fix(web): add background and border to popover content

- Add padding, border, border-radius, and background to popover .content
- Fixes popover appearing invisible without background styling

Author: pallyoung

packages/web/src/components/ui/popover/index.module.css

@@ -12,4 +12,8 @@
   overflow: auto;
   outline: none;
   z-index: var(--z-modal);
+  padding: var(--sp-3);
+  border: 1px solid var(--border);
+  border-radius: var(--radius-lg);
+  background: var(--bg-surface);
 }