From 239ad7459e22121a5a899dce42a3a8850ed74f31 Mon Sep 17 00:00:00 2001
From: Chris Wanstrath <chris@ozmm.org>
Date: Wed, 11 Mar 2026 13:15:38 -0700
Subject: [PATCH] Add global css() function for element/reset styles

---
 src/index.tsx            | 13 +++++++
 src/tests/index.test.tsx | 77 +++++++++++++++++++++++++++++++++++++++-
 2 files changed, 89 insertions(+), 1 deletion(-)

diff --git a/src/index.tsx b/src/index.tsx
index 08a711b..820aeb5 100644
--- a/src/index.tsx
+++ b/src/index.tsx
@@ -318,5 +318,18 @@ function tagName(base: string): string {
   return capitalized === 'A' ? 'Anchor' : capitalized
 }
 
+// global CSS for resets, element defaults, pseudo-elements
+export function css(rules: Record<string, TagDef>) {
+  for (const [selector, def] of Object.entries(rules)) {
+    styles[selector] = makeStyle(def)
+
+    for (const [state, stateDef] of Object.entries(def.states ?? {}))
+      styles[`${selector}${stateName(state)}`] = makeStyle(stateDef)
+  }
+
+  injectStylesInBrowser()
+}
+
 // shortcut so you only have to import one thing, if you want
 define.Styles = Styles
+define.css = css
diff --git a/src/tests/index.test.tsx b/src/tests/index.test.tsx
index c1f3a03..bff980b 100644
--- a/src/tests/index.test.tsx
+++ b/src/tests/index.test.tsx
@@ -1,5 +1,5 @@
 import { describe, test, expect } from 'bun:test'
-import { define } from '../index'
+import { define, css } from '../index'
 import { renderToString, getStylesCSS, parseCSS } from './test_helpers'
 
 describe('define - basic functionality', () => {
@@ -1057,3 +1057,78 @@ describe('edge cases', () => {
     expect(html).toContain('Second')
   })
 })
+
+describe('css() - global styles', () => {
+  test('registers bare element selectors', () => {
+    css({
+      'body': { margin: 0, fontFamily: 'system-ui' }
+    })
+
+    const out = getStylesCSS()
+    expect(out).toContain('body {')
+    expect(out).toContain('font-family: system-ui')
+    expect(out).toContain('margin: 0px')
+  })
+
+  test('registers universal selector', () => {
+    css({
+      '*': { boxSizing: 'border-box' }
+    })
+
+    const out = getStylesCSS()
+    expect(out).toContain('* {')
+    expect(out).toContain('box-sizing: border-box')
+  })
+
+  test('registers compound selectors', () => {
+    css({
+      '*, *::before, *::after': { boxSizing: 'border-box' }
+    })
+
+    const out = getStylesCSS()
+    expect(out).toContain('*, *::before, *::after {')
+  })
+
+  test('registers pseudo-element selectors', () => {
+    css({
+      '::-webkit-scrollbar': { width: 8 }
+    })
+
+    const out = getStylesCSS()
+    expect(out).toContain('::-webkit-scrollbar {')
+    expect(out).toContain('width: 8px')
+  })
+
+  test('handles states on global selectors', () => {
+    css({
+      'a': {
+        color: 'blue',
+        states: {
+          hover: { color: 'darkblue' }
+        }
+      }
+    })
+
+    const out = getStylesCSS()
+    expect(out).toContain('a {')
+    expect(out).toContain('a:hover {')
+    expect(out).toContain('color: darkblue')
+  })
+
+  test('registers multiple selectors at once', () => {
+    css({
+      'html': { lineHeight: 1.5 },
+      'h1': { fontSize: 32 },
+      'p': { margin: 0 }
+    })
+
+    const out = getStylesCSS()
+    expect(out).toContain('html {')
+    expect(out).toContain('h1 {')
+    expect(out).toContain('p {')
+  })
+
+  test('accessible via define.css', () => {
+    expect(define.css).toBe(css)
+  })
+})