CSS file to a CSS file which works with old browsers.
 #[derive(Debug)]
 pub struct Compiler {
     #[allow(unused)]