:root {
  --bg: #0f0f0f;
  --bg2: #1a1a1a;
  --bg3: #222222;
  --border: #2e2e2e;
  --text: #e8e8e8;
  --text-muted: #888;
  --accent: #c0392b;
  --accent-light: #e74c3c;
  --accent-dim: rgba(192, 57, 43, 0.15);
  --link: #e67e73;
  --sidebar-w: 260px;
  --header-h: 56px;
  --radius: 6px;
  --font: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  font-size: 15px;ㄱ
}

a { color: var(--link); text-decoration: none; }
a:hover { text-decoration: underline; color: var(--accent-light); }

/* ── Header ── */
header {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--header-h);
  background: var(--bg2);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  padding: 0 20px;
  gap: 16px;
  z-index: 100;
}

.logo {
  font-size: 18px;
  font-weight: 700;
  color: var(--accent-light);
  letter-spacing: -0.3px;
  white-space: nowrap;
}
.logo span { color: var(--text-muted); font-weight: 400; }

.search-bar {
  flex: 1;
  max-width: 480px;
  position: relative;
}
.search-bar input {
  width: 100%;
  background: var(--bg3);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 7px 16px;
  color: var(--text);
  font-size: 13px;
  outline: none;
  transition: border-color 0.2s;
}
.search-bar input:focus { border-color: var(--accent); }
.search-bar .icon {
  position: absolute;
  left: 12px; top: 50%;
  transform: translateY(-50%);
  color: var(--text-muted);
  font-size: 13px;
}
#search-results {
  position: absolute;
  top: calc(100% + 6px);
  left: 0; right: 0;
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  max-height: 320px;
  overflow-y: auto;
  display: none;
  z-index: 200;
}
#search-results.show { display: block; }
#search-results .result-item {
  padding: 10px 14px;
  cursor: pointer;
  border-bottom: 1px solid var(--border);
}
#search-results .result-item:last-child { border-bottom: none; }
#search-results .result-item:hover { background: var(--bg3); }
#search-results .result-item .r-title { font-weight: 600; font-size: 13px; }
#search-results .result-item .r-cat { font-size: 11px; color: var(--text-muted); margin-top: 2px; }

.visitor-count {
  font-size: 12px;
  color: var(--text-muted);
  white-space: nowrap;
  flex-shrink: 0;
}
.visitor-count span { color: var(--text); font-weight: 600; }

nav.top-nav {
  display: flex;
  gap: 4px;
  margin-left: auto;
}
nav.top-nav a {
  padding: 6px 12px;
  border-radius: 4px;
  font-size: 13px;
  color: var(--text-muted);
  white-space: nowrap;
  transition: background 0.15s, color 0.15s;
}
nav.top-nav a:hover, nav.top-nav a.active {
  background: var(--accent-dim);
  color: var(--accent-light);
  text-decoration: none;
}

/* ── Layout ── */
.layout {
  display: flex;
  padding-top: var(--header-h);
  min-height: 100vh;
}

/* ── Sidebar ── */
aside {
  width: var(--sidebar-w);
  flex-shrink: 0;
  position: fixed;
  top: var(--header-h);
  bottom: 0;
  left: 0;
  overflow-y: auto;
  background: var(--bg2);
  border-right: 1px solid var(--border);
  padding: 16px 0;
}
aside::-webkit-scrollbar { width: 4px; }
aside::-webkit-scrollbar-thumb { background: var(--border); border-radius: 2px; }

.sidebar-section { margin-bottom: 8px; }
.sidebar-section-title {
  padding: 6px 16px;
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 1px;
  text-transform: uppercase;
  color: var(--text-muted);
}
.sidebar-section ul { list-style: none; }
.sidebar-section ul li a {
  display: block;
  padding: 6px 16px 6px 20px;
  font-size: 13px;
  color: var(--text-muted);
  border-left: 2px solid transparent;
  transition: all 0.15s;
}
.sidebar-section ul li a:hover {
  color: var(--text);
  background: var(--bg3);
  text-decoration: none;
}
.sidebar-section ul li a.active {
  color: var(--accent-light);
  border-left-color: var(--accent);
  background: var(--accent-dim);
}

/* ── Main ── */
main {
  margin-left: var(--sidebar-w);
  flex: 1;
  padding: 40px 60px;
  max-width: 900px;
}

/* ── Page ── */
.page { display: none; }
.page.active { display: block; }

/* ── Article ── */
.article-header { margin-bottom: 32px; border-bottom: 1px solid var(--border); padding-bottom: 24px; }
.article-header .category-tag {
  display: inline-block;
  background: var(--accent-dim);
  color: var(--accent-light);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  padding: 3px 10px;
  border-radius: 3px;
  margin-bottom: 12px;
}
.article-header h1 {
  font-size: 32px;
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.5px;
  margin-bottom: 12px;
}
.article-header .subtitle {
  font-size: 16px;
  color: var(--text-muted);
  line-height: 1.5;
}
.article-meta {
  display: flex;
  gap: 16px;
  margin-top: 16px;
  font-size: 12px;
  color: var(--text-muted);
}
.article-meta span { display: flex; align-items: center; gap: 4px; }

.toc {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 20px;
  margin-bottom: 32px;
}
.toc-title { font-size: 12px; font-weight: 700; color: var(--text-muted); text-transform: uppercase; letter-spacing: 0.5px; margin-bottom: 8px; }
.toc ol { padding-left: 18px; }
.toc ol li { margin: 4px 0; }
.toc ol li a { font-size: 13px; color: var(--link); }

h2 {
  font-size: 22px;
  font-weight: 700;
  margin: 40px 0 16px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border);
  color: var(--text);
}
h3 { font-size: 17px; font-weight: 600; margin: 28px 0 12px; color: var(--text); }
p { margin-bottom: 16px; color: #ccc; }
ul, ol { padding-left: 24px; margin-bottom: 16px; }
ul li, ol li { margin: 6px 0; color: #ccc; }
strong { color: var(--text); }

blockquote {
  border-left: 3px solid var(--accent);
  padding: 12px 20px;
  background: var(--accent-dim);
  border-radius: 0 var(--radius) var(--radius) 0;
  margin: 24px 0;
  font-style: italic;
  color: #ddd;
}

.callout {
  border-radius: var(--radius);
  padding: 16px 20px;
  margin: 60px 0 32px;
  display: flex;
  gap: 12px;
}
.callout.info { background: rgba(52, 152, 219, 0.12); border: 1px solid rgba(52, 152, 219, 0.3); }
.callout.warning { background: rgba(243, 156, 18, 0.12); border: 1px solid rgba(243, 156, 18, 0.3); }
.callout.danger { background: rgba(192, 57, 43, 0.15); border: 1px solid rgba(192, 57, 43, 0.4); }
.callout.success { background: rgba(39, 174, 96, 0.12); border: 1px solid rgba(39, 174, 96, 0.3); }
.callout-icon { font-size: 18px; flex-shrink: 0; margin-top: 1px; }
.callout-body .callout-title { font-weight: 700; font-size: 13px; margin-bottom: 4px; }
.callout.info .callout-title { color: #5dade2; }
.callout.warning .callout-title { color: #f0b429; }
.callout.danger .callout-title { color: var(--accent-light); }
.callout.success .callout-title { color: #58d68d; }
.callout-body p { margin: 0; font-size: 13px; }

.tag-list { display: flex; flex-wrap: wrap; gap: 8px; margin: 20px 0; }
.tag {
  background: var(--bg3);
  border: 1px solid var(--border);
  color: var(--text-muted);
  font-size: 12px;
  padding: 3px 10px;
  border-radius: 20px;
  cursor: pointer;
  transition: all 0.15s;
}
.tag:hover { border-color: var(--accent); color: var(--accent-light); }

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 16px;
  margin: 24px 0;
}
.card {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  cursor: pointer;
  transition: border-color 0.2s, transform 0.1s;
}
.card:hover { border-color: var(--accent); transform: translateY(-2px); }
.card-icon { font-size: 24px; margin-bottom: 10px; }
.card-title { font-weight: 700; font-size: 14px; margin-bottom: 6px; }
.card-desc { font-size: 12px; color: var(--text-muted); line-height: 1.5; }

.glossary-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
  margin: 20px 0;
}
.glossary-item {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 20px;
}
.glossary-item dt {
  font-weight: 700;
  font-size: 15px;
  color: var(--accent-light);
  margin-bottom: 6px;
}
.glossary-item dd { font-size: 13px; color: #ccc; line-height: 1.6; }

.alphabet-nav {
  display: flex; flex-wrap: wrap; gap: 6px; margin: 16px 0 24px;
}
.alphabet-nav button {
  background: var(--bg3);
  border: 1px solid var(--border);
  color: var(--text-muted);
  width: 32px; height: 32px;
  border-radius: 4px;
  cursor: pointer;
  font-size: 13px;
  transition: all 0.15s;
}
.alphabet-nav button:hover, .alphabet-nav button.active {
  background: var(--accent-dim);
  border-color: var(--accent);
  color: var(--accent-light);
}

table {
  width: 100%;
  border-collapse: collapse;
  margin: 20px 0;
  font-size: 13px;
}
th {
  background: var(--bg2);
  padding: 10px 14px;
  text-align: left;
  font-weight: 600;
  border-bottom: 2px solid var(--border);
  color: var(--text-muted);
  text-transform: uppercase;
  font-size: 11px;
  letter-spacing: 0.5px;
}
td {
  padding: 10px 14px;
  border-bottom: 1px solid var(--border);
  color: #ccc;
}
tr:hover td { background: var(--bg2); }

.badge {
  display: inline-block;
  padding: 2px 8px;
  border-radius: 3px;
  font-size: 11px;
  font-weight: 600;
}
.badge-red { background: rgba(192,57,43,0.2); color: #e74c3c; }
.badge-green { background: rgba(39,174,96,0.2); color: #58d68d; }
.badge-blue { background: rgba(52,152,219,0.2); color: #5dade2; }

/* ── Home page ── */
.hero {
  padding: 16px 0 8px;
  margin-bottom: 16px;
}
.hero h1 {
  font-size: 40px;
  font-weight: 800;
  letter-spacing: -1px;
  line-height: 1.1;
  margin-bottom: 16px;
}
.hero h1 .accent { color: var(--accent-light); }
.hero p { font-size: 16px; color: var(--text-muted); max-width: 560px; margin-bottom: 24px; }
.hero-cta {
  display: flex; gap: 12px; flex-wrap: wrap;
}
.btn {
  padding: 9px 20px;
  border-radius: var(--radius);
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: all 0.15s;
}
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: var(--accent-light); color: #fff; text-decoration: none; }
.btn-secondary { background: var(--bg3); color: var(--text); border: 1px solid var(--border); }
.btn-secondary:hover { border-color: var(--accent); color: var(--accent-light); text-decoration: none; }

.stats-row {
  display: flex; gap: 24px; flex-wrap: wrap; margin: 32px 0;
}
.stat-box {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 24px;
  flex: 1;
  min-width: 120px;
}
.stat-box .num { font-size: 28px; font-weight: 800; color: var(--accent-light); }
.stat-box .label { font-size: 12px; color: var(--text-muted); margin-top: 2px; }

/* ── Footer ── */
footer {
  margin-left: var(--sidebar-w);
  border-top: 1px solid var(--border);
  background: var(--bg2);
}
.footer-inner {
  max-width: 900px;
  padding: 40px 60px;
}
.footer-logo {
  font-size: 20px;
  font-weight: 700;
  color: var(--accent-light);
  margin-bottom: 12px;
}
footer p {
  font-size: 12px;
  color: var(--text-muted);
  line-height: 1.7;
  margin-bottom: 20px;
}
.footer-links {
  display: flex;
  gap: 20px;
  margin-bottom: 20px;
}
.footer-links a {
  font-size: 12px;
  color: var(--text-muted);
}
.footer-links a:hover { color: var(--accent-light); }
.footer-copy {
  font-size: 11px;
  color: #555;
}

@media (max-width: 768px) {
  footer { margin-left: 0; }
  .footer-inner { padding: 32px 20px; }
}

/* ── Mobile ── */
.menu-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--text);
  font-size: 20px;
  cursor: pointer;
  padding: 4px;
}
.overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.5);
  z-index: 90;
}

@media (max-width: 768px) {
  .menu-toggle { display: block; }
  aside {
    transform: translateX(-100%);
    transition: transform 0.25s ease;
    z-index: 95;
  }
  aside.open { transform: translateX(0); }
  .overlay.show { display: block; }
  main { margin-left: 0; padding: 24px 20px; }
  nav.top-nav { display: none; }
  .hero h1 { font-size: 28px; }
  .card-grid { grid-template-columns: 1fr; }
}