Remove unused or unnecessary CSS

src/styles/sidebar/components/annotation-share-control.scss

@@ -14,7 +14,6 @@
   right: 5px;
   bottom: 32px;
   width: 275px;
-  box-shadow: 0px 0px 5px 0px rgba(0, 0, 0, 0.15);
   cursor: default;
 
   &__input {

src/styles/sidebar/components/annotation-user.scss

@@ -4,13 +4,5 @@
   &__user-name {
     color: var.$color-text;
     font-weight: bold;
-
-    .is-dimmed & {
-      color: var.$color-text-light;
-    }
-
-    .is-highlighted & {
-      color: var.$color-text;
-    }
   }
 }

src/styles/sidebar/components/annotation.scss

@@ -24,23 +24,6 @@
 .annotation {
   @include layout.vertical-rhythm;
 
-  &.is-highlighted {
-    // Slightly darken the bodies of highlighted annotations to
-    // make them stand out next to others, which will have the `is-dimmed` state
-    // set
-    .annotation-body {
-      color: var.$color-text;
-    }
-  }
-
-  &.is-dimmed {
-    // Lighten the bodies of dimmed annotations to make other
-    // annotations which are not dimmed stand out
-    .annotation-body {
-      color: var.$color-text-light;
-    }
-  }
-
   &__reply-toggle {
     @include buttons.button--link;
   }