diff --git a/package.json b/package.json
index 5ec1248..e309c5c 100644
--- a/package.json
+++ b/package.json
@@ -39,7 +39,7 @@
   "devEngines": {
     "packageManager": {
       "name": "pnpm",
-      "version": "11.21.0"
+      "version": "11.22.0"
     }
   },
   "devDependencies": {
@@ -53,8 +53,8 @@
     "typescript": "~7.0.2"
   },
   "dependencies": {
-    "@csstools/css-tokenizer": "^4.0.0",
-    "postcss-value-parser": "^4.2.0"
+    "@csstools/css-parser-algorithms": "^4.0.0",
+    "@csstools/css-tokenizer": "^4.0.0"
   },
   "peerDependencies": {
     "postcss": "^8.5.25"
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index be4ba1a..0fba150 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -7,52 +7,52 @@ importers:
     configDependencies: {}
     packageManagerDependencies:
       '@pnpm/exe':
-        specifier: 11.21.0
-        version: 11.21.0
+        specifier: 11.22.0
+        version: 11.22.0
       pnpm:
-        specifier: 11.21.0
-        version: 11.21.0
+        specifier: 11.22.0
+        version: 11.22.0
 
 packages:
 
-  '@pnpm/exe@11.21.0':
-    resolution: {integrity: sha512-zawQxIewH1od72HhlmXWq3No6XyuWn+nMvQ9BjWWGNBVskmS+RDlTu7ey2ruL650PbbyuCATYSal1DaXFKBdcw==}
+  '@pnpm/exe@11.22.0':
+    resolution: {integrity: sha512-B1SGeKm+v9pX9YkzMmrnO2FbgBd8TDwzZ3jSj6J6ThxdyGvI4TsOfMeHARW4Wb25visPpmMDfIXrU76EZdJM4g==}
     hasBin: true
 
-  '@pnpm/linux-arm64@11.21.0':
-    resolution: {integrity: sha512-gOSfQKr6kZjEwHyoRwMt9qrqQ9sqbZmUm2hbgJJG8bp0ZR9YkQ4BZV2k4qlQA2jtsmHV1u1MwiaLcuK7DauvBg==}
+  '@pnpm/linux-arm64@11.22.0':
+    resolution: {integrity: sha512-xzzn3jYG9QaiFZPaHcWM3yX4Fm9UGz5E42mzpbvUEvXYf5O9fwNolenOhGLpRl2qS5u35fjZSvDZbWlOwHMcug==}
     cpu: [arm64]
     os: [linux]
 
-  '@pnpm/linux-x64@11.21.0':
-    resolution: {integrity: sha512-X+kBR8yscKyhhElO+WLrb6sFbl/3Ow70B+6fqZUYI8T8wtmlCw5GtcPXVBJPDJcLN5joe227h7lyCCZo4tdKdw==}
+  '@pnpm/linux-x64@11.22.0':
+    resolution: {integrity: sha512-isvaPctGinbsM2hsTtRsMarN8Sr5QhXDTNmn8Xv9Lp1PjincCvH2RBbhpo+xYIOxzgls1dtQSdgoORUbfRVALQ==}
     cpu: [x64]
     os: [linux]
 
-  '@pnpm/linuxstatic-arm64@11.21.0':
-    resolution: {integrity: sha512-IUJfAclH0b3QxaHuQuVxXQIzEkDtTm0C+G3tgG0ET5tDRGc7wH7eU0GEM75ojHOwzqv7s0y00xPVVCIsxUM4Nw==}
+  '@pnpm/linuxstatic-arm64@11.22.0':
+    resolution: {integrity: sha512-i4J+AQWW0T3JBdXaLsvxu8ZmMG1HLS6JZQESdOR9uBv8Zumb4yg8GYT83eWRLacr6ngVdhEBiC3W4eOG64MFbA==}
     cpu: [arm64]
     os: [linux]
     libc: [musl]
 
-  '@pnpm/linuxstatic-x64@11.21.0':
-    resolution: {integrity: sha512-6Y2u+AfOUuTqWgTCpFhySL8HAcONDucCFixKle9tWoW7bm8RF0+fwQBRWNWGdx+Toau07wZ1LNZPqN8gpgeBDQ==}
+  '@pnpm/linuxstatic-x64@11.22.0':
+    resolution: {integrity: sha512-QYzk8jhSuSbVthW/OxEOhU3f3zhjpw4HqgedrlwbVNb7btCWn5del2Hb5PsYYka2PbmKq5EtF5IzYN8Yp1CfxQ==}
     cpu: [x64]
     os: [linux]
     libc: [musl]
 
-  '@pnpm/macos-arm64@11.21.0':
-    resolution: {integrity: sha512-sLMGvVJXWdhFAouY2icjeZ2VCFmyPPZvvtHkfj1oeCWGppsbWcP5cExSw9yU1Uw7ALwrV0I2lRZv33yWYfDtcQ==}
+  '@pnpm/macos-arm64@11.22.0':
+    resolution: {integrity: sha512-Io8Axk5kutPgMuAfOg1QGj3J0/KpLvH5iiPcmp7up8D4q7BNWT02ndQo3RyGWqrlkf5nwspM41GFpWTShrZ4Aw==}
     cpu: [arm64]
     os: [darwin]
 
-  '@pnpm/win-arm64@11.21.0':
-    resolution: {integrity: sha512-79Nc+YI5B2ddH5MQD2YITL/PKnmXdcQKwmwx0HaD4QnsCco8DFaTho242e5sd9QfXKxYRvB9AOnuqIV4VjhAAw==}
+  '@pnpm/win-arm64@11.22.0':
+    resolution: {integrity: sha512-QgaRuKGQKov7xW2utPCgDT83fn/PU5cD6HFgib48oTslz7wv26E89d4jMCxL4GRmEL2YCfkYuj5ITj1oVWg5WQ==}
     cpu: [arm64]
     os: [win32]
 
-  '@pnpm/win-x64@11.21.0':
-    resolution: {integrity: sha512-zT3TufmVOroWPrzXTPPPgYvIsTZIsK13kjpmgXlICyEFrhd16RFLoTWFhP+8UqHXpTNmVbtTHzg+fEVYy9rlEQ==}
+  '@pnpm/win-x64@11.22.0':
+    resolution: {integrity: sha512-iWYsiSwpgxqur+TwsnSoPdOQaEfd4ygB84mb5tJUOgim6PHr1xhKJBndaQzH+At/WkLxLdYN+K8dYc4M7naezg==}
     cpu: [x64]
     os: [win32]
 
@@ -116,45 +116,45 @@ packages:
     resolution: {integrity: sha512-Btj2BOOO83o3WyH59e8MgXsxEQVcarkUOpEYrubB0urwnN10yQ364rsiByU11nZlqWYZm05i/of7io4mzihBtQ==}
     engines: {node: '>=8'}
 
-  pnpm@11.21.0:
-    resolution: {integrity: sha512-UhcFvOaJkk6scvWjWHEi82JonvZXHlW6gAdv1jfBETLs/62ib61Op5xIW/3b/T1aKlsFgFp36JPeceyKbMo7sQ==}
+  pnpm@11.22.0:
+    resolution: {integrity: sha512-H/hwxMYTPf2I+yr8Rt0T1H8JyXlLQ4xv20fKmMrzvBY4HuC+k6CRuOOCTPAfiJ9G19niCRD7C+GrD7W6qA3WIQ==}
     engines: {node: '>=22.13'}
     hasBin: true
 
 snapshots:
 
-  '@pnpm/exe@11.21.0':
+  '@pnpm/exe@11.22.0':
     dependencies:
       '@reflink/reflink': 0.1.19
       detect-libc: 2.1.2
     optionalDependencies:
-      '@pnpm/linux-arm64': 11.21.0
-      '@pnpm/linux-x64': 11.21.0
-      '@pnpm/linuxstatic-arm64': 11.21.0
-      '@pnpm/linuxstatic-x64': 11.21.0
-      '@pnpm/macos-arm64': 11.21.0
-      '@pnpm/win-arm64': 11.21.0
-      '@pnpm/win-x64': 11.21.0
+      '@pnpm/linux-arm64': 11.22.0
+      '@pnpm/linux-x64': 11.22.0
+      '@pnpm/linuxstatic-arm64': 11.22.0
+      '@pnpm/linuxstatic-x64': 11.22.0
+      '@pnpm/macos-arm64': 11.22.0
+      '@pnpm/win-arm64': 11.22.0
+      '@pnpm/win-x64': 11.22.0
 
-  '@pnpm/linux-arm64@11.21.0':
+  '@pnpm/linux-arm64@11.22.0':
     optional: true
 
-  '@pnpm/linux-x64@11.21.0':
+  '@pnpm/linux-x64@11.22.0':
     optional: true
 
-  '@pnpm/linuxstatic-arm64@11.21.0':
+  '@pnpm/linuxstatic-arm64@11.22.0':
     optional: true
 
-  '@pnpm/linuxstatic-x64@11.21.0':
+  '@pnpm/linuxstatic-x64@11.22.0':
     optional: true
 
-  '@pnpm/macos-arm64@11.21.0':
+  '@pnpm/macos-arm64@11.22.0':
     optional: true
 
-  '@pnpm/win-arm64@11.21.0':
+  '@pnpm/win-arm64@11.22.0':
     optional: true
 
-  '@pnpm/win-x64@11.21.0':
+  '@pnpm/win-x64@11.22.0':
     optional: true
 
   '@reflink/reflink-darwin-arm64@0.1.19':
@@ -194,7 +194,7 @@ snapshots:
 
   detect-libc@2.1.2: {}
 
-  pnpm@11.21.0: {}
+  pnpm@11.22.0: {}
 
 ---
 lockfileVersion: '9.0'
@@ -207,12 +207,12 @@ importers:
 
   .:
     dependencies:
+      '@csstools/css-parser-algorithms':
+        specifier: ^4.0.0
+        version: 4.0.0(@csstools/css-tokenizer@4.0.0)
       '@csstools/css-tokenizer':
         specifier: ^4.0.0
         version: 4.0.0
-      postcss-value-parser:
-        specifier: ^4.2.0
-        version: 4.2.0
     devDependencies:
       '@csstools/css-calc':
         specifier: ^3.3.0
@@ -666,9 +666,6 @@ packages:
   picocolors@1.1.1:
     resolution: {integrity: sha512-xceH2snhtb5M9liqDsmEw56le376mTZkEX/jEb/RxNFyegNul7eNslCXP9FDj/Lcu0X8KEyMceP2ntpaHrDEVA==}
 
-  postcss-value-parser@4.2.0:
-    resolution: {integrity: sha512-1NNCs6uurfkVbeXG4S8JFT9t19m45ICnif8zWLd5oPSZ50QnwMfK+H3jv408d4jw/7Bttv5axS5IiHoLaVNHeQ==}
-
   postcss@8.5.26:
     resolution: {integrity: sha512-u82N74LFzG8ca+dD8puPnplTXoGH4fTPpVGuIbt36G3qvNlkvfD0lEAZSxaly3KX8TS/L1A1gsCEmvKmBcVbkQ==}
     engines: {node: ^10 || ^12 || >=14}
@@ -939,8 +936,6 @@ snapshots:
 
   picocolors@1.1.1: {}
 
-  postcss-value-parser@4.2.0: {}
-
   postcss@8.5.26:
     dependencies:
       nanoid: 3.3.18
diff --git a/src/index.js b/src/index.js
index 93fbdad..aed35b8 100644
--- a/src/index.js
+++ b/src/index.js
@@ -1,13 +1,25 @@
 // PostCSS adapter. Walks declaration values (and optionally @rule params
 // and selectors), feeds calc() bodies through tokenize → parse → simplify
 // → serialize, and writes the result back.
-import valueParser from 'postcss-value-parser';
+import { tokenize as cssTokenize } from '@csstools/css-tokenizer';
+import {
+  isFunctionNode,
+  isSimpleBlockNode,
+  parseListOfComponentValues,
+} from '@csstools/css-parser-algorithms';
 import { tokenize } from './lib/tokenizer.js';
 import { parse } from './lib/parser.js';
 import { simplify } from './lib/simplify.js';
 import { isSupportedMathFunction } from './lib/simplify/call.js';
 import { serialize } from './lib/serialize.js';
 
+// The outer walk is deliberately forgiving: it only needs to locate calc()/
+// math-function boundaries in otherwise arbitrary (and possibly non-standard)
+// CSS values, so parse errors from the outer tokenizer/parser are swallowed.
+// Genuine syntax problems inside a matched call are
+// caught below via our own tokenize/parse/simplify pipeline.
+const NOOP_PARSE_ERROR = { onParseError: () => {} };
+
 const MATCH_CALC = /^(?:-(?:moz|webkit)-)?calc$/i;
 
 /**
@@ -22,6 +34,80 @@ const MATCH_CALC = /^(?:-(?:moz|webkit)-)?calc$/i;
 
 /** @typedef {Required<Omit<PluginOptions, 'onParseError'>> & Pick<PluginOptions, 'onParseError'>} ResolvedOptions */
 
+/**
+ * Fields threaded unchanged through the recursive `transformList` walk.
+ * `value` is the original full property text, used only for the
+ * warnWhenCannotResolve message.
+ *
+ * @typedef {object} TransformContext
+ * @property {ResolvedOptions} options
+ * @property {import('postcss').Result} result
+ * @property {import('postcss').ChildNode} item
+ * @property {string} value
+ */
+
+/**
+ * Walks a list of component values in place, replacing matched calc()/math
+ * function nodes with their simplified form. Unlike the library's generic
+ * `walk` helper, this recurses manually so a matched node's own (stale,
+ * pre-simplification) children are never independently re-visited.
+ *
+ * @param {import('@csstools/css-parser-algorithms').ComponentValue[]} list
+ * @param {TransformContext} ctx
+ * @return {void}
+ */
+function transformList(list, ctx) {
+  for (let i = 0; i < list.length; i++) {
+    const node = list[i];
+    if (!isFunctionNode(node)) {
+      if (isSimpleBlockNode(node)) {
+        transformList(node.value, ctx);
+      }
+      continue;
+    }
+
+    const name = node.getName();
+    const isCalc = MATCH_CALC.test(name);
+    const isMath = !isCalc && isSupportedMathFunction(name);
+    if (!isCalc && !isMath) {
+      transformList(node.value, ctx);
+      continue;
+    }
+
+    // calc(): feed the body. Bare math: feed the whole call.
+    const inner = node.value.map((child) => child.toString()).join('');
+    const contents = isCalc ? inner : `${name}(${inner})`;
+    try {
+      const simplified = simplify(parse(tokenize(contents)));
+      const str = serialize(simplified, {
+        precision: ctx.options.precision,
+        calcName: isCalc ? name : 'calc', // preserve vendor prefix on calc()
+      });
+
+      if (ctx.options.warnWhenCannotResolve && str.startsWith(`${name}(`)) {
+        ctx.result.warn('Could not reduce expression: ' + ctx.value, {
+          plugin: 'postcss-calc',
+          node: ctx.item,
+        });
+      }
+
+      const replacement = parseListOfComponentValues(
+        cssTokenize({ css: str }),
+        NOOP_PARSE_ERROR
+      );
+      list.splice(i, 1, ...replacement);
+      i += replacement.length - 1;
+    } catch (error) {
+      const err = error instanceof Error ? error : new Error('Error');
+      if (ctx.options.onParseError) {
+        ctx.options.onParseError(err, contents);
+      } else {
+        ctx.result.warn(err.message, { node: ctx.item });
+      }
+    }
+  }
+}
+
 /**
  * @param {string} value
  * @param {ResolvedOptions} options
@@ -30,49 +116,40 @@ const MATCH_CALC = /^(?:-(?:moz|webkit)-)?calc$/i;
  * @return {string}
  */
 function transformValue(value, options, result, item) {
-  return valueParser(value)
-    .walk((node) => {
-      if (node.type !== 'function') {
-        return;
-      }
-      const isCalc = MATCH_CALC.test(node.value);
-      const isMath = !isCalc && isSupportedMathFunction(node.value);
-      if (!isCalc && !isMath) {
-        return;
-      }
+  const componentValues = parseListOfComponentValues(
+    cssTokenize({ css: value }),
+    NOOP_PARSE_ERROR
+  );
 
-      // calc(): feed the body. Bare math: feed the whole call.
-      const inner = valueParser.stringify(node.nodes);
-      const contents = isCalc ? inner : `${node.value}(${inner})`;
-      try {
-        const simplified = simplify(parse(tokenize(contents)));
-        const str = serialize(simplified, {
-          precision: options.precision,
-          calcName: isCalc ? node.value : 'calc', // preserve vendor prefix on calc()
-        });
+  transformList(componentValues, { options, result, item, value });
 
-        if (options.warnWhenCannotResolve && str.startsWith(`${node.value}(`)) {
-          result.warn('Could not reduce expression: ' + value, {
-            plugin: 'postcss-calc',
-            node: item,
-          });
-        }
+  return componentValues.map((node) => node.toString()).join('');
+}
 
-        // Re-tag as `word` so value-parser emits `str` verbatim instead of
-        // re-wrapping it as `name(...)`. Cast widens the `'function'` literal.
-        /** @type {{type: string}} */ (node).type = 'word';
-        node.value = str;
-      } catch (error) {
-        const err = error instanceof Error ? error : new Error('Error');
-        if (options.onParseError) {
-          options.onParseError(err, contents);
-        } else {
-          result.warn(err.message, { node: item });
-        }
-      }
-      return false;
-    })
-    .toString();
+/**
+ * Runs `transformValue` over one text property of a decl/atrule/rule node
+ * and, per `options.preserve`, either updates it in place or inserts a
+ * clone carrying the transformed value ahead of the untouched original.
+ * `setProp` closes over the property name and the concrete node type at
+ * each call site, since `Declaration`/`AtRule`/`Rule` don't share a typed
+ * "text property" name to index generically.
+ *
+ * @param {import('postcss').ChildNode} node
+ * @param {string} current
+ * @param {(target: import('postcss').ChildNode, value: string) => void} setProp
+ * @param {ResolvedOptions} options
+ * @param {import('postcss').Result} result
+ * @return {void}
+ */
+function applyTransform(node, current, setProp, options, result) {
+  const next = transformValue(current, options, result, node);
+  if (options.preserve && current !== next && node.parent) {
+    const clone = node.clone();
+    setProp(clone, next);
+    node.parent.insertBefore(node, clone);
+  } else {
+    setProp(node, next);
+  }
 }
 
 /**
@@ -99,36 +176,39 @@ function pluginCreator(opts) {
     OnceExit(css, { result }) {
       css.walk((node) => {
         if (node.type === 'decl') {
-          const next = transformValue(node.value, options, result, node);
-          if (options.preserve && node.value !== next && node.parent) {
-            const clone = node.clone();
-            clone.value = next;
-            node.parent.insertBefore(node, clone);
-          } else {
-            node.value = next;
-          }
+          applyTransform(
+            node,
+            node.value,
+            (n, v) => {
+              /** @type {import('postcss').Declaration} */ (n).value = v;
+            },
+            options,
+            result
+          );
         }
         if (node.type === 'atrule' && options.mediaQueries) {
-          const next = transformValue(node.params, options, result, node);
-          if (options.preserve && node.params !== next && node.parent) {
-            const clone = node.clone();
-            clone.params = next;
-            node.parent.insertBefore(node, clone);
-          } else {
-            node.params = next;
-          }
+          applyTransform(
+            node,
+            node.params,
+            (n, v) => {
+              /** @type {import('postcss').AtRule} */ (n).params = v;
+            },
+            options,
+            result
+          );
         }
         if (node.type === 'rule' && options.selectors) {
           // Reduces `:nth-child(calc(...))` via the function walk. calc() in a
           // quoted attribute value is a literal match, so it's left untouched.
-          const next = transformValue(node.selector, options, result, node);
-          if (options.preserve && node.selector !== next && node.parent) {
-            const clone = node.clone();
-            clone.selector = next;
-            node.parent.insertBefore(node, clone);
-          } else {
-            node.selector = next;
-          }
+          applyTransform(
+            node,
+            node.selector,
+            (n, v) => {
+              /** @type {import('postcss').Rule} */ (n).selector = v;
+            },
+            options,
+            result
+          );
         }
       });
     },
diff --git a/src/lib/parser.js b/src/lib/parser.js
index 8ffdde0..097a923 100644
--- a/src/lib/parser.js
+++ b/src/lib/parser.js
@@ -1,7 +1,7 @@
 // Pratt parser. +/- emit Sum nodes; */÷ emit Product nodes. node.js
 // constructors flatten and normalize on construction, while parenthesized
 // sums retain a grouping marker for the opaque-subtraction invariant.
-import { mkSum, mkProduct, negate } from './node.js';
+import { mkSum, mkProduct, negate, ident, call } from './node.js';
 
 /**
  * @typedef {import('./tokenizer.js').Token} Token
@@ -174,7 +174,7 @@ function parseOpaqueCall(p, name) {
   const flush = () => {
     const trimmed = buf.trim();
     if (trimmed) {
-      args.push({ type: 'Ident', name: trimmed });
+      args.push(ident(trimmed));
     }
     buf = '';
   };
@@ -191,7 +191,7 @@ function parseOpaqueCall(p, name) {
         if (depth === 0) {
           p.next();
           flush();
-          return { type: 'Call', name, args };
+          return call(name, args);
         }
       } else if (tk.value === ',' && depth === 1) {
         p.next();
@@ -254,13 +254,13 @@ const PREFIX = {
         }
       }
       p.expect('punct', ')');
-      return { type: 'Call', name: t.value, args };
+      return call(t.value, args);
     }
     const kw = foldCalcKeyword(t.value);
     if (kw) {
       return kw;
     }
-    return { type: 'Ident', name: t.value };
+    return ident(t.value);
   },
 
   '(': (p) => {
diff --git a/src/lib/simplify/abs.js b/src/lib/simplify/abs.js
index 65138e2..0a03118 100644
--- a/src/lib/simplify/abs.js
+++ b/src/lib/simplify/abs.js
@@ -1,4 +1,4 @@
-import { num, dim } from '../node.js';
+import { num, dim, call } from '../node.js';
 
 /** @typedef {import('../node.js').Node} Node */
 
@@ -8,7 +8,7 @@ import { num, dim } from '../node.js';
  */
 function simplifyAbs(args) {
   if (args.length !== 1) {
-    return { type: 'Call', name: 'abs', args };
+    return call('abs', args);
   }
   const a = args[0];
   if (a.type === 'Num') {
@@ -17,7 +17,7 @@ function simplifyAbs(args) {
   if (a.type === 'Dim' && a.unit !== '%') {
     return dim(Math.abs(a.value), a.unit);
   }
-  return { type: 'Call', name: 'abs', args: [a] };
+  return call('abs', [a]);
 }
 
 export { simplifyAbs };
diff --git a/src/lib/simplify/atan2.js b/src/lib/simplify/atan2.js
index 3b7fe2c..d459f7a 100644
--- a/src/lib/simplify/atan2.js
+++ b/src/lib/simplify/atan2.js
@@ -1,7 +1,7 @@
 /* §10.4 — atan2. foldConstArgs already rejects percentages (property-
  context-resolved) and enforces shared base + static convertibility. */
 
-import { num, dim } from '../node.js';
+import { num, dim, call } from '../node.js';
 import { foldConstArgs } from './fold.js';
 
 /** @typedef {import('../node.js').Node} Node */
@@ -12,11 +12,11 @@ import { foldConstArgs } from './fold.js';
  */
 function simplifyAtan2(args) {
   if (args.length !== 2) {
-    return { type: 'Call', name: 'atan2', args };
+    return call('atan2', args);
   }
   const fold = foldConstArgs(args);
   if (fold === null) {
-    return { type: 'Call', name: 'atan2', args };
+    return call('atan2', args);
   }
   const [y, x] = /** @type {[number, number]} */ (fold.values);
   const radians = Math.atan2(y, x);
diff --git a/src/lib/simplify/call.js b/src/lib/simplify/call.js
index b701d18..8d51b6b 100644
--- a/src/lib/simplify/call.js
+++ b/src/lib/simplify/call.js
@@ -16,6 +16,8 @@ import { simplifyExp } from './exp.js';
 import { simplifyLog } from './log.js';
 import { simplifyHypot } from './hypot.js';
 
+import { call } from '../node.js';
+
 /** @typedef {import('../node.js').Node} Node */
 /** @typedef {import('../simplify.js').SimplifyFn} SimplifyFn */
 
@@ -86,7 +88,7 @@ function simplifyCall(node, simplify) {
     );
   }
 
-  return { type: 'Call', name: node.name, args };
+  return call(node.name, args);
 }
 
 export { isSupportedMathFunction, simplifyCall };
diff --git a/src/lib/simplify/clamp.js b/src/lib/simplify/clamp.js
index ee51514..56fd3f0 100644
--- a/src/lib/simplify/clamp.js
+++ b/src/lib/simplify/clamp.js
@@ -1,4 +1,4 @@
-import { num, dim } from '../node.js';
+import { num, dim, call } from '../node.js';
 import { foldConstArgs } from './fold.js';
 
 /** @typedef {import('../node.js').Node} Node */
@@ -18,7 +18,7 @@ function simplifyClamp(args) {
       return fold.unit === '' ? num(clamped) : dim(clamped, fold.unit);
     }
   }
-  return { type: 'Call', name: 'clamp', args };
+  return call('clamp', args);
 }
 
 export { simplifyClamp };
diff --git a/src/lib/simplify/exp.js b/src/lib/simplify/exp.js
index c7e6817..0cacbc3 100644
--- a/src/lib/simplify/exp.js
+++ b/src/lib/simplify/exp.js
@@ -1,4 +1,4 @@
-import { num } from '../node.js';
+import { num, call } from '../node.js';
 
 /** @typedef {import('../node.js').Node} Node */
 
@@ -8,7 +8,7 @@ import { num } from '../node.js';
  */
 function simplifyExp(args) {
   if (args.length !== 1 || args[0].type !== 'Num') {
-    return { type: 'Call', name: 'exp', args };
+    return call('exp', args);
   }
   return num(Math.exp(args[0].value));
 }
diff --git a/src/lib/simplify/hypot.js b/src/lib/simplify/hypot.js
index 2e13c46..c1fcdf2 100644
--- a/src/lib/simplify/hypot.js
+++ b/src/lib/simplify/hypot.js
@@ -1,6 +1,6 @@
 // §10.5 — hypot. Empty args return null from foldConstArgs naturally.
 
-import { num, dim } from '../node.js';
+import { num, dim, call } from '../node.js';
 import { foldConstArgs } from './fold.js';
 
 /** @typedef {import('../node.js').Node} Node */
@@ -12,7 +12,7 @@ import { foldConstArgs } from './fold.js';
 function simplifyHypot(args) {
   const fold = foldConstArgs(args);
   if (fold === null) {
-    return { type: 'Call', name: 'hypot', args };
+    return call('hypot', args);
   }
   const sumSq = fold.values.reduce((acc, v) => acc + v * v, 0);
   const result = Math.sqrt(sumSq);
diff --git a/src/lib/simplify/inverse-trig.js b/src/lib/simplify/inverse-trig.js
index 0b9677b..a1374ed 100644
--- a/src/lib/simplify/inverse-trig.js
+++ b/src/lib/simplify/inverse-trig.js
@@ -1,6 +1,6 @@
 // §10.4 — asin/acos/atan. Bare <number> in, <angle> in degrees out.
 
-import { num, dim } from '../node.js';
+import { num, dim, call } from '../node.js';
 
 /** @typedef {import('../node.js').Node} Node */
 
@@ -17,11 +17,11 @@ const INVERSE_TRIG_OPS = /** @type {const} */ ({
  */
 function simplifyInverseTrig(name, args) {
   if (args.length !== 1) {
-    return { type: 'Call', name, args };
+    return call(name, args);
   }
   const a = args[0];
   if (a.type !== 'Num') {
-    return { type: 'Call', name, args };
+    return call(name, args);
   }
   const radians = INVERSE_TRIG_OPS[name](a.value);
   if (isNaN(radians)) {
diff --git a/src/lib/simplify/log.js b/src/lib/simplify/log.js
index fad084b..ef36258 100644
--- a/src/lib/simplify/log.js
+++ b/src/lib/simplify/log.js
@@ -1,4 +1,4 @@
-import { num } from '../node.js';
+import { num, call } from '../node.js';
 
 /** @typedef {import('../node.js').Node} Node */
 
@@ -13,7 +13,7 @@ function simplifyLog(args) {
   if (args.length === 2 && args[0].type === 'Num' && args[1].type === 'Num') {
     return num(Math.log(args[0].value) / Math.log(args[1].value));
   }
-  return { type: 'Call', name: 'log', args };
+  return call('log', args);
 }
 
 export { simplifyLog };
diff --git a/src/lib/simplify/min-max.js b/src/lib/simplify/min-max.js
index 080781e..5120120 100644
--- a/src/lib/simplify/min-max.js
+++ b/src/lib/simplify/min-max.js
@@ -1,4 +1,4 @@
-import { num, dim } from '../node.js';
+import { num, dim, call } from '../node.js';
 import { foldConstArgs } from './fold.js';
 
 /** @typedef {import('../node.js').Node} Node */
@@ -15,7 +15,7 @@ function simplifyMinMax(name, args) {
     const value = fn(...fold.values);
     return fold.unit === '' ? num(value) : dim(value, fold.unit);
   }
-  return { type: 'Call', name, args };
+  return call(name, args);
 }
 
 export { simplifyMinMax };
diff --git a/src/lib/simplify/mod-rem.js b/src/lib/simplify/mod-rem.js
index 0d82f18..d6a9306 100644
--- a/src/lib/simplify/mod-rem.js
+++ b/src/lib/simplify/mod-rem.js
@@ -1,4 +1,4 @@
-import { num, dim } from '../node.js';
+import { num, dim, call } from '../node.js';
 import { foldConstArgs } from './fold.js';
 
 /** @typedef {import('../node.js').Node} Node */
@@ -10,11 +10,11 @@ import { foldConstArgs } from './fold.js';
  */
 function simplifyModRem(name, args) {
   if (args.length !== 2) {
-    return { type: 'Call', name, args };
+    return call(name, args);
   }
   const fold = foldConstArgs(args);
   if (fold === null) {
-    return { type: 'Call', name, args };
+    return call(name, args);
   }
   const [a, b] = /** @type {[number, number]} */ (fold.values);
   const result = applyModRem(name, a, b);
diff --git a/src/lib/simplify/pow.js b/src/lib/simplify/pow.js
index 12e85a4..073da21 100644
--- a/src/lib/simplify/pow.js
+++ b/src/lib/simplify/pow.js
@@ -1,6 +1,6 @@
 // §10.5 — pow is <number>-only.
 
-import { num } from '../node.js';
+import { num, call } from '../node.js';
 
 /** @typedef {import('../node.js').Node} Node */
 
@@ -10,7 +10,7 @@ import { num } from '../node.js';
  */
 function simplifyPow(args) {
   if (args.length !== 2 || args[0].type !== 'Num' || args[1].type !== 'Num') {
-    return { type: 'Call', name: 'pow', args };
+    return call('pow', args);
   }
   return num(Math.pow(args[0].value, args[1].value));
 }
diff --git a/src/lib/simplify/round.js b/src/lib/simplify/round.js
index e86d22b..f3c4565 100644
--- a/src/lib/simplify/round.js
+++ b/src/lib/simplify/round.js
@@ -1,4 +1,4 @@
-import { num, dim } from '../node.js';
+import { num, dim, ident, call } from '../node.js';
 import { foldConstArgs } from './fold.js';
 
 /** @typedef {import('../node.js').Node} Node */
@@ -18,21 +18,15 @@ function simplifyRound(args) {
     const n = first.name.toLowerCase();
     if (!ROUND_STRATEGIES.has(n)) {
       // Unrecognized strategy ident — opaque rather than guessing intent.
-      return { type: 'Call', name: 'round', args };
+      return call('round', args);
     }
     strategy = /** @type {RoundStrategy} */ (n);
     rest = args.slice(1);
   }
 
   /** @type {() => Node} */
-  const passthrough = () => ({
-    type: 'Call',
-    name: 'round',
-    args:
-      strategy === 'nearest'
-        ? rest
-        : [{ type: 'Ident', name: strategy }, ...rest],
-  });
+  const passthrough = () =>
+    call('round', strategy === 'nearest' ? rest : [ident(strategy), ...rest]);
 
   // B omitted: defaults to 1 when A is <number>; else opaque.
   const argsForFold = argsForRoundFold(rest);
diff --git a/src/lib/simplify/sign.js b/src/lib/simplify/sign.js
index cfaf7d4..3752111 100644
--- a/src/lib/simplify/sign.js
+++ b/src/lib/simplify/sign.js
@@ -1,4 +1,4 @@
-import { num } from '../node.js';
+import { num, call } from '../node.js';
 
 /** @typedef {import('../node.js').Node} Node */
 
@@ -8,7 +8,7 @@ import { num } from '../node.js';
  */
 function simplifySign(args) {
   if (args.length !== 1) {
-    return { type: 'Call', name: 'sign', args };
+    return call('sign', args);
   }
   const a = args[0];
   if (a.type === 'Num') {
@@ -18,7 +18,7 @@ function simplifySign(args) {
   if (a.type === 'Dim' && a.unit !== '%') {
     return num(Math.sign(a.value));
   }
-  return { type: 'Call', name: 'sign', args: [a] };
+  return call('sign', [a]);
 }
 
 export { simplifySign };
diff --git a/src/lib/simplify/sqrt.js b/src/lib/simplify/sqrt.js
index a3febc2..a4b28a5 100644
--- a/src/lib/simplify/sqrt.js
+++ b/src/lib/simplify/sqrt.js
@@ -1,4 +1,4 @@
-import { num } from '../node.js';
+import { num, call } from '../node.js';
 
 /** @typedef {import('../node.js').Node} Node */
 /**
@@ -7,7 +7,7 @@ import { num } from '../node.js';
  */
 function simplifySqrt(args) {
   if (args.length !== 1 || args[0].type !== 'Num') {
-    return { type: 'Call', name: 'sqrt', args };
+    return call('sqrt', args);
   }
   return num(Math.sqrt(args[0].value));
 }
diff --git a/src/lib/simplify/trig.js b/src/lib/simplify/trig.js
index 81e3649..0242112 100644
--- a/src/lib/simplify/trig.js
+++ b/src/lib/simplify/trig.js
@@ -1,6 +1,6 @@
 // §10.4 — sin/cos/tan. <number> is radians; <angle> dim is converted.
 
-import { num } from '../node.js';
+import { num, call } from '../node.js';
 import { baseOf, convert } from '../convertUnits.js';
 
 /** @typedef {import('../node.js').Node} Node */
@@ -18,7 +18,7 @@ const TRIG_OPS = /** @type {const} */ ({
  */
 function simplifyTrig(name, args) {
   if (args.length !== 1) {
-    return { type: 'Call', name, args };
+    return call(name, args);
   }
   const a = args[0];
   /** @type {number | null} */ let radians = null;
@@ -36,7 +36,7 @@ function simplifyTrig(name, args) {
     }
   }
   if (radians === null) {
-    return { type: 'Call', name, args };
+    return call(name, args);
   }
   return num(TRIG_OPS[name](radians));
 }
diff --git a/test/unit/plugin.test.mjs b/test/unit/plugin.test.mjs
index 514a5df..6bc9e43 100644
--- a/test/unit/plugin.test.mjs
+++ b/test/unit/plugin.test.mjs
@@ -173,13 +173,24 @@ test('plugin: onParseError catches errors in @media params (mediaQueries: true)'
   assert.equal(errors.length, 1);
 });
 test('plugin: selectors:true reduces calc() in selector text', async () => {
-  // Walking the selector with value-parser surfaces calc() function nodes
-  // that aren't safely buried in attribute-value strings.
+  // Walking the selector surfaces calc() function nodes that aren't safely
+  // buried in attribute-value strings.
   const { css } = await process('a:nth-child(calc(1 + 2)) { b: c }', {
     selectors: true,
   });
   assert.match(css, /:nth-child\(3\)/);
 });
+test('plugin: selectors + preserve clones the rule', async () => {
+  // Same shape as the mediaQueries + preserve case: the simplified rule
+  // appears first, followed by the original (preserve clones into the
+  // parent before the live node).
+  const { css } = await process('a:nth-child(calc(1 + 2)) { b: c }', {
+    selectors: true,
+    preserve: true,
+  });
+  assert.match(css, /:nth-child\(3\)/);
+  assert.match(css, /:nth-child\(calc\(1 \+ 2\)\)/);
+});
 test('plugin: onParseError does not fire for fully-resolved inputs', async () => {
   const errors = [];
   await process('a{b:calc(1px + 2px)}', {
@@ -227,3 +238,31 @@ test('plugin: leaves opaque-arg bare min() preserved', async () => {
   const { css } = await process('a{ width: min(1px, var(--x)) }');
   assert.equal(css, 'a{ width: min(1px, var(--x)) }');
 });
+// --- Outer-walk round-trip ------
+// The outer traversal runs the whole declaration/selector/param text
+// through @csstools/css-tokenizer + css-parser-algorithms (a strict,
+// spec-compliant parser). These tests pin down that content having
+// nothing to do with calc() still round-trips byte-for-byte through the
+// tokenizer.
+test('plugin: IE backslash hack survives the outer walk untouched', async () => {
+  const { css } = await process('a{width:calc(1px + 2px)\\9}');
+  assert.equal(css, 'a{width:3px\\9}');
+});
+test('plugin: escaped content value survives the outer walk untouched', async () => {
+  const { css } = await process('a{content:"\\e901"}');
+  assert.equal(css, 'a{content:"\\e901"}');
+});
+test('plugin: unicode-range descriptor survives the outer walk untouched', async () => {
+  const { css } = await process('@font-face{unicode-range:U+0025-00FF}');
+  assert.equal(css, '@font-face{unicode-range:U+0025-00FF}');
+});
+test('plugin: url() contents are opaque, even when they look like calc()', async () => {
+  const { css } = await process('a{background:url(calc(1px).png)}');
+  assert.equal(css, 'a{background:url(calc(1px).png)}');
+});
+test('plugin: grid line names survive alongside a reduced calc() term', async () => {
+  const { css } = await process(
+    'a{grid-template-columns:[full-start] calc(1px + 2px) [full-end]}'
+  );
+  assert.equal(css, 'a{grid-template-columns:[full-start] 3px [full-end]}');
+});
diff --git a/types/index.d.ts b/types/index.d.ts
index 65310c8..d901194 100644
--- a/types/index.d.ts
+++ b/types/index.d.ts
@@ -10,6 +10,12 @@ export type PluginOptions = {
     onParseError?: (error: Error, input: string) => void;
 };
 export type ResolvedOptions = Required<Omit<PluginOptions, 'onParseError'>> & Pick<PluginOptions, 'onParseError'>;
+export type TransformContext = {
+    options: ResolvedOptions;
+    result: import('postcss').Result;
+    item: import('postcss').ChildNode;
+    value: string;
+};
 /**
  * @param {PluginOptions} [opts]
  * @return {import('postcss').Plugin}