Improve item visual separation in full(er) log view.

- Add shading to the commit header to make it easier to identify commit
  boundaries in a long list of verbose commit data.
- Disable hover highlighting on verbose commit logs, since that served a
  similar pupose of visual separation.

Change-Id: I0d388d2ccaf9655c612fc2a5e27f229d38d3825f

gitiles-servlet/src/main/resources/com/google/gitiles/static/gitiles.css

diff --git a/gitiles-servlet/src/main/resources/com/google/gitiles/static/gitiles.css b/gitiles-servlet/src/main/resources/com/google/gitiles/static/gitiles.css
index f1d5326..25c0754 100644
--- a/gitiles-servlet/src/main/resources/com/google/gitiles/static/gitiles.css
+++ b/gitiles-servlet/src/main/resources/com/google/gitiles/static/gitiles.css
@@ -189,10 +189,6 @@
   margin: 0;
 }
 
-ol.log ul.diff-tree {
-  margin-left: 2em;
-  padding: 5px 0 5px 0;
-}
 ul.diff-tree {
   border-top: #ddd solid 1px; /* BORDER */
   font-size: 9pt;
@@ -278,17 +274,25 @@
   padding-bottom: 2px;
 }
 ol.full.log > li, ol.fuller.log > li {
+  padding-top: 0;
   padding-bottom: 5px;
 }
+ol.full.log .git-commit, ol.fuller.log .git-commit {
+  background: #eee;
+}
 ol.log > li.first {
   border-top: #ddd solid 1px; /* BORDER */
 }
-ol.log > li:hover {
+ol.default.log > li:hover, ol.oneline.log > li:hover {
   background: #eee; /* HOVER_BACKGROUND */
 }
 ol.log span.sha1 {
   font-family: monospace;
 }
+ol.log ul.diff-tree {
+  margin-left: 2em;
+  padding: 5px 0 5px 0;
+}
 .log-nav {
   margin-top: 5px;
   text-align: center;