cmd/coordinator: unify headers visually

A header is displayed on 3 pages:

	• farmer.golang.org          - the coordinator status page
	• farmer.golang.org/builders - list of builders
	• build.golang.org           - the build dashboard page
	                               (now served by coordinator)

They look slightly different visually. There's also no good way
to navigate from the dashboard back to coordinator status page.

This change makes them all look the same, making it easier to
refactor them in the future, and improves ability to navigate.

Apply the same change to the work-in-progress dashboard V2 page,
to keep it in sync.

For golang/go#34744.
Fixes golang/go#47477.

Change-Id: Ib17d3e2955fa42afbb4bccb249ec5a8786ceab6e
Reviewed-on: https://go-review.googlesource.com/c/build/+/340116
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Dmitri Shuralyov <dmitshur@golang.org>
Trust: Alexander Rakoczy <alex@golang.org>
Reviewed-by: Alexander Rakoczy <alex@golang.org>
Reviewed-by: Carlos Amedee <carlos@golang.org>
diff --git a/cmd/coordinator/builders.go b/cmd/coordinator/builders.go
index f7e3ea8..5ce0b99 100644
--- a/cmd/coordinator/builders.go
+++ b/cmd/coordinator/builders.go
@@ -47,10 +47,14 @@
 <head><link rel="stylesheet" href="/style.css"/><title>Go Farmer</title></head>
 <body>
 <header>
-	<h1>Go Build Coordinator</h1>
+	<h1>
+		<a href="/">Go Build Coordinator</a>
+	</h1>
 	<nav>
-		<a href="https://build.golang.org">Dashboard</a>
-		<a href="/builders">Builders</a>
+		<ul>
+			<li><a href="https://build.golang.org/">Dashboard</a></li>
+			<li><a href="/builders">Builders</a></li>
+		</ul>
 	</nav>
 	<div class="clear"></div>
 </header>
diff --git a/cmd/coordinator/internal/dashboard/dashboard.html b/cmd/coordinator/internal/dashboard/dashboard.html
index 1d9074a..b11de13 100644
--- a/cmd/coordinator/internal/dashboard/dashboard.html
+++ b/cmd/coordinator/internal/dashboard/dashboard.html
@@ -40,7 +40,15 @@
 
 <body class="Dashboard">
 <header class="Dashboard-topbar">
-<h1>Go Dashboard</h1>
+  <h1>
+    <a href="/">Go Build Coordinator</a>
+  </h1>
+  <nav>
+    <ul>
+      <li><a href="/dashboard">Dashboard</a></li>
+      <li><a href="/builders">Builders</a></li>
+    </ul>
+  </nav>
 </header>
 
 <form action="../.." method="GET">
diff --git a/cmd/coordinator/internal/legacydash/static/style.css b/cmd/coordinator/internal/legacydash/static/style.css
index 34c6603..b651569 100644
--- a/cmd/coordinator/internal/legacydash/static/style.css
+++ b/cmd/coordinator/internal/legacydash/static/style.css
@@ -69,19 +69,31 @@
   background: #E0EBF5;
 }
  
-#topbar a {
-  color: #222;
-}
 #topbar h1 {
-  float: left;
+  display: inline;
   margin: 0;
   padding-top: 5px;
 }
+#topbar h1 a {
+  color: #375EAB;
+  text-decoration: none;
+}
+#topbar h1 a:hover {
+  text-decoration: underline;
+}
  
 #topbar nav { 
-  float: left;
+  display: inline-block;
   margin-left: 20px;
 }
+#topbar nav ul {
+  list-style: none;
+  margin: 0;
+  padding: 0;
+}
+#topbar nav ul li {
+  display: inline-block;
+}
 #topbar nav a {
   display: inline-block;
   padding: 10px;
diff --git a/cmd/coordinator/internal/legacydash/ui.html b/cmd/coordinator/internal/legacydash/ui.html
index 3ff7ac8..952fc43 100644
--- a/cmd/coordinator/internal/legacydash/ui.html
+++ b/cmd/coordinator/internal/legacydash/ui.html
@@ -20,7 +20,15 @@
 
   <body>
     <header id="topbar">
-      <h1>Go Dashboard</h1>
+      <h1>
+        <a href="https://farmer.golang.org/">Go Build Coordinator</a>
+      </h1>
+      <nav>
+        <ul>
+          <li><a href="/">Dashboard</a></li>
+          <li><a href="https://farmer.golang.org/builders">Builders</a></li>
+        </ul>
+      </nav>
       <div class="clear"></div>
     </header>
 
diff --git a/cmd/coordinator/status.go b/cmd/coordinator/status.go
index be7278c..1228747 100644
--- a/cmd/coordinator/status.go
+++ b/cmd/coordinator/status.go
@@ -852,10 +852,14 @@
 <head><link rel="stylesheet" href="/style.css"/><title>Go Farmer</title></head>
 <body>
 <header>
-	<h1>Go Build Coordinator</h1>
+	<h1>
+		<a href="/">Go Build Coordinator</a>
+	</h1>
 	<nav>
-		<a href="https://build.golang.org">Dashboard</a>
-		<a href="/builders">Builders</a>
+		<ul>
+			<li><a href="https://build.golang.org/">Dashboard</a></li>
+			<li><a href="/builders">Builders</a></li>
+		</ul>
 	</nav>
 	<div class="clear"></div>
 </header>
diff --git a/cmd/coordinator/style.css b/cmd/coordinator/style.css
index da98275..ec18158 100644
--- a/cmd/coordinator/style.css
+++ b/cmd/coordinator/style.css
@@ -49,18 +49,26 @@
   margin: -10px -10px 0 -10px;
   padding: 10px 10px;
 }
-header a {
-  color: #222;
-}
 header h1 {
   display: inline;
   margin: 0;
   padding-top: 5px;
 }
+header h1 a {
+  display: initial;
+}
 header nav {
   display: inline-block;
   margin-left: 20px;
 }
+header nav ul {
+  list-style: none;
+  margin: 0;
+  padding: 0;
+}
+header nav ul li {
+  display: inline-block;
+}
 header nav a {
   background: #375eab;
   border: 1px solid #375eab;
@@ -98,7 +106,7 @@
 }
 .Dashboard-topbar {
   margin: 0;
-  padding: 1rem 0.625rem;
+  padding: 0.625rem 0.625rem;
 }
 table.Build tbody tr:nth-child(even) {
   background-color: #f4f4f4;