static/frontend: fix for links to have underline on keyboard focus

https://screencast.googleplex.com/cast/NTczMjY4ODQ2OTE2NDAzMnwxYmNkMWJkNS0yNQ

Change-Id: Ic16bcc9571f221ea833f68368969437585d29668
Reviewed-on: https://go-review.googlesource.com/c/pkgsite/+/515337
Reviewed-by: Hyang-Ah Hana Kim <[email protected]>
Run-TryBot: Hyang-Ah Hana Kim <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Auto-Submit: Hyang-Ah Hana Kim <[email protected]>
kokoro-CI: kokoro <[email protected]>

Author: Prudhvi Krishna Chintala

static/frontend/frontend.min.css

@@ -63,10 +63,6 @@
   margin-top: 1.5rem;
 }
 
-.Documentation a {
-  text-decoration: none;
-}
-
 .Documentation a:hover {
   text-decoration: underline;
 }

static/frontend/frontend.min.css.map

@@ -326,6 +326,10 @@
   padding: 0;
 }
 
+.go-Header-submenu .go-Header-submenuItem a:focus {
+  text-decoration: underline !important;
+}
+
 .go-Header-inner--dark .go-Header-menuItem:hover > a:not(.forced-closed).js-desktop-menu-hover,
 .go-Header-inner--dark
   .go-Header-menuItem:focus-within

static/frontend/unit/main/_doc.css

@@ -124,7 +124,8 @@ a:visited {
   text-decoration: none;
 }
 
-a:hover {
+a:hover,
+a:focus {
   color: var(--color-brand-primary);
   text-decoration: underline;
 }