Fix sticky headers so they don't hide behind header bar on desktop

scripts/css/basic.css

@@ -465,12 +465,24 @@ dl.glossary dt {
 /* -- proposals page -------------------------------------------------------- */
 
 #tables-of-tracked-proposals h2 {
-  margin-top: 7px;
     padding-left: 10px;
     position: -webkit-sticky;
     position: sticky;
+}
+
+/* Move sticky headers below header bar on desktop */
+@media all and (min-width:980px) {
+    #tables-of-tracked-proposals h2 {
+        top: 52px;
+    }
+}
+
+/* Sticky headers stick to the top on mobile */
+@media all and (min-width:0px) and (max-width: 980px) {
+    #tables-of-tracked-proposals h2 {
         top: 0px;
     }
+}
 
 /* -- code displays --------------------------------------------------------- */