.assist-theme-control {
  display: inline-flex; align-items: center; justify-content: center;
  width: 40px; height: 40px; padding: 8px; margin-bottom: 12px;
  border: 1px solid var(--border); border-radius: 50%;
  color: var(--text-secondary); background: var(--bg-card); cursor: pointer;
}
.assist-theme-control svg { width: 20px; height: 20px; fill: none; stroke: currentColor; stroke-width: 1.7; stroke-linecap: round; stroke-linejoin: round; }
.assist-theme-control:hover { color: var(--accent-text); border-color: var(--accent); }
.assist-theme-control:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; }
body > .assist-theme-control { position: fixed; top: 16px; right: 16px; z-index: 90; }
@media (max-width: 768px) { .assist-theme-control { width: 44px; height: 44px; } }