Implement most of the remaining layout changes

Includes the mobile UX optimizations and the tweaks we've made to cut down on wasted space, but does not yet include the change to embed the spotlight tile within the grid.

src/tile/GridTile.module.css

@@ -22,7 +22,7 @@ limitations under the License.
 
 /* Use a pseudo-element to create the expressive speaking border, since CSS
 borders don't support gradients */
-.tile[data-maximised="false"]::before {
+.tile::before {
   content: "";
   position: absolute;
   z-index: -1; /* Put it below the outline */
@@ -43,27 +43,22 @@ borders don't support gradients */
   background-blend-mode: overlay, normal;
 }
 
-.tile[data-maximised="false"].speaking {
+.tile.speaking {
   /* !important because speaking border should take priority over hover */
   outline: var(--cpd-border-width-1) solid var(--cpd-color-bg-canvas-default) !important;
 }
 
-.tile[data-maximised="false"].speaking::before {
+.tile.speaking::before {
   opacity: 1;
 }
 
 @media (hover: hover) {
-  .tile[data-maximised="false"]:hover {
+  .tile:hover {
     outline: var(--cpd-border-width-2) solid
       var(--cpd-color-border-interactive-hovered);
   }
 }
 
-.tile[data-maximised="true"] {
-  --media-view-border-radius: 0;
-  --media-view-fg-inset: 10px;
-}
-
 .muteIcon[data-muted="true"] {
   color: var(--cpd-color-icon-secondary);
 }