dev-five-git · owjs3901 · Dec 16, 2025 · Dec 16, 2025 · Dec 16, 2025 · Dec 16, 2025
diff --git a/.gitignore b/.gitignore
@@ -16,3 +16,4 @@ tarpaulin-report.html
 tarpaulin-report.json
 *storybook.log
 storybook-static
+.claude
diff --git a/README.md b/README.md
@@ -3,9 +3,13 @@
 </div>
 
 <h3 align="center">
-    Zero Config, Zero FOUC, Zero Runtime, CSS in JS Preprocessor
+    The Future of CSS-in-JS — Zero Runtime, Full Power
 </h3>
 
+<p align="center">
+    <strong>Zero Config · Zero FOUC · Zero Runtime · Complete CSS-in-JS Syntax Coverage</strong>
+</p>
+
 ---
 
 <div>
@@ -31,6 +35,18 @@
 
 English | [한국어](README_ko.md)
 
+## Why Devup UI?
+
+**Devup UI isn't just another CSS-in-JS library — it's the next evolution.**
+
+Traditional CSS-in-JS solutions force you to choose between developer experience and performance. Devup UI eliminates this trade-off entirely by processing all styles at build time using a Rust-powered preprocessor.
+
+- **Complete Syntax Coverage**: Every CSS-in-JS pattern you know — variables, conditionals, responsive arrays, pseudo-selectors — all fully supported
+- **Familiar API**: `styled()` API compatible with styled-components and Emotion patterns
+- **True Zero Runtime**: No JavaScript execution for styling at runtime. Period.
+- **Smallest Bundle Size**: Optimized class names (`a`, `b`, ... `aa`, `ab`) minimize CSS output
+- **Fastest Build Times**: Rust + WebAssembly delivers unmatched preprocessing speed
+
 ## Install
 
 ```sh
@@ -51,87 +67,84 @@ npm install @devup-ui/webpack-plugin
 
 ## Features
 
-- Preprocessor
-- Zero Config
-- Zero FOUC
-- Zero Runtime
-- RSC Support
-- Must not use JavaScript, client-side logic, or hybrid solutions
-- Support Library mode
-- Zero Cost Dynamic Theme Support based on CSS Variables
-- Theme with Typing
-- Smallest size, fastest speed
-
-## Inspirations
-
-- Styled System
-- Chakra UI
-- Theme UI
-- Vanilla Extract
-- Rainbow Sprinkles
-- Kuma UI
+- **Preprocessor** — All CSS extraction happens at build time
+- **Zero Config** — Works out of the box with sensible defaults
+- **Zero FOUC** — No flash of unstyled content, no Provider required
+- **Zero Runtime** — No client-side JavaScript for styling
+- **RSC Support** — Full React Server Components compatibility
+- **Library Mode** — Build component libraries with extracted styles
+- **Dynamic Themes** — Zero-cost theme switching via CSS variables
+- **Type-Safe Themes** — Full TypeScript support for theme tokens
+- **Smallest & Fastest** — Proven by benchmarks
 
 ## Comparison Benchmarks
 
 Next.js Build Time and Build Size (github action - ubuntu-latest)
 
-| Library                        | Version | Build Time | Build Size        |
-| ------------------------------ | ------- | ---------- | ----------------- |
-| tailwindcss                    | 4.1.13  | 19.31s     | 59,521,539 bytes  |
-| styleX                         | 0.15.4  | 41.78s     | 86,869,452 bytes  |
-| vanilla-extract                | 1.17.4  | 19.50s     | 61,494,033 bytes  |
-| kuma-ui                        | 1.5.9   | 20.93s     | 69,924,179 bytes  |
-| panda-css                      | 1.3.1   | 20.64s     | 64,573,260 bytes  |
-| chakra-ui                      | 3.27.0  | 28.81s     | 222,435,802 bytes |
-| mui                            | 7.3.2   | 20.86s     | 97,964,458 bytes  |
-| devup-ui(per-file css)         | 1.0.18  | 16.90s     | 59,540,459 bytes  |
-| devup-ui(single css)           | 1.0.18  | 17.05s     | 59,520,196 bytes  |
-| tailwindcss(turbopack)         | 4.1.13  | 6.72s      | 5,355,082 bytes   |
-| devup-ui(single css+turbopack) | 1.0.18  | 10.34s     | 4,772,050 bytes   |
+| Library                            | Version | Build Time | Build Size           |
+| ---------------------------------- | ------- | ---------- | -------------------- |
+| tailwindcss                        | 4.1.13  | 19.31s     | 59,521,539 bytes     |
+| styleX                             | 0.15.4  | 41.78s     | 86,869,452 bytes     |
+| vanilla-extract                    | 1.17.4  | 19.50s     | 61,494,033 bytes     |
+| kuma-ui                            | 1.5.9   | 20.93s     | 69,924,179 bytes     |
+| panda-css                          | 1.3.1   | 20.64s     | 64,573,260 bytes     |
+| chakra-ui                          | 3.27.0  | 28.81s     | 222,435,802 bytes    |
+| mui                                | 7.3.2   | 20.86s     | 97,964,458 bytes     |
+| **devup-ui(per-file css)**         | 1.0.18  | **16.90s** | 59,540,459 bytes     |
+| **devup-ui(single css)**           | 1.0.18  | **17.05s** | **59,520,196 bytes** |
+| tailwindcss(turbopack)             | 4.1.13  | 6.72s      | 5,355,082 bytes      |
+| **devup-ui(single css+turbopack)** | 1.0.18  | 10.34s     | **4,772,050 bytes**  |
 
 ## How it works
 
-Devup UI is a CSS in JS preprocessor that does not require runtime.
-Devup UI eliminates the performance degradation of the browser through the CSS in JS preprocessor.
-We develop a preprocessor that considers all grammatical cases.
+Devup UI transforms your components at build time. Class names are generated using a compact base-37 encoding for minimal CSS size.
+
+**Basic transformation:**
 
 ```tsx
-const before = <Box bg="red" />
+// You write:
+const variable = <Box _hover={{ bg: 'blue' }} bg="red" p={4} />
+
+// Devup UI generates:
+const variable = <div className="a b c" />
 
-const after = <div className="d0" />
+// With CSS:
+// .a { background-color: red; }
+// .b { padding: 1rem; }
+// .c:hover { background-color: blue; }
 ```
 
-Variables are fully supported.
+**Dynamic values become CSS variables:**
 
 ```tsx
-const before = <Box bg={colorVariable} />
+// You write:
+const example = <Box bg={colorVariable} />
 
-const after = (
-  <div
-    className="d0"
-    style={{
-      '--d0': colorVariable,
-    }}
-  />
-)
+// Devup UI generates:
+const example = <div className="a" style={{ '--a': colorVariable }} />
+
+// With CSS:
+// .a { background-color: var(--a); }
 ```
 
-Various expressions and responsiveness are also fully supported.
+**Complex expressions and responsive arrays — fully supported:**
 
 ```tsx
-const before = <Box bg={['red', 'blue', a > b ? 'yellow' : variable]} />
+// You write:
+const example = <Box bg={['red', 'blue', isActive ? 'green' : dynamicColor]} />
 
-const after = (
+// Devup UI generates:
+const example = (
   <div
-    className={`d0 d1 ${a > b ? 'd2' : 'd3'}`}
-    style={{
-      '--d2': variable,
-    }}
+    className={`a b ${isActive ? 'c' : 'd'}`}
+    style={{ '--d': dynamicColor }}
   />
 )
+
+// With responsive CSS for each breakpoint
 ```
 
-Support Theme with Typing
+**Type-safe theming:**
 
 `devup.json`
 
@@ -140,33 +153,79 @@ Support Theme with Typing
   "theme": {
     "colors": {
       "default": {
+        "primary": "#0070f3",
         "text": "#000"
       },
       "dark": {
-        "text": "white"
+        "primary": "#3291ff",
+        "text": "#fff"
+      }
+    },
+    "typography": {
+      "heading": {
+        "fontFamily": "Pretendard",
+        "fontSize": "24px",
+        "fontWeight": 700,
+        "lineHeight": 1.3
       }
     }
   }
 }
 ```
 
 ```tsx
-// Type Safe
-<Text color="$text" />
+// Type-safe theme tokens
+const textExample = <Text color="$primary" />
+const boxExample = <Box typography="$heading" />
 ```
 
-Support Responsive And Pseudo Selector
-
-You can use responsive and pseudo selector.
+**Responsive + Pseudo selectors together:**
 
 ```tsx
-// Responsive with Selector
-const box = <Box _hover={{ bg: ['red', 'blue'] }} />
+// Responsive with pseudo selector
+const example = <Box _hover={{ bg: ['red', 'blue'] }} />
 
-// Same
-const box = <Box _hover={[{ bg: 'red' }, { bg: 'blue' }]} />
+// Equivalent syntax
+const example2 = <Box _hover={[{ bg: 'red' }, { bg: 'blue' }]} />
+```
+
+**styled-components / Emotion compatible `styled()` API:**
+
+```tsx
+import { styled } from '@devup-ui/react'
+
+// Familiar syntax for styled-components and Emotion users
+const Card = styled('div', {
+  bg: 'white',
+  p: 4, // 4 * 4 = 16px
+  borderRadius: '8px',
+  boxShadow: '0 4px 6px rgba(0, 0, 0, 0.1)',
+  _hover: {
+    boxShadow: '0 10px 15px rgba(0, 0, 0, 0.1)',
+  },
+})
+
+const Button = styled('button', {
+  px: 4, // 4 * 4 = 16px
+  py: 2, // 2 * 4 = 8px
+  borderRadius: '4px',
+  cursor: 'pointer',
+})
+
+// Usage
+const cardExample = <Card>Content</Card>
+const buttonExample = <Button>Click me</Button>
 ```
 
+## Inspirations
+
+- Styled System
+- Chakra UI
+- Theme UI
+- Vanilla Extract
+- Rainbow Sprinkles
+- Kuma UI
+
 ## How to Contribute
 
 ### Requirements