:root { color-scheme: dark light; }
* { box-sizing: border-box; }
body { margin: 0; font-family: system-ui, -apple-system, Segoe UI, Roboto, Arial, sans-serif; }
.wrap { max-width: 1100px; margin: 0 auto; padding: 16px; }

.topbar { position: sticky; top: 0; backdrop-filter: blur(10px); border-bottom: 1px solid rgba(0,0,0,.12); }
.topbar-inner { display: flex; align-items: center; justify-content: space-between; gap: 12px; }
.brand { font-weight: 700; }

.actions { display: flex; gap: 8px; flex-wrap: wrap; }
.btn {
  display: inline-block; padding: 8px 12px; border-radius: 10px;
  border: 1px solid rgba(0,0,0,.18); text-decoration: none; color: inherit;
}
.btn.primary { border-color: rgba(0,0,0,.35); font-weight: 600; }
.btn:hover { opacity: .9; }

.layout { display: grid; grid-template-columns: 260px 1fr; gap: 16px; }
@media (max-width: 900px) { .layout { grid-template-columns: 1fr; } .toc { order: 2; } }

.toc { border: 1px solid rgba(0,0,0,.12); border-radius: 16px; padding: 12px; }
.toc-title { font-weight: 700; margin-bottom: 8px; }
.toc ul { list-style: none; padding-left: 0; margin: 0; display: grid; gap: 6px; }
.toc li.h3 { padding-left: 12px; opacity: .9; }
.toc a { text-decoration: none; color: inherit; border-bottom: 1px dotted transparent; }
.toc a:hover { border-bottom-color: currentColor; }

.content { border: 1px solid rgba(0,0,0,.12); border-radius: 16px; padding: 18px; }
.content img { max-width: 100%; border-radius: 12px; }
.content table { width: 100%; border-collapse: collapse; overflow: hidden; border-radius: 12px; }
.content th, .content td { border: 1px solid rgba(0,0,0,.14); padding: 8px; text-align: left; }

.muted { opacity: .7; }
.editor-actions { display: flex; align-items: center; gap: 12px; margin: 10px 0 16px; }