Implement new in-call header and footer designs

src/index.css

@@ -45,6 +45,10 @@ limitations under the License.
   --stopgap-color-on-solid-accent: var(--cpd-color-bg-canvas-default);
   --stopgap-background-85: rgba(255, 255, 255, 0.85);
   --stopgap-bgColor3: #444;
+
+  /* The distance to inset non-full-width content from the edge of the window
+  along the inline axis */
+  --inline-content-inset: max(var(--cpd-space-4x), calc((100vw - 1180px) / 2));
 }
 
 .cpd-theme-dark {