:root {
  --bg: #0d1117;
  --bg-card: #161b22;
  --bg-card-hover: #1c2333;
  --border: #30363d;
  --text: #e6edf3;
  --text-secondary: #8b949e;
  --accent: #58a6ff;
  --accent-dim: #1f6feb;
  --green: #3fb950;
  --orange: #d2991d;
  --red: #f85149;
  --purple: #a371f7;
  --font-mono: 'SF Mono', 'Fira Code', 'Cascadia Code', 'JetBrains Mono', 'Consolas', monospace;
  --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
}
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

nav {
  border-bottom: 1px solid var(--border);
  background: rgba(13,17,23,0.92);
  backdrop-filter: blur(12px);
  position: sticky; top: 0; z-index: 10;
}
.nav-inner {
  max-width: 820px; margin: 0 auto; padding: 0 24px;
  display: flex; align-items: center; justify-content: space-between; height: 52px;
}
.nav-logo { font-family: var(--font-mono); font-weight: 700; font-size: 0.95rem; color: var(--green); }
.nav-logo a { color: var(--green); }
.nav-logo a:hover { text-decoration: none; opacity: 0.85; }
.nav-links { display: flex; gap: 20px; list-style: none; }
.nav-links a { font-size: 0.82rem; color: var(--text-secondary); transition: color 0.15s; }
.nav-links a:hover { color: var(--text); text-decoration: none; }

main { max-width: 820px; margin: 0 auto; padding: 0 24px 64px; }

.breadcrumb { padding: 20px 0 0; font-size: 0.82rem; color: var(--text-secondary); }
.breadcrumb a { color: var(--text-secondary); }
.breadcrumb a:hover { color: var(--accent); text-decoration: none; }
.breadcrumb span { color: var(--text); }

/* Hero (landing page) */
.hero { text-align: center; padding: 64px 0 48px; border-bottom: 1px solid var(--border); }
.hero-badge {
  display: inline-block; font-family: var(--font-mono); font-size: 0.72rem; font-weight: 600;
  color: var(--green); background: rgba(63,185,80,0.1); border: 1px solid rgba(63,185,80,0.25);
  padding: 4px 12px; border-radius: 100px; margin-bottom: 20px; letter-spacing: 0.04em;
}
.hero h1 { font-size: 2rem; font-weight: 800; line-height: 1.25; margin-bottom: 12px; letter-spacing: -0.02em; }
.hero .subtitle { font-size: 1.05rem; color: var(--text-secondary); max-width: 560px; margin: 0 auto 24px; line-height: 1.6; }
.hero .cost-bite {
  display: inline-flex; align-items: center; gap: 8px;
  background: var(--bg-card); border: 1px solid var(--border); border-radius: 8px;
  padding: 10px 20px; font-family: var(--font-mono); font-size: 0.82rem; color: var(--orange);
}
.hero .cost-bite .dollar { color: var(--red); font-weight: 700; }

/* Sub-page header */
.sub-hero { padding: 48px 0 32px; border-bottom: 1px solid var(--border); }
.sub-hero .method-badge {
  display: inline-block; font-family: var(--font-mono); font-size: 0.72rem; font-weight: 600;
  color: var(--accent); background: rgba(88,166,255,0.08); border: 1px solid rgba(88,166,255,0.2);
  padding: 4px 12px; border-radius: 100px; margin-bottom: 16px; letter-spacing: 0.04em;
}
.sub-hero .method-badge.rec { color: var(--purple); background: rgba(163,113,247,0.12); border-color: rgba(163,113,247,0.25); }
.sub-hero h1 { font-size: 1.75rem; font-weight: 800; line-height: 1.3; margin-bottom: 10px; letter-spacing: -0.02em; }
.sub-hero .subtitle { font-size: 1rem; color: var(--text-secondary); max-width: 620px; line-height: 1.6; }
.sub-hero .savings-tag {
  display: inline-flex; align-items: center; gap: 6px; margin-top: 14px;
  font-family: var(--font-mono); font-size: 0.78rem; color: var(--orange);
  background: rgba(210,153,29,0.08); border: 1px solid rgba(210,153,29,0.2);
  border-radius: 6px; padding: 5px 12px;
}

.section { padding: 48px 0; border-bottom: 1px solid var(--border); }
.section:last-of-type { border-bottom: none; }
.section h2 { font-size: 1.35rem; font-weight: 700; margin-bottom: 8px; }
.section h3 { font-size: 1.05rem; font-weight: 700; margin-bottom: 6px; margin-top: 20px; }
.section .intro { font-size: 0.95rem; color: var(--text-secondary); line-height: 1.7; margin-bottom: 24px; }
.section p { font-size: 0.92rem; color: var(--text-secondary); line-height: 1.7; margin-bottom: 14px; }
.section ul, .section ol { font-size: 0.92rem; color: var(--text-secondary); line-height: 1.7; margin-bottom: 14px; padding-left: 20px; }
.section li { margin-bottom: 6px; }

.method-card {
  background: var(--bg-card); border: 1px solid var(--border); border-radius: 12px;
  padding: 28px; margin-bottom: 20px; transition: border-color 0.2s, background 0.2s;
  display: block; color: inherit; text-decoration: none;
}
a.method-card:hover { border-color: var(--accent-dim); background: var(--bg-card-hover); text-decoration: none; }
.method-card.recommended { border-color: var(--purple); border-width: 2px; }
.method-card.recommended .rec-badge {
  display: inline-block; font-family: var(--font-mono); font-size: 0.68rem; font-weight: 700;
  color: var(--purple); background: rgba(163,113,247,0.12); padding: 2px 10px; border-radius: 100px;
  margin-bottom: 10px; letter-spacing: 0.05em; text-transform: uppercase;
}
.method-card .card-arrow { font-family: var(--font-mono); font-size: 0.76rem; color: var(--accent); margin-top: 10px; transition: transform 0.2s; }
a.method-card:hover .card-arrow { transform: translateX(4px); }
.method-header { display: flex; align-items: baseline; gap: 14px; margin-bottom: 10px; }
.method-num { font-family: var(--font-mono); font-size: 0.85rem; font-weight: 700; color: var(--accent); min-width: 28px; flex-shrink: 0; }
.method-header h3 { font-size: 1.1rem; font-weight: 700; margin-top: 0; }
.method-desc { font-size: 0.92rem; color: var(--text-secondary); line-height: 1.7; margin-bottom: 14px; }
.tool-tag {
  display: inline-flex; align-items: center; gap: 6px;
  background: rgba(88,166,255,0.08); border: 1px solid rgba(88,166,255,0.2); border-radius: 6px;
  padding: 6px 14px; font-family: var(--font-mono); font-size: 0.78rem; color: var(--accent);
}
.stars-badge {
  display: inline-flex; align-items: center; gap: 4px;
  font-family: var(--font-mono); font-size: 0.76rem; color: var(--orange); margin-left: 8px;
}

.code-block {
  background: #0d1117; border: 1px solid var(--border); border-radius: 8px;
  padding: 16px 20px; margin: 14px 0; overflow-x: auto;
  font-family: var(--font-mono); font-size: 0.8rem; line-height: 1.6; color: #e6edf3;
}
.code-block .kw { color: #ff7b72; }
.code-block .st { color: #a5d6ff; }
.code-block .cm { color: #8b949e; font-style: italic; }
.code-block .fn { color: #d2a8ff; }

.compare-table { width: 100%; border-collapse: collapse; margin: 20px 0; font-size: 0.88rem; }
.compare-table th {
  text-align: left; padding: 10px 14px; font-weight: 600; font-size: 0.76rem;
  text-transform: uppercase; letter-spacing: 0.06em; color: var(--text-secondary);
  border-bottom: 2px solid var(--border);
}
.compare-table td { padding: 10px 14px; border-bottom: 1px solid var(--border); color: var(--text-secondary); }
.compare-table .win { color: var(--green); font-weight: 700; }
.compare-table .mid { color: var(--orange); }

.decision-table { width: 100%; border-collapse: collapse; margin: 20px 0; font-size: 0.88rem; }
.decision-table th {
  text-align: left; padding: 10px 14px; font-weight: 600; font-size: 0.76rem;
  text-transform: uppercase; letter-spacing: 0.06em; color: var(--text-secondary);
  border-bottom: 2px solid var(--border);
}
.decision-table td { padding: 10px 14px; border-bottom: 1px solid var(--border); color: var(--text-secondary); }
.decision-table td:first-child { color: var(--text); font-weight: 600; }
.decision-table .best { color: var(--green); font-weight: 700; }

.tip-box {
  background: rgba(63,185,80,0.06); border: 1px solid rgba(63,185,80,0.2); border-radius: 10px;
  padding: 18px 22px; margin: 20px 0; font-size: 0.9rem; color: var(--green); line-height: 1.6;
}

.faq-item { border-bottom: 1px solid var(--border); }
.faq-item:last-child { border-bottom: none; }
.faq-q {
  width: 100%; background: none; border: none; padding: 16px 0; font-size: 0.95rem;
  font-weight: 600; font-family: inherit; text-align: left; cursor: pointer; color: var(--text);
  display: flex; justify-content: space-between; align-items: center; gap: 12px;
}
.faq-q::after { content: '+'; font-size: 1.2rem; font-weight: 400; color: var(--text-secondary); flex-shrink: 0; }
.faq-q.open::after { content: '\2212'; }
.faq-a { max-height: 0; overflow: hidden; transition: max-height 0.3s ease, padding 0.3s ease; font-size: 0.9rem; color: var(--text-secondary); line-height: 1.7; padding: 0; }
.faq-a.open { max-height: 500px; padding-bottom: 16px; }

.back-link {
  display: inline-flex; align-items: center; gap: 6px; font-family: var(--font-mono); font-size: 0.82rem;
  color: var(--text-secondary); margin: 24px 0; transition: color 0.15s;
}
.back-link:hover { color: var(--accent); text-decoration: none; }

.related-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin: 20px 0; }

footer {
  border-top: 1px solid var(--border); text-align: center; padding: 32px 24px;
  font-size: 0.82rem; color: var(--text-secondary);
}
footer .sub-hint {
  display: flex; justify-content: center; gap: 24px; flex-wrap: wrap; margin-bottom: 16px;
}
footer .sub-hint a {
  font-family: var(--font-mono); font-size: 0.78rem; color: var(--text-secondary);
  border: 1px solid var(--border); border-radius: 6px; padding: 6px 14px; transition: border-color 0.2s, color 0.2s;
}
footer .sub-hint a:hover { border-color: var(--accent-dim); color: var(--accent); text-decoration: none; }

@media (max-width: 640px) {
  .hero h1, .sub-hero h1 { font-size: 1.5rem; }
  .hero { padding: 40px 0 32px; }
  .sub-hero { padding: 32px 0 24px; }
  .section { padding: 32px 0; }
  .method-card { padding: 20px; }
  .nav-links { gap: 12px; }
  .related-grid { grid-template-columns: 1fr; }
}
@media (max-width: 480px) {
  .hero h1, .sub-hero h1 { font-size: 1.3rem; }
  main { padding: 0 16px 48px; }
  .method-header h3 { font-size: 0.95rem; }
  .sub-hero .subtitle { font-size: 0.9rem; }
}

/* Token Counter */
.tk-counter {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 24px;
  margin-top: -12px;
  margin-bottom: 36px;
}
.tk-textarea {
  width: 100%;
  min-height: 160px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 14px 16px;
  color: var(--text);
  font-family: var(--font-mono);
  font-size: 0.85rem;
  line-height: 1.6;
  resize: vertical;
  outline: none;
  transition: border-color 0.2s;
}
.tk-textarea:focus { border-color: var(--accent); }
.tk-textarea::placeholder { color: var(--text-secondary); opacity: 0.5; }
.tk-results {
  display: flex;
  gap: 24px;
  margin-top: 16px;
  flex-wrap: wrap;
}
.tk-stat {
  flex: 1;
  min-width: 100px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 14px 16px;
  text-align: center;
}
.tk-stat-value {
  font-family: var(--font-mono);
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--green);
  line-height: 1.2;
}
.tk-stat-label {
  font-size: 0.75rem;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-top: 4px;
}
.tk-saved { color: var(--green); }
.tk-compare-toggle {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: none;
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 6px 14px;
  color: var(--accent);
  font-size: 0.82rem;
  cursor: pointer;
  margin-bottom: 12px;
  transition: border-color 0.2s, background 0.2s;
}
.tk-compare-toggle:hover { border-color: var(--accent); background: rgba(88,166,255,0.06); }
.tk-compare-toggle.active { background: rgba(88,166,255,0.1); border-color: var(--accent); }
.tk-compare-panel { display: none; margin-top: 16px; }
.tk-compare-panel.visible { display: block; }
.tk-compare-label {
  font-size: 0.78rem;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin: 10px 0 6px;
}
.tk-compare-label span { color: var(--accent); }
.tk-diff {
  display: flex;
  gap: 24px;
  margin-top: 16px;
  flex-wrap: wrap;
}
.tk-diff .tk-saved-amount {
  font-family: var(--font-mono);
  font-size: 1.4rem;
  font-weight: 700;
}
@media (max-width: 640px) {
  .tk-results { gap: 12px; }
  .tk-stat-value { font-size: 1.3rem; }
  .tk-diff { gap: 12px; }
}