From b1e2c8fd5cb5dfa46bc440a12eafaf56cd844b1c Mon Sep 17 00:00:00 2001
From: Philipp Tanlak <philipp.tanlak@gmail.com>
Date: Mon, 24 Nov 2025 20:54:57 +0100
Subject: Docs

---
 .../tailwindcss/src/lib/resolveDefaultsAtRules.js  | 163 +++++++++++++++++++++
 1 file changed, 163 insertions(+)
 create mode 100644 node_modules/tailwindcss/src/lib/resolveDefaultsAtRules.js

(limited to 'node_modules/tailwindcss/src/lib/resolveDefaultsAtRules.js')

diff --git a/node_modules/tailwindcss/src/lib/resolveDefaultsAtRules.js b/node_modules/tailwindcss/src/lib/resolveDefaultsAtRules.js
new file mode 100644
index 0000000..389ea4b
--- /dev/null
+++ b/node_modules/tailwindcss/src/lib/resolveDefaultsAtRules.js
@@ -0,0 +1,163 @@
+import postcss from 'postcss'
+import selectorParser from 'postcss-selector-parser'
+import { flagEnabled } from '../featureFlags'
+
+let getNode = {
+  id(node) {
+    return selectorParser.attribute({
+      attribute: 'id',
+      operator: '=',
+      value: node.value,
+      quoteMark: '"',
+    })
+  },
+}
+
+function minimumImpactSelector(nodes) {
+  let rest = nodes
+    .filter((node) => {
+      // Keep non-pseudo nodes
+      if (node.type !== 'pseudo') return true
+
+      // Keep pseudo nodes that have subnodes
+      // E.g.: `:not()` contains subnodes inside the parentheses
+      if (node.nodes.length > 0) return true
+
+      // Keep pseudo `elements`
+      // This implicitly means that we ignore pseudo `classes`
+      return (
+        node.value.startsWith('::') ||
+        [':before', ':after', ':first-line', ':first-letter'].includes(node.value)
+      )
+    })
+    .reverse()
+
+  let searchFor = new Set(['tag', 'class', 'id', 'attribute'])
+
+  let splitPointIdx = rest.findIndex((n) => searchFor.has(n.type))
+  if (splitPointIdx === -1) return rest.reverse().join('').trim()
+
+  let node = rest[splitPointIdx]
+  let bestNode = getNode[node.type] ? getNode[node.type](node) : node
+
+  rest = rest.slice(0, splitPointIdx)
+
+  let combinatorIdx = rest.findIndex((n) => n.type === 'combinator' && n.value === '>')
+  if (combinatorIdx !== -1) {
+    rest.splice(0, combinatorIdx)
+    rest.unshift(selectorParser.universal())
+  }
+
+  return [bestNode, ...rest.reverse()].join('').trim()
+}
+
+export let elementSelectorParser = selectorParser((selectors) => {
+  return selectors.map((s) => {
+    let nodes = s.split((n) => n.type === 'combinator' && n.value === ' ').pop()
+    return minimumImpactSelector(nodes)
+  })
+})
+
+let cache = new Map()
+
+function extractElementSelector(selector) {
+  if (!cache.has(selector)) {
+    cache.set(selector, elementSelectorParser.transformSync(selector))
+  }
+
+  return cache.get(selector)
+}
+
+export default function resolveDefaultsAtRules({ tailwindConfig }) {
+  return (root) => {
+    let variableNodeMap = new Map()
+
+    /** @type {Set<import('postcss').AtRule>} */
+    let universals = new Set()
+
+    root.walkAtRules('defaults', (rule) => {
+      if (rule.nodes && rule.nodes.length > 0) {
+        universals.add(rule)
+        return
+      }
+
+      let variable = rule.params
+      if (!variableNodeMap.has(variable)) {
+        variableNodeMap.set(variable, new Set())
+      }
+
+      variableNodeMap.get(variable).add(rule.parent)
+
+      rule.remove()
+    })
+
+    if (flagEnabled(tailwindConfig, 'optimizeUniversalDefaults')) {
+      for (let universal of universals) {
+        /** @type {Map<string, Set<string>>} */
+        let selectorGroups = new Map()
+
+        let rules = variableNodeMap.get(universal.params) ?? []
+
+        for (let rule of rules) {
+          for (let selector of extractElementSelector(rule.selector)) {
+            // If selector contains a vendor prefix after a pseudo element or class,
+            // we consider them separately because merging the declarations into
+            // a single rule will cause browsers that do not understand the
+            // vendor prefix to throw out the whole rule
+            let selectorGroupName =
+              selector.includes(':-') || selector.includes('::-') ? selector : '__DEFAULT__'
+
+            let selectors = selectorGroups.get(selectorGroupName) ?? new Set()
+            selectorGroups.set(selectorGroupName, selectors)
+
+            selectors.add(selector)
+          }
+        }
+
+        if (flagEnabled(tailwindConfig, 'optimizeUniversalDefaults')) {
+          if (selectorGroups.size === 0) {
+            universal.remove()
+            continue
+          }
+
+          for (let [, selectors] of selectorGroups) {
+            let universalRule = postcss.rule({
+              source: universal.source,
+            })
+
+            universalRule.selectors = [...selectors]
+
+            universalRule.append(universal.nodes.map((node) => node.clone()))
+            universal.before(universalRule)
+          }
+        }
+
+        universal.remove()
+      }
+    } else if (universals.size) {
+      let universalRule = postcss.rule({
+        selectors: ['*', '::before', '::after'],
+      })
+
+      for (let universal of universals) {
+        universalRule.append(universal.nodes)
+
+        if (!universalRule.parent) {
+          universal.before(universalRule)
+        }
+
+        if (!universalRule.source) {
+          universalRule.source = universal.source
+        }
+
+        universal.remove()
+      }
+
+      let backdropRule = universalRule.clone({
+        selectors: ['::backdrop'],
+      })
+
+      universalRule.after(backdropRule)
+    }
+  }
+}
-- 
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