:root { color-scheme: light; }
:root[data-theme="dark"] { color-scheme: dark; }
.theme-toggle { display: inline-flex; align-items: center; justify-content: center; gap: 8px; min-height: 44px; min-width: 44px; padding: 8px 12px; border: 1px solid var(--line); border-radius: 22px; background: var(--surface, var(--ground)); color: var(--fg, var(--ink)); font: inherit; font-size: 13px; font-weight: 700; cursor: pointer; }
.theme-toggle svg { width: 20px; height: 20px; flex-shrink: 0; }
.theme-toggle-track { position: relative; flex-shrink: 0; width: 40px; height: 24px; border-radius: 12px; background: var(--muted, #66786f); transition: background-color 160ms ease; }
.theme-toggle-track::after { content: ""; position: absolute; left: 2px; top: 2px; width: 20px; height: 20px; border-radius: 50%; background: var(--surface, #fff); transition: transform 160ms ease; }
.theme-toggle[aria-checked="true"] .theme-toggle-track { background: var(--accent, var(--green)); }
.theme-toggle[aria-checked="true"] .theme-toggle-track::after { transform: translateX(16px); }
.theme-toggle[aria-checked="true"] { border-color: var(--accent, var(--green)); }
.theme-toggle:focus-visible { outline: 3px solid var(--accent, var(--green)); outline-offset: 3px; }
.theme-error { padding: 12px 20px; margin: 0; background: var(--surface, var(--ground)); color: var(--fg, var(--ink)); font: 14px/1.5 sans-serif; }
@media (max-width: 700px) {
  .site-header .theme-toggle { padding-inline: 6px; }
  .site-header .theme-toggle-label { display: none; }
}
@media (prefers-reduced-motion: reduce) {
  .theme-toggle-track, .theme-toggle-track::after { transition: none; }
}