:root {
  color-scheme: light;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --bg: #f7f7f8;
  --surface: #ffffff;
  --text: #1f2328;
  --heading: #111827;
  --muted: #4b5563;
  --subtle: #64748b;
  --border: #e5e7eb;
  --link: #2563eb;
  --topbar-bg: #111827;
  --topbar-text: #ffffff;
  --topbar-link: #dbeafe;
  --active-bg: #dbeafe;
  --active-text: #1d4ed8;
  --nav-number: #94a3b8;
  --shadow: 0 8px 24px rgb(15 23 42 / 0.05);
  --inline-code-bg: #eef2ff;
  --inline-code-text: #3730a3;
  --editor-bg: #0f172a;
  --editor-text: #e5e7eb;
  --danger: #b91c1c;
  --error: #fecaca;
  --selection: rgb(59 130 246 / 0.35);
}

@media (prefers-color-scheme: dark) {
  :root {
    color-scheme: dark;
    --bg: #0b1120;
    --surface: #111827;
    --text: #d1d5db;
    --heading: #f9fafb;
    --muted: #9ca3af;
    --subtle: #94a3b8;
    --border: #334155;
    --link: #60a5fa;
    --topbar-bg: #020617;
    --topbar-text: #f8fafc;
    --topbar-link: #bfdbfe;
    --active-bg: #1e3a8a;
    --active-text: #bfdbfe;
    --nav-number: #64748b;
    --shadow: 0 8px 24px rgb(0 0 0 / 0.25);
    --inline-code-bg: #1e293b;
    --inline-code-text: #bfdbfe;
    --danger: #fca5a5;
  }
}

body {
  background: var(--bg);
  color: var(--text);
  margin: 0;
}

a {
  color: var(--link);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

.topbar {
  align-items: center;
  background: var(--topbar-bg);
  color: var(--topbar-text);
  display: flex;
  height: 56px;
  justify-content: space-between;
  padding: 0 24px;
}

.brand {
  color: var(--topbar-text);
  font-size: 20px;
  font-weight: 700;
}

.topnav {
  display: flex;
  gap: 18px;
}

.topnav a {
  color: var(--topbar-link);
}

.layout {
  display: grid;
  grid-template-columns: 300px minmax(0, 1fr);
  min-height: calc(100vh - 56px);
}

.playground-layout {
  display: block;
}

.sidebar {
  background: var(--surface);
  border-right: 1px solid var(--border);
  overflow: auto;
  padding: 22px 18px;
}

.sidebar-title {
  color: var(--heading);
  display: block;
  font-weight: 700;
  margin-bottom: 12px;
}

.nav-tree {
  list-style: none;
  margin: 0;
  padding-left: 0;
}

.nav-tree .nav-tree {
  margin: 4px 0 6px 12px;
}

.nav-tree a {
  border-radius: 6px;
  color: var(--text);
  display: flex;
  font-size: 14px;
  gap: 6px;
  line-height: 1.35;
  padding: 4px 8px;
}

.nav-number {
  color: var(--nav-number);
  flex: 0 0 auto;
  font-variant-numeric: tabular-nums;
}

.nav-tree a.active {
  background: var(--active-bg);
  color: var(--active-text);
  font-weight: 600;
}

.nav-tree a.active .nav-number {
  color: var(--link);
}

main {
  min-width: 0;
  padding: 36px;
}

main.playground {
  padding: 10px;
}

.markdown {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  box-shadow: var(--shadow);
  margin: 0 auto;
  max-width: 920px;
  padding: 24px 36px 42px;
}

.markdown h1,
.markdown h2,
.markdown h3 {
  color: var(--heading);
}

.markdown pre,
.output-pane pre {
  background: var(--editor-bg);
  border-radius: 10px;
  color: var(--editor-text);
  overflow: auto;
  padding: 14px;
}

.markdown code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", monospace;
}

.markdown :not(pre) > code {
  background: var(--inline-code-bg);
  border-radius: 4px;
  color: var(--inline-code-text);
  padding: 1px 4px;
}

.markdown table {
  border-collapse: collapse;
  display: block;
  margin: 20px 0;
  overflow-x: auto;
  width: 100%;
}

.markdown th,
.markdown td {
  border: 1px solid var(--border);
  padding: 8px 10px;
  text-align: left;
  vertical-align: top;
}

.markdown th {
  background: var(--inline-code-bg);
  color: var(--heading);
  font-weight: 700;
}

.markdown tr:nth-child(even) td {
  background: color-mix(in srgb, var(--surface) 92%, var(--border));
}

.tok-keyword {
  color: #93c5fd;
  font-weight: 700;
}

.tok-type {
  color: #67e8f9;
}

.tok-literal,
.tok-number {
  color: #fbbf24;
}

.tok-string,
.tok-regex {
  color: #86efac;
}

.tok-comment {
  color: var(--nav-number);
  font-style: italic;
}

.tok-operator {
  color: #f9a8d4;
}

.playground-page {
  height: calc(100vh - 76px);
}

.playground-header {
  align-items: center;
  display: flex;
  gap: 16px;
  justify-content: space-between;
  margin-bottom: 8px;
}

.playground-header h1 {
  font-size: 20px;
  margin: 0 0 2px;
}

.playground-header p {
  color: var(--muted);
  font-size: 13px;
  margin: 0;
}

.playground-header code {
  background: var(--inline-code-bg);
  border-radius: 4px;
  color: var(--inline-code-text);
  padding: 1px 4px;
}

.playground-actions {
  align-items: center;
  display: flex;
  gap: 12px;
}

button {
  background: var(--link);
  border: 0;
  border-radius: 8px;
  color: var(--topbar-text);
  cursor: pointer;
  font-weight: 700;
  padding: 8px 14px;
}

button:disabled {
  cursor: not-allowed;
  opacity: 0.5;
}

.playground-shell {
  display: grid;
  gap: 10px;
  grid-template-columns: 220px minmax(360px, 1.25fr) minmax(320px, 1fr);
  height: calc(100% - 52px);
  min-height: 0;
}

.file-panel,
.pane {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  display: flex;
  flex-direction: column;
  min-height: 0;
  overflow: hidden;
}

.panel-header,
.pane > span {
  align-items: center;
  border-bottom: 1px solid var(--border);
  color: var(--text);
  display: flex;
  font-size: 13px;
  font-weight: 700;
  justify-content: space-between;
  min-height: 38px;
  padding: 0 10px;
  text-transform: uppercase;
}

.panel-header button {
  font-size: 12px;
  padding: 5px 8px;
  text-transform: none;
}

.file-tree {
  flex: 1;
  min-height: 0;
  overflow: auto;
  padding: 8px;
}

.file-tree ul {
  list-style: none;
  margin: 0;
  padding-left: 12px;
}

.file-tree > ul {
  padding-left: 0;
}

.file-tree li {
  margin: 2px 0;
}

.file-tree .folder {
  color: var(--subtle);
  display: block;
  font-size: 13px;
  font-weight: 700;
  padding: 4px 6px;
}

.file-tree .file {
  background: transparent;
  border-radius: 6px;
  color: var(--text);
  display: block;
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", monospace;
  font-size: 13px;
  font-weight: 500;
  padding: 5px 7px;
  text-align: left;
  width: 100%;
}

.file-tree .file:hover,
.file-tree .file.active {
  background: var(--active-bg);
  color: var(--active-text);
  text-decoration: none;
}

.danger-button {
  background: transparent;
  border-top: 1px solid var(--border);
  border-radius: 0;
  color: var(--danger);
  padding: 9px 10px;
  text-align: left;
}

.editor-wrap {
  background: var(--editor-bg);
  flex: 1;
  min-height: 0;
  position: relative;
}

.editor-wrap pre,
.editor-wrap textarea {
  border: 0;
  box-sizing: border-box;
  font: 14px/1.5 ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", monospace;
  inset: 0;
  margin: 0;
  overflow: auto;
  padding: 12px;
  position: absolute;
  tab-size: 2;
  white-space: pre;
}

.editor-wrap pre {
  color: var(--editor-text);
  pointer-events: none;
}

.editor-wrap textarea {
  background: transparent;
  caret-color: var(--editor-text);
  color: transparent;
  outline: none;
  resize: none;
  width: 100%;
}

.editor-wrap textarea::selection {
  background: var(--selection);
}

.output-pane pre {
  border-radius: 0;
  flex: 1;
  margin: 0;
}

.output-pane pre.error {
  color: var(--error);
}

.status {
  color: var(--muted);
  font-size: 13px;
  margin: 0;
  white-space: nowrap;
}

@media (max-width: 900px) {
  .layout {
    grid-template-columns: 1fr;
  }
  .sidebar {
    border-bottom: 1px solid var(--border);
    border-right: 0;
    max-height: 260px;
  }
  .playground-shell {
    grid-template-columns: 1fr;
  }
}