Rename surround-thumbnails to just surround.

src/scss/surround-basic.scss

@@ -0,0 +1,21 @@
+:host {
+  width: 100%;
+  height: 100%;
+
+  // Share the screen space with thumbnails that may be above/below.
+  display: flex;
+  flex-direction: column;
+
+  // Set the drawer relative to this host.
+  position: relative;
+
+  // Hide any content outside the main pane (e.g. side drawers) to ensure the
+  // user cannot scroll across to the drawers without opening them.
+  overflow: hidden;
+}
+
+::slotted:not([name]) {
+  // Expand the main body to fill available content not otherwise used by the
+  // surround.
+  flex: 1;
+}

src/scss/surround-thumbnails.scss

@@ -1,5 +0,0 @@
-:host {
-  width: 100%;
-  height: 100%;
-  display: block;
-}

src/scss/surround.scss

@@ -1,21 +1,5 @@
 :host {
   width: 100%;
   height: 100%;
-
-  // Share the screen space with thumbnails that may be above/below.
-  display: flex;
-  flex-direction: column;
-
-  // Set the drawer relative to this host.
-  position: relative;
-
-  // Hide any content outside the main pane (e.g. side drawers) to ensure the
-  // user cannot scroll across to the drawers without opening them.
-  overflow: hidden;
-}
-
-::slotted:not([name]) {
-  // Expand the main body to fill available content not otherwise used by the
-  // surround.
-  flex: 1;
-}
+  display: block;
+}

src/scss/timeline-core.scss

@@ -60,7 +60,7 @@ div.timeline {
 // ensure the background (recordings) always span the full height. Otherwise, in
 // cases where there are no events, the background is incorrectly rendered too
 // short by visjs.
-:host:not([groups]) .vis-item.vis-background {
+:host(:not([groups])) .vis-item.vis-background {
   min-height: 100%;
 }