Some work on the tool menu styles.

Highlighting the background of items was added at some point, but did
not extend to fill the entire width and was not applied to the section
elements. This attempts to make things a bit more visually appealing
and consistent.

Additionally there are some debatable changes:

- Removed the indent for items, I think it is clear from the size and
  weight changes
- Remove underlines, the background highlight is an equally good
  indicator that these are clickable
- Top level labels are now large like the sections, second level
  returns to the default font size

client/galaxy/scripts/entry/panels/tool-panel.js

@@ -141,9 +141,9 @@ const ToolPanel = Backbone.View.extend({
                     <div class="toolSectionPad"/>
                     <div class="toolSectionPad"/>
                     <div class="toolSectionTitle" id="title_XXinternalXXworkflow">
-                        <span>
+                        <a>
                             ${_l("Workflows")}
-                        </span>
+                        </a>
                     </div>
                         <div id="internal-workflows" class="toolSectionBody">
                             <div class="toolSectionBg"/>

client/galaxy/style/scss/base.scss

@@ -1477,11 +1477,10 @@ div.permissionContainer {
 .toolMenuContainer {
     color: $panel-text-color;
     a {
-        color: $panel-text-color;
+	color: $panel-text-color;
     }
     background: $panel-bg-color;
     min-height: 100%;
-    @extend .m-3;
 }
 
 div.toolSectionWrapper {
@@ -1491,35 +1490,46 @@ div.toolSectionWrapper {
 div.toolSectionTitle {
     font-weight: 500;
     font-size: $h4-font-size;
-}
-
-div.toolPanelLabel {
-    @extend .mt-3;
-    @extend .mb-2;
-    font-weight: bold;
-    color: $gray-600;
-    text-transform: uppercase;
-}
-
-div.toolTitle {
-    @extend .m-2;
-    display: block;
-    .labels {
-        float: right;
-    }
-}
-
-div a.tool-link {
-    text-decoration: none;
-    display: block;
-    span.tool-old-link {
-        text-decoration: underline;
-    }
     &:hover {
         background: darken($panel-bg-color, 5%);
     }
 }
 
+div.toolPanelLabel {
+    @extend .mt-3;
+    @extend .mb-2;
+    @extend .px-3;
+    font-weight: bold;
+    font-size: $h4-font-size;
+    color: $gray-600;
+    text-transform: uppercase;
+}
+
+div.toolSectionWrapper div.toolPanelLabel {
+    font-size: inherit;
+}
+
+div.toolSectionTitle, div.toolTitle {
+    display: block;
+    .labels {
+        float: right;
+    }
+
+    a {
+	@extend .px-3;
+	@extend .py-1;
+	text-decoration: none;
+	display: block;
+	span.tool-old-link {
+	    font-weight: 500;
+            // text-decoration: underline;
+	}
+	&:hover {
+            background: darken($panel-bg-color, 5%);
+	}
+    }
+}
+    
 div.toolTitleNoSection {
     @extend .pb-1;
     font-weight: bold;