/* ============================================
   synclib.io — Styles
   ============================================ */

/* --- CSS Custom Properties --- */
:root {
  --bg: #0a0a0a;
  --bg-raised: #141414;
  --bg-code: #0d1117;
  --bg-card: #111111;
  --border: #1e1e1e;
  --border-hover: #333;
  --text: #e6e6e6;
  --text-muted: #888;
  --text-dim: #666;
  --accent: #3b82f6;
  --accent-hover: #60a5fa;
  --gradient-start: #3b82f6;
  --gradient-end: #06b6d4;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'SF Mono', Consolas, monospace;
  --max-width: 1120px;
  --radius: 8px;
  --radius-lg: 12px;
}

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color 0.2s;
}

a:hover {
  color: var(--accent-hover);
}

img, svg {
  display: block;
  max-width: 100%;
}

/* --- Layout --- */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

section {
  padding: 80px 0;
}

/* --- Typography --- */
h1, h2, h3, h4 {
  font-weight: 600;
  line-height: 1.2;
  letter-spacing: -0.02em;
}

h1 { font-size: 3rem; }
h2 { font-size: 2rem; margin-bottom: 16px; }
h3 { font-size: 1.25rem; margin-bottom: 8px; }

.section-subtitle {
  color: var(--text-muted);
  font-size: 1.1rem;
  max-width: 640px;
  margin: 0 auto 48px;
  text-align: center;
}

.gradient-text {
  background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

/* --- Navigation --- */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(10, 10, 10, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}

.nav .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}

.nav-logo {
  font-family: var(--font-mono);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text);
  letter-spacing: -0.03em;
}

.nav-logo:hover {
  color: var(--text);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 24px;
  list-style: none;
}

.nav-links a {
  color: var(--text-muted);
  font-size: 0.9rem;
  font-weight: 500;
  transition: color 0.2s;
}

.nav-links a:hover {
  color: var(--text);
}

.nav-links .btn-sm {
  color: var(--text);
  background: var(--bg-raised);
  border: 1px solid var(--border);
  padding: 6px 14px;
  border-radius: 6px;
  font-size: 0.85rem;
}

.nav-links .btn-sm:hover {
  border-color: var(--border-hover);
  background: #1a1a1a;
}

/* --- Buttons --- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 24px;
  border-radius: var(--radius);
  font-weight: 600;
  font-size: 0.95rem;
  cursor: pointer;
  border: none;
  transition: all 0.2s;
}

.btn-primary {
  background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
  color: #fff;
}

.btn-primary:hover {
  opacity: 0.9;
  color: #fff;
  transform: translateY(-1px);
}

.btn-secondary {
  background: var(--bg-raised);
  border: 1px solid var(--border);
  color: var(--text);
}

.btn-secondary:hover {
  border-color: var(--border-hover);
  color: var(--text);
  transform: translateY(-1px);
}

.btn-group {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

/* --- Hero --- */
.hero {
  padding: 140px 0 80px;
  text-align: center;
}

.hero h1 {
  margin-bottom: 20px;
}

.hero .subtitle {
  color: var(--text-muted);
  font-size: 1.15rem;
  max-width: 600px;
  margin: 0 auto 36px;
  line-height: 1.7;
}

.hero .btn-group {
  justify-content: center;
  margin-bottom: 56px;
}

/* Hero code window */
.hero-code {
  max-width: 680px;
  margin: 0 auto;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  overflow: hidden;
  text-align: left;
}

.code-window-bar {
  background: #1a1a1a;
  padding: 10px 16px;
  display: flex;
  align-items: center;
  gap: 8px;
  border-bottom: 1px solid var(--border);
}

.code-window-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: #333;
}

.code-window-dot:nth-child(1) { background: #ff5f57; }
.code-window-dot:nth-child(2) { background: #ffbd2e; }
.code-window-dot:nth-child(3) { background: #28c840; }

.code-window-title {
  color: var(--text-dim);
  font-size: 0.8rem;
  font-family: var(--font-mono);
  margin-left: 8px;
}

/* --- Code Blocks --- */
pre {
  background: var(--bg-code);
  font-family: var(--font-mono);
  font-size: 0.85rem;
  line-height: 1.7;
  padding: 24px;
  overflow-x: auto;
  tab-size: 2;
}

/* Syntax highlighting classes */
.kw { color: #ff7b72; }        /* keywords: import, from, await, const, final */
.fn { color: #d2a8ff; }        /* functions/methods */
.st { color: #a5d6ff; }        /* strings */
.ty { color: #79c0ff; }        /* types/classes */
.cm { color: #8b949e; }        /* comments */
.pr { color: #ffa657; }        /* properties/parameters */
.op { color: #c9d1d9; }        /* operators/punctuation */
.nu { color: #79c0ff; }        /* numbers */

/* --- Code Example Section (Tabs) --- */
.code-examples {
  background: var(--bg-raised);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.code-examples h2 {
  text-align: center;
}

/* CSS-only tabs */
.tabs {
  max-width: 720px;
  margin: 0 auto;
}

.tabs input[type="radio"] {
  display: none;
}

.tab-labels {
  display: flex;
  gap: 0;
  border-bottom: 1px solid var(--border);
}

.tab-labels label {
  flex: 1;
  padding: 12px 20px;
  text-align: center;
  cursor: pointer;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-muted);
  border-bottom: 2px solid transparent;
  transition: all 0.2s;
}

.tab-labels label:hover {
  color: var(--text);
}

.tab-panels .tab-panel {
  display: none;
}

#tab-ts:checked ~ .tab-labels [for="tab-ts"],
#tab-dart:checked ~ .tab-labels [for="tab-dart"] {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

#tab-ts:checked ~ .tab-panels .panel-ts,
#tab-dart:checked ~ .tab-panels .panel-dart {
  display: block;
}

.tab-panels pre {
  border-radius: 0 0 var(--radius-lg) var(--radius-lg);
  border: 1px solid var(--border);
  border-top: none;
}

/* --- How It Works --- */
.how-it-works h2 {
  text-align: center;
}

.layers {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  max-width: 900px;
  margin: 0 auto;
}

.layer-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 32px;
}

.layer-img {
  width: 100%;
  border-radius: var(--radius);
  margin-bottom: 20px;
}

.layer-card .layer-label {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  padding: 4px 10px;
  border-radius: 4px;
  margin-bottom: 16px;
}

.layer-card:nth-child(1) .layer-label {
  background: rgba(59, 130, 246, 0.15);
  color: var(--accent);
}

.layer-card:nth-child(2) .layer-label {
  background: rgba(6, 182, 212, 0.15);
  color: #06b6d4;
}

.layer-card h3 {
  font-size: 1.3rem;
  margin-bottom: 12px;
}

.layer-card ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.layer-card li {
  color: var(--text-muted);
  font-size: 0.95rem;
  padding-left: 20px;
  position: relative;
}

.layer-card li::before {
  content: '→';
  position: absolute;
  left: 0;
  color: var(--text-dim);
}

.layer-card .layer-result {
  margin-top: 16px;
  padding-top: 16px;
  border-top: 1px solid var(--border);
  font-weight: 600;
  font-size: 0.9rem;
}

.layer-card:nth-child(1) .layer-result {
  color: var(--accent);
}

.layer-card:nth-child(2) .layer-result {
  color: #06b6d4;
}

/* --- Features Grid --- */
.features h2 {
  text-align: center;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

@media (max-width: 1024px) {
  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px;
  transition: border-color 0.2s;
}

.feature-card:hover {
  border-color: var(--border-hover);
}

.feature-icon {
  font-size: 1.5rem;
  margin-bottom: 12px;
}

.feature-card h3 {
  font-size: 1.05rem;
}

.feature-card p {
  color: var(--text-muted);
  font-size: 0.9rem;
  line-height: 1.6;
}

/* --- Architecture --- */
.architecture {
  background: var(--bg-raised);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.architecture h2 {
  text-align: center;
}

.arch-diagram {
  max-width: 800px;
  margin: 0 auto;
  background: var(--bg-code);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 40px 24px;
  text-align: center;
}

.arch-flow {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0;
  flex-wrap: wrap;
}

.arch-node {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px 24px;
  text-align: center;
  min-width: 160px;
}

.arch-node-label {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 4px;
}

.arch-node-sub {
  font-size: 0.8rem;
  color: var(--text-muted);
}

.arch-arrow {
  font-family: var(--font-mono);
  color: var(--text-dim);
  font-size: 1.2rem;
  padding: 0 12px;
  flex-shrink: 0;
}

.arch-steps {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 16px;
  margin-top: 32px;
  max-width: 800px;
  margin-left: auto;
  margin-right: auto;
}

.arch-step {
  text-align: center;
  color: var(--text-muted);
  font-size: 0.85rem;
}

.arch-step-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: rgba(59, 130, 246, 0.15);
  color: var(--accent);
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 600;
  margin-bottom: 8px;
}

/* --- Repos --- */
.repos h2 {
  text-align: center;
}

.repos-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 16px;
  max-width: 900px;
  margin: 0 auto;
}

.repo-card {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 20px 24px;
  transition: border-color 0.2s, transform 0.2s;
}

.repo-card:hover {
  border-color: var(--border-hover);
  transform: translateY(-2px);
  color: var(--text);
}

.repo-icon {
  flex-shrink: 0;
  width: 20px;
  height: 20px;
  color: var(--text-muted);
  margin-top: 2px;
}

.repo-info {
  min-width: 0;
}

.repo-name {
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--accent);
  margin-bottom: 4px;
}

.repo-card:hover .repo-name {
  color: var(--accent-hover);
}

.repo-desc {
  color: var(--text-muted);
  font-size: 0.85rem;
  line-height: 1.5;
}

/* --- Firestore Migration --- */
.firestore-migration {
  text-align: center;
}

.firestore-migration h2 {
  text-align: center;
}

.migration-demo {
  max-width: 560px;
  margin: 0 auto;
  text-align: left;
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}

.migration-demo pre {
  padding: 20px 24px;
  margin: 0;
  font-size: 0.88rem;
  line-height: 1.7;
}

.migration-demo .del {
  text-decoration: line-through;
  opacity: 0.5;
}

.migration-demo .add {
  background: rgba(56, 189, 126, 0.15);
  border-radius: 3px;
  padding: 1px 2px;
}

/* --- Managed / Cloud --- */
.managed {
  padding-bottom: 48px;
}

.managed-card {
  max-width: 800px;
  margin: 0 auto;
  text-align: center;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 48px 40px;
}

.managed-card h2 {
  margin-bottom: 12px;
}

.managed-card > p {
  color: var(--text-muted);
  font-size: 1rem;
  line-height: 1.7;
  max-width: 580px;
  margin: 0 auto 32px;
}

.managed-options {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  margin-bottom: 32px;
}

.managed-option {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  text-align: left;
}

.managed-option h3 {
  font-size: 1rem;
  margin-bottom: 6px;
}

.managed-option p {
  color: var(--text-muted);
  font-size: 0.9rem;
  line-height: 1.6;
}

@media (max-width: 768px) {
  .managed-options {
    grid-template-columns: 1fr;
  }

  .managed-card {
    padding: 32px 24px;
  }
}

/* --- Footer --- */
.footer {
  border-top: 1px solid var(--border);
  padding: 40px 0;
  text-align: center;
  color: var(--text-dim);
  font-size: 0.85rem;
}

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

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

.footer-links {
  display: flex;
  justify-content: center;
  gap: 20px;
  margin-top: 8px;
}

/* --- Responsive --- */
@media (max-width: 768px) {
  section {
    padding: 56px 0;
  }

  h1 {
    font-size: 2rem;
  }

  h2 {
    font-size: 1.5rem;
  }

  .hero {
    padding: 110px 0 56px;
  }

  .hero .subtitle {
    font-size: 1rem;
  }

  .layers {
    grid-template-columns: 1fr;
  }

  .features-grid {
    grid-template-columns: 1fr;
  }

  .arch-flow {
    flex-direction: column;
    gap: 8px;
  }

  .arch-arrow {
    transform: rotate(90deg);
    padding: 4px 0;
  }

  .repos-grid {
    grid-template-columns: 1fr;
  }

  .nav-links {
    gap: 16px;
  }

  pre {
    font-size: 0.78rem;
    padding: 16px;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 16px;
  }

  h1 {
    font-size: 1.75rem;
  }

  .btn {
    padding: 10px 18px;
    font-size: 0.9rem;
  }

  .btn-group {
    flex-direction: column;
    align-items: stretch;
  }

  .btn-group .btn {
    justify-content: center;
  }
}