diff --git a/eslint.config.js b/eslint.config.js
index e073f46c3d7..8168702a8ee 100644
--- a/eslint.config.js
+++ b/eslint.config.js
@@ -361,6 +361,16 @@ module.exports = [
       'no-nested-ternary': 'error',
     },
   },
+  {
+    name: 'grafana/css-in-js-validation-unified',
+    plugins: {
+      '@grafana': grafanaPlugin,
+    },
+    files: ['public/app/features/alerting/unified/**/*.{ts,tsx}'],
+    rules: {
+      '@grafana/no-invalid-css-properties': 'error',
+    },
+  },
   {
     // Sections of codebase that have all translation markup issues fixed
     name: 'grafana/i18n-overrides',
diff --git a/package.json b/package.json
index 756c996742b..f4ed86268b4 100644
--- a/package.json
+++ b/package.json
@@ -210,6 +210,7 @@
     "github-codeowners": "^0.2.1",
     "glob": "11.1.0",
     "html-loader": "5.1.0",
+    "html-tags": "^5.1.0",
     "html-webpack-plugin": "5.6.3",
     "http-server": "14.1.1",
     "i18next-cli": "^1.24.22",
@@ -225,6 +226,7 @@
     "jest-watch-typeahead": "^2.2.2",
     "jimp": "^1.6.0",
     "jsdom-testing-mocks": "^1.13.1",
+    "known-css-properties": "^0.37.0",
     "lerna": "9.0.3",
     "madge": "^8.0.0",
     "mini-css-extract-plugin": "2.9.2",
diff --git a/packages/grafana-eslint-rules/README.md b/packages/grafana-eslint-rules/README.md
index aa6d4e880ff..7c36931ca03 100644
--- a/packages/grafana-eslint-rules/README.md
+++ b/packages/grafana-eslint-rules/README.md
@@ -20,6 +20,58 @@ To improve the consistency across Grafana we encourage devs to use tokens instea
 
 Instead of using `0` to remove a previously set border-radius, use `unset`.
 
+### `no-invalid-css-properties`
+
+Disallow invalid CSS property names in Emotion `css()` calls.
+
+This rule catches typos and invalid CSS properties in Emotion's `css()` function calls, helping prevent bugs where styles are silently ignored by browsers. It uses the [`known-css-properties`](https://www.npmjs.com/package/known-css-properties) package (the same one used by Stylelint) to validate property names against all standard CSS properties.
+
+The rule automatically converts camelCase property names to kebab-case for validation and allows:
+
+- Valid CSS properties (e.g., `paddingLeft`, `backgroundColor`)
+- CSS custom properties/variables (e.g., `--my-custom-property`)
+- Nested selectors and pseudo-classes (e.g., `&:hover`, `& > div`)
+- At-rules (e.g., `@media`, `@supports`)
+- HTML tag selectors (e.g., `button`, `span`)
+
+#### Examples
+
+```tsx
+// Bad ❌ - Typo in property name
+const styles = css({
+  addingLeft: 10, // Should be "paddingLeft"
+  backgroudColor: 'red', // Should be "backgroundColor"
+});
+
+// Good ✅ - Valid CSS properties
+const styles = css({
+  paddingLeft: 10,
+  backgroundColor: 'red',
+});
+
+// Good ✅ - CSS custom properties
+const styles = css({
+  '--my-custom-property': '10px',
+});
+
+// Good ✅ - Nested selectors and pseudo-classes
+const styles = css({
+  '&:hover': {
+    backgroundColor: 'blue',
+  },
+  '& > span': {
+    color: 'red',
+  },
+});
+
+// Good ✅ - Media queries
+const styles = css({
+  '@media (max-width: 768px)': {
+    display: 'none',
+  },
+});
+```
+
 ### `no-unreduced-motion`
 
 Avoid direct use of `animation*` or `transition*` properties.
diff --git a/packages/grafana-eslint-rules/index.cjs b/packages/grafana-eslint-rules/index.cjs
index 89a76ee60a1..0028e58894d 100644
--- a/packages/grafana-eslint-rules/index.cjs
+++ b/packages/grafana-eslint-rules/index.cjs
@@ -5,6 +5,7 @@ const themeTokenUsage = require('./rules/theme-token-usage.cjs');
 const noRestrictedImgSrcs = require('./rules/no-restricted-img-srcs.cjs');
 const consistentStoryTitles = require('./rules/consistent-story-titles.cjs');
 const noPluginExternalImportPaths = require('./rules/no-plugin-external-import-paths.cjs');
+const noInvalidCssProperties = require('./rules/no-invalid-css-properties.cjs');
 
 module.exports = {
   rules: {
@@ -15,5 +16,6 @@ module.exports = {
     'no-restricted-img-srcs': noRestrictedImgSrcs,
     'consistent-story-titles': consistentStoryTitles,
     'no-plugin-external-import-paths': noPluginExternalImportPaths,
+    'no-invalid-css-properties': noInvalidCssProperties,
   },
 };
diff --git a/packages/grafana-eslint-rules/rules/no-invalid-css-properties.cjs b/packages/grafana-eslint-rules/rules/no-invalid-css-properties.cjs
new file mode 100644
index 00000000000..41b627fc658
--- /dev/null
+++ b/packages/grafana-eslint-rules/rules/no-invalid-css-properties.cjs
@@ -0,0 +1,153 @@
+const { ESLintUtils, AST_NODE_TYPES } = require('@typescript-eslint/utils');
+const { all: allCssProperties } = require('known-css-properties');
+const htmlTagsModule = require('html-tags');
+
+const createRule = ESLintUtils.RuleCreator(
+  (name) => `https://github.com/grafana/grafana/blob/main/packages/grafana-eslint-rules/README.md#${name}`
+);
+
+// Get valid CSS properties from the known-css-properties package
+// This package maintains an up-to-date list of all standard CSS properties
+// It's the same package used by Stylelint for property validation
+const VALID_CSS_PROPERTIES = new Set(allCssProperties);
+
+// HTML tags used as nested selectors in CSS-in-JS
+// Using the html-tags package (same as Stylelint uses)
+const htmlTags = htmlTagsModule.default || htmlTagsModule;
+const HTML_TAGS = new Set(htmlTags);
+
+// Regex to match CSS selector characters (nested selectors, pseudo-classes, etc.)
+const SELECTOR_PATTERN = /[&:[\]>+~@]/;
+
+// Valid keyframe selectors
+const KEYFRAME_SELECTORS = new Set(['from', 'to']);
+
+function isValidProperty(propertyName) {
+  // Allow CSS custom properties (variables)
+  if (propertyName.startsWith('--')) {
+    return true;
+  }
+
+  // Allow nested selectors and at-rules (CSS-in-JS feature)
+  // Examples: '&:hover', '& > div', '[disabled]', '@media', etc.
+  if (SELECTOR_PATTERN.test(propertyName)) {
+    return true;
+  }
+
+  // Allow valid HTML tags used as nested selectors
+  if (HTML_TAGS.has(propertyName.toLowerCase())) {
+    return true;
+  }
+
+  // Allow keyframe selectors (from, to)
+  if (KEYFRAME_SELECTORS.has(propertyName)) {
+    return true;
+  }
+
+  // Check against valid CSS properties from known-css-properties
+  // Convert camelCase to kebab-case (also handles vendor prefixes)
+  const kebabCase = propertyName.replace(/[A-Z]/g, (m) => '-' + m.toLowerCase());
+  return VALID_CSS_PROPERTIES.has(kebabCase);
+}
+
+function isInsideFunctionCall(node) {
+  // Check if this property is an argument to a function call (not a CSS property)
+  // by looking at the immediate context
+  let parent = node.parent;
+
+  // Walk up to find the ObjectExpression that contains this property
+  while (parent && parent.type !== AST_NODE_TYPES.ObjectExpression) {
+    parent = parent.parent;
+  }
+
+  if (!parent) {
+    return false;
+  }
+
+  // Check if the ObjectExpression is an argument to a CallExpression
+  const objectParent = parent.parent;
+  if (objectParent && objectParent.type === AST_NODE_TYPES.CallExpression && objectParent.arguments.includes(parent)) {
+    // Make sure it's not the css() call itself - that's the top level
+    if (objectParent.callee.type === AST_NODE_TYPES.Identifier && objectParent.callee.name === 'css') {
+      return false;
+    }
+    // This object is a function argument, not a CSS object
+    return true;
+  }
+
+  return false;
+}
+
+function isInsideKeyframes(node) {
+  // Check if this property is inside a @keyframes rule
+  let parent = node.parent;
+
+  while (parent) {
+    // If parent is a Property with a key that starts with '@keyframes'
+    if (parent.type === AST_NODE_TYPES.Property) {
+      const key = parent.key;
+      if (key.type === AST_NODE_TYPES.Literal && typeof key.value === 'string') {
+        if (key.value.startsWith('@keyframes')) {
+          return true;
+        }
+      }
+      if (key.type === AST_NODE_TYPES.Identifier && key.name.startsWith('@keyframes')) {
+        return true;
+      }
+    }
+    parent = parent.parent;
+  }
+
+  return false;
+}
+
+const invalidCssPropertiesRule = createRule({
+  create(context) {
+    return {
+      [`${AST_NODE_TYPES.CallExpression}[callee.name="css"] ${AST_NODE_TYPES.Property}`]: function (node) {
+        if (
+          node.type === AST_NODE_TYPES.Property &&
+          node.key.type === AST_NODE_TYPES.Identifier &&
+          !node.computed // Skip computed properties like [narrowScreenQuery]: {...}
+        ) {
+          const propertyName = node.key.name;
+
+          // Skip properties that are inside function calls (not direct CSS properties)
+          if (isInsideFunctionCall(node)) {
+            return;
+          }
+
+          // Skip properties that are inside @keyframes rules
+          if (isInsideKeyframes(node)) {
+            return;
+          }
+
+          if (!isValidProperty(propertyName)) {
+            context.report({
+              node: node.key,
+              messageId: 'invalidProperty',
+              data: {
+                propertyName,
+              },
+            });
+          }
+        }
+      },
+    };
+  },
+  name: 'no-invalid-css-properties',
+  meta: {
+    type: 'problem',
+    docs: {
+      description: 'Disallow invalid CSS property names in Emotion css() calls',
+    },
+    messages: {
+      invalidProperty:
+        'Invalid CSS property "{{propertyName}}" in css() call. This property will be ignored by browsers.',
+    },
+    schema: [],
+  },
+  defaultOptions: [],
+});
+
+module.exports = invalidCssPropertiesRule;
diff --git a/public/app/features/alerting/unified/components/rule-editor/alert-rule-form/simplifiedRouting/AlertManagerRouting.tsx b/public/app/features/alerting/unified/components/rule-editor/alert-rule-form/simplifiedRouting/AlertManagerRouting.tsx
index 88db4e44596..a03a92c2e47 100644
--- a/public/app/features/alerting/unified/components/rule-editor/alert-rule-form/simplifiedRouting/AlertManagerRouting.tsx
+++ b/public/app/features/alerting/unified/components/rule-editor/alert-rule-form/simplifiedRouting/AlertManagerRouting.tsx
@@ -106,7 +106,7 @@ const getStyles = (theme: GrafanaTheme2) => ({
     backgroundColor: theme.colors.secondary.main,
   }),
   alertManagerName: css({
-    with: 'fit-content',
+    width: 'fit-content',
   }),
   secondAlertManagerLine: css({
     height: '1px',
diff --git a/public/app/features/alerting/unified/triage/rows/GenericRow.tsx b/public/app/features/alerting/unified/triage/rows/GenericRow.tsx
index 1588520fb48..bb1a81f2698 100644
--- a/public/app/features/alerting/unified/triage/rows/GenericRow.tsx
+++ b/public/app/features/alerting/unified/triage/rows/GenericRow.tsx
@@ -121,7 +121,7 @@ export const getStyles = (theme: GrafanaTheme2) => {
       css({
         padding: 5,
         width: '100%',
-        addingLeft: depth ? `calc(${theme.spacing(depth)} + 5px)` : 5,
+        paddingLeft: depth ? `calc(${theme.spacing(depth)} + 5px)` : 5,
       }),
     groupItemWrapper: (width: number) =>
       css({
diff --git a/yarn.lock b/yarn.lock
index df6f25da132..bcfe6566f51 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -20841,6 +20841,7 @@ __metadata:
     glob: "npm:11.1.0"
     history: "npm:4.10.1"
     html-loader: "npm:5.1.0"
+    html-tags: "npm:^5.1.0"
     html-webpack-plugin: "npm:5.6.3"
     http-server: "npm:14.1.1"
     i18next: "npm:^25.0.0"
@@ -20869,6 +20870,7 @@ __metadata:
     json-source-map: "npm:0.6.1"
     jsurl: "npm:^0.1.5"
     kbar: "npm:0.1.0-beta.48"
+    known-css-properties: "npm:^0.37.0"
     lerna: "npm:9.0.3"
     leven: "npm:^4.0.0"
     lodash: "npm:^4.17.23"
@@ -21431,6 +21433,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"html-tags@npm:^5.1.0":
+  version: 5.1.0
+  resolution: "html-tags@npm:5.1.0"
+  checksum: 10/73d0448496ad9ac4a905427717908a3e72b8676d514e077437aaa9310deb43fd9f3eda58ac6b01b651db7431f3ddcc914e1f8e24052375dfe11d3ddfe4a20de7
+  languageName: node
+  linkType: hard
+
 "html-to-text@npm:9.0.5":
   version: 9.0.5
   resolution: "html-to-text@npm:9.0.5"