feat(hoveroverlay): remove Sourcegraph styling assumptions

Read --border-color for border and decouple from Sourcegraph styles

Author: felixfbecker

src/HoverOverlay.scss

@@ -1,9 +1,6 @@
 .hover-overlay {
-    $color-border: #2b3750;
-    $color-light-border: #cad2e2;
-
     position: absolute;
-    width: 30rem;
+    width: 32rem;
     max-height: 15rem;
     display: flex;
     flex-direction: column;
@@ -18,17 +15,15 @@
         padding: 0.25rem;
         background: inherit;
         z-index: 1;
+        border: none;
     }
 
     &__row {
         display: block;
         width: 100%;
         margin: 0;
         &:not(:first-child) {
-            border-top: 1px solid $color-border;
-            .theme-light & {
-                border-top-color: $color-light-border;
-            }
+            border-top: 1px solid var(--border-color);
         }
     }
 
@@ -52,14 +47,13 @@
     }
 
     &__action:not(:first-child) {
-        border-left: 1px solid $color-border;
-        .theme-light & {
-            border-left-color: $color-light-border;
-        }
+        border-left: 1px solid var(--border-color);
     }
 
     &__action {
         width: percentage(1/3);
+        text-align: center;
+        border: none;
     }
 
     &__action,
@@ -83,4 +77,8 @@
         margin: 0;
         overflow-y: auto;
     }
+
+    code {
+        white-space: pre;
+    }
 }