Update left side nav border UI

app/assets/stylesheets/framework/contextual_sidebar.scss

@@ -68,8 +68,7 @@
 }
 
 .nav-sidebar {
-  transition: width $sidebar-transition-duration,
-    left $sidebar-transition-duration;
+  transition: width $sidebar-transition-duration, left $sidebar-transition-duration;
   position: fixed;
   z-index: 400;
   width: $contextual-sidebar-width;
@@ -77,12 +76,12 @@
   bottom: 0;
   left: 0;
   background-color: $gray-light;
-  box-shadow: inset -2px 0 0 $border-color;
+  box-shadow: inset -1px 0 0 $border-color;
   transform: translate3d(0, 0, 0);
 
   &:not(.sidebar-collapsed-desktop) {
     @media (min-width: map-get($grid-breakpoints, sm)) and (max-width: map-get($grid-breakpoints, sm)) {
-      box-shadow: inset -2px 0 0 $border-color,
+      box-shadow: inset -1px 0 0 $border-color,
         2px 1px 3px $dropdown-shadow-color;
     }
   }
@@ -214,7 +213,7 @@
   > li {
     > a {
       @include media-breakpoint-up(sm) {
-        margin-right: 2px;
+        margin-right: 1px;
       }
 
       &:hover {
@@ -224,7 +223,7 @@
 
     &.is-showing-fly-out {
       > a {
-        margin-right: 2px;
+        margin-right: 1px;
       }
 
       .sidebar-sub-level-items {
@@ -317,14 +316,14 @@
 
 .toggle-sidebar-button,
 .close-nav-button {
-  width: $contextual-sidebar-width - 2px;
+  width: $contextual-sidebar-width - 1px;
   transition: width $sidebar-transition-duration;
   position: fixed;
   bottom: 0;
   padding: $gl-padding;
   background-color: $gray-light;
   border: 0;
-  border-top: 2px solid $border-color;
+  border-top: 1px solid $border-color;
   color: $gl-text-color-secondary;
   display: flex;
   align-items: center;
@@ -379,7 +378,7 @@
 
   .toggle-sidebar-button {
     padding: 16px;
-    width: $contextual-sidebar-collapsed-width - 2px;
+    width: $contextual-sidebar-collapsed-width - 1px;
 
     .collapse-text,
     .icon-angle-double-left {