diff --git a/package-lock.json b/package-lock.json
index cb93db3ff76..6a193d527a8 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -28,7 +28,7 @@
         "@mdx-js/react": "1.6.22",
         "@playwright/test": "^1.55.0",
         "@prettier/sync": "0.5.5",
-        "@primer/stylelint-config": "13.3.0",
+        "@primer/stylelint-config": "13.4.1",
         "@size-limit/preset-big-lib": "11.2.0",
         "@types/semver": "^7.7.1",
         "@vitest/browser": "^4.0.3",
@@ -78,8 +78,8 @@
         "react-dom": "^18.3.1"
       },
       "devDependencies": {
-        "@primer/react": "38.0.0",
-        "@primer/styled-react": "0.2.0",
+        "@primer/react": "38.1.0",
+        "@primer/styled-react": "0.3.0",
         "@types/react": "^18.3.11",
         "@types/react-dom": "^18.3.0",
         "@vitejs/plugin-react": "^4.3.3",
@@ -92,8 +92,8 @@
       "name": "example-nextjs",
       "version": "0.0.0",
       "dependencies": {
-        "@primer/react": "38.0.0",
-        "@primer/styled-react": "0.2.0",
+        "@primer/react": "38.1.0",
+        "@primer/styled-react": "0.3.0",
         "next": "^16.0.0",
         "react": "^19.2.0",
         "react-dom": "^19.2.0",
@@ -135,8 +135,8 @@
       "version": "0.0.0",
       "dependencies": {
         "@primer/octicons-react": "^19.14.0",
-        "@primer/react": "38.0.0",
-        "@primer/styled-react": "0.2.0",
+        "@primer/react": "38.1.0",
+        "@primer/styled-react": "0.3.0",
         "clsx": "^2.1.1",
         "next": "^16.0.0",
         "react": "^19.2.0",
@@ -6454,7 +6454,9 @@
       "link": true
     },
     "node_modules/@primer/stylelint-config": {
-      "version": "13.3.0",
+      "version": "13.4.1",
+      "resolved": "https://registry.npmjs.org/@primer/stylelint-config/-/stylelint-config-13.4.1.tgz",
+      "integrity": "sha512-qhv8Nb137/Fv4ggjnKyFy2UUvhHQyuP6dncsi7s8gizTUokhlSYnlhtu2RsqUMe1Ftv4Y4Zoxy8dN97ZE8Y3jQ==",
       "dev": true,
       "license": "MIT",
       "dependencies": {
@@ -6463,9 +6465,9 @@
         "postcss-styled-syntax": "^0.7.0",
         "postcss-value-parser": "^4.0.2",
         "string.prototype.matchall": "^4.0.2",
-        "stylelint": "^16.11.0",
+        "stylelint": "^16.20.0",
         "stylelint-browser-compat": "^1.0.0-beta.140",
-        "stylelint-config-standard": "^37.0.0",
+        "stylelint-config-standard": "^38.0.0",
         "stylelint-scss": "^6.2.0",
         "stylelint-value-no-unknown-custom-properties": "^6.0.1"
       },
@@ -6473,7 +6475,7 @@
         "node": ">16.0.0"
       },
       "peerDependencies": {
-        "@primer/primitives": "9.x || 10.x"
+        "@primer/primitives": "10.x || 11.x"
       }
     },
     "node_modules/@publint/pack": {
@@ -23862,7 +23864,9 @@
       }
     },
     "node_modules/stylelint-config-recommended": {
-      "version": "15.0.0",
+      "version": "16.0.0",
+      "resolved": "https://registry.npmjs.org/stylelint-config-recommended/-/stylelint-config-recommended-16.0.0.tgz",
+      "integrity": "sha512-4RSmPjQegF34wNcK1e1O3Uz91HN8P1aFdFzio90wNK9mjgAI19u5vsU868cVZboKzCaa5XbpvtTzAAGQAxpcXA==",
       "dev": true,
       "funding": [
         {
@@ -23879,11 +23883,13 @@
         "node": ">=18.12.0"
       },
       "peerDependencies": {
-        "stylelint": "^16.13.0"
+        "stylelint": "^16.16.0"
       }
     },
     "node_modules/stylelint-config-standard": {
-      "version": "37.0.0",
+      "version": "38.0.0",
+      "resolved": "https://registry.npmjs.org/stylelint-config-standard/-/stylelint-config-standard-38.0.0.tgz",
+      "integrity": "sha512-uj3JIX+dpFseqd/DJx8Gy3PcRAJhlEZ2IrlFOc4LUxBX/PNMEQ198x7LCOE2Q5oT9Vw8nyc4CIL78xSqPr6iag==",
       "dev": true,
       "funding": [
         {
@@ -23897,13 +23903,13 @@
       ],
       "license": "MIT",
       "dependencies": {
-        "stylelint-config-recommended": "^15.0.0"
+        "stylelint-config-recommended": "^16.0.0"
       },
       "engines": {
         "node": ">=18.12.0"
       },
       "peerDependencies": {
-        "stylelint": "^16.13.0"
+        "stylelint": "^16.18.0"
       }
     },
     "node_modules/stylelint-scss": {
@@ -27266,7 +27272,7 @@
     },
     "packages/react": {
       "name": "@primer/react",
-      "version": "38.0.0",
+      "version": "38.1.0",
       "license": "MIT",
       "dependencies": {
         "@github/mini-throttle": "^2.1.1",
@@ -27277,7 +27283,7 @@
         "@primer/behaviors": "^1.8.2",
         "@primer/live-region-element": "^0.7.1",
         "@primer/octicons-react": "^19.13.0",
-        "@primer/primitives": "11.3.0",
+        "@primer/primitives": "10.x || 11.x",
         "clsx": "^2.1.1",
         "color2k": "^2.0.3",
         "deepmerge": "^4.3.1",
@@ -27844,7 +27850,7 @@
     },
     "packages/styled-react": {
       "name": "@primer/styled-react",
-      "version": "0.2.0",
+      "version": "0.3.0",
       "dependencies": {
         "@styled-system/css": "^5.1.5",
         "@styled-system/props": "^5.1.5",
@@ -27857,7 +27863,7 @@
       "devDependencies": {
         "@babel/preset-react": "^7.28.5",
         "@babel/preset-typescript": "^7.28.5",
-        "@primer/react": "^38.0.0",
+        "@primer/react": "^38.1.0",
         "@rollup/plugin-babel": "^6.1.0",
         "@types/react": "18.3.11",
         "@types/react-dom": "18.3.1",
@@ -27874,7 +27880,7 @@
         "typescript": "^5.9.2"
       },
       "peerDependencies": {
-        "@primer/react": "38.0.0",
+        "@primer/react": "^38.0.0",
         "@types/react": "18.x || 19.x",
         "@types/react-dom": "18.x || 19.x",
         "@types/react-is": "18.x || 19.x",
diff --git a/package.json b/package.json
index 70a04c5b192..157a1c37bdf 100644
--- a/package.json
+++ b/package.json
@@ -56,7 +56,7 @@
     "@mdx-js/react": "1.6.22",
     "@playwright/test": "^1.55.0",
     "@prettier/sync": "0.5.5",
-    "@primer/stylelint-config": "13.3.0",
+    "@primer/stylelint-config": "13.4.1",
     "@size-limit/preset-big-lib": "11.2.0",
     "@types/semver": "^7.7.1",
     "@vitest/browser": "^4.0.3",
diff --git a/packages/react/src/AvatarStack/AvatarStack.module.css b/packages/react/src/AvatarStack/AvatarStack.module.css
index c960b963d84..a5e1bc3a9a9 100644
--- a/packages/react/src/AvatarStack/AvatarStack.module.css
+++ b/packages/react/src/AvatarStack/AvatarStack.module.css
@@ -44,12 +44,12 @@
 
   &:where([data-avatar-count='1'][data-shape='square']) .AvatarItem {
     /* stylelint-disable-next-line primer/box-shadow */
-    box-shadow: 1px 0 rgba(0, 0, 0, 1);
+    box-shadow: 1px 0 rgb(0, 0, 0, 1);
   }
 
   &:where([data-avatar-count='1'][data-shape='square'][data-align-right]) .AvatarItem {
     /* stylelint-disable-next-line primer/box-shadow */
-    box-shadow: -1px 0 rgba(0, 0, 0, 1);
+    box-shadow: -1px 0 rgb(0, 0, 0, 1);
   }
 
   &:where([data-avatar-count='2']) {
@@ -145,12 +145,12 @@
 
   .AvatarStack:where([data-shape='square']) &:is(img) {
     /* stylelint-disable-next-line primer/box-shadow */
-    box-shadow: 1px 0 rgba(255, 255, 255, 1);
+    box-shadow: 1px 0 rgb(255, 255, 255, 1);
   }
 
   .AvatarStack:where([data-shape='square'][data-align-right]) &:is(img) {
     /* stylelint-disable-next-line primer/box-shadow */
-    box-shadow: -1px 0 rgba(255, 255, 255, 1);
+    box-shadow: -1px 0 rgb(255, 255, 255, 1);
   }
 
   &:first-child {
@@ -184,13 +184,13 @@
   /* Circular mask */
   .AvatarStack:where([data-shape='circle']) &:nth-child(n + 2) {
     /* stylelint-disable-next-line declaration-property-value-no-unknown */
-    mask-image: radial-gradient(at 50% 50%, rgb(0, 0, 0) 70%, rgba(0, 0, 0, 0) 71%), linear-gradient(rgb(0, 0, 0) 0 0);
+    mask-image: radial-gradient(at 50% 50%, rgb(0, 0, 0) 70%, rgb(0, 0, 0, 0) 71%), linear-gradient(rgb(0, 0, 0) 0 0);
   }
 
   /* Square mask */
   .AvatarStack:where([data-shape='square']) &:nth-child(n + 2) {
     /* stylelint-disable-next-line declaration-property-value-no-unknown */
-    mask-image: linear-gradient(at 50% 50%, rgb(0, 0, 0) 70%, rgba(0, 0, 0, 0) 71%), linear-gradient(rgb(0, 0, 0) 0 0);
+    mask-image: linear-gradient(at 50% 50%, rgb(0, 0, 0) 70%, rgb(0, 0, 0, 0) 71%), linear-gradient(rgb(0, 0, 0) 0 0);
   }
 
   /* Cascade variant override for nth-child(n + 3) */
diff --git a/packages/react/src/ProgressBar/ProgressBar.module.css b/packages/react/src/ProgressBar/ProgressBar.module.css
index d029536dcd2..3efe013c28f 100644
--- a/packages/react/src/ProgressBar/ProgressBar.module.css
+++ b/packages/react/src/ProgressBar/ProgressBar.module.css
@@ -19,7 +19,7 @@
 
   @media (prefers-reduced-motion: no-preference) {
     &[data-animated='true'] {
-      mask-image: linear-gradient(75deg, #000 30%, rgba(0, 0, 0, 0.65) 80%);
+      mask-image: linear-gradient(75deg, #000 30%, rgb(0, 0, 0, 0.65) 80%);
       mask-size: 200%;
       animation-name: shimmer;
       animation-duration: 1s;
diff --git a/packages/react/src/Skeleton/SkeletonBox.module.css b/packages/react/src/Skeleton/SkeletonBox.module.css
index 011ff190098..b060bdb265d 100644
--- a/packages/react/src/Skeleton/SkeletonBox.module.css
+++ b/packages/react/src/Skeleton/SkeletonBox.module.css
@@ -16,7 +16,7 @@
   animation: shimmer;
 
   @media (prefers-reduced-motion: no-preference) {
-    mask-image: linear-gradient(75deg, #000 30%, rgba(0, 0, 0, 0.65) 80%);
+    mask-image: linear-gradient(75deg, #000 30%, rgb(0, 0, 0, 0.65) 80%);
     mask-size: 200%;
     animation: shimmer;
     animation-duration: var(--base-duration-1000);
diff --git a/packages/react/src/ToggleSwitch/ToggleSwitch.module.css b/packages/react/src/ToggleSwitch/ToggleSwitch.module.css
index 8b7c12fded6..036043cca0c 100644
--- a/packages/react/src/ToggleSwitch/ToggleSwitch.module.css
+++ b/packages/react/src/ToggleSwitch/ToggleSwitch.module.css
@@ -136,13 +136,13 @@
 .SwitchButton:where([data-checked='false']:not([data-disabled='true']):hover),
 .SwitchButton:where([data-checked='false']:not([data-disabled='true']):focus-visible) {
   /* stylelint-disable-next-line primer/colors */
-  background-color: var(--controlTrack-bgColor-hover, var(--color-switch-track-hover-bg, hsla(210deg, 24%, 90%, 1)));
+  background-color: var(--controlTrack-bgColor-hover, var(--color-switch-track-hover-bg, hsl(210deg, 24%, 90%, 1)));
 }
 
 .SwitchButton:where([data-checked='false']:not([data-disabled='true']):active),
 .SwitchButton:where([data-checked='false']:not([data-disabled='true']):active:focus-visible) {
   /* stylelint-disable-next-line primer/colors */
-  background-color: var(--controlTrack-bgColor-active, var(--color-switch-track-active-bg, hsla(210deg, 24%, 88%, 1)));
+  background-color: var(--controlTrack-bgColor-active, var(--color-switch-track-active-bg, hsl(210deg, 24%, 88%, 1)));
 }
 
 .SwitchButton:where([data-checked='true']:not([data-disabled='true'])) {
diff --git a/packages/react/src/Token/IssueLabelToken.module.css b/packages/react/src/Token/IssueLabelToken.module.css
index cea4aa99b5a..e8f45ab2f76 100644
--- a/packages/react/src/Token/IssueLabelToken.module.css
+++ b/packages/react/src/Token/IssueLabelToken.module.css
@@ -6,7 +6,7 @@
 
   background: rgb(var(--label-r), var(--label-g), var(--label-b));
   color: hsl(0deg, 0%, calc(var(--lightness-switch) * 100%));
-  border-color: hsla(var(--label-h), calc(var(--label-s) * 1%), calc((var(--label-l) - 25) * 1%), var(--border-alpha));
+  border-color: hsl(var(--label-h), calc(var(--label-s) * 1%), calc((var(--label-l) - 25) * 1%), var(--border-alpha));
 
   /* Selected state */
   &:where([data-selected='true']) {
@@ -20,7 +20,7 @@
 
   /* Interactive hover states */
   &:where([data-cursor-is-interactive='true']:hover) {
-    background-image: linear-gradient(rgba(0, 0, 0, 0.15), rgba(0, 0, 0, 0.15)),
+    background-image: linear-gradient(rgb(0, 0, 0, 0.15), rgb(0, 0, 0, 0.15)),
       linear-gradient(
         rgb(var(--label-r), var(--label-g), var(--label-b)),
         rgb(var(--label-r), var(--label-g), var(--label-b))
@@ -35,9 +35,9 @@
   --border-alpha: 0.3;
   --lighten-by: calc(((var(--lightness-threshold) - var(--perceived-lightness)) * 100) * var(--lightness-switch));
 
-  background: rgba(var(--label-r), var(--label-g), var(--label-b), var(--background-alpha));
+  background: rgb(var(--label-r), var(--label-g), var(--label-b), var(--background-alpha));
   color: hsl(var(--label-h), calc(var(--label-s) * 1%), calc((var(--label-l) + var(--lighten-by)) * 1%));
-  border-color: hsla(
+  border-color: hsl(
     var(--label-h),
     calc(var(--label-s) * 1%),
     calc((var(--label-l) + var(--lighten-by)) * 1%),
@@ -53,7 +53,7 @@
 
   /* Interactive hover states */
   &:where([data-cursor-is-interactive='true']:hover) {
-    background: hsla(var(--label-h), calc(var(--label-s) * 1%), calc(calc(var(--label-l) + 10) * 1%), 0.3);
+    background: hsl(var(--label-h), calc(var(--label-s) * 1%), calc(calc(var(--label-l) + 10) * 1%), 0.3);
     box-shadow: var(--shadow-resting-medium);
   }
 }
diff --git a/packages/react/src/stories/deprecated/ActionListStories.module.css b/packages/react/src/stories/deprecated/ActionListStories.module.css
index b8dc0fe5aa4..135064ed0af 100644
--- a/packages/react/src/stories/deprecated/ActionListStories.module.css
+++ b/packages/react/src/stories/deprecated/ActionListStories.module.css
@@ -2,8 +2,8 @@
   border-radius: var(--borderRadius-large);
   /* stylelint-disable primer/box-shadow */
   box-shadow:
-    0 1px 3px rgba(0, 0, 0, 0.12),
-    0 8px 24px rgba(149, 157, 165, 0.2);
+    0 1px 3px rgb(0, 0, 0, 0.12),
+    0 8px 24px rgb(149, 157, 165, 0.2);
   /* stylelint-enable primer/box-shadow */
   overflow: hidden;
 }
diff --git a/packages/react/src/stories/deprecated/ActionMenuStories.module.css b/packages/react/src/stories/deprecated/ActionMenuStories.module.css
index 4968006ec4c..1ea135a4938 100644
--- a/packages/react/src/stories/deprecated/ActionMenuStories.module.css
+++ b/packages/react/src/stories/deprecated/ActionMenuStories.module.css
@@ -2,7 +2,7 @@
 .ErsatzOverlay {
   border-radius: var(--borderRadius-large);
   box-shadow:
-    0 1px 3px rgba(0, 0, 0, 0.12),
-    0 8px 24px rgba(149, 157, 165, 0.2);
+    0 1px 3px rgb(0, 0, 0, 0.12),
+    0 8px 24px rgb(149, 157, 165, 0.2);
   padding: var(--base-size-8);
 }
diff --git a/stylelint.config.mjs b/stylelint.config.mjs
index de5aee57247..5eb82300b04 100644
--- a/stylelint.config.mjs
+++ b/stylelint.config.mjs
@@ -13,6 +13,7 @@ export default {
         message: '"%s" selector should be written in PascalCase or BEM format (e.g. block__element--modifier)',
       },
     ],
+    'layer-name-pattern': '^[a-z][a-zA-Z0-9.-]*$',
   },
   overrides: [
     {