1 files changed, 61 insertions, 0 deletions

diff --git a/src/bem/_theme.scss b/src/bem/_theme.scss
new file mode 100644
index 0000000..b4bcc76
--- /dev/null
+++ b/src/bem/_theme.scss
@@ -0,0 +1,61 @@
+////
+/// @group BEM
+///
+/// @access public
+////
+
+/// 
+/// Declare new rules for the current block for when this theme is active.
+///
+/// @param {string} $name  - First theme block name
+/// @param {string} $names - More theme block names
+///
+/// @content
+///
+@mixin iro-bem-at-theme($name, $names...) {
+    $result:   iro-bem-at-theme($name, $names...);
+    $selector: nth($result, 1);
+    $context:  nth($result, 2);
+
+    @include iro-bem-validate(
+        'at-theme',
+        (name: $name, names: $names),
+        $selector,
+        $context
+    );
+
+    @include iro-context-push($iro-bem-context-id, $context...);
+    @at-root #{$selector} {
+        @content;
+    }
+    @include iro-context-pop($iro-bem-context-id);
+}
+
+///
+/// Declare new rules for the current block for when this theme is active.
+/// Check the respective mixin documentation for more information.
+/// 
+/// @return {list} A list with two items: 1. selector, 2. context or `null`
+///
+/// @see {mixin} iro-bem-at-theme
+///
+@function iro-bem-at-theme($name, $names...) {
+    $noop: iro-context-assert-stack-must-contain($iro-bem-context-id, 'block');
+
+    $parent-context:  iro-context-get($iro-bem-context-id, 'block');
+    $parent-selector: map-get(nth($parent-context, 2), 'selector');
+
+    @if not iro-selector-suffix-match(&, $parent-selector) {
+        @error 'An at-theme rule must be an immediate child of a block';
+    }
+
+    $selector: iro-bem-theme-selector($name, $names...);
+    $selector: selector-nest($selector, &);
+
+    $context: 'at-theme', (
+        'name':     join($name, $names),
+        'selector': $selector
+    );
+
+    @return $selector $context;
+}