/* ── Reset & Base Styles ── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg: #ffffff;
  --text: #0f172a;
  --text-muted: #475569;
  --text-light: #94a3b8;
  --border: #f1f5f9;
  --border-dark: #e2e8f0;
  --accent: #4f46e5;
  --accent-hover: #4338ca;
  --bg-card: #f8fafc;
  --bg-code: #0f172a;
  --nav-bg: rgba(255, 255, 255, 0.8);
  --comment: #16a34a;
  --radius: 8px;
  --radius-lg: 12px;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', monospace;
}

[data-theme="dark"] {
  --bg: #090d16;
  --text: #f8fafc;
  --text-muted: #cbd5e1;
  --text-light: #64748b;
  --border: #1e293b;
  --border-dark: #334155;
  --accent: #818cf8;
  --accent-hover: #a5b4fc;
  --bg-card: #0f172a;
  --nav-bg: rgba(9, 13, 22, 0.8);
  --comment: #4ade80;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  transition: background-color 0.25s, color 0.25s;
}

.container {
  max-width: 1000px;
  margin: 0 auto;
  padding: 0 24px;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color 0.15s;
}
a:hover {
  color: var(--accent-hover);
}

/* ── Navigation ── */
nav {
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  background: var(--nav-bg);
  backdrop-filter: blur(8px);
  z-index: 100;
  transition: background-color 0.25s, border-color 0.25s;
}
.nav-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 64px;
}
.nav-logo {
  font-weight: 800;
  font-size: 1.2rem;
  letter-spacing: -0.03em;
  color: var(--text);
  transition: color 0.25s;
}
.nav-links {
  display: flex;
  gap: 24px;
  list-style: none;
  align-items: center;
}
.nav-links a {
  font-size: 0.88rem;
  color: var(--text-muted);
  font-weight: 500;
  transition: color 0.25s;
}
.nav-links a:hover,
.nav-links a.active {
  color: var(--text);
}
.nav-cta {
  background: var(--text);
  color: var(--bg) !important;
  padding: 6px 14px;
  border-radius: var(--radius);
  font-weight: 600 !important;
  transition: background-color 0.25s, color 0.25s;
}
.nav-cta:hover {
  background: var(--accent);
  color: var(--bg) !important;
}
.theme-toggle-btn {
  background: none;
  border: none;
  padding: 0;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  outline: none;
}
.theme-toggle-track {
  width: 44px;
  height: 24px;
  border-radius: 99px;
  background: var(--border-dark);
  border: 1px solid var(--border-dark);
  position: relative;
  transition: background-color 0.25s, border-color 0.25s;
  display: block;
}
.theme-toggle-knob {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--text);
  position: absolute;
  top: 2px;
  left: 2px;
  transition: transform 0.25s, background-color 0.25s;
  display: block;
}
[data-theme="dark"] .theme-toggle-knob {
  transform: translateX(20px);
}
[data-theme="dark"] .theme-toggle-track {
  background: var(--bg-card);
  border-color: var(--border-dark);
}

/* ── Hero ── */
.hero {
  padding: 80px 0 60px;
  border-bottom: 1px solid var(--border);
}
.badge {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  background: var(--bg-card);
  border: 1px solid var(--border-dark);
  padding: 4px 12px;
  border-radius: 99px;
  margin-bottom: 16px;
  color: var(--text-muted);
}
.hero h1 {
  font-size: clamp(2rem, 5vw, 3.2rem);
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: -0.04em;
  margin-bottom: 16px;
}
.hero p {
  font-size: 1.1rem;
  color: var(--text-muted);
  max-width: 600px;
  margin-bottom: 24px;
}
.hero-actions {
  display: flex;
  gap: 12px;
}
.btn {
  display: inline-flex;
  align-items: center;
  padding: 10px 20px;
  border-radius: var(--radius);
  font-size: 0.9rem;
  font-weight: 600;
  transition: all 0.15s;
}
.btn-primary {
  background: var(--text);
  color: var(--bg);
}
.btn-primary:hover {
  background: var(--accent);
  color: var(--bg);
}
.btn-secondary {
  border: 1px solid var(--border-dark);
  color: var(--text-muted);
}
.btn-secondary:hover {
  border-color: var(--text);
  color: var(--text);
}

/* ── Stats ── */
.stats-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  padding: 32px 0;
  border-bottom: 1px solid var(--border);
}
.stat-card {
  text-align: center;
}
.stat-num {
  font-size: 1.8rem;
  font-weight: 800;
  color: var(--text);
}
.stat-label {
  font-size: 0.78rem;
  color: var(--text-muted);
  text-transform: uppercase;
  font-weight: 600;
  letter-spacing: 0.05em;
}

/* ── Sections ── */
section {
  padding: 64px 0;
  border-bottom: 1px solid var(--border);
}
.section-title {
  font-size: 1.75rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  margin-bottom: 8px;
}
.section-subtitle {
  font-size: 0.95rem;
  color: var(--text-muted);
  margin-bottom: 36px;
}

/* ── Features ── */
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
}
.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  transition: all 0.15s;
}
.feature-card:hover {
  border-color: var(--border-dark);
}
.feature-card h3 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 8px;
}
.feature-card p {
  font-size: 0.88rem;
  color: var(--text-muted);
  line-height: 1.5;
}

/* ── Pipeline ── */
.pipeline-container {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 40px;
}
.pipeline-steps {
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.pipeline-step {
  display: flex;
  gap: 16px;
  padding: 16px;
  border-radius: var(--radius);
  border: 1px solid transparent;
  transition: all 0.15s;
}
.pipeline-step:hover {
  background: var(--bg-card);
  border-color: var(--border);
}
.step-num {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--text);
  color: var(--bg);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.8rem;
  font-weight: 700;
  flex-shrink: 0;
}
.step-body h4 {
  font-size: 0.95rem;
  font-weight: 700;
  margin-bottom: 4px;
}
.step-body p {
  font-size: 0.85rem;
  color: var(--text-muted);
}
.pipeline-diagram {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 24px;
  align-self: start;
}
.diag-box {
  background: var(--bg);
  border: 1px solid var(--border-dark);
  border-radius: var(--radius);
  padding: 8px 12px;
  font-size: 0.78rem;
  font-family: var(--font-mono);
  text-align: center;
  margin-bottom: 6px;
}
.diag-box.highlight {
  background: var(--text);
  color: var(--bg);
  border-color: var(--text);
  font-weight: 600;
}
.diag-arrow {
  text-align: center;
  font-size: 0.9rem;
  color: var(--text-light);
  margin-bottom: 6px;
}

/* SVG flowchart highlights */
.flow-group rect, .flow-group text {
  transition: fill 0.2s, stroke 0.2s, stroke-width 0.2s;
}
.flow-group.active-highlight rect {
  stroke: var(--accent) !important;
  stroke-width: 2px !important;
  fill: var(--bg-card) !important;
}
.flow-group.active-highlight text {
  fill: var(--accent) !important;
}

/* ── Tiers ── */
.tiers-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 12px;
}
.tier-card {
  border: 1px solid var(--border-dark);
  border-radius: var(--radius);
  padding: 16px;
  text-align: center;
}
.tier-title {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 6px;
}
.tier-val {
  font-size: 1.25rem;
  font-weight: 800;
  margin-bottom: 4px;
}
.tier-desc {
  font-size: 0.75rem;
  color: var(--text-muted);
}
.tier-card.vw { border-left: 4px solid #ef4444; }
.tier-card.w  { border-left: 4px solid #f97316; }
.tier-card.m  { border-left: 4px solid #eab308; }
.tier-card.s  { border-left: 4px solid #22c55e; }
.tier-card.vs { border-left: 4px solid #6366f1; }

/* ── Usage tabs ── */
.tabs-nav {
  display: flex;
  border-bottom: 1px solid var(--border-dark);
  margin-bottom: 20px;
}
.tab-btn {
  border: none;
  background: none;
  padding: 10px 16px;
  font-family: var(--font-sans);
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--text-muted);
  cursor: pointer;
  border-bottom: 2px solid transparent;
  margin-bottom: -1px;
}
.tab-btn.active {
  color: var(--text);
  border-bottom-color: var(--text);
}
.tab-pane {
  display: none;
}
.tab-pane.active {
  display: block;
}

/* ── Code blocks ── */
pre {
  background: var(--bg-code);
  border-radius: var(--radius-lg);
  padding: 20px;
  overflow-x: auto;
  margin-bottom: 20px;
  position: relative;
}
.copy-btn {
  position: absolute;
  top: 12px;
  right: 12px;
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.15);
  color: #94a3b8;
  padding: 4px 8px;
  border-radius: 4px;
  font-size: 0.72rem;
  cursor: pointer;
  font-family: var(--font-sans);
  transition: all 0.15s;
}
.copy-btn:hover {
  background: rgba(255, 255, 255, 0.15);
  color: #f8fafc;
}
pre code {
  color: #cbd5e1;
}
code {
  font-family: var(--font-mono);
  font-size: 0.84rem;
  color: var(--text);
  transition: color 0.25s;
}
/* Simple highlighting */
.kw { color: #f43f5e; } /* keyword */
.fn { color: #38bdf8; } /* function */
.str { color: #34d399; } /* string */
.cmt { color: var(--comment); font-style: italic; } /* comment */
.cls { color: #a78bfa; } /* class */

/* ── Example Output Box ── */
.output-box {
  border: 1px solid var(--border-dark);
  border-radius: var(--radius-lg);
  background: var(--bg-card);
  padding: 24px;
  margin-top: 32px;
}
.output-header {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-muted);
  border-bottom: 1px solid var(--border-dark);
  padding-bottom: 12px;
  margin-bottom: 16px;
  display: flex;
  justify-content: space-between;
}
.output-body {
  font-family: var(--font-mono);
  font-size: 0.84rem;
  line-height: 1.8;
}
.out-item {
  display: flex;
  justify-content: space-between;
  border-bottom: 1px dashed var(--border);
  padding: 4px 0;
}
.out-item:last-child {
  border-bottom: none;
}
.out-k { font-weight: 500; }
.out-v { color: var(--text-muted); }
.out-bad { color: #ef4444; font-weight: 600; }
.out-warn { color: #d97706; font-weight: 600; }
.out-good { color: #16a34a; font-weight: 600; }

.preview-btn {
  border: 1px solid var(--border-dark);
  background: var(--bg-card);
  padding: 6px 14px;
  font-family: var(--font-sans);
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--text-muted);
  cursor: pointer;
  border-radius: 99px;
  transition: all 0.15s;
  outline: none;
}
.preview-btn.active {
  background: var(--text);
  color: var(--bg);
  border-color: var(--text);
}
.preview-btn:hover:not(.active) {
  border-color: var(--text);
  color: var(--text);
}

.fmt-btn {
  border: none;
  background: none;
  padding: 2px 8px;
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--text-muted);
  cursor: pointer;
  font-family: var(--font-sans);
  transition: all 0.1s;
  border-radius: 2px;
  outline: none;
}
.fmt-btn.active {
  background: var(--border-dark);
  color: var(--text);
}
.fmt-btn:hover:not(.active) {
  color: var(--text);
}

/* ── API Reference Table ── */
.table-wrapper {
  overflow-x: auto;
}
table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 24px;
}
th {
  text-align: left;
  border-bottom: 2px solid var(--border-dark);
  padding: 10px 12px;
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
td {
  padding: 12px 12px;
  border-bottom: 1px solid var(--border);
  font-size: 0.85rem;
  color: var(--text-muted);
  vertical-align: top;
}
code.inline {
  background: var(--bg-card);
  border: 1px solid var(--border-dark);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 0.78rem;
  color: var(--text);
}

/* ── Design Philosophy Grid ── */
.philosophy-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
}
.philosophy-card {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  background: var(--bg-card);
}
.philosophy-card h3 {
  font-size: 0.95rem;
  font-weight: 700;
  margin-bottom: 6px;
}
.philosophy-card p {
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* ── File Tree ── */
.file-tree {
  background: var(--bg-card);
  border: 1px solid var(--border-dark);
  border-radius: var(--radius-lg);
  padding: 24px;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  line-height: 1.8;
  overflow-x: auto;
}
.tree-indent {
  padding-left: 20px;
}
.tree-dir {
  font-weight: 700;
}
.tree-cmt {
  color: var(--comment);
}

/* ── Footer ── */
footer {
  padding: 48px 0;
  border-top: 1px solid var(--border);
  background: var(--bg-card);
  font-size: 0.82rem;
  color: var(--text-muted);
}
.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
}

/* ── Responsive ── */
@media (max-width: 768px) {
  .pipeline-container {
    grid-template-columns: 1fr;
  }
  .pipeline-diagram {
    display: none;
  }
  .stats-row {
    grid-template-columns: repeat(2, 1fr);
    gap: 24px;
  }
  .nav-links {
    display: none;
  }
}