fix(ui): render code blocks without outlines (google#4278)

Code blocks now render as a single panel instead of per-line outlines.

Fixes google#4273

Author: ashmod

gcp/website/frontend3/src/styles.scss

@@ -682,6 +682,15 @@ md-icon-button.mdc-data-table__sort-icon-button {
     box-shadow: 0 0 2px white;
   }
 
+  pre code {
+    display: block;
+    background: none;
+    padding: 0;
+    margin: 0;
+    border-radius: 0;
+    box-shadow: none;
+  }
+
   @media (max-width: $osv-mobile-breakpoint) {
     .title {
       font-size: $osv-heading-size-mobile;
@@ -1756,6 +1765,15 @@ div.highlight {
     box-shadow: 0 0 2px white;
   }
 
+  pre code {
+    display: block;
+    background: none;
+    padding: 0;
+    margin: 0;
+    border-radius: 0;
+    box-shadow: none;
+  }
+
   img {
     border-radius: $osv-border-radius-small;
     box-shadow: 0 0 3px white;