No need to work on the first-child, work on the li directly

app/assets/stylesheets/scss/navbar.scss

@@ -134,42 +134,32 @@
 }
 
 nav.navbar .nav > li:not(.profile--image-dropdown) {
-  & > *:first-child {
-    -moz-osx-font-smoothing: grayscale;
-    position: relative;
+  -moz-osx-font-smoothing: grayscale;
+  position: relative;
 
+  &:before {
+      content: "";
+      position: absolute;
+      left: 0;
+      right: 0;
+      bottom: 0;
+      background: $navbar-inverse-link-color;
+      height: 0px;
+      -webkit-transition-property: height;
+      transition-property: height;
+      -webkit-transition-duration: 0.3s;
+      transition-duration: 0.3s;
+      -webkit-transition-timing-function: ease-out;
+      transition-timing-function: ease-out;
+  }
+
+  &:hover, &:focus, &:active {
     &:before {
-        content: "";
-        position: absolute;
-        left: 0;
-        right: 0;
-        bottom: 0;
-        background: $navbar-inverse-link-color;
-        height: 0px;
-        -webkit-transition-property: height;
-        transition-property: height;
-        -webkit-transition-duration: 0.3s;
-        transition-duration: 0.3s;
-        -webkit-transition-timing-function: ease-out;
-        transition-timing-function: ease-out;
-    }
-
-    &:hover, &:focus, &:active {
-      &:before {
-        height: 4px
-      }
+      height: 4px
     }
   }
 
-  &.active *:first-child:before {
+  &.active:before {
     height: 4px;
   }
-
-  & > .btn {
-    line-height: 50px;
-    width: 44px;
-    margin: 0;
-    border: 0;
-    padding: 0;
-  }
 }