various tweaks for pages:

- support page column size, page deletion
- page deletion only enabled if has size, for now
- sorter can default to desc, tweak color for pages panel, default sort by time, descending

src/url-resources.js

@@ -199,6 +199,7 @@ class URLResources extends LitElement
     :host {
       display: flex;
       flex-direction: column;
+      height: 100%;
     }
     .notification {
       width: 100%;