--- /dev/null
+# selector-pseudo-class-parentheses-space-inside
+
+Require a single space or disallow whitespace on the inside of the parentheses within pseudo-class selectors.
+
+```css
+input:not( [type="submit"] ) {}
+/** ↑ ↑
+ * The space inside these two parentheses */
+```
+
+## Options
+
+`string`: `"always"|"never"`
+
+### `"always"`
+
+There *must always* be a single space inside the parentheses.
+
+The following patterns are considered violations:
+
+```css
+input:not([type="submit"]) {}
+```
+
+```css
+input:not([type="submit"] ) {}
+```
+
+The following patterns are *not* considered violations:
+
+```css
+input:not( [type="submit"] ) {}
+```
+
+### `"never"`
+
+There *must never* be whitespace on the inside the parentheses.
+
+The following patterns are considered violations:
+
+```css
+input:not( [type="submit"] ) {}
+```
+
+```css
+input:not( [type="submit"]) {}
+```
+
+The following patterns are *not* considered violations:
+
+```css
+input:not([type="submit"]) {}
+```