:root{--bg:#fff;--fg:#0f172a;--muted:#5b6475;--line:#e6e8ee;--soft:#f6f7fb;--brand:#4f46e5;--brand2:#06b6d4;--radius:14px;--max:1120px}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;font-family:Inter,system-ui,-apple-system,"Segoe UI",Roboto,"PingFang SC","Microsoft YaHei","Noto Sans CJK SC",sans-serif;color:var(--fg);background:var(--bg);line-height:1.6;-webkit-font-smoothing:antialiased}
a{color:var(--brand);text-decoration:none}a:hover{text-decoration:underline}
img{max-width:100%}
.container{max-width:var(--max);margin:0 auto;padding:0 20px}
/* language toggle */
html[lang="zh"] .en{display:none!important}
html:not([lang="zh"]) .zh{display:none!important}
/* header */
.site-header{position:sticky;top:0;z-index:20;background:rgba(255,255,255,.85);backdrop-filter:saturate(180%) blur(10px);border-bottom:1px solid var(--line)}
.nav{display:flex;align-items:center;justify-content:space-between;height:64px;gap:16px}
.logo{display:flex;align-items:center;gap:10px;font-weight:800;font-size:20px;color:var(--fg)}
.logo:hover{text-decoration:none}
.logo img{width:30px;height:30px}
.nav-links{display:flex;align-items:center;gap:22px}
.nav-links a{color:var(--muted);font-weight:500}
.nav-links a:hover,.nav-links a.active{color:var(--fg);text-decoration:none}
.lang-btn{border:1px solid var(--line);background:#fff;border-radius:999px;padding:6px 12px;font:inherit;font-size:14px;cursor:pointer;color:var(--fg)}
.lang-btn:hover{border-color:var(--brand)}
.menu-btn{display:none;border:0;background:none;font-size:24px;cursor:pointer;color:var(--fg)}
@media (max-width:760px){
 .menu-btn{display:block}
 .nav-links{display:none;position:absolute;top:64px;left:0;right:0;flex-direction:column;align-items:flex-start;background:#fff;border-bottom:1px solid var(--line);padding:16px 20px;gap:14px}
 .nav-links.open{display:flex}
}
/* buttons */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;padding:12px 22px;border-radius:12px;font-weight:600;border:1px solid transparent;cursor:pointer;font-size:16px;transition:transform .08s ease,box-shadow .2s}
.btn:hover{text-decoration:none;transform:translateY(-1px)}
.btn-primary{background:linear-gradient(135deg,var(--brand),#7c3aed);color:#fff;box-shadow:0 8px 24px -8px rgba(79,70,229,.6)}
.btn-ghost{background:#fff;color:var(--fg);border-color:var(--line)}
.btn-block{width:100%}
/* hero */
.hero{padding:80px 0 56px;background:radial-gradient(1200px 400px at 50% -10%,rgba(79,70,229,.12),transparent),radial-gradient(600px 300px at 90% 10%,rgba(6,182,212,.12),transparent)}
.hero-grid{display:grid;grid-template-columns:1.1fr .9fr;gap:48px;align-items:center}
.eyebrow{display:inline-block;font-size:13px;font-weight:600;color:var(--brand);background:rgba(79,70,229,.08);padding:5px 12px;border-radius:999px;margin-bottom:16px}
h1{font-size:clamp(34px,5vw,54px);line-height:1.1;margin:0 0 18px;letter-spacing:-.02em}
.grad{background:linear-gradient(135deg,var(--brand),var(--brand2));-webkit-background-clip:text;background-clip:text;color:transparent}
.lead{font-size:19px;color:var(--muted);margin:0 0 28px;max-width:560px}
.cta-row{display:flex;gap:12px;flex-wrap:wrap}
.note{font-size:13px;color:var(--muted);margin-top:14px}
@media (max-width:900px){.hero-grid{grid-template-columns:1fr}.hero{padding:56px 0 40px}}
/* chat mock */
.chat{background:#fff;border:1px solid var(--line);border-radius:20px;box-shadow:0 30px 60px -30px rgba(15,23,42,.35);overflow:hidden}
.chat-top{display:flex;align-items:center;gap:8px;padding:12px 16px;border-bottom:1px solid var(--line);background:var(--soft);font-size:14px;font-weight:600}
.dot{width:10px;height:10px;border-radius:50%;background:#e2e8f0}
.chat-body{padding:18px;display:flex;flex-direction:column;gap:12px;background:#fbfbfe}
.msg{max-width:82%;padding:10px 14px;border-radius:14px;font-size:15px}
.msg small{display:block;margin-top:6px;padding-top:6px;border-top:1px dashed rgba(0,0,0,.12);color:var(--muted);font-size:13px}
.msg.in{background:#fff;border:1px solid var(--line);align-self:flex-start}
.msg.out{background:#eef2ff;align-self:flex-end}
.chat-input{display:flex;gap:8px;padding:12px;border-top:1px solid var(--line)}
.chat-input div{flex:1;border:1px solid var(--line);border-radius:10px;padding:8px 12px;font-size:14px;color:var(--muted)}
.chat-input .send{background:var(--brand);color:#fff;border-radius:10px;padding:8px 12px;font-size:13px;font-weight:600}
/* sections */
section{padding:72px 0}
.section-soft{background:var(--soft)}
.section-head{text-align:center;max-width:680px;margin:0 auto 44px}
h2{font-size:clamp(26px,3.4vw,36px);margin:0 0 12px;letter-spacing:-.01em;line-height:1.2}
.section-head p{color:var(--muted);font-size:17px;margin:0}
.grid-3{display:grid;grid-template-columns:repeat(3,1fr);gap:20px}
.grid-2{display:grid;grid-template-columns:repeat(2,1fr);gap:20px}
@media (max-width:900px){.grid-3{grid-template-columns:1fr 1fr}}
@media (max-width:620px){.grid-3,.grid-2{grid-template-columns:1fr}}
.card{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:24px}
.card h3{margin:10px 0 6px;font-size:18px}
.card p{margin:0;color:var(--muted)}
.icon{width:42px;height:42px;border-radius:12px;display:grid;place-items:center;font-size:20px;background:linear-gradient(135deg,rgba(79,70,229,.12),rgba(6,182,212,.12))}
.steps{counter-reset:s}
.step{position:relative;padding-left:0}
.step .num{width:36px;height:36px;border-radius:50%;background:var(--brand);color:#fff;display:grid;place-items:center;font-weight:700}
/* FAQ */
.faq{max-width:780px;margin:0 auto}
details{border:1px solid var(--line);border-radius:12px;background:#fff;padding:0 20px;margin-bottom:12px}
summary{cursor:pointer;font-weight:600;padding:18px 0;list-style:none;display:flex;justify-content:space-between;gap:12px}
summary::-webkit-details-marker{display:none}
summary::after{content:"+";color:var(--muted);font-size:20px;line-height:1}
details[open] summary::after{content:"–"}
details p{margin:0 0 18px;color:var(--muted)}
/* pricing */
.pricing{display:grid;grid-template-columns:repeat(3,1fr);gap:20px;align-items:stretch}
@media (max-width:900px){.pricing{grid-template-columns:1fr;max-width:460px;margin:0 auto}}
.plan{display:flex;flex-direction:column;background:#fff;border:1px solid var(--line);border-radius:18px;padding:28px;position:relative}
.plan.featured{border:2px solid var(--brand);box-shadow:0 24px 48px -24px rgba(79,70,229,.45)}
.badge{position:absolute;top:-12px;left:50%;transform:translateX(-50%);background:var(--brand);color:#fff;font-size:12px;font-weight:700;padding:4px 12px;border-radius:999px;white-space:nowrap}
.plan h3{margin:0;font-size:20px}
.price{font-size:42px;font-weight:800;margin:12px 0 0;letter-spacing:-.02em}
.price span{font-size:16px;font-weight:500;color:var(--muted)}
.plan .sub{color:var(--muted);font-size:14px;margin:4px 0 20px;min-height:22px}
.plan ul{list-style:none;padding:0;margin:0 0 24px;flex:1}
.plan li{padding:7px 0 7px 28px;position:relative}
.plan li::before{content:"✓";position:absolute;left:0;color:var(--brand);font-weight:700}
.plan li.no{color:var(--muted)}.plan li.no::before{content:"–";color:#cbd5e1}
table.compare{width:100%;border-collapse:collapse;background:#fff;border:1px solid var(--line);border-radius:12px;overflow:hidden;font-size:15px}
.compare th,.compare td{padding:12px 16px;border-bottom:1px solid var(--line);text-align:left}
.compare th{background:var(--soft)}
.table-wrap{overflow-x:auto}
/* legal */
.page-head{padding:56px 0 24px;border-bottom:1px solid var(--line);background:var(--soft)}
.page-head h1{font-size:clamp(30px,4vw,42px);margin-bottom:8px}
.page-head p{color:var(--muted);margin:0}
.legal{max-width:800px;margin:0 auto;padding:40px 20px 72px}
.legal h2{font-size:22px;margin:36px 0 10px}
.legal h3{font-size:17px;margin:22px 0 6px}
.legal p,.legal li{color:#2b3343}
.legal ul{padding-left:22px}
.callout{background:#fffbeb;border:1px solid #fde68a;border-radius:12px;padding:14px 18px;font-size:15px;margin:20px 0}
.callout.info{background:#eff6ff;border-color:#bfdbfe}
.todo{background:#fef3c7;border-bottom:2px dotted #d97706;padding:0 3px;border-radius:3px}
/* contact */
.contact-grid{display:grid;grid-template-columns:1fr 1fr;gap:24px;max-width:900px;margin:0 auto}
@media (max-width:760px){.contact-grid{grid-template-columns:1fr}}
.email-big{font-size:20px;font-weight:700;word-break:break-all}
/* footer */
.site-footer{border-top:1px solid var(--line);padding:40px 0;color:var(--muted);font-size:14px;background:#fff}
.footer-grid{display:flex;justify-content:space-between;gap:24px;flex-wrap:wrap}
.footer-links{display:flex;gap:18px;flex-wrap:wrap}
.footer-links a{color:var(--muted)}
.cta-band{background:linear-gradient(135deg,var(--brand),#7c3aed);color:#fff;border-radius:22px;padding:48px 32px;text-align:center}
.cta-band h2{color:#fff}.cta-band p{opacity:.9;margin:0 0 24px}
.cta-band .btn{background:#fff;color:var(--brand)}
/* hero demo */
.chat-body{height:330px;overflow:hidden;transition:opacity .5s}
.chat-body.fade-out{opacity:0}
.live-pill{margin-left:auto;font-size:11px;font-weight:700;color:#059669;background:#d1fae5;border-radius:999px;padding:2px 8px}
.pop{animation:pop .35s ease-out both}
@keyframes pop{from{opacity:0;transform:translateY(8px) scale(.98)}to{opacity:1;transform:none}}
.fade-in{animation:fadein .4s ease-out both}
@keyframes fadein{from{opacity:0}to{opacity:1}}
.translating{color:var(--brand)!important;font-style:italic}
.dots{display:inline-flex;gap:3px;margin-left:5px;vertical-align:middle}
.dots b{width:4px;height:4px;border-radius:50%;background:currentColor;animation:blink 1s infinite}
.dots b:nth-child(2){animation-delay:.15s}.dots b:nth-child(3){animation-delay:.3s}
@keyframes blink{0%,80%,100%{opacity:.25}40%{opacity:1}}
#demo-input.typing-on{color:var(--fg)}
#demo-input.typing-on>span::after{content:"";display:inline-block;width:1px;height:1em;background:var(--fg);margin-left:1px;vertical-align:-2px;animation:blink 1s infinite}
.chat-input .send{transition:transform .15s,background .15s}
.chat-input .send.pressed{transform:scale(.92);background:#3730a3}
@media (prefers-reduced-motion: reduce){.pop,.fade-in,.dots b{animation:none!important}}
/* affiliate */
.aff-band{display:flex;align-items:center;justify-content:space-between;gap:24px;background:#fff;border:1px solid var(--line);border-radius:20px;padding:32px}
.aff-band p{color:var(--muted);margin:0}
@media (max-width:760px){.aff-band{flex-direction:column;align-items:flex-start}}
.kv{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}
@media (max-width:760px){.kv{grid-template-columns:1fr}}
.kv .card b{display:block;font-size:24px;margin-top:4px}

/* v5: one-account band, download cards, comparison tables */
.one-acct-wrap{padding:8px 0 0}
.one-acct{display:flex;align-items:center;gap:20px;background:linear-gradient(135deg,rgba(79,70,229,.08),rgba(6,182,212,.08));border:1px solid rgba(79,70,229,.25);border-radius:var(--radius);padding:24px 28px}
.one-acct .icon{font-size:34px;margin:0}
.one-acct h2{margin:0 0 6px;font-size:24px}
.one-acct p{margin:0;color:var(--muted)}
.one-acct .btn{flex-shrink:0}
@media(max-width:760px){.one-acct{flex-direction:column;align-items:flex-start}}
.browser-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:18px}
@media(max-width:960px){.browser-grid{grid-template-columns:repeat(2,1fr)}}
@media(max-width:560px){.browser-grid{grid-template-columns:1fr}}
.browser{position:relative;display:flex;flex-direction:column}
.browser .bicon{width:52px;height:52px;border-radius:14px;display:grid;place-items:center;font-weight:800;color:#fff;font-size:22px;margin-bottom:12px}
.browser p{flex:1}
.browser .btn{margin-top:14px}
.browser.detected{border-color:var(--brand);box-shadow:0 0 0 3px rgba(79,70,229,.15)}
.browser .here{display:none;position:absolute;top:14px;right:14px;font-size:12px;font-weight:700;color:var(--brand);background:rgba(79,70,229,.1);padding:3px 9px;border-radius:999px}
.browser.detected .here{display:inline-block}
.btn.soon{background:var(--soft);color:var(--muted);border-color:var(--line);box-shadow:none;cursor:default;pointer-events:none}
.table-wrap{overflow-x:auto;border:1px solid var(--line);border-radius:var(--radius);background:#fff}
table.cmp{width:100%;border-collapse:collapse;font-size:15px;min-width:760px}
table.cmp th,table.cmp td{padding:12px 14px;border-bottom:1px solid var(--line);text-align:left;vertical-align:top}
table.cmp thead th{background:var(--soft);font-size:14px}
table.cmp tr:last-child td{border-bottom:0}
table.cmp tr.us td{background:rgba(79,70,229,.06)}
table.cmp tr.us td:first-child{font-weight:700}
table.cmp sup a{font-size:11px}
.cmp small{color:var(--muted);display:block}
.sources{font-size:13px;color:var(--muted);margin-top:18px}
.sources li{margin:4px 0;word-break:break-word}

/* voice (coming soon) */
.voice-pill{display:inline-flex;align-items:center;gap:8px;font-size:13px;font-weight:600;color:#0f766e;background:rgba(6,182,212,.12);border:1px solid rgba(6,182,212,.35);padding:5px 12px 5px 5px;border-radius:999px;margin:0 0 12px}
.voice-pill:hover{text-decoration:none;border-color:#0891b2}
.vp-new{background:linear-gradient(135deg,var(--brand),var(--brand2));color:#fff;border-radius:999px;padding:2px 8px;font-size:11px;letter-spacing:.04em}
.soon-badge{display:inline-block;font-size:12px;font-weight:700;color:#92400e;background:#fef3c7;border:1px solid #fde68a;padding:3px 10px;border-radius:999px;margin-bottom:12px}
.voice-sec{padding-top:56px}
.voice-grid{display:grid;grid-template-columns:1.2fr 1fr;gap:40px;align-items:center}
@media(max-width:860px){.voice-grid{grid-template-columns:1fr}}
.voice-steps{color:var(--muted);padding-left:20px;margin:0}
.voice-steps li{margin:6px 0}
.voice-msg .wave{font-family:ui-monospace,monospace;letter-spacing:1px;color:var(--brand);font-weight:600}
.voice-plan{display:flex;align-items:center;justify-content:space-between;gap:20px;margin-top:20px;border:1px dashed rgba(79,70,229,.4);background:linear-gradient(135deg,rgba(79,70,229,.05),rgba(6,182,212,.06));border-radius:var(--radius);padding:22px 26px}
.voice-plan h3{margin:0 0 6px}.voice-plan h3 small{font-weight:500;color:var(--muted);font-size:14px}
.voice-plan p{margin:0;color:var(--muted)}
.voice-plan .btn{flex-shrink:0}
@media(max-width:760px){.voice-plan{flex-direction:column;align-items:flex-start}}