Cleanup nav-stacked .active state styles, remove unnecessary nesting

app/assets/stylesheets/common/admin/admin_base.scss

@@ -375,11 +375,6 @@ td.flaggers td {
   width: 18.018%;
   position: relative;
 
-  li a.active {
-    color: $secondary;
-    background-color: $quaternary;
-  }
-
   // The admin-nav becomes a slide-out menu at the mobile-nav breakpoint
   @media (max-width: $mobile-breakpoint) {
     position: absolute;

app/assets/stylesheets/common/base/rtl.scss

@@ -27,7 +27,7 @@
 
 // Changes the triangle arrow direction in .nav-stacked .active
 // The 'left' and 'right' in these selectors is not being flipped by r2.
-.rtl .nav-stacked .active > a::after {
+.rtl .nav-stacked a.active::after {
   border-left-color: transparent !important;
   border-right-color: $secondary !important;
 }

app/assets/stylesheets/common/components/navs.scss

@@ -76,29 +76,28 @@
     &.indent {
       padding-left: 15px;
     }
-
-    a {
-      margin: 0;
-      padding: 13px;
-      font-size: 1.143em;
-      line-height: 20px;
-      cursor: pointer;
-      color: $primary;
-    }
   }
 
-  .active > a,
-  li > a.active {
-    color: $secondary;
-    background-color: $quaternary;
+  a {
+    margin: 0;
+    padding: 13px;
+    font-size: 1.143em;
+    line-height: 20px;
+    cursor: pointer;
+    color: $primary;
 
-    &:after {
-      left: 90%;
-      top: 33%;
-      content: " ";
-      position: absolute;
-      border: 8px solid transparent;
-      border-left-color: $secondary;
+    &.active {
+      color: $secondary;
+      background-color: $quaternary;
+
+      &::after {
+        left: 90%;
+        top: 33%;
+        content: " ";
+        position: absolute;
+        border: 8px solid transparent;
+        border-left-color: $secondary;
+      }
     }
   }
 

app/assets/stylesheets/desktop/user.scss

@@ -113,25 +113,27 @@
 
   .nav-stacked {
     background-color: transparent;
+
     li {
       border-bottom: none;
 
-      a {
-        color: dark-light-choose(scale-color($primary, $lightness: 40%), scale-color($secondary, $lightness: 40%));
+      &.archive {
+        padding-left: 15px;
       }
+    }
 
-      a.active {
+    a {
+      color: dark-light-choose(scale-color($primary, $lightness: 40%), scale-color($secondary, $lightness: 40%));
+
+      &.active {
         color: $primary;
         font-weight: bold;
         background-color: transparent;
 
         &:after {
-        display: none;
+          display: none;
         }
       }
-      &.archive {
-        padding-left: 15px;
-      }
     }
   }
 }