:root {
  --bg: #0d1117;
  --bg-elev: #161b22;
  --card: #1c2333;
  --card-hover: #232c42;
  --border: #2a3344;
  --text: #f0f3f8;
  --text-dim: #9aa5b8;
  --accent: #ffb547;
  --accent-2: #6ea8ff;
  --danger: #ff6b6b;
  --good: #4ade80;
  --maxw: 880px;
  --radius: 16px;
}

* { box-sizing: border-box; -webkit-tap-highlight-color: transparent; }

html { scroll-behavior: smooth; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', sans-serif;
  font-size: 17px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  -webkit-text-size-adjust: 100%;
  word-wrap: break-word;
}

a { color: var(--accent-2); text-decoration: none; }
a:hover { text-decoration: underline; }
a:active { opacity: 0.7; }

img { max-width: 100%; height: auto; }

.container {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 20px 18px 80px;
}

header.site {
  border-bottom: 1px solid var(--border);
  background: radial-gradient(circle at top, rgba(110,168,255,0.08), transparent 60%), linear-gradient(180deg, #0d1117 0%, #161b22 100%);
}

header.site .container {
  padding-top: 32px;
  padding-bottom: 32px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--text);
  font-weight: 700;
  font-size: 16px;
  letter-spacing: 0.3px;
  margin-bottom: 6px;
}

.brand .icon {
  width: 32px; height: 32px;
  display: inline-flex; align-items: center; justify-content: center;
  background: var(--accent);
  color: #1a1a1a;
  border-radius: 8px;
  font-size: 18px;
}

h1 {
  font-size: clamp(26px, 6vw, 38px);
  line-height: 1.25;
  margin: 18px 0 12px;
  font-weight: 800;
  letter-spacing: -0.5px;
}

h2 {
  font-size: clamp(20px, 4.5vw, 26px);
  margin: 36px 0 14px;
  line-height: 1.3;
  font-weight: 700;
}

h3 {
  font-size: clamp(17px, 3.8vw, 20px);
  margin: 28px 0 10px;
  color: var(--accent);
  font-weight: 700;
  line-height: 1.35;
}

p { margin: 12px 0; }

.lead {
  font-size: clamp(15px, 3.5vw, 17px);
  color: var(--text-dim);
  margin-bottom: 22px;
  max-width: 680px;
}

.meta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 12px;
}

.chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 6px 12px;
  font-size: 13px;
  color: var(--text-dim);
}

.section-title {
  margin-top: 36px;
  margin-bottom: 12px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border);
}

.section-title .num {
  display: block;
  color: var(--accent);
  font-weight: 700;
  font-size: 12px;
  letter-spacing: 2px;
  margin-bottom: 4px;
}

.section-title h2 {
  margin: 0;
  font-size: clamp(19px, 4.5vw, 24px);
}

.topic-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 10px;
  margin: 14px 0;
}

@media (min-width: 640px) {
  .topic-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
  }
}

.topic-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 16px 14px;
  display: block;
  color: var(--text);
  transition: background 0.15s ease, border-color 0.15s ease, transform 0.1s ease;
  min-height: 88px;
  position: relative;
}

.topic-card:hover {
  text-decoration: none;
  background: var(--card-hover);
  border-color: var(--accent);
}

.topic-card:active {
  transform: scale(0.985);
}

.topic-card .head {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 6px;
}

.topic-card .emoji {
  font-size: 22px;
  line-height: 1;
}

.topic-card .num {
  font-size: 11px;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: 1.5px;
  background: rgba(255,181,71,0.12);
  padding: 3px 8px;
  border-radius: 6px;
}

.topic-card .title {
  font-size: 15.5px;
  font-weight: 600;
  line-height: 1.4;
  color: var(--text);
}

.topic-card .status {
  margin-top: 8px;
  font-size: 12px;
  color: var(--text-dim);
}

.topic-card.ready .status { color: var(--good); }

.back {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--text-dim);
  margin-bottom: 8px;
  font-size: 15px;
  padding: 8px 0;
}
.back:hover { color: var(--accent); text-decoration: none; }

article.topic {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px 20px 26px;
  margin-top: 8px;
}

article.topic h1 {
  margin-top: 6px;
  font-size: clamp(24px, 5.5vw, 32px);
}

article.topic .tagline {
  color: var(--text-dim);
  font-size: clamp(14px, 3.5vw, 16px);
  margin-bottom: 14px;
}

.callout {
  border-left: 4px solid var(--accent);
  background: rgba(255,181,71,0.07);
  padding: 14px 16px;
  border-radius: 0 10px 10px 0;
  margin: 18px 0;
  font-size: 15.5px;
}

.callout.danger {
  border-left-color: var(--danger);
  background: rgba(255,107,107,0.08);
}

.callout.good {
  border-left-color: var(--good);
  background: rgba(74,222,128,0.08);
}

.callout p:first-child { margin-top: 0; }
.callout p:last-child { margin-bottom: 0; }

table {
  width: 100%;
  border-collapse: collapse;
  margin: 16px 0;
  font-size: 15px;
  display: block;
  overflow-x: auto;
}

table th, table td {
  text-align: left;
  padding: 10px 12px;
  border-bottom: 1px solid var(--border);
  white-space: nowrap;
}

table th {
  background: var(--card);
  color: var(--accent);
  font-weight: 600;
}

ul, ol {
  padding-left: 22px;
  margin: 12px 0;
}

ul li, ol li {
  margin: 8px 0;
  line-height: 1.65;
}

code {
  background: rgba(255,255,255,0.06);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 0.92em;
  font-family: 'JetBrains Mono', 'Fira Code', monospace;
}

strong { color: #fff; font-weight: 700; }

.hook {
  font-style: italic;
  color: var(--text);
  background: linear-gradient(135deg, rgba(110,168,255,0.12), rgba(255,181,71,0.08));
  padding: 18px 20px;
  border-radius: 14px;
  border: 1px solid var(--border);
  margin: 18px 0 22px;
  font-size: clamp(15px, 3.7vw, 17px);
  line-height: 1.6;
}

.tip {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 14px 16px;
  margin: 14px 0;
  font-size: 15px;
}

.tip .label {
  font-weight: 700;
  color: var(--accent);
  font-size: 11px;
  letter-spacing: 1.5px;
  margin-bottom: 6px;
}

.fact-box {
  display: grid;
  gap: 8px;
  margin: 14px 0;
}

.fact {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 10px 14px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 14px;
  font-size: 15px;
}

.fact .v { font-weight: 700; color: var(--accent); font-size: 16px; white-space: nowrap; }
.fact .l { color: var(--text-dim); font-size: 14px; }

.toc {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 14px 16px;
  margin: 16px 0;
}

.toc-title {
  font-size: 12px;
  letter-spacing: 1.5px;
  color: var(--accent);
  font-weight: 700;
  margin-bottom: 8px;
}

.toc ol {
  margin: 0;
  padding-left: 20px;
}

.toc ol li { margin: 4px 0; }

.toc a { color: var(--text); }

footer.site {
  border-top: 1px solid var(--border);
  color: var(--text-dim);
  font-size: 14px;
  padding: 24px 0 32px;
  margin-top: 50px;
  text-align: center;
}

@media (max-width: 480px) {
  .container { padding: 14px 14px 60px; }
  article.topic { padding: 18px 16px 22px; border-radius: 12px; }
  .topic-card { padding: 14px 14px 12px; }
  .hook { padding: 16px 16px; }
  h1 { font-size: 24px; }
  .topic-card .title { font-size: 15px; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}