/* Product website: one stylesheet for every page. No external fonts or scripts.
   Colours come only from the tokens below; contrast_check.py reads these tokens. */
:root{
  --bg:#FFFFFF;--surface:#F4F7FA;--surface-2:#E8EFF5;--ink:#0F1B26;--ink-2:#33475B;--muted:#5B6B7B;--line:#DCE4EC;
  --brand:#0E3A5B;--accent:#1F5F8B;--amber:#F2A33A;
  --btn-bg:#0E3A5B;--btn-ink:#FFFFFF;--icon:#0E3A5B;
  --warn-bg:#FFF3D6;--warn-ink:#6B4500;--bad:#B3261E;
  --font:-apple-system,BlinkMacSystemFont,"Segoe UI","Hiragino Sans","Hiragino Kaku Gothic ProN","PingFang SC","Hiragino Sans GB","Microsoft YaHei UI","Microsoft YaHei","Yu Gothic UI","Meiryo","Noto Sans CJK SC","Noto Sans CJK JP",sans-serif;
  --mono:"SF Mono","Cascadia Mono",Consolas,"Liberation Mono",monospace;
  --radius:14px;color-scheme:light;
}
@media (prefers-color-scheme:dark){:root:not([data-theme="light"]){
  --bg:#0B1621;--surface:#12212F;--surface-2:#18293A;--ink:#E8EFF5;--ink-2:#B8C7D6;--muted:#8DA0B3;--line:#23384C;
  --brand:#8CC4EE;--accent:#8CC4EE;--amber:#F2A33A;
  --btn-bg:#F2A33A;--btn-ink:#0B1621;--icon:#8CC4EE;
  --warn-bg:#3D2E0E;--warn-ink:#FFD98A;--bad:#FF8A80;color-scheme:dark}}
:root[data-theme="dark"]{
  --bg:#0B1621;--surface:#12212F;--surface-2:#18293A;--ink:#E8EFF5;--ink-2:#B8C7D6;--muted:#8DA0B3;--line:#23384C;
  --brand:#8CC4EE;--accent:#8CC4EE;--amber:#F2A33A;
  --btn-bg:#F2A33A;--btn-ink:#0B1621;--icon:#8CC4EE;
  --warn-bg:#3D2E0E;--warn-ink:#FFD98A;--bad:#FF8A80;color-scheme:dark}
*{box-sizing:border-box}
[hidden]{display:none!important}
html{-webkit-text-size-adjust:100%;background:var(--bg)}
body{margin:0;background:var(--bg);color:var(--ink);font:16px/1.75 var(--font);-webkit-font-smoothing:antialiased;overflow-wrap:break-word;min-height:100vh;display:flex;flex-direction:column}
main{flex:1 0 auto}
a{color:var(--accent);text-underline-offset:2px}
img{max-width:100%;height:auto;display:block}
code{font-family:var(--mono);font-size:.88em;background:var(--surface);border:1px solid var(--line);border-radius:5px;padding:0 .3em;overflow-wrap:anywhere}
.wrap{max-width:1080px;margin:0 auto;padding:0 20px}
.narrow{max-width:760px}

/* light/dark logo swap */
.on-dark{display:none}
@media (prefers-color-scheme:dark){:root:not([data-theme="light"]) .on-dark{display:block}:root:not([data-theme="light"]) .on-light{display:none}}
:root[data-theme="dark"] .on-dark{display:block}:root[data-theme="dark"] .on-light{display:none}

/* header */
.top{position:sticky;top:0;z-index:5;background:color-mix(in srgb,var(--bg) 90%,transparent);backdrop-filter:saturate(1.4) blur(10px);border-bottom:1px solid var(--line)}
.top .wrap{display:flex;align-items:center;gap:18px;height:62px}
.brand{display:flex;align-items:center;gap:9px;color:var(--ink);text-decoration:none;font-weight:700;font-size:17px;white-space:nowrap;letter-spacing:-.01em}
.brand img{width:34px;height:auto}
.brand .alt-name{font-weight:600;color:var(--ink-2);font-size:14px;margin-left:2px}
.nav{display:flex;gap:2px;margin-left:auto;overflow-x:auto;scrollbar-width:none}
.nav::-webkit-scrollbar{display:none}
.nav a{color:var(--ink-2);text-decoration:none;font-size:14.5px;padding:6px 10px;border-radius:8px;white-space:nowrap}
.nav a:hover{background:var(--surface);color:var(--ink)}
.nav a[aria-current="page"]{color:var(--ink);background:var(--surface-2);font-weight:600}
.lang{display:inline-flex;border:1px solid var(--line);border-radius:8px;overflow:hidden;flex:none}
.lang button{border:0;background:none;color:var(--ink-2);font:inherit;font-size:13px;padding:4px 10px;cursor:pointer;min-height:30px}
.lang button+button{border-left:1px solid var(--line)}
.lang button[aria-pressed="true"]{background:var(--surface-2);color:var(--ink);font-weight:600}
@media (max-width:760px){.top .wrap{height:auto;flex-wrap:wrap;padding-top:10px;padding-bottom:8px;gap:8px 12px}.nav{order:3;width:calc(100% + 20px);margin:0 -10px}.lang{margin-left:auto}}

/* language switching: every page carries all its languages; site.js sets <html lang> */
[data-l]{display:none!important}
html[lang="en"] [data-l="en"],html[lang="zh-CN"] [data-l="zh"],html[lang="ja"] [data-l="ja"]{display:revert!important}

/* hero */
.hero{padding:76px 0 44px;text-align:center}
.eyebrow{display:inline-flex;align-items:center;gap:8px;font-size:13.5px;font-weight:600;color:var(--ink);background:color-mix(in srgb,var(--amber) 16%,var(--bg));border:1px solid color-mix(in srgb,var(--amber) 45%,var(--bg));border-radius:999px;padding:3px 14px;margin-bottom:20px}
.eyebrow::before{content:"";width:8px;height:8px;border-radius:50%;background:var(--amber);flex:none}
.hero h1{font-size:clamp(32px,5.4vw,56px);line-height:1.12;letter-spacing:-.02em;margin:0 auto 18px;max-width:15em;color:var(--ink)}
.hero h1 .hl{color:var(--brand)}
html[lang="ja"] .hero h1{line-height:1.3}
.nw{white-space:nowrap}
.hero p.lead{font-size:clamp(17px,2.1vw,20px);color:var(--ink-2);max-width:36em;margin:0 auto 28px}
.cta{display:flex;gap:12px;justify-content:center;flex-wrap:wrap}
.cta.left{justify-content:flex-start}
.btn{display:inline-flex;align-items:center;gap:8px;padding:11px 20px;border-radius:10px;font:inherit;font-weight:600;text-decoration:none;font-size:15.5px;line-height:1.4;border:1px solid transparent;cursor:pointer}
.btn.primary{background:var(--btn-bg);color:var(--btn-ink)}
.btn.primary:hover{filter:brightness(1.08)}
.btn.ghost,.btn.secondary{border-color:var(--line);color:var(--ink);background:var(--bg)}
.btn.ghost:hover,.btn.secondary:hover{background:var(--surface)}
.btn[aria-disabled="true"]{opacity:.55;pointer-events:none}
.note{font-size:13.5px;color:var(--muted);margin-top:14px}
.shot{margin:44px auto 0;max-width:1000px;border-radius:12px;overflow:hidden;border:1px solid var(--line);box-shadow:0 24px 60px -24px rgba(14,58,91,.35)}

/* sections */
section{padding:60px 0}
section.alt{background:var(--surface)}
h2{font-size:clamp(24px,3vw,32px);line-height:1.25;letter-spacing:-.01em;margin:0 0 12px;color:var(--ink)}
h3{font-size:18px;line-height:1.4;margin:0 0 6px;color:var(--ink)}
.sub{color:var(--ink-2);max-width:42em;margin:0 0 32px}
.grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%,280px),1fr));gap:18px}
.card{background:var(--bg);border:1px solid var(--line);border-radius:var(--radius);padding:22px;min-width:0}
.card p{margin:0;color:var(--ink-2);font-size:15px}
.ic{width:38px;height:38px;border-radius:10px;background:var(--surface-2);display:grid;place-items:center;margin-bottom:12px;color:var(--icon);position:relative}
.ic::after{content:"";position:absolute;right:-2px;top:-2px;width:8px;height:8px;border-radius:50%;background:var(--amber)}
.ic svg{width:20px;height:20px;stroke:currentColor;fill:none;stroke-width:2;stroke-linecap:round;stroke-linejoin:round}
section.alt .ic{background:var(--surface-2)}
ul.checks{list-style:none;padding:0;margin:14px 0 0}
ul.checks li{position:relative;padding-left:26px;margin:6px 0;color:var(--ink-2)}
ul.checks li::before{content:"";position:absolute;left:2px;top:.55em;width:12px;height:7px;border-left:2px solid var(--accent);border-bottom:2px solid var(--accent);transform:rotate(-45deg)}
.split{display:grid;grid-template-columns:1fr 1fr;gap:36px;align-items:start}
@media (max-width:820px){.split{grid-template-columns:1fr;gap:20px}}
.policy-link{display:flex;flex-wrap:wrap;gap:8px 18px;margin-top:22px;font-weight:600}

/* documents (privacy, guide, faq, support, feedback) */
.doc{padding:44px 20px 72px}
.doc h1{font-size:clamp(28px,4vw,38px);line-height:1.25;margin:0 0 6px;color:var(--ink)}
.doc .date{color:var(--muted);font-size:14px;margin-bottom:28px}
.doc h2{font-size:21px;margin:40px 0 10px;scroll-margin-top:90px}
.doc h3{font-size:17px;margin:24px 0 6px}
.doc p,.doc li{color:var(--ink-2)}
.doc li{margin:.3em 0}
.doc p.note{font-size:14.5px;background:var(--surface);border-left:3px solid var(--amber);border-radius:0 10px 10px 0;padding:10px 14px;margin:0 0 24px;color:var(--ink-2)}
.sum{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:18px 20px;margin-bottom:28px}
.sum ul{margin:0;padding-left:1.2em}.sum li{margin:.35em 0}
.sum strong{color:var(--ink)}
.tw{border:1px solid var(--line);border-radius:12px;overflow:auto;margin:12px 0}
table{width:100%;border-collapse:collapse;font-size:14.5px}
th,td{text-align:left;vertical-align:top;padding:10px 12px;border-top:1px solid var(--line)}
th{background:var(--surface);color:var(--ink);font-weight:600;border-top:0}
td:first-child{font-weight:600;font-size:13.5px;color:var(--ink);min-width:9em;overflow-wrap:anywhere}
td:first-child code{font-weight:400}
@media (max-width:600px){.tw table,.tw tbody,.tw tr,.tw td{display:block}.tw thead{display:none}
  .tw tr{padding:10px 0;border-top:1px solid var(--line)}.tw tr:first-child{border-top:0}.tw td{border:0;padding:3px 14px;min-width:0}
  .net td:nth-child(3){color:var(--muted);font-size:13.5px}
  [data-l="zh"] .net td:nth-child(3)::before{content:"登录信息："}[data-l="en"] .net td:nth-child(3)::before{content:"Sign-in: "}[data-l="ja"] .net td:nth-child(3)::before{content:"ログイン情報："}}
.steps{counter-reset:s;list-style:none;padding:0;margin:18px 0}
.steps>li{counter-increment:s;position:relative;padding:0 0 18px 48px}
.steps>li::before{content:counter(s);position:absolute;left:0;top:0;width:32px;height:32px;border-radius:50%;background:var(--btn-bg);color:var(--btn-ink);font-weight:700;display:grid;place-items:center;font-size:14px}
.steps>li h3{margin-top:3px}
.steps>li p{margin:0}
details{border:1px solid var(--line);border-radius:12px;padding:12px 16px;margin:10px 0;background:var(--bg)}
details summary{cursor:pointer;font-weight:600;color:var(--ink)}
details[open] summary{margin-bottom:6px}
details p{margin:.4em 0}
.callout{background:var(--warn-bg);color:var(--warn-ink);border-radius:10px;padding:10px 14px;font-size:14.5px}
.callout strong{color:inherit}
.tag{display:inline-block;font-size:12px;font-weight:600;border-radius:999px;padding:2px 10px;background:var(--surface-2);color:var(--ink-2)}
.toc{display:flex;flex-wrap:wrap;gap:6px 8px;margin:0 0 8px;padding:0;list-style:none}
.toc a{display:inline-block;font-size:14px;padding:3px 10px;border:1px solid var(--line);border-radius:999px;text-decoration:none;color:var(--ink-2)}
.toc a:hover{background:var(--surface)}

/* feedback form */
.privacy-note{padding:12px 14px;border-radius:12px;background:color-mix(in srgb,var(--accent) 9%,var(--bg));border:1px solid color-mix(in srgb,var(--accent) 22%,var(--bg));font-size:14.5px;color:var(--ink-2);margin-bottom:24px}
.privacy-note b{color:var(--ink)}
form.fb{display:grid;gap:20px}
form.fb fieldset{border:0;margin:0;padding:0;min-width:0}
form.fb legend,form.fb .lab{display:block;font-weight:600;font-size:14.5px;margin-bottom:8px;padding:0;color:var(--ink)}
form.fb .opt{font-weight:400;color:var(--muted);font-size:13px;margin-left:6px}
form.fb .req{color:var(--bad);margin-left:4px}
.types{display:grid;grid-template-columns:repeat(auto-fill,minmax(200px,1fr));gap:8px}
.types label{display:flex;gap:10px;align-items:flex-start;padding:10px 12px;border:1px solid var(--line);border-radius:10px;cursor:pointer;background:var(--bg);color:var(--ink);font-size:15px;line-height:1.5}
.types label:has(input:checked){border-color:var(--accent);background:color-mix(in srgb,var(--accent) 9%,var(--bg))}
.types input{margin-top:4px;accent-color:var(--accent)}
.types small{display:block;color:var(--muted);font-size:12.5px;line-height:1.5}
form.fb input[type=text],form.fb input[type=email],form.fb select,form.fb textarea{width:100%;font:inherit;font-size:15px;color:var(--ink);background:var(--bg);border:1px solid var(--line);border-radius:10px;padding:10px 12px}
form.fb textarea{min-height:170px;resize:vertical;line-height:1.6}
form.fb input:focus,form.fb select:focus,form.fb textarea:focus{outline:2px solid var(--accent);outline-offset:0;border-color:transparent}
.help{font-size:13px;color:var(--muted);margin-top:6px}
.help.warn{color:var(--warn-ink);background:var(--warn-bg);border-radius:6px;padding:2px 8px;display:inline-block}
.count{float:right;font-variant-numeric:tabular-nums}
.row2{display:grid;grid-template-columns:1fr 1fr;gap:16px}
@media (max-width:560px){.row2{grid-template-columns:1fr}}
.diag{border:1px solid var(--line);border-radius:12px;padding:12px 14px;background:var(--surface)}
.diag>label{display:flex;gap:10px;align-items:flex-start;font-weight:600;font-size:14.5px;cursor:pointer;color:var(--ink)}
.diag>label input{margin-top:5px;accent-color:var(--accent)}
.diag>label small{display:block;font-weight:400;color:var(--muted);font-size:13px}
.diag ul{list-style:none;margin:10px 0 0;padding:0;display:grid;gap:6px}
.diag li{display:flex;align-items:center;gap:10px;padding:6px 10px;border-radius:8px;background:var(--bg);border:1px solid var(--line);font-size:13.5px;margin:0}
.diag li .k{color:var(--muted);min-width:96px}
.diag li code{font-size:13px;overflow-wrap:anywhere;flex:1;background:none;border:0;padding:0}
.diag li button{font:inherit;font-size:12.5px;border:1px solid var(--line);background:var(--surface);color:var(--ink-2);border-radius:6px;padding:2px 8px;cursor:pointer}
.diag .none{color:var(--muted);font-size:13px;margin:8px 0 0}
.diag.off ul{opacity:.5}
.hp{position:absolute!important;left:-10000px!important;width:1px;height:1px;overflow:hidden}
.actions{display:flex;flex-wrap:wrap;gap:10px;align-items:center}
.btn.primary:disabled{opacity:.6;cursor:progress}
.status{padding:12px 14px;border-radius:10px;font-size:14px;color:var(--ink)}
.status.ok{background:color-mix(in srgb,var(--accent) 12%,var(--bg))}
.status.err{background:color-mix(in srgb,var(--bad) 12%,var(--bg))}
.status.info{background:var(--surface);color:var(--ink-2)}
.preview{font-family:var(--mono);font-size:12.5px;white-space:pre-wrap;overflow-wrap:anywhere;background:var(--surface);border:1px solid var(--line);border-radius:10px;padding:10px 12px;max-height:260px;overflow:auto;margin:8px 0 0;color:var(--ink)}
details.sent{border:0;padding:0;margin:8px 0 0;background:none}
details.sent summary{color:var(--accent);font-size:14px;font-weight:600}

/* footer */
footer.foot{border-top:1px solid var(--line);padding:32px 0 44px;color:var(--muted);font-size:13.5px;background:var(--bg)}
footer.foot .wrap{display:flex;flex-wrap:wrap;gap:16px 28px;justify-content:space-between}
footer.foot .fine{max-width:560px;display:grid;gap:4px}
footer.foot .wm{width:150px;margin-bottom:6px}
footer.foot nav{display:flex;flex-wrap:wrap;gap:6px 18px;align-content:flex-start}
footer.foot a{color:var(--ink-2)}
.skip{position:absolute;left:-9999px}.skip:focus{left:12px;top:10px;z-index:9;background:var(--bg);padding:6px 10px;border-radius:6px}
:focus-visible{outline:2px solid var(--accent);outline-offset:2px}