simplify style sheet

content/common/kwant.css

-/*
-Style sheet for http://kwant-project.org/
-*/
-
 @import url(html4css1.css);
 
 body {
@@ -11,17 +7,29 @@ body {
     font-family: "Bitstream Vera Serif",  Georgia, serif;
 }
 
-#header { margin-top: 0.5em; height: 150px; }
+ul.navigation{
+    display: block;
+    text-align: center;
+    padding: 0;
+}
+
+ul.navigation li{
+    display: inline;
+    margin: 0 0.5em;
+}
+
+.hidden_structure h1, h2, h3, h4, h5, h6 {
+    display: none;
+}
+
+#header { margin-top: 0.5em; }
 #footer { margin: 2em 0; }
 #header, #header a:link, #header a:visited, #footer {
     color: gray;
-    font-family: "Bitstream Vera Sans",  Verdana, sans-serif;
 }
 #header a:hover { color: black }
 
 h1, h2, h3, h4, h5, h6 {
-    line-height: 1.4em;
-    text-align: left;
     font-family: "Bitstream Vera Sans",  Verdana, sans-serif;
 }
 
@@ -29,46 +37,13 @@ li {
     margin: 0.3em 0
 }
 
-pre, code { background-color: #eee; border: 1px solid #ccc; }
-pre { padding: 0.3em; }
-code { padding: 0 0.1em; }
-pre > code { border: none; padding: 0; }
-
 img {
     display: block;
     margin-left: auto;
     margin-right: auto;
 }
 
-img.left {
-    float: left;
-    margin: 2em;
-    clear: both;
-}
-
-img.right {
-    float: right;
-    margin: 2em;
-    clear: both;
-}
-
-p.center {
-  text-align: center;
-}
-
-/* Navigation */
-ul.navigation{
-display:block;
-text-align:center;
-margin:20;
-padding:0;
-}
-
-ul.navigation li{
-display:inline;
-padding:0 10px;
-}
-
-.hidden_structure h1, h2, h3, h4, h5, h6 {
-    display: none;
-}
+pre, code { background-color: #eee; border: 1px solid #ccc; }
+pre { padding: 0.3em; }
+code { padding: 0 0.1em; }
+pre > code { border: none; padding: 0; }