:root{
  --bg:#0b0f1a;--bg2:#0f1526;--panel:#131a2e;--panel2:#182038;--line:rgba(255,255,255,.08);
  --text:#e8ecf5;--muted:#8d97b3;--brand:#4f7cff;--brand2:#22d3ee;--ok:#22c55e;--warn:#f59e0b;--bad:#ef4444;
  --radius:16px;--shadow:0 20px 60px rgba(0,0,0,.45);
  --font:-apple-system,BlinkMacSystemFont,"PingFang SC","Hiragino Sans GB","Microsoft YaHei","Noto Sans SC","Noto Sans CJK SC","Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;font-family:var(--font);background:var(--bg);color:var(--text);line-height:1.6;-webkit-font-smoothing:antialiased}
a{color:inherit;text-decoration:none}
img,svg{max-width:100%}
.container{max-width:1140px;margin:0 auto;padding:0 24px}
.hidden{display:none!important}
.muted{color:var(--muted)}.small{font-size:13px}.center{text-align:center}
.sep{opacity:.4;margin:0 6px}

/* buttons */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;border:1px solid transparent;border-radius:12px;padding:10px 18px;font-weight:600;font-size:15px;cursor:pointer;transition:.15s;white-space:nowrap;font-family:inherit}
.btn-primary{background:linear-gradient(135deg,var(--brand),#3b5bdb);color:#fff;box-shadow:0 8px 24px rgba(79,124,255,.35)}
.btn-primary:hover{transform:translateY(-1px);box-shadow:0 12px 30px rgba(79,124,255,.45)}
.btn-ghost{background:rgba(255,255,255,.04);border-color:var(--line);color:var(--text)}
.btn-ghost:hover{background:rgba(255,255,255,.08)}
.btn-lg{padding:14px 26px;font-size:16px;border-radius:14px}
.btn-sm{padding:7px 13px;font-size:13px;border-radius:10px}
.btn-block{width:100%}
.btn:disabled{opacity:.5;cursor:not-allowed;transform:none}

/* nav */
.nav{position:sticky;top:0;z-index:50;backdrop-filter:blur(14px);background:rgba(11,15,26,.75);border-bottom:1px solid var(--line)}
.nav-inner{display:flex;align-items:center;justify-content:space-between;height:64px;gap:16px}
.brand{display:flex;align-items:center;gap:10px;font-weight:700;font-size:18px}
.logo{width:34px;height:34px;border-radius:9px;object-fit:cover;box-shadow:0 2px 8px rgba(34,211,238,.25)}
.footer .logo{width:28px;height:28px;border-radius:7px;margin-right:8px;vertical-align:middle}
.nav-links{display:flex;gap:28px;font-size:15px;color:var(--muted)}
.nav-links a:hover{color:var(--text)}
.nav-actions{display:flex;align-items:center;gap:12px}
.lang-switch{display:flex;border:1px solid var(--line);border-radius:10px;overflow:hidden}
.lang-switch button{background:transparent;border:0;color:var(--muted);padding:6px 11px;font-size:13px;font-weight:600;cursor:pointer;font-family:inherit}
.lang-switch button.active{background:rgba(255,255,255,.1);color:var(--text)}

/* hero */
.hero{position:relative;overflow:hidden;padding:88px 0 72px}
.hero-glow{position:absolute;inset:-20% -10% auto;height:700px;background:radial-gradient(600px 400px at 30% 20%,rgba(79,124,255,.28),transparent 60%),radial-gradient(500px 350px at 80% 30%,rgba(34,211,238,.18),transparent 60%);pointer-events:none}
.hero-inner{position:relative;display:grid;grid-template-columns:1.15fr .85fr;gap:48px;align-items:center}
.pill{display:inline-flex;align-items:center;gap:8px;border:1px solid var(--line);background:rgba(255,255,255,.04);border-radius:999px;padding:6px 14px;font-size:13px;color:var(--muted);margin-bottom:22px}
.pill .dot{width:8px;height:8px;border-radius:50%;background:var(--ok);box-shadow:0 0 0 4px rgba(34,197,94,.2)}
h1{font-size:clamp(38px,6vw,64px);line-height:1.12;margin:0 0 20px;font-weight:800;letter-spacing:-.02em}
.lead{font-size:18px;color:var(--muted);max-width:540px;margin:0 0 30px}
.hero-actions{display:flex;gap:12px;flex-wrap:wrap;margin-bottom:40px}
.hero-stats{display:flex;gap:36px}
.stat-v{font-size:26px;font-weight:800;font-variant-numeric:tabular-nums}
.stat-l{font-size:13px;color:var(--muted)}

/* phone mock */
.hero-visual{display:flex;justify-content:center}
.phone{width:300px;background:var(--panel);border:1px solid var(--line);border-radius:28px;padding:14px;box-shadow:var(--shadow);transform:rotate(-3deg)}
.phone-top{display:flex;justify-content:space-between;align-items:center;padding:8px 6px 12px;border-bottom:1px solid var(--line);font-weight:600}
.ph-status{display:flex;align-items:center;gap:6px;font-size:12px;color:var(--muted);font-weight:500}
.ph-status i{width:7px;height:7px;border-radius:50%;background:var(--ok)}
.phone-body{padding:14px 4px;display:flex;flex-direction:column;gap:10px;min-height:220px}
.bub{max-width:80%;padding:9px 13px;border-radius:16px;font-size:13.5px;line-height:1.45}
.bub.them{background:var(--panel2);border-bottom-left-radius:5px;align-self:flex-start}
.bub.me{background:linear-gradient(135deg,var(--brand),#3b5bdb);color:#fff;border-bottom-right-radius:5px;align-self:flex-end}
.bub.typing{display:flex;gap:4px;padding:11px 14px}
.bub.typing span{width:6px;height:6px;border-radius:50%;background:rgba(255,255,255,.8);animation:blink 1.2s infinite}
.bub.typing span:nth-child(2){animation-delay:.2s}.bub.typing span:nth-child(3){animation-delay:.4s}
@keyframes blink{0%,80%,100%{opacity:.3}40%{opacity:1}}
.phone-input{display:flex;justify-content:space-between;align-items:center;background:var(--bg);border:1px solid var(--line);border-radius:14px;padding:9px 14px;font-size:13px;color:var(--muted)}
.phone-input b{color:var(--brand)}

/* sections */
.section{padding:80px 0}
.section-head{max-width:680px;margin:0 auto 44px;text-align:center}
.eyebrow{display:inline-block;color:var(--brand2);font-weight:700;font-size:13px;letter-spacing:.08em;text-transform:uppercase;margin-bottom:12px}
h2{font-size:clamp(28px,4vw,40px);margin:0 0 14px;letter-spacing:-.02em;line-height:1.2}
.section-head p{color:var(--muted);font-size:16px;margin:0}
.grid-3{display:grid;grid-template-columns:repeat(3,1fr);gap:20px}
.card{background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);padding:26px}
.card .ico{font-size:26px;margin-bottom:12px}
.card h3{margin:0 0 8px;font-size:17px}
.card p{margin:0;color:var(--muted);font-size:14.5px}

/* demo */
.demo{background:var(--bg2);border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.demo-grid{display:grid;grid-template-columns:300px 1fr;gap:28px;align-items:start}
.steps{list-style:none;margin:0 0 20px;padding:0;display:flex;flex-direction:column;gap:14px}
.steps li{display:flex;gap:14px;align-items:flex-start}
.steps b{flex:none;width:30px;height:30px;border-radius:10px;background:linear-gradient(135deg,var(--brand),var(--brand2));color:#fff;display:flex;align-items:center;justify-content:center;font-size:14px}
.steps strong{display:block;font-size:15px;margin-bottom:2px}
.steps span{color:var(--muted);font-size:13.5px}
.tip{background:rgba(245,158,11,.08);border:1px solid rgba(245,158,11,.25);border-radius:12px;padding:14px;font-size:13px;color:#e5c07b}
.tip strong{display:block;margin-bottom:4px;color:#fbbf24}

.chat{background:var(--panel);border:1px solid var(--line);border-radius:20px;box-shadow:var(--shadow);overflow:hidden;min-height:560px;display:flex;flex-direction:column}
.chat-join{flex:1;display:flex;align-items:center;justify-content:center;padding:40px 24px}
.chat-join-inner{width:100%;max-width:380px}
.chat-join h3{margin:0 0 20px;font-size:22px;text-align:center}
.chat-join label{display:block;margin-bottom:14px}
.chat-join label span{display:block;font-size:13px;color:var(--muted);margin-bottom:6px}
input{width:100%;background:var(--bg);border:1px solid var(--line);color:var(--text);border-radius:12px;padding:11px 14px;font-size:15px;font-family:inherit;outline:none;transition:.15s}
input:focus{border-color:var(--brand);box-shadow:0 0 0 3px rgba(79,124,255,.2)}
.chat-join .btn{margin-top:6px}

.chat-main{flex:1;display:flex;flex-direction:column;min-height:560px}
.chat-head{display:flex;justify-content:space-between;align-items:center;padding:14px 18px;border-bottom:1px solid var(--line);gap:12px;flex-wrap:wrap}
.chat-room{font-weight:700;font-size:16px}
.chat-meta{font-size:12.5px;color:var(--muted);display:flex;align-items:center;flex-wrap:wrap}
.conn{display:inline-flex;align-items:center;gap:6px}
.conn i{width:8px;height:8px;border-radius:50%;background:var(--warn)}
.conn.ok i{background:var(--ok);box-shadow:0 0 0 3px rgba(34,197,94,.2)}
.conn.bad i{background:var(--bad)}
.chat-head-r{display:flex;gap:8px}
.chat-body{flex:1;display:grid;grid-template-columns:1fr 180px;min-height:0}
.chat-messages{padding:16px 18px;overflow-y:auto;max-height:420px;display:flex;flex-direction:column;gap:8px}
.chat-users{border-left:1px solid var(--line);padding:14px;font-size:13px;overflow-y:auto;max-height:420px}
.chat-users-t{color:var(--muted);font-size:12px;text-transform:uppercase;letter-spacing:.06em;margin-bottom:10px}
.chat-users ul{list-style:none;margin:0;padding:0;display:flex;flex-direction:column;gap:6px}
.chat-users li{display:flex;align-items:center;gap:8px}
.chat-users li i{width:7px;height:7px;border-radius:50%;background:var(--ok);flex:none}
.chat-users li.me{color:var(--brand2)}
.msg{max-width:78%;display:flex;flex-direction:column;gap:3px}
.msg .who{font-size:11.5px;color:var(--muted);padding:0 4px}
.msg .body{padding:9px 13px;border-radius:15px;font-size:14.5px;line-height:1.45;word-break:break-word;white-space:pre-wrap}
.msg .time{font-size:10.5px;color:var(--muted);padding:0 4px;opacity:.8}
.msg.them{align-self:flex-start}.msg.them .body{background:var(--panel2);border-bottom-left-radius:5px}
.msg.me{align-self:flex-end;align-items:flex-end}.msg.me .body{background:linear-gradient(135deg,var(--brand),#3b5bdb);color:#fff;border-bottom-right-radius:5px}
.msg.me.pending .body{opacity:.6}
.msg.me.failed .body{background:var(--bad);opacity:.8}.msg.me.failed .time{color:var(--bad)}
.msg.sys{align-self:center;max-width:100%}.msg.sys .body{background:transparent;color:var(--muted);font-size:12px;padding:2px 10px}
.chat-typing{height:22px;padding:0 18px;font-size:12px;color:var(--muted);font-style:italic}
.chat-input{display:flex;gap:10px;padding:12px 14px;border-top:1px solid var(--line)}
.chat-input input{flex:1}

/* download */
.dl-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:18px;margin-bottom:22px}
.dl-grid.cols-3{grid-template-columns:repeat(5,1fr);gap:14px}
.dl-grid.cols-3 .dl{padding:44px 16px 16px;min-height:0}
.dl-grid.cols-3 .dl-head{flex-direction:column;gap:10px}
.dl-grid.cols-3 .dl-ico{width:40px;height:40px;font-size:22px}
.dl-grid.cols-3 .dl-t{font-size:15px}
.dl-grid.cols-3 .dl-s{font-size:12px}
.dl-grid.cols-3 .btn{font-size:13.5px;padding:10px 10px;white-space:normal;line-height:1.3;text-align:center}
.dl-grid.cols-3 .dl-qr{gap:10px;font-size:12px}
.dl-grid.cols-3 .dl-qr img{width:64px;height:64px}
.dl-grid.cols-3 .dl-sha{font-size:11px;flex-wrap:nowrap}
.dl-grid.cols-3 .dl-sha>span:first-child{display:none}
.dl-grid.cols-3 .dl-sha code{white-space:nowrap}
.dl-grid.cols-3 .dl-url{font-size:11px}
.dl-grid.cols-3 .dl-hint{font-size:11.5px}
.dl-grid.cols-3 > .dl > .dl-head > .badge{top:12px;right:12px;font-size:10.5px;padding:3px 8px}
/* Align header / button / extras / checksum rows across all download cards */
@supports (grid-template-rows: subgrid) {
  .dl-grid.cols-3{grid-auto-rows:auto}
  .dl-grid.cols-3 .dl{display:grid;grid-template-rows:subgrid;grid-row:span 4;gap:12px;align-content:start}
  .dl-grid.cols-3 .dl-body{display:contents}
  .dl-grid.cols-3 .dl-head{grid-row:1;align-self:start}
  .dl-grid.cols-3 .dl-body>.dl-qr,.dl-grid.cols-3 .dl-body>.dl-hint,.dl-grid.cols-3 .dl-body>.dl-url{grid-row:2;align-self:start}
  .dl-grid.cols-3 .dl-sha{grid-row:3;align-self:end}
  .dl-grid.cols-3 .dl-body>.btn{grid-row:4;align-self:stretch;margin-top:4px}
}

.dl-group{font-size:13px;font-weight:700;letter-spacing:.08em;text-transform:uppercase;color:var(--muted);margin:0 0 14px;text-align:center}
.dl-grid+.dl-group{margin-top:18px}
.dl-windows{border-color:rgba(56,189,248,.35);background:linear-gradient(180deg,rgba(56,189,248,.06),transparent 60%),var(--panel)}
.dl-hint{font-size:12px;color:var(--muted);line-height:1.5}
.dl{position:relative;background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);padding:48px 20px 20px;display:flex;flex-direction:column;gap:16px;transition:.15s;min-height:250px}
.dl>.dl-head>.badge{position:absolute;top:14px;right:14px}
.dl:hover{border-color:rgba(79,124,255,.5);transform:translateY(-2px)}
.dl-android{border-color:rgba(61,220,132,.35);background:linear-gradient(180deg,rgba(61,220,132,.06),transparent 60%),var(--panel)}
.dl-soon{opacity:.75}
.dl-head{display:flex;align-items:flex-start;gap:12px}
.dl-head>div{flex:1;min-width:0}
.dl-ico{flex:none;width:44px;height:44px;border-radius:12px;background:rgba(255,255,255,.05);display:flex;align-items:center;justify-content:center;font-size:24px}
.dl-t{display:block;font-weight:700;font-size:16px;line-height:1.3}
.dl-s{display:block;font-size:12.5px;color:var(--muted);margin-top:3px;line-height:1.45}
.dl-body{margin-top:auto;display:flex;flex-direction:column;gap:12px}
.dl-qr{display:flex;align-items:center;gap:12px;font-size:12.5px;color:var(--muted)}
.dl-qr img{width:84px;height:84px;border-radius:8px;background:#fff;padding:4px;flex:none}
.dl-url{font-size:12px;color:var(--muted);text-align:center;font-family:ui-monospace,SFMono-Regular,Menlo,monospace}
.dl-sha{display:flex;align-items:center;gap:8px;font-size:11.5px;color:var(--muted);flex-wrap:wrap}
.dl-sha code{font-family:ui-monospace,SFMono-Regular,Menlo,monospace;background:rgba(255,255,255,.05);padding:2px 6px;border-radius:6px;color:var(--text)}
.linkbtn{background:none;border:0;color:var(--brand2);font-size:11.5px;cursor:pointer;padding:0;font-family:inherit;font-weight:600}
.linkbtn:hover{text-decoration:underline}
.badge{flex:none;font-size:11px;font-weight:700;letter-spacing:.04em;padding:4px 10px;border-radius:999px;background:rgba(245,158,11,.14);color:#fbbf24;white-space:nowrap}
.badge.live{background:rgba(34,197,94,.14);color:#4ade80}
.dl-notes{max-width:760px;margin:0;text-align:left}
.dl-notes p{margin:6px 0}

/* feedback */
.feedback{background:var(--bg2);border-top:1px solid var(--line);border-bottom:1px solid var(--line);padding:56px 0}
.feedback-inner{display:flex;justify-content:space-between;align-items:center;gap:24px;flex-wrap:wrap}
.feedback h2{font-size:26px;margin-bottom:6px}.feedback p{margin:0;color:var(--muted)}

.footer{padding:28px 0}
.footer-inner{display:flex;justify-content:space-between;align-items:center;gap:12px;flex-wrap:wrap}

.toast{position:fixed;bottom:24px;left:50%;transform:translateX(-50%) translateY(20px);background:#1f2a48;border:1px solid var(--line);color:#fff;padding:10px 18px;border-radius:12px;font-size:14px;opacity:0;pointer-events:none;transition:.2s;z-index:100;box-shadow:var(--shadow)}
.toast.show{opacity:1;transform:translateX(-50%) translateY(0)}

@media (max-width:1100px){
  .dl-grid.cols-3{grid-template-columns:repeat(3,1fr)}
}
@media (max-width:960px){
  .hero-inner{grid-template-columns:1fr}
  .hero-visual{display:none}
  .grid-3{grid-template-columns:1fr 1fr}
  .demo-grid{grid-template-columns:1fr}
  .dl-grid,.dl-grid.cols-3{grid-template-columns:1fr 1fr}
  .dl-grid.cols-3 .dl-head{flex-direction:row}
  .nav-links{display:none}
}
@media (max-width:600px){
  .hero{padding:56px 0 48px}
  .grid-3,.dl-grid,.dl-grid.cols-3{grid-template-columns:1fr}
  .dl{min-height:0}
  .chat-body{grid-template-columns:1fr}
  .chat-users{display:none}
  .hero-stats{gap:22px}
  .section{padding:56px 0}
  .nav-actions .btn{display:none}
}