--- /dev/null
+# at-rule-no-vendor-prefix
+
+Disallow vendor prefixes for at-rules.
+
+```css
+ @-webkit-keyframes { 0% { top: 0; } }
+/** ↑
+ * These prefixes */
+```
+
+## Options
+
+### `true`
+
+The following patterns are considered violations:
+
+```css
+@-webkit-keyframes { 0% { top: 0; } }
+```
+
+```css
+@-ms-viewport { orientation: landscape; }
+```
+
+The following patterns are *not* considered violations:
+
+```css
+@keyframes { 0% { top: 0; } }
+```
+
+```css
+@viewport { orientation: landscape; }
+```