/* ================================================================
   LingType — Unified Design System
   ================================================================ */

/* --- Tokens (light) --- */
:root{
  --bg:#f5f7fb;
  --bg-2:#edf2f8;
  --surface:#ffffff;
  --surface-2:#f7f9fc;
  --surface-alpha:rgba(255,255,255,0.82);
  --header-bg:rgba(245,247,251,0.82);
  --text:#101827;
  --text2:#617086;
  --muted:#98a7be;
  --border:rgba(78,97,126,0.18);
  --accent:#0a66ff;
  --accent-2:#0f766e;
  --accent-3:#b45309;
  --accent-soft:rgba(10,102,255,0.08);
  --accent-soft-2:rgba(15,118,110,0.08);
  --accent-soft-3:rgba(180,83,9,0.08);
  --shadow-sm:0 10px 24px rgba(16,24,39,0.06);
  --shadow-md:0 18px 48px rgba(16,24,39,0.08);
  --shadow-lg:0 28px 64px rgba(16,24,39,0.12);
  --radius:18px;
  --radius-lg:26px;
  --max:1160px;
}

/* --- Tokens (dark) --- */
[data-theme="dark"]{
  --bg:#08101c;
  --bg-2:#0c1624;
  --surface:#0f1928;
  --surface-2:#121f31;
  --surface-alpha:rgba(15,25,40,0.82);
  --header-bg:rgba(8,16,28,0.82);
  --text:#eef5ff;
  --text2:#98a7be;
  --muted:#617086;
  --border:rgba(122,147,184,0.2);
  --accent:#7fb0ff;
  --accent-2:#4ad9c1;
  --accent-3:#f59e0b;
  --accent-soft:rgba(127,176,255,0.08);
  --accent-soft-2:rgba(74,217,193,0.08);
  --accent-soft-3:rgba(245,158,11,0.08);
  --shadow-sm:0 10px 24px rgba(0,0,0,0.2);
  --shadow-md:0 18px 48px rgba(0,0,0,0.28);
  --shadow-lg:0 28px 64px rgba(0,0,0,0.36);
}

/* --- Reset --- */
*,*::before,*::after{ box-sizing:border-box; }
html{ height:100%; scroll-behavior:smooth; }
body{
  margin:0;
  min-height:100%;
  font-family:-apple-system,BlinkMacSystemFont,"SF Pro Display","Helvetica Neue","Segoe UI",sans-serif;
  color:var(--text);
  line-height:1.6;
  -webkit-font-smoothing:antialiased;
  background:
    radial-gradient(circle at top left, var(--accent-soft), transparent 30%),
    linear-gradient(180deg, var(--bg) 0%, var(--bg-2) 100%);
}
html[lang="zh-CN"] body{
  font-family:"PingFang SC","Hiragino Sans GB","Noto Sans CJK SC","Microsoft YaHei",sans-serif;
}
a{ color:var(--text); text-decoration:none; }
a:hover{ color:var(--accent); }

/* --- Layout --- */
.container{
  width:100%;
  max-width:var(--max);
  margin:0 auto;
  padding:0 24px;
}

/* --- Header --- */
.header{
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:24px;
  padding:20px 24px;
  position:sticky;
  top:0;
  z-index:100;
  background:var(--header-bg);
  backdrop-filter:blur(14px);
  -webkit-backdrop-filter:blur(14px);
  border-bottom:1px solid var(--border);
}

/* --- Brand --- */
.brand{
  display:flex;
  align-items:center;
  gap:12px;
  color:var(--text);
}
.brand.small{ font-size:14px; }
.brand-mark{
  width:30px;
  height:30px;
  border-radius:9px;
  display:block;
  box-shadow:0 10px 20px rgba(31,111,235,0.18);
}
.brand.small .brand-mark{
  width:22px;
  height:22px;
  border-radius:7px;
}
.brand-copy{
  display:flex;
  flex-direction:column;
  line-height:1.05;
}
.brand-name{
  font-size:18px;
  font-weight:700;
  letter-spacing:-0.02em;
}
.brand.small .brand-name{ font-size:15px; }
.brand-sub{
  margin-top:3px;
  font-size:11px;
  color:var(--muted);
  letter-spacing:0.08em;
  text-transform:uppercase;
}

/* --- Nav --- */
.nav{
  display:flex;
  align-items:center;
  gap:8px;
  font-size:14px;
}
.nav a{
  color:var(--text2);
  padding:8px 12px;
  border-radius:999px;
  transition:background 160ms,color 160ms;
}
.nav a:hover{
  color:var(--text);
  background:var(--accent-soft);
}

/* Theme toggle */
.theme-toggle{
  appearance:none;
  border:1px solid var(--border);
  border-radius:999px;
  background:transparent;
  color:var(--text2);
  font:inherit;
  font-size:12px;
  font-weight:600;
  padding:6px 16px;
  min-height:36px;
  cursor:pointer;
  transition:all 160ms;
  letter-spacing:0.04em;
}
.theme-toggle:hover{
  border-color:var(--accent);
  color:var(--accent);
}

/* Lang switch */
.lang-switch{
  display:flex;
  gap:4px;
  font-size:13px;
}
.lang-switch a{
  color:var(--muted);
  padding:4px 8px;
  border-radius:999px;
}
.lang-switch a.active{
  color:var(--text);
  font-weight:700;
  background:var(--accent-soft);
}

/* --- Buttons --- */
.btn{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  min-height:44px;
  padding:11px 20px;
  border-radius:999px;
  border:1px solid var(--border);
  background:var(--surface-alpha);
  box-shadow:var(--shadow-sm);
  font-size:14px;
  font-weight:600;
  color:var(--text);
  cursor:pointer;
  text-decoration:none;
  transition:transform 160ms,box-shadow 160ms,border-color 160ms,background 160ms;
}
.btn:hover{
  color:var(--text);
  transform:translateY(-1px);
  box-shadow:var(--shadow-md);
}
.btn-primary{
  background:linear-gradient(135deg,#2478ff 0%,#1458dd 100%);
  border-color:#175fdc;
  color:#fff;
}
.btn-primary:hover{
  color:#fff;
  background:linear-gradient(135deg,#3986ff 0%,#0f4dc6 100%);
}
.btn-ghost{
  background:var(--accent-soft);
  border-color:transparent;
}
.btn-ghost:hover{
  background:var(--accent-soft-2);
}

/* --- Page Layout (sub-pages) --- */
.section{
  padding:72px 24px 0;
}
.page-intro{
  margin-bottom:18px;
}
.page-kicker{
  font-size:11px;
  font-weight:700;
  letter-spacing:0.12em;
  text-transform:uppercase;
  color:var(--accent);
}
.page-copy{
  margin:8px 0 0;
  max-width:45rem;
  color:var(--text2);
  font-size:16px;
}
.section-head{
  display:flex;
  align-items:flex-end;
  justify-content:space-between;
  gap:16px;
  margin-bottom:24px;
}
.section-head h2{
  margin:0;
  font-size:clamp(2rem,3vw,2.9rem);
  font-weight:700;
  line-height:1.05;
  letter-spacing:-0.03em;
}
.section-head p{
  margin:0;
  color:var(--muted);
  font-size:15px;
}

/* --- Cards --- */
.card{
  border:1px solid var(--border);
  border-radius:var(--radius);
  background:var(--surface-alpha);
  padding:22px;
  box-shadow:var(--shadow-sm);
  transition:transform 180ms,box-shadow 180ms,border-color 180ms;
}
.card:hover{
  transform:translateY(-2px);
  box-shadow:var(--shadow-md);
}
.card + .card{ margin-top:16px; }
.card h3{
  margin:0 0 8px;
  font-size:18px;
  line-height:1.2;
  letter-spacing:-0.02em;
}
.card p{
  margin:0;
  color:var(--text2);
  font-size:15px;
}
.cta-row{
  display:flex;
  gap:12px;
  flex-wrap:wrap;
}

/* --- Callout --- */
.callout{
  margin-top:18px;
  padding:18px;
  border:1px solid var(--accent-soft-2);
  border-radius:var(--radius);
  background:var(--accent-soft-2);
}
.callout-title{
  margin-bottom:6px;
  font-weight:700;
  font-size:13px;
  color:var(--accent-2);
  letter-spacing:0.05em;
  text-transform:uppercase;
}
.callout-body{
  color:var(--text2);
  font-size:14px;
}

/* --- Overlay (download) --- */
.overlay{
  display:none;
  position:fixed;
  inset:0;
  z-index:200;
  background:rgba(0,0,0,0.3);
  backdrop-filter:blur(8px);
  -webkit-backdrop-filter:blur(8px);
  align-items:center;
  justify-content:center;
}
.overlay.visible{ display:flex; }
.overlay-card{
  position:relative;
  width:min(430px,92%);
  padding:36px 30px 28px;
  border:1px solid var(--border);
  border-radius:var(--radius-lg);
  background:var(--surface);
  box-shadow:var(--shadow-lg);
  text-align:center;
}
.overlay-close{
  position:absolute;
  top:10px;
  right:10px;
  width:34px;
  height:34px;
  border:none;
  border-radius:50%;
  background:transparent;
  color:var(--muted);
  font-size:22px;
  cursor:pointer;
}
.overlay-close:hover{
  background:var(--accent-soft);
  color:var(--text);
}
.overlay-lead{
  margin:0 0 20px;
  font-size:17px;
  font-weight:700;
  line-height:1.55;
}
.overlay-input{
  display:block;
  width:100%;
  margin-bottom:12px;
  padding:12px 14px;
  border:1px solid var(--border);
  border-radius:14px;
  background:var(--surface-2);
  font-size:15px;
  color:var(--text);
  outline:none;
}
.overlay-input:focus{
  border-color:var(--accent);
  box-shadow:0 0 0 4px var(--accent-soft);
}
.overlay-submit{ width:100%; margin-bottom:12px; }
.overlay-note{ margin:0 0 10px; font-size:12px; }
.overlay-skip{
  display:inline-block;
  font-size:13px;
  color:var(--muted);
}
.overlay-skip:hover{ color:var(--text); }

/* --- Install Steps --- */
.install-steps{
  margin:14px 0 0;
  padding-left:20px;
  color:var(--text2);
  font-size:15px;
  line-height:1.85;
}
.install-steps li{ margin-bottom:4px; }

/* --- Footer --- */
.footer{
  display:flex;
  justify-content:space-between;
  align-items:flex-start;
  gap:18px;
  padding:52px 24px 42px;
  margin-top:72px;
  border-top:1px solid var(--border);
  color:var(--muted);
  font-size:14px;
}
.footer-left{ display:flex; flex-direction:column; gap:8px; }
.footer-right{
  display:flex;
  gap:16px;
  flex-wrap:wrap;
}
.footer a{ color:var(--muted); }
.footer a:hover{ color:var(--text); }

/* --- Utilities --- */
.muted{ color:var(--muted); }
.mono{ font-family:ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,monospace; }


/* ================================================================
   Index Page
   ================================================================ */
body[data-page="index"]{
  --idx-bg:var(--bg);
  --idx-bg-2:var(--bg-2);
  --idx-text:var(--text);
  --idx-muted:var(--text2);
  --idx-line:var(--border);
  --idx-accent:var(--accent);
  --idx-shadow:var(--shadow-md);
  background:
    radial-gradient(circle at top left, var(--accent-soft), transparent 24%),
    linear-gradient(180deg, var(--idx-bg) 0%, var(--idx-bg-2) 100%);
}

/* --- Index header --- */
body[data-page="index"] .idx-header{
  padding:22px 24px 18px;
}
body[data-page="index"] .idx-nav{
  gap:10px;
}
body[data-page="index"] .idx-nav a{
  color:var(--idx-muted);
  padding:8px 0;
  border-radius:0;
  background:none;
}
body[data-page="index"] .idx-nav a:hover{
  color:var(--idx-text);
  background:none;
}
body[data-page="index"] .idx-brand{
  color:var(--idx-text);
}
body[data-page="index"] .idx-brand-copy{ gap:1px; }
body[data-page="index"] .idx-brand .brand-name{ font-size:18px; }
body[data-page="index"] .idx-brand .brand-sub{
  margin-top:2px;
  color:var(--idx-muted);
  font-size:11px;
  letter-spacing:0.16em;
}

/* --- Hero (centered, text-only, Apple-style) --- */
body[data-page="index"] .idx-main{
  color:var(--idx-text);
}
body[data-page="index"] .idx-hero{
  display:flex;
  flex-direction:column;
  align-items:center;
  text-align:center;
  padding:72px 24px 56px;
  border-bottom:1px solid var(--idx-line);
}
body[data-page="index"] .idx-eyebrow{
  margin:0;
  color:var(--idx-accent);
  font-size:11px;
  font-weight:700;
  letter-spacing:0.14em;
  text-transform:uppercase;
}
body[data-page="index"] .idx-title{
  margin:18px 0;
  font-size:clamp(3rem,7vw,5.8rem);
  font-weight:700;
  line-height:1.05;
  letter-spacing:-0.04em;
}
body[data-page="index"] .idx-subtitle{
  margin:0;
  max-width:36rem;
  color:var(--idx-muted);
  font-size:18px;
  line-height:1.7;
}
body[data-page="index"] .idx-actions{
  display:flex;
  gap:12px;
  flex-wrap:wrap;
  justify-content:center;
  margin-top:28px;
}
body[data-page="index"] .idx-btn-secondary{
  background:none;
  border:1px solid var(--idx-line);
  box-shadow:none;
}

/* --- Demos (tabbed, all 4 in one area) --- */
body[data-page="index"] .idx-demos{
  padding:48px 24px 0;
}

/* Tab pills */
body[data-page="index"] .idx-demos-tabs{
  position:relative;
  display:flex;
  gap:4px;
  padding:4px;
  background:var(--surface-alpha);
  border:1px solid var(--idx-line);
  border-radius:999px;
  width:fit-content;
  margin:0 auto;
  box-shadow:inset 0 1px 0 rgba(255,255,255,0.45);
  isolation:isolate;
}
body[data-page="index"] .idx-tab-highlight{
  position:absolute;
  top:4px;
  left:4px;
  height:calc(100% - 8px);
  border-radius:999px;
  background:var(--text);
  box-shadow:
    0 10px 24px rgba(15,23,35,0.14),
    inset 0 1px 0 rgba(255,255,255,0.1);
  transition:
    transform 620ms cubic-bezier(0.22, 1, 0.36, 1),
    width 620ms cubic-bezier(0.22, 1, 0.36, 1),
    height 220ms ease;
  will-change:transform, width;
  z-index:0;
}
body[data-page="index"] .idx-tab{
  position:relative;
  z-index:1;
  padding:8px 18px;
  border:none;
  border-radius:999px;
  background:transparent;
  font:inherit;
  font-size:13px;
  font-weight:600;
  color:var(--idx-muted);
  cursor:pointer;
  transition:color 180ms ease, transform 180ms ease;
  white-space:nowrap;
}
body[data-page="index"] .idx-tab:hover{
  color:var(--idx-text);
  transform:translateY(-1px);
}
body[data-page="index"] .idx-tab.active{
  color:var(--bg);
}
body[data-page="index"] .idx-tab:active{
  transform:translateY(0);
}

/* Demo panels */
body[data-page="index"] .idx-demo-panel{
  display:none;
  grid-template-columns:minmax(0,0.7fr) minmax(0,1.3fr);
  gap:32px;
  align-items:center;
  margin-top:32px;
  padding:28px;
  border:1px solid var(--idx-line);
  border-radius:var(--radius-lg);
  background:var(--surface-alpha);
}
body[data-page="index"] .idx-demo-panel.active{
  display:grid;
}
body[data-page="index"] .idx-demo-info h3{
  margin:0 0 12px;
  font-size:clamp(1.5rem,3vw,2.2rem);
  font-weight:700;
  line-height:1.1;
  letter-spacing:-0.03em;
}
body[data-page="index"] .idx-demo-info p{
  margin:0;
  color:var(--idx-muted);
  font-size:15px;
  line-height:1.7;
}
body[data-page="index"] .idx-demo-frame{
  position:relative;
  overflow:hidden;
  border:1px solid var(--idx-line);
  border-radius:calc(var(--radius-lg) - 6px);
  background:#090d14;
  aspect-ratio:2420 / 1540;
}
body[data-page="index"] .idx-demo-frame video{
  width:100%;
  height:100%;
  display:block;
  object-fit:cover;
  object-position:left top;
  transform:scale(2);
  transform-origin:left top;
  background:#090d14;
}

/* --- Why Section --- */
body[data-page="index"] .idx-why{
  padding:80px 24px 52px;
}
body[data-page="index"] .idx-why-head{
  padding-bottom:24px;
}
body[data-page="index"] .idx-why-head h2{
  margin:0;
  max-width:14ch;
  font-size:clamp(2.4rem,5vw,3.8rem);
  font-weight:700;
  line-height:1.05;
  letter-spacing:-0.04em;
}
body[data-page="index"] .idx-why-grid{
  display:grid;
  grid-template-columns:repeat(3, minmax(0,1fr));
  gap:28px;
}
body[data-page="index"] .idx-why-grid article{
  padding:18px 0 0;
  border-top:3px solid var(--accent);
}
body[data-page="index"] .idx-why-grid article:nth-child(2){
  border-top-color:var(--accent-2);
}
body[data-page="index"] .idx-why-grid article:nth-child(3){
  border-top-color:var(--accent-3);
}
body[data-page="index"] .idx-why-grid h3{
  margin:0 0 12px;
  font-size:clamp(1.4rem,2.4vw,1.8rem);
  font-weight:700;
  line-height:1.1;
  letter-spacing:-0.03em;
}
body[data-page="index"] .idx-why-grid p{
  margin:0;
  color:var(--idx-muted);
  font-size:15px;
  line-height:1.75;
}

/* --- Closing CTA --- */
body[data-page="index"] .idx-closing{
  padding:28px 24px 90px;
}
body[data-page="index"] .idx-closing-banner{
  display:grid;
  grid-template-columns:minmax(0,1fr) auto;
  gap:28px;
  align-items:center;
  padding:34px 38px;
  border-radius:var(--radius-lg);
  background:linear-gradient(135deg, #2f69dc 0%, #2a7ed7 46%, #228d8f 100%);
  color:#fbf6ef;
  box-shadow:0 30px 70px rgba(48,105,220,0.2);
}
body[data-page="index"] .idx-closing-copy{
  display:grid;
  gap:12px;
}
body[data-page="index"] .idx-closing-copy .idx-eyebrow{
  color:rgba(251,246,239,0.76);
}
body[data-page="index"] .idx-closing-copy h2{
  margin:0;
  max-width:18ch;
  font-size:clamp(2.4rem,5vw,4rem);
  font-weight:700;
  line-height:1.05;
  letter-spacing:-0.04em;
}
body[data-page="index"] .idx-closing-copy p{
  margin:0;
  color:rgba(251,246,239,0.82);
  font-size:16px;
  line-height:1.7;
}
body[data-page="index"] .idx-closing-company{
  color:rgba(251,246,239,0.72) !important;
  font-size:12px !important;
  text-transform:uppercase;
  letter-spacing:0.16em;
  font-weight:700;
}
body[data-page="index"] .idx-closing-button{
  min-height:72px;
  padding:0 30px;
  border-radius:999px;
  background:#fbf4ea;
  color:#171d29;
  border:none;
  box-shadow:none;
  font-weight:700;
}
body[data-page="index"] .idx-closing-button:hover{
  background:#ffffff;
  color:#171d29;
}

/* --- Index footer --- */
body[data-page="index"] .idx-footer{
  margin-top:0;
  padding-top:0;
  border-top:none;
  color:var(--idx-muted);
}
body[data-page="index"] .idx-footer a,
body[data-page="index"] .idx-footer .muted{
  color:var(--idx-muted);
}
body[data-page="index"] .idx-footer a:hover{
  color:var(--idx-text);
}


/* ================================================================
   Responsive
   ================================================================ */
@media (max-width:980px){
  body[data-page="index"] .idx-closing-banner{
    grid-template-columns:1fr;
  }
  body[data-page="index"] .idx-demo-panel,
  body[data-page="index"] .idx-demo-panel.active{
    grid-template-columns:1fr;
  }
  body[data-page="index"] .idx-why-grid{
    grid-template-columns:1fr;
  }
}

@media (max-width:760px){
  .header,
  .footer{
    flex-direction:column;
    align-items:flex-start;
  }
  .nav{
    flex-wrap:wrap;
    gap:6px;
  }
  .section-head{
    flex-direction:column;
    align-items:flex-start;
  }
  body[data-page="index"] .idx-header,
  body[data-page="index"] .idx-footer{
    flex-direction:column;
    align-items:flex-start;
  }
  body[data-page="index"] .idx-nav{
    flex-wrap:wrap;
  }
  body[data-page="index"] .idx-hero{
    padding:48px 24px 40px;
  }
  body[data-page="index"] .idx-demos{
    padding:32px 16px 0;
  }
  body[data-page="index"] .idx-demos-tabs{
    flex-wrap:wrap;
    border-radius:var(--radius);
    width:100%;
    justify-content:center;
  }
  body[data-page="index"] .idx-demo-panel{
    padding:18px;
    margin-top:20px;
  }
  body[data-page="index"] .idx-why{
    padding:56px 24px 40px;
  }
  body[data-page="index"] .idx-closing{
    padding:20px 24px 60px;
  }
  body[data-page="index"] .idx-closing-banner{
    padding:26px 22px;
    border-radius:24px;
  }
  body[data-page="index"] .idx-closing-copy h2{
    max-width:12ch;
  }
}