/* ═══════════════════════════════════════════════════════════
   BinTranslate — dark tech theme (哥飞标准)
   ═══════════════════════════════════════════════════════════ */
:root {
  --bg: #09090b;
  --surface: #18181b;
  --surface-el: #27272a;
  --border: #3f3f46;
  --border-hover: #22d3ee;
  --primary: #22d3ee;
  --primary-hover: #06b6d4;
  --primary-muted: rgba(34, 211, 238, 0.08);
  --text: #e4e4e7;
  --text-heading: #fafafa;
  --text-muted: #a1a1aa;
  --text-dim: #71717a;
  --accent: #22d3ee;
  --danger: #ef4444;
  --success: #4ade80;
  --warning: #fbbf24;
  --radius-sm: 6px;
  --radius: 10px;
  --radius-lg: 16px;
  --radius-xl: 20px;
  --font: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'SF Mono', SFMono-Regular, 'JetBrains Mono', 'Cascadia Code', Consolas, monospace;
  --ease: cubic-bezier(0.16, 1, 0.3, 1);
  --shadow: 0 1px 3px rgba(0,0,0,0.4);
  --shadow-md: 0 4px 16px rgba(0,0,0,0.4);
  --shadow-lg: 0 8px 32px rgba(0,0,0,0.5);
}
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
}
a { color: var(--primary); text-decoration: none; transition: color .2s; }
a:hover { color: var(--primary-hover); }
strong { color: var(--text-heading); font-weight: 600; }
code {
  font-family: var(--font-mono);
  background: var(--surface);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 0.88em;
  color: var(--primary);
  border: 1px solid var(--border);
}
img { max-width: 100%; height: auto; display: block; }

/* ── Nav (sticky enhanced) ── */
.top-bar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}
.top-bar-inner {
  max-width: 1000px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 56px;
  padding: 0 20px;
  gap: 12px;
}
.top-bar .brand {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-heading);
  text-decoration: none;
  white-space: nowrap;
  font-family: var(--font-mono);
}
.top-bar .brand:hover { color: var(--primary); text-decoration: none; }
.top-bar .brand svg { width: 22px; height: 22px; }
.nav-links {
  display: flex;
  gap: 2px;
  align-items: center;
  overflow-x: auto;
  scrollbar-width: none;
  -ms-overflow-style: none;
}
.nav-links::-webkit-scrollbar { display: none; }
.nav-links a {
  color: var(--text-muted);
  font-size: 0.8rem;
  padding: 6px 10px;
  border-radius: var(--radius-sm);
  transition: all .2s var(--ease);
  white-space: nowrap;
  text-decoration: none;
}
.nav-links a:hover { color: var(--text); background: var(--primary-muted); text-decoration: none; }
.nav-links a.active { color: var(--primary); background: var(--primary-muted); font-weight: 600; }
.nav-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--text);
  font-size: 1.3rem;
  cursor: pointer;
  padding: 4px 6px;
}

/* ── Container ── */
.container { max-width: 1000px; margin: 0 auto; padding: 0 20px; width: 100%; }

/* ── Hero ── */
.hero {
  padding: 48px 0 32px;
  text-align: center;
}
.hero h1 {
  font-size: clamp(1.6rem, 3.2vw, 2.4rem);
  font-weight: 700;
  line-height: 1.2;
  color: var(--text-heading);
  max-width: 720px;
  margin: 0 auto 12px;
}
.hero p {
  color: var(--text-muted);
  font-size: 1.05rem;
  max-width: 560px;
  margin: 0 auto;
}

.hero-stats{display:flex;justify-content:center;gap:40px;margin-top:20px;flex-wrap:wrap}
.hero-stat{text-align:center}
.hero-stat .num{font-size:1.5rem;font-weight:800;color:var(--text-heading);letter-spacing:-.02em}
.hero-stat .label{font-size:.72rem;color:#94a3b8;text-transform:uppercase;letter-spacing:.04em;margin-top:2px}

.hero-stats{display:flex;justify-content:center;gap:40px;margin-top:20px;flex-wrap:wrap}
.hero-stat{text-align:center}
.hero-stat .num{font-size:1.5rem;font-weight:800;color:var(--text-heading);letter-spacing:-.02em}
.hero-stat .label{font-size:.72rem;color:#94a3b8;text-transform:uppercase;letter-spacing:.04em;margin-top:2px}

/* ── Header (内页) ── */
.page-header {
  padding: 32px 0 16px;
  text-align: center;
}
.page-header h1 {
  font-size: clamp(1.3rem, 2.5vw, 1.8rem);
  font-weight: 700;
  color: var(--text-heading);
}
.page-header p {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin-top: 6px;
}
.breadcrumb {
  font-size: 0.8rem;
  color: var(--text-dim);
  margin-bottom: 12px;
}
.breadcrumb a { color: var(--text-muted); }
.breadcrumb a:hover { color: var(--primary); }

/* ── Mode Tabs ── */
.mode-tabs {
  display: flex;
  gap: 4px;
  padding: 4px;
  background: var(--surface);
  border-radius: var(--radius);
  border: 1px solid var(--border);
  margin: 0 0 20px;
  overflow-x: auto;
  scrollbar-width: none;
}
.mode-tabs::-webkit-scrollbar { display: none; }
.mode-tab {
  flex: 1;
  min-width: fit-content;
  padding: 8px 14px;
  border: none;
  background: transparent;
  color: var(--text-muted);
  font-family: var(--font);
  font-size: 0.82rem;
  font-weight: 500;
  border-radius: 6px;
  cursor: pointer;
  transition: all .2s var(--ease);
  white-space: nowrap;
  display: flex;
  align-items: center;
  gap: 4px;
}
.mode-tab:hover { color: var(--text); background: var(--primary-muted); }
.mode-tab.active {
  color: var(--text-heading);
  background: var(--surface-el);
  font-weight: 600;
}
.mode-tab.active::before {
  content: '>';
  color: var(--primary);
  font-family: var(--font-mono);
  font-weight: 700;
}

/* ── Converter Card ── */
.converter-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 24px;
  margin: 0 0 24px;
}
.converter-card textarea {
  width: 100%;
  min-height: 120px;
  padding: 14px;
  background: var(--bg);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-family: var(--font-mono);
  font-size: 0.92rem;
  line-height: 1.6;
  resize: vertical;
  outline: none;
  transition: border-color .2s;
}
.converter-card textarea:focus { border-color: var(--primary); box-shadow: 0 0 0 1px var(--primary); }
.converter-card textarea::placeholder { color: var(--text-dim); }
.btn-group {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin: 12px 0;
}
.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 9px 20px;
  border: none;
  border-radius: var(--radius);
  font-family: var(--font);
  font-size: 0.88rem;
  font-weight: 600;
  cursor: pointer;
  transition: all .2s var(--ease);
  text-decoration: none;
}
.btn-primary { background: var(--primary); color: #09090b; }
.btn-primary:hover { background: var(--primary-hover); color: #09090b; }
.btn-secondary {
  background: var(--surface-el);
  color: var(--text);
  border: 1px solid var(--border);
}
.btn-secondary:hover { border-color: var(--primary); color: var(--primary); }
.btn-secondary:active { transform: scale(0.97); }
.btn-sm { padding: 6px 12px; font-size: 0.8rem; }
.label-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin: 8px 0 4px;
}
.label-row label { font-size: 0.85rem; font-weight: 600; color: var(--text-muted); }
.label-row > div { display: flex; align-items: center; gap: 8px; }
.char-count { font-size: 0.75rem; color: var(--text-dim); font-family: var(--font-mono); }
.copy-btn, .btn-download {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text-muted);
  padding: 4px 12px;
  border-radius: var(--radius-sm);
  font-size: 0.78rem;
  cursor: pointer;
  font-family: var(--font);
  transition: all .2s;
}
.copy-btn:hover, .btn-download:hover { border-color: var(--primary); color: var(--primary); }

.knowledge-card {
  display: none;
  margin-top: 16px;
  padding: 14px;
  background: var(--bg);
  border-radius: var(--radius);
  border: 1px solid var(--border);
  border-left: 3px solid var(--primary);
  font-size: 0.85rem;
  line-height: 1.6;
}
.knowledge-card .label { color: var(--primary); font-weight: 600; margin-bottom: 4px; display: flex; align-items: center; gap: 6px; }
.knowledge-card .text { color: var(--text-muted); }

/* ── Info Section (内页内容) ── */
.info-section { display: flex; flex-direction: column; gap: 20px; margin: 24px 0; }
.info-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 24px;
}
.info-card h2 {
  font-size: clamp(1rem, 1.8vw, 1.2rem);
  font-weight: 600;
  color: var(--text-heading);
  margin-bottom: 12px;
}
.info-card h3 {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-heading);
  margin: 20px 0 8px;
}
.info-card h3:first-child { margin-top: 0; }
.info-card p { color: var(--text-muted); font-size: 0.92rem; line-height: 1.75; margin-bottom: 12px; }
.info-card p:last-child { margin-bottom: 0; }
.info-card ul, .info-card ol {
  color: var(--text-muted);
  font-size: 0.92rem;
  line-height: 1.75;
  padding-left: 20px;
  margin-bottom: 12px;
}
.info-card ul:last-child, .info-card ol:last-child { margin-bottom: 0; }
.info-card li { margin-bottom: 6px; }
.info-card li strong { color: var(--text); }

/* ── 首页 info-grid (3列) ── */
.info-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 12px;
  margin: 24px 0;
}

/* ── FAQ ── */
.faq-section { margin: 24px 0; }
.faq-item {
  border-bottom: 1px solid var(--border);
  padding: 14px 0;
}
.faq-item:last-child { border-bottom: none; }
.faq-item h3 {
  font-size: 0.92rem;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 4px;
}
.faq-item p {
  color: var(--text-muted);
  font-size: 0.88rem;
  line-height: 1.7;
  margin: 0;
}

/* ── Related / Internal Links ── */
.related-section { margin: 24px 0; }
.related-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}
.related-btn {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 8px 16px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text-muted);
  font-size: 0.85rem;
  font-weight: 500;
  text-decoration: none;
  transition: all .2s var(--ease);
}
.related-btn:hover {
  border-color: var(--primary);
  color: var(--primary);
  text-decoration: none;
}

/* ── Table ── */
.data-table {
  width: 100%;
  border-collapse: collapse;
  margin: 16px 0;
  font-size: 0.88rem;
}
.data-table th {
  background: var(--surface);
  color: var(--text-heading);
  font-weight: 600;
  padding: 10px 12px;
  text-align: left;
  border-bottom: 2px solid var(--border);
}
.data-table td {
  padding: 10px 12px;
  border-bottom: 1px solid var(--border);
  color: var(--text-muted);
}
.data-table tr:hover td { background: var(--primary-muted); }

/* ── 首页 Mode Tab 下的示例按钮 ── */
.example-label { font-size: 0.8rem; color: var(--text-dim); margin-bottom: 6px; }

/* ── Footer ── */
.site-footer {
  margin-top: auto;
  padding: 28px 20px;
  border-top: 1px solid var(--border);
  background: var(--surface);
}
.footer-inner {
  max-width: 1000px;
  margin: 0 auto;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}
.footer-links {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}
.footer-links a { color: var(--text-dim); font-size: 0.82rem; }
.footer-links a:hover { color: var(--primary); }
.footer-copy { color: var(--text-dim); font-size: 0.82rem; }

/* ── Back to Top ── */
.back-to-top {
  position: fixed;
  bottom: 24px;
  right: 24px;
  z-index: 50;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--surface-el);
  color: var(--text-muted);
  border: 1px solid var(--border);
  cursor: pointer;
  font-size: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transform: translateY(12px);
  pointer-events: none;
  transition: all .25s var(--ease);
}
.back-to-top.visible { opacity: 1; transform: translateY(0); pointer-events: auto; }
.back-to-top:hover { border-color: var(--primary); color: var(--primary); }

/* ── Animations ── */
@keyframes fadeIn { 0% { opacity: 0; } 100% { opacity: 1; } }
@keyframes slideUp { 0% { opacity: 0; transform: translateY(20px); } 100% { opacity: 1; transform: translateY(0); } }

.anim-fade { animation: fadeIn 0.5s ease-out forwards; }
.anim-up { animation: slideUp 0.5s var(--ease) forwards; }
.anim-delay-1 { animation-delay: 0.1s; }
.anim-delay-2 { animation-delay: 0.2s; }
.anim-delay-3 { animation-delay: 0.3s; }

.info-card, .faq-item, .converter-card { animation: slideUp 0.5s var(--ease) both; }
.converter-card { animation-delay: 0.05s; }
.info-card:nth-child(1) { animation-delay: 0.1s; }
.info-card:nth-child(2) { animation-delay: 0.15s; }
.info-card:nth-child(3) { animation-delay: 0.2s; }
.info-card:nth-child(4) { animation-delay: 0.25s; }
.info-card:nth-child(5) { animation-delay: 0.3s; }

/* ── Responsive ── */
@media (max-width: 768px) {
  .nav-links { display: none; }
  .nav-links.open { display: flex; flex-wrap: wrap; position: absolute; top: 56px; left: 0; right: 0; padding: 12px 20px 16px; background: var(--bg); border-bottom: 1px solid var(--border); gap: 4px; }
  .nav-toggle { display: block; }
  .hero { padding: 32px 0 24px; }
  .page-header { padding: 24px 0 12px; }
  .converter-card { padding: 16px; }
  .info-card { padding: 16px; }
  .mode-tabs { gap: 2px; padding: 3px; }
  .mode-tab { padding: 6px 10px; font-size: 0.78rem; }
  .info-grid { grid-template-columns: 1fr; }
}
@media (max-width: 480px) {
  .top-bar-inner { padding: 0 12px; }
  .container { padding: 0 12px; }
  .hero h1 { font-size: 1.3rem; }
  .converter-card { padding: 12px; border-radius: var(--radius); }
  .info-card { padding: 14px; }
}