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node_modules/stylelint/lib/rules/no-duplicate-selectors/README.md

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+# no-duplicate-selectors
+
+Disallow duplicate selectors within a stylesheet.
+
+```css
+    .foo {} .bar {} .foo {}
+/** ↑              ↑
+ * These duplicates */
+```
+
+This rule checks for two types of duplication:
+
+-   Duplication of a single selector with a rule's selector list, e.g. `a, b, a {}`.
+-   Duplication of a selector list within a stylesheet, e.g. `a, b {} a, b {}`. Duplicates are found even if the selectors come in different orders or have different spacing, e.g. `a d, b > c {} b>c, a   d {}`.
+
+The same selector *is* allowed to repeat in the following circumstances:
+
+-   It is used in different selector lists, e.g. `a {} a, b {}`.
+-   The duplicates are determined to originate in different stylesheets, e.g. you have concatenated or compiled files in a way that produces sourcemaps for PostCSS to read, e.g. postcss-import).
+-   The duplicates are in rules with different parent nodes, e.g. inside and outside of a media query.
+
+This rule resolves nested selectors. So `a b {} a { & b {} }` counts as a warning, because the resolved selectors end up with a duplicate.
+
+## Options
+
+### `true`
+
+The following patterns are considered warnings:
+
+```css
+.foo,
+.bar,
+.foo {}
+```
+
+```css
+.foo {}
+.bar {}
+.foo {}
+```
+
+```css
+.foo .bar {}
+.bar {}
+.foo .bar {}
+```
+
+```css
+@media (min-width: 10px) {
+  .foo {}
+  .foo {}
+}
+```
+
+```css
+.foo, .bar {}
+.bar, .foo {}
+```
+
+```css
+a .foo, b + .bar {}
+b+.bar,
+a
+  .foo {}
+```
+
+```css
+a b {}
+a {
+  & b {}
+}
+```
+
+The following patterns are *not* considered warnings:
+
+```css
+.foo {}
+@media (min-width: 10px) {
+  .foo {}
+}
+```
+
+```css
+.foo {
+  .foo {}
+}
+```
+
+```css
+.foo {}
+.bar {}
+.foo .bar {}
+.bar .foo {}
+```
+
+```css
+a b {}
+a {
+  & b,
+  & c {}
+}
+```