/* ========== Language Toggle ========== */
[data-lang="en"] .zh { display: none !important; }
[data-lang="zh"] .en { display: none !important; }
/* Default: hide zh when no data-lang set */
:root:not([data-lang]) .zh { display: none !important; }

.lang-toggle {
  background: var(--bg-card, #1a2332);
  border: 1px solid var(--border, #2d3748);
  color: var(--text-2, #94a3b8);
  padding: 0.25rem 0.65rem;
  border-radius: 4px;
  cursor: pointer;
  font-size: 0.75rem;
  font-weight: 600;
  font-family: inherit;
  transition: all .2s;
  letter-spacing: 0.03em;
}
.lang-toggle:hover { color: var(--blue, #3b82f6); border-color: var(--blue, #3b82f6); }

/* ========== PI Pages - Shared Styles ========== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg: #0a0e17;
  --bg-2: #111827;
  --bg-card: #1a2332;
  --bg-card-hover: #1f2b3d;
  --border: #2d3748;
  --text: #e2e8f0;
  --text-2: #94a3b8;
  --text-3: #64748b;
  --blue: #3b82f6;
  --cyan: #06b6d4;
  --purple: #8b5cf6;
  --green: #10b981;
  --amber: #f59e0b;
  --red: #ef4444;
  --pink: #ec4899;
  --pi: #3b82f6;
  --pua: #ef4444;
  --nopua: #10b981;
  --radius: 12px;
  --radius-sm: 8px;
  --font: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --mono: 'JetBrains Mono', 'Fira Code', monospace;
  --max-w: 1200px;
  --glow-blue: 0 0 30px rgba(59, 130, 246, 0.15);
}

html { scroll-behavior: smooth; }

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

body::before {
  content: '';
  position: fixed;
  inset: 0;
  background-image:
    linear-gradient(rgba(59, 130, 246, 0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(59, 130, 246, 0.03) 1px, transparent 1px);
  background-size: 60px 60px;
  pointer-events: none;
  z-index: 0;
}

::selection { background: var(--blue); color: #fff; }

a { color: var(--blue); text-decoration: none; transition: opacity .2s; }
a:hover { opacity: .75; }

.container {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 24px;
  position: relative;
  z-index: 1;
}

/* ========== Navigation ========== */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(10, 14, 23, 0.85);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
}

.nav-inner {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0.7rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 800;
  font-size: 1.15rem;
  color: var(--text);
}

.nav-brand .logo {
  font-size: 1.5rem;
  background: linear-gradient(135deg, var(--blue), var(--cyan));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.nav-links a {
  color: var(--text-2);
  font-size: 0.85rem;
  font-weight: 500;
  transition: color .2s;
}

.nav-links a:hover, .nav-links a.active {
  color: var(--text);
  opacity: 1;
}

.nav-links a.active {
  color: var(--blue);
}

/* ========== Hero ========== */
.hero {
  text-align: center;
  padding: 5rem 0 4rem;
  position: relative;
}

.hero::after {
  content: '';
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(59, 130, 246, 0.08), transparent 70%);
  pointer-events: none;
  z-index: -1;
}

.hero h1 {
  font-size: 3.2rem;
  font-weight: 900;
  background: linear-gradient(135deg, var(--blue), var(--cyan), var(--purple));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: -0.03em;
  line-height: 1.15;
  margin-bottom: 1rem;
}

.hero .tagline {
  font-size: 1.25rem;
  color: var(--text-2);
  max-width: 700px;
  margin: 0 auto 2rem;
  line-height: 1.6;
}

.hero .quote {
  font-size: 0.9rem;
  color: var(--text-3);
  font-style: italic;
  margin-bottom: 2.5rem;
}

/* ========== Buttons ========== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.75rem;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  border: none;
  transition: all .2s;
}

.btn-primary {
  background: linear-gradient(135deg, var(--blue), var(--cyan));
  color: #fff;
  box-shadow: var(--glow-blue);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 0 40px rgba(59, 130, 246, 0.25);
  color: #fff;
  opacity: 1;
}

.btn-outline {
  background: transparent;
  color: var(--text-2);
  border: 1px solid var(--border);
}

.btn-outline:hover {
  border-color: var(--blue);
  color: var(--blue);
  opacity: 1;
}

.btn-group {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}

/* ========== Sections ========== */
section {
  padding: 4rem 0;
}

section + section {
  border-top: 1px solid var(--border);
}

.section-title {
  font-size: 2rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: 0.5rem;
}

.section-sub {
  color: var(--text-2);
  font-size: 0.95rem;
  margin-bottom: 2.5rem;
}

/* ========== Cards ========== */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  transition: all .3s;
}

.card:hover {
  border-color: rgba(59, 130, 246, 0.3);
  box-shadow: var(--glow-blue);
  transform: translateY(-2px);
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.25rem;
}

.card h3 {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.card p {
  font-size: 0.88rem;
  color: var(--text-2);
  line-height: 1.6;
}

/* ========== Stats Row ========== */
.stats-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 1.25rem;
  margin: 2rem 0;
}

.stat-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  text-align: center;
}

.stat-card .number {
  font-size: 2.5rem;
  font-weight: 900;
  font-family: var(--mono);
  background: linear-gradient(135deg, var(--blue), var(--cyan));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1.2;
}

.stat-card .label {
  font-size: 0.78rem;
  color: var(--text-3);
  margin-top: 0.3rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* ========== Tables ========== */
.table-wrap {
  overflow-x: auto;
  margin: 1.5rem 0;
  border-radius: var(--radius);
  border: 1px solid var(--border);
}

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.85rem;
}

th {
  text-align: left;
  padding: 0.7rem 1rem;
  background: var(--bg-2);
  color: var(--text-3);
  font-weight: 600;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  border-bottom: 1px solid var(--border);
}

td {
  padding: 0.65rem 1rem;
  border-bottom: 1px solid rgba(45, 55, 72, 0.5);
  color: var(--text-2);
}

tr:hover td {
  background: rgba(59, 130, 246, 0.04);
}

td.pi { color: var(--blue); font-weight: 700; }
td.pua { color: var(--red); font-weight: 600; }
td.nopua { color: var(--green); font-weight: 600; }

.winner {
  background: rgba(59, 130, 246, 0.08);
}

/* ========== Chart containers ========== */
.chart-container {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem;
  margin: 1.5rem 0;
}

.chart-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
}

/* ========== Bars ========== */
.bar-group {
  margin: 1.5rem 0;
}

.bar-item {
  margin-bottom: 1rem;
}

.bar-label {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.3rem;
  font-size: 0.82rem;
}

.bar-label .name {
  font-weight: 600;
}

.bar-label .value {
  font-family: var(--mono);
  font-weight: 700;
  font-size: 0.9rem;
}

.bar-track {
  height: 28px;
  background: var(--bg-2);
  border-radius: 6px;
  overflow: hidden;
  position: relative;
}

.bar-fill {
  height: 100%;
  border-radius: 6px;
  transition: width 1.5s cubic-bezier(0.4, 0, 0.2, 1);
  position: relative;
}

.bar-fill.pi { background: linear-gradient(90deg, var(--blue), var(--cyan)); }
.bar-fill.pua { background: linear-gradient(90deg, var(--red), var(--pink)); }
.bar-fill.nopua { background: linear-gradient(90deg, var(--green), #34d399); }

/* ========== Tags / Badges ========== */
.tag {
  display: inline-flex;
  align-items: center;
  padding: 0.2rem 0.6rem;
  border-radius: 4px;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.03em;
}

.tag-blue { background: rgba(59, 130, 246, 0.15); color: var(--blue); }
.tag-red { background: rgba(239, 68, 68, 0.15); color: var(--red); }
.tag-green { background: rgba(16, 185, 129, 0.15); color: var(--green); }
.tag-amber { background: rgba(245, 158, 11, 0.15); color: var(--amber); }
.tag-purple { background: rgba(139, 92, 246, 0.15); color: var(--purple); }

/* ========== Install Code Block ========== */
.install-block {
  background: var(--bg-2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem 1.5rem;
  font-family: var(--mono);
  font-size: 0.88rem;
  color: var(--green);
  position: relative;
  overflow-x: auto;
  margin: 1.5rem 0;
}

.install-block .prompt { color: var(--text-3); }

.copy-btn {
  position: absolute;
  top: 0.75rem;
  right: 0.75rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  color: var(--text-3);
  padding: 0.3rem 0.6rem;
  border-radius: 4px;
  cursor: pointer;
  font-size: 0.72rem;
  font-family: var(--font);
  transition: all .2s;
}

.copy-btn:hover { color: var(--blue); border-color: var(--blue); }

/* ========== Footer ========== */
.footer {
  border-top: 1px solid var(--border);
  padding: 2rem 0;
  text-align: center;
  color: var(--text-3);
  font-size: 0.78rem;
}

.footer a { color: var(--text-2); }

/* ========== Verdict / Callout ========== */
.callout {
  border-left: 3px solid var(--blue);
  padding: 1rem 1.25rem;
  background: rgba(59, 130, 246, 0.05);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin: 1.5rem 0;
  font-size: 0.9rem;
  color: var(--text-2);
}

.callout.warn {
  border-left-color: var(--amber);
  background: rgba(245, 158, 11, 0.05);
}

.callout.error {
  border-left-color: var(--red);
  background: rgba(239, 68, 68, 0.05);
}

.callout.success {
  border-left-color: var(--green);
  background: rgba(16, 185, 129, 0.05);
}

.callout strong { color: var(--text); }

/* ========== Verdict table (research page) ========== */
.verdict-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
  margin: 2rem 0;
}

.verdict-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
}

.verdict-card h4 {
  font-size: 0.85rem;
  color: var(--text-3);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.5rem;
}

.verdict-card .verdict {
  font-size: 1.1rem;
  font-weight: 700;
}

.verdict-card .verdict.true { color: var(--green); }
.verdict-card .verdict.partial { color: var(--amber); }
.verdict-card .verdict.false { color: var(--red); }

.verdict-card .detail {
  font-size: 0.82rem;
  color: var(--text-2);
  margin-top: 0.5rem;
  line-height: 1.6;
}

/* ========== Prose (research page) ========== */
.prose h2 {
  font-size: 1.5rem;
  font-weight: 800;
  margin: 3rem 0 1rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border);
}

.prose h2:first-child {
  border-top: none;
  padding-top: 0;
  margin-top: 0;
}

.prose h3 {
  font-size: 1.15rem;
  font-weight: 700;
  margin: 2rem 0 0.75rem;
  color: var(--text);
}

.prose p {
  font-size: 0.9rem;
  color: var(--text-2);
  margin-bottom: 1rem;
  line-height: 1.8;
}

.prose ul, .prose ol {
  font-size: 0.88rem;
  color: var(--text-2);
  margin: 0 0 1.25rem 1.5rem;
  line-height: 1.8;
}

.prose li { margin-bottom: 0.4rem; }
.prose strong { color: var(--text); }

.prose blockquote {
  border-left: 3px solid var(--blue);
  padding: 0.75rem 1rem;
  background: rgba(59, 130, 246, 0.05);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin: 1.25rem 0;
  font-size: 0.88rem;
  color: var(--text-2);
  font-style: italic;
}

/* ========== Platform logos ========== */
.platform-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  justify-content: center;
  margin: 1.5rem 0;
}

.platform-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.4rem 0.8rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 0.78rem;
  color: var(--text-2);
  font-weight: 500;
}

/* ========== Comparison highlight ========== */
.vs-highlight {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: 1.5rem;
  align-items: center;
  margin: 2rem 0;
}

.vs-highlight .vs-label {
  font-size: 1.5rem;
  font-weight: 900;
  color: var(--text-3);
  text-align: center;
}

/* ========== Responsive ========== */
@media (max-width: 768px) {
  .hero h1 { font-size: 2.2rem; }
  .hero .tagline { font-size: 1rem; }
  .card-grid { grid-template-columns: 1fr; }
  .chart-row { grid-template-columns: 1fr; }
  .verdict-grid { grid-template-columns: 1fr; }
  .vs-highlight { grid-template-columns: 1fr; }
  .stats-row { grid-template-columns: repeat(2, 1fr); }
  .nav-links a.hide-mobile { display: none; }
}

@media (max-width: 480px) {
  .hero h1 { font-size: 1.8rem; }
  .stats-row { grid-template-columns: 1fr 1fr; }
  .stat-card .number { font-size: 2rem; }
}