add sticky header'

_sass/custom/custom.scss

@@ -81,4 +81,54 @@ code span[style*="color: red"] {
 
 code[style*="color: red"] {
   color: var(--red-color) !important;
+}
+
+// Begin UCB header fixes
+
+// If width of display is less than content-width, header is invisible
+// so no extra CSS is needed
+
+// If width of display is at least content width:
+@media (min-width: $content-width) {
+  .main-header {
+    position: fixed;  // Sticky header (stays on top as you scroll)
+    top: 0;           // Forces header on top of page
+    z-index: 1000;    // Forces header drawn on top of everything else
+  }
+
+  // Forces site title in sidebar to be flush with header
+  .side-bar {
+    top: 0;
+    left: 0;
+  }
+
+  // Add whitespace between header and start of content (site title, logo)
+  .main-content-wrap {
+    margin-top: 60px;
+  }
+
+  // Make the site title in the sidebar smaller
+  .site-title {
+    font-size: 19px !important;
+  }
+
+  // Header width should be all of display, minus sidebar
+  // Seems like JTD fixes sidebar to 15.5rem in this layout (might be wrong tho)
+  .main-header {
+    width: calc(100% - 15.5rem);
+  }
+}
+
+// If width of display is at least content+nav width
+// (i.e. whitespace on either side of site):
+@media (min-width: $content-width + $nav-width) {
+  // Set default site title in sidebar font size
+  .site-title {
+    font-size: 24px !important;
+  }
+
+  // Header should match content width (e.g. in wider.scss)
+  .main-header {
+    width: $content-width;
+  }
 }