feat: update BEM naming

lib/modifiers/annotation.scss

@@ -0,0 +1,37 @@
+/*
+ * Author: Sivan [sun.sivan@gmail.com]
+ * Description: define interlinear annotation styles.
+ */
+@import "../variables";
+
+@mixin hetiAnnotationModifier {
+  &--annotation {
+    // 首行缩进且行间距加大，去除段落间距
+    p {
+      margin-block-start: 0;
+      margin-block-end: 0;
+      line-height: $line-height-expanded-ultra;
+      text-indent: $text-indent-length;
+    }
+
+    // 着重号不应影响行间距，经测试最小可用行高为 1.7
+    em {
+      -webkit-text-emphasis: filled circle;
+      -webkit-text-emphasis-position: under;
+      font-weight: $font-weight-normal;
+
+      @include non-cjk-block {
+        -webkit-text-emphasis: none;
+      }
+    }
+
+    // 元信息保持间距
+    #{$root-selector}-meta {
+      margin-block-start: $std-block-unit / 2;
+      margin-block-end: $std-block-unit;
+    }
+
+    // ruby 不应影响行间距，经测试最小可用行高为 2
+    //ruby {}
+  }
+}