/* ============================================================
   TongYou — GitHub Pages Stylesheet
   Teal theme (#06b6d4) · Responsive · Dark-mode aware
   ============================================================ */

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

:root {
  --accent: #06b6d4;
  --accent-light: #67e8f9;
  --accent-dark: #0891b2;
  --bg: #ffffff;
  --bg-alt: #f8f9fa;
  --text: #2d3436;
  --text-secondary: #636e72;
  --card-bg: #ffffff;
  --card-border: #e0e0e0;
  --code-bg: #f1f2f6;
  --shadow: 0 2px 12px rgba(0, 0, 0, 0.08);
  --radius: 12px;
  --max-width: 1140px;
  --font: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Helvetica Neue",
    Arial, sans-serif;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f172a;
    --bg-alt: #1e293b;
    --text: #e2e8f0;
    --text-secondary: #94a3b8;
    --card-bg: #1e293b;
    --card-border: #334155;
    --code-bg: #283548;
    --shadow: 0 2px 12px rgba(0, 0, 0, 0.3);
  }
}

html {
  scroll-behavior: smooth;
}

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

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

a:hover {
  text-decoration: underline;
}

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

code {
  background: var(--code-bg);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 0.88rem;
  font-family: "SF Mono", Menlo, Monaco, "Cascadia Code", monospace;
}

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

section {
  padding: 80px 0;
}

section:nth-child(even) {
  background: var(--bg-alt);
}

.section-title {
  font-size: 2rem;
  font-weight: 700;
  text-align: center;
  margin-bottom: 12px;
}

.section-subtitle {
  text-align: center;
  color: var(--text-secondary);
  margin-bottom: 48px;
  font-size: 1.1rem;
}

/* ---------- Fade-in animation ---------- */
.fade-in {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ---------- Header / Nav ---------- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: var(--bg);
  border-bottom: 1px solid var(--card-border);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

@media (prefers-color-scheme: dark) {
  .site-header {
    background: rgba(15, 23, 42, 0.85);
  }
}

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

.nav-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 1.15rem;
  color: var(--text);
}

.nav-brand img {
  width: 32px;
  height: 32px;
  border-radius: 8px;
}

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

.nav-links a {
  color: var(--text-secondary);
  font-size: 0.95rem;
  transition: color 0.2s;
}

.nav-links a:hover {
  color: var(--accent);
  text-decoration: none;
}

.lang-switch {
  font-size: 0.85rem;
  padding: 4px 12px;
  border: 1px solid var(--card-border);
  border-radius: 6px;
  color: var(--text-secondary);
  transition: border-color 0.2s, color 0.2s;
}

.lang-switch:hover {
  border-color: var(--accent);
  color: var(--accent);
  text-decoration: none;
}

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

.hero-icon {
  width: 96px;
  height: 96px;
  border-radius: 22px;
  box-shadow: var(--shadow);
  margin-bottom: 24px;
}

.hero h1 {
  font-size: 2.8rem;
  font-weight: 800;
  margin-bottom: 16px;
  letter-spacing: -0.5px;
}

.hero h1 span {
  color: var(--accent);
}

.hero .tagline {
  font-size: 1.25rem;
  color: var(--text-secondary);
  max-width: 640px;
  margin: 0 auto 32px;
}

.hero-buttons {
  display: flex;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: 8px;
  font-size: 1rem;
  font-weight: 600;
  transition: background 0.2s, transform 0.15s;
  cursor: pointer;
  border: none;
}

.btn:hover {
  transform: translateY(-1px);
  text-decoration: none;
}

.btn-primary {
  background: var(--accent);
  color: #fff;
}

.btn-primary:hover {
  background: var(--accent-dark);
  color: #fff;
}

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

.btn-secondary:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.version-badge {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 500;
  background: var(--bg-alt);
  color: var(--text-secondary);
  padding: 2px 10px;
  border-radius: 20px;
  margin-top: 16px;
}

/* ---------- Features grid ---------- */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.feature-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  padding: 28px 24px;
  transition: box-shadow 0.2s, transform 0.2s;
}

.feature-card:hover {
  box-shadow: var(--shadow);
  transform: translateY(-2px);
}

.feature-icon {
  font-size: 2rem;
  margin-bottom: 12px;
}

.feature-card h3 {
  font-size: 1.1rem;
  margin-bottom: 8px;
}

.feature-card p {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

/* ---------- Architecture / How it works ---------- */
.steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
  text-align: center;
}

.step {
  position: relative;
}

.step-number {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--accent);
  color: #fff;
  font-size: 1.4rem;
  font-weight: 700;
  margin-bottom: 16px;
}

.step h3 {
  font-size: 1.15rem;
  margin-bottom: 8px;
}

.step p {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

/* ---------- Tech specs table ---------- */
.table-wrapper {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.compare-table {
  width: 100%;
  border-collapse: collapse;
  background: var(--card-bg);
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--card-border);
}

.compare-table th,
.compare-table td {
  padding: 14px 20px;
  text-align: left;
  border-bottom: 1px solid var(--card-border);
}

.compare-table th {
  background: var(--accent);
  color: #fff;
  font-weight: 600;
  font-size: 0.95rem;
}

.compare-table tr:last-child td {
  border-bottom: none;
}

.compare-table tr:hover td {
  background: var(--bg-alt);
}

.badge-yes,
.badge-no {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  padding: 2px 8px;
  border-radius: 4px;
}

.badge-yes {
  background: #34c759;
  color: #fff;
}

.badge-no {
  font-weight: 500;
  background: var(--bg-alt);
  color: var(--text-secondary);
}

/* ---------- Installation ---------- */
.install-options {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  max-width: 800px;
  margin: 0 auto;
}

.install-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  padding: 32px 28px;
  transition: box-shadow 0.2s, transform 0.2s;
}

.install-card:hover {
  box-shadow: var(--shadow);
  transform: translateY(-2px);
}

.install-card h3 {
  font-size: 1.2rem;
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.install-card p {
  color: var(--text-secondary);
  font-size: 0.95rem;
  margin-bottom: 20px;
}

.install-card .btn {
  width: 100%;
  justify-content: center;
}

pre.code-block {
  background: var(--code-bg);
  border-radius: 8px;
  padding: 16px;
  overflow-x: auto;
  font-size: 0.88rem;
  line-height: 1.6;
  margin: 0;
  font-family: "SF Mono", Menlo, Monaco, "Cascadia Code", monospace;
  color: var(--text);
}

/* ---------- Keybindings table ---------- */
.keybinding-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
  max-width: 800px;
  margin: 0 auto;
}

.keybinding-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 8px;
  padding: 12px 16px;
}

.keybinding-item span:first-child {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

.keybinding-item kbd {
  background: var(--code-bg);
  border: 1px solid var(--card-border);
  border-radius: 4px;
  padding: 3px 8px;
  font-size: 0.85rem;
  font-family: "SF Mono", Menlo, Monaco, monospace;
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.05);
}

/* ---------- Footer ---------- */
.site-footer {
  padding: 40px 0;
  border-top: 1px solid var(--card-border);
  text-align: center;
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 24px;
  list-style: none;
  margin-bottom: 16px;
  flex-wrap: wrap;
}

.footer-links a {
  color: var(--text-secondary);
  transition: color 0.2s;
}

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

/* ---------- Responsive ---------- */
@media (max-width: 900px) {
  .features-grid,
  .steps {
    grid-template-columns: repeat(2, 1fr);
  }

  .install-options {
    grid-template-columns: 1fr;
  }

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

@media (max-width: 600px) {
  .hero h1 {
    font-size: 2rem;
  }

  .hero .tagline {
    font-size: 1.05rem;
  }

  section {
    padding: 56px 0;
  }

  .section-title {
    font-size: 1.6rem;
  }

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

  .nav-links .nav-link-text {
    display: none;
  }

  .nav-links {
    gap: 16px;
  }
}