opencode/packages/ui/src/components/dock-surface.css

[data-dock-surface="shell"] {
  background-color: var(--surface-raised-stronger-non-alpha);
  box-shadow: var(--shadow-xs-border);
  position: relative;
  z-index: 10;
  border-radius: 12px;
  overflow: clip;
}

[data-dock-surface="tray"] {
  background-color: var(--background-base);
  border: 1px solid var(--border-weak-base);
  position: relative;
  z-index: 0;
  border-radius: 12px;
  overflow: clip;
}

[data-dock-surface="tray"][data-dock-attach="top"] {
  margin-top: -0.875rem;
  border-top-left-radius: 0;
  border-top-right-radius: 0;
}