/* Layout: full-width bands with a 1120px inner column; tools use a two-column form + result layout that stacks on phones */
:root{
  --bg:#F3F6F5; --surface:#FFFFFF; --tint:#E3EEEC; --ink:#13302F; --muted:#4C6867; --line:#D5E0DE;
  --accent:#0E6E68; --accent-ink:#FFFFFF; --accent-soft:#E0F0EE;
  --stamp:#9A5A0E; --stamp-soft:#F7EBD9;
  --good:#1E7A45; --good-soft:#E2F2E8; --bad:#A23B2E; --bad-soft:#F8E4E1;
  --band:#13302F; --band-ink:#E4EFED; --band-muted:#B9CFCC; --band-btn:#5CC4BA; --band-btn-ink:#0E1B1B;
  --display:"Bricolage Grotesque","Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei","Noto Sans SC",system-ui,sans-serif;
  --body:"Source Sans 3","Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei","Noto Sans SC",system-ui,sans-serif;
  --mono:"IBM Plex Mono",ui-monospace,Menlo,monospace;
}
@media (prefers-color-scheme: dark){:root:not([data-theme="light"]){
  --bg:#0E1B1B; --surface:#152626; --tint:#1A3030; --ink:#E4EFED; --muted:#9DB6B3; --line:#284040;
  --accent:#5CC4BA; --accent-ink:#0E1B1B; --accent-soft:#183634;
  --stamp:#E3A651; --stamp-soft:#33291A;
  --good:#6FD39A; --good-soft:#173323; --bad:#F08A7B; --bad-soft:#3A1F1B;
  --band:#091313; --band-ink:#E4EFED; --band-muted:#9DB6B3; --band-btn:#5CC4BA; --band-btn-ink:#0E1B1B;
  color-scheme:dark}}
:root[data-theme="dark"]{
  --bg:#0E1B1B; --surface:#152626; --tint:#1A3030; --ink:#E4EFED; --muted:#9DB6B3; --line:#284040;
  --accent:#5CC4BA; --accent-ink:#0E1B1B; --accent-soft:#183634;
  --stamp:#E3A651; --stamp-soft:#33291A;
  --good:#6FD39A; --good-soft:#173323; --bad:#F08A7B; --bad-soft:#3A1F1B;
  --band:#091313; --band-ink:#E4EFED; --band-muted:#9DB6B3; --band-btn:#5CC4BA; --band-btn-ink:#0E1B1B;
  color-scheme:dark}

*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--ink);font:17px/1.6 var(--body)}
img{max-width:100%}
[hidden]{display:none!important}
a{color:var(--accent)}
a:focus-visible,button:focus-visible,input:focus-visible,summary:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
p{margin:0}
.wrap{max-width:1120px;margin:0 auto;padding-left:max(16px,env(safe-area-inset-left,0px));padding-right:max(16px,env(safe-area-inset-right,0px))}
.narrow{max-width:800px}

h1,h2,h3{font-family:var(--display);text-wrap:balance;line-height:1.12;margin:0}
h1{font-weight:800;font-size:clamp(34px,5.5vw,56px);letter-spacing:-.01em}
h2{font-weight:800;font-size:clamp(26px,3.6vw,36px)}
h3{font-weight:600;font-size:20px}
.eyebrow{font:500 13px/1.3 var(--mono);letter-spacing:.06em;text-transform:uppercase;color:var(--accent)}
.lead{font-size:20px;color:var(--muted);max-width:60ch}
.muted{color:var(--muted)}
.fine{font-size:14px;color:var(--muted)}

/* Preview strip, header, footer */
.preview-bar{background:var(--stamp-soft);color:var(--stamp);font:500 12px/1.4 var(--mono);letter-spacing:.05em;text-transform:uppercase}
.preview-bar .wrap{padding-block:8px}
header.site{background:var(--surface);border-bottom:1px solid var(--line)}
header.site .wrap{display:flex;flex-wrap:wrap;justify-content:space-between;align-items:center;gap:8px 24px;padding-block:12px}
.brand{font:800 21px/1 var(--display);color:var(--ink);text-decoration:none;display:inline-flex;align-items:center;gap:10px;min-height:44px}
.stamp{font:500 11px/1 var(--mono);letter-spacing:.06em;border:1.5px solid var(--stamp);color:var(--stamp);padding:4px 6px;border-radius:3px;transform:rotate(-3deg);display:inline-block}
nav.main{display:flex;flex-wrap:wrap;gap:4px 20px;align-items:center}
nav.main a{color:var(--ink);text-decoration:none;font-size:16px;padding:10px 0}
nav.main a[aria-current="page"]{color:var(--accent);font-weight:600;text-decoration:underline;text-underline-offset:6px}
nav.main a.lang{display:inline-flex;align-items:center;gap:6px;min-height:44px;padding:6px 12px;border:1px solid var(--line);border-radius:999px;font-size:15px}
nav.main a.btn{color:var(--accent-ink);padding:8px 16px;text-decoration:none}
footer.site{background:var(--band);color:var(--band-ink);margin-top:0}
footer.site .wrap{padding-block:40px 48px;display:flex;flex-direction:column;gap:12px}
footer.site .fine{color:var(--band-muted)}
footer.site a{color:var(--band-ink)}

html[lang^="zh"] body{line-height:1.75}
html[lang^="zh"] h1,html[lang^="zh"] h2,html[lang^="zh"] h3{line-height:1.3;letter-spacing:0}

/* Buttons */
.btn{display:inline-flex;align-items:center;justify-content:center;min-height:44px;padding:10px 20px;border-radius:8px;background:var(--accent);color:var(--accent-ink);
  font:600 16px/1.2 var(--body);text-decoration:none;border:1px solid var(--accent);cursor:pointer}
.btn.ghost{background:transparent;color:var(--accent)}
.btn.big{font-size:18px;padding:14px 24px;min-height:52px}
.actions{display:flex;flex-wrap:wrap;gap:12px}

/* Sections */
section.block{padding-block:72px}
section.band{background:var(--surface);border-block:1px solid var(--line)}
section.tint{background:var(--tint)}
section.dark{background:var(--band);color:var(--band-ink)}
section.dark h2{color:var(--band-ink)}
section.dark .muted{color:var(--band-muted)}
section.dark .btn{background:var(--band-btn);border-color:var(--band-btn);color:var(--band-btn-ink)}
.stack{display:flex;flex-direction:column;gap:16px}
.stack.lg{gap:28px}
.split{display:flex;flex-wrap:wrap;gap:40px;align-items:flex-start}
.split>*{flex:1 1 320px;min-width:0}
.hero{padding-block:72px 64px}
.chips{display:flex;flex-wrap:wrap;gap:8px}
.chip{font-size:15px;padding:6px 12px;border:1px solid var(--line);border-radius:999px;background:var(--surface)}

.cards{display:grid;grid-template-columns:repeat(auto-fit,minmax(260px,1fr));gap:16px}
.card{background:var(--surface);border:1px solid var(--line);border-radius:10px;padding:22px;display:flex;flex-direction:column;gap:10px;min-width:0}
.card p{color:var(--muted)}
.card .more{margin-top:auto;font-weight:600;padding-top:6px}
.card .tag{font:500 12px var(--mono);letter-spacing:.05em;color:var(--muted);text-transform:uppercase}

/* Stage sequence */
.stages{list-style:none;margin:0;padding:0;display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px;counter-reset:st}
@media (max-width:760px){.stages{grid-template-columns:1fr}}
.stages li{background:var(--surface);border:1px solid var(--line);border-radius:10px;padding:22px;display:flex;flex-direction:column;gap:8px;counter-increment:st;position:relative}
.stages li::before{content:"Stage " counter(st);font:500 12px var(--mono);letter-spacing:.06em;text-transform:uppercase;color:var(--accent)}
.code{font:500 14px var(--mono);color:var(--stamp)}

/* Forms and tools */
.tool{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1.05fr);gap:32px;align-items:start}
@media (max-width:860px){.tool{grid-template-columns:1fr}}
form.q{display:flex;flex-direction:column;gap:24px;min-width:0}
fieldset{border:0;padding:0;margin:0;display:flex;flex-direction:column;gap:10px;min-width:0}
legend{font:600 18px/1.3 var(--display);margin-bottom:10px;padding:0}
.hint{font-size:15px;color:var(--muted)}
.opts{display:flex;flex-wrap:wrap;gap:8px}
.opts label{position:relative;display:inline-flex}
.opts input{position:absolute;opacity:0;inset:0;margin:0;cursor:pointer}
.opts span{display:inline-flex;align-items:center;min-height:44px;padding:8px 16px;border:1px solid var(--line);border-radius:999px;background:var(--surface);cursor:pointer;transition:background .15s,border-color .15s}
.opts input:checked+span{background:var(--accent);border-color:var(--accent);color:var(--accent-ink);font-weight:600}
.opts input:focus-visible+span{outline:2px solid var(--accent);outline-offset:2px}
.result{position:sticky;top:16px;display:flex;flex-direction:column;gap:14px;min-width:0}
@media (max-width:860px){.result{position:static}}
.panel{background:var(--surface);border:1px solid var(--line);border-radius:12px;padding:24px;display:flex;flex-direction:column;gap:14px}
.status{align-self:flex-start;font-size:14px;font-weight:600;padding:4px 12px;border-radius:999px}
.status.good{background:var(--good-soft);color:var(--good)}
.status.warn{background:var(--stamp-soft);color:var(--stamp)}
.status.bad{background:var(--bad-soft);color:var(--bad)}
.flags{list-style:none;margin:0;padding:0;display:flex;flex-direction:column;gap:10px}
.flags li{display:flex;gap:10px;align-items:flex-start;font-size:16px}
.flags .k{flex:0 0 auto;font:500 11px/1 var(--mono);letter-spacing:.05em;text-transform:uppercase;padding:5px 7px;border-radius:4px;margin-top:3px}
.k.warn{background:var(--stamp-soft);color:var(--stamp)}
.k.bad{background:var(--bad-soft);color:var(--bad)}
.k.info{background:var(--accent-soft);color:var(--accent)}
.next{margin:0;padding-left:20px;display:flex;flex-direction:column;gap:6px}

/* Checklist */
.progress{height:10px;background:var(--tint);border-radius:999px;overflow:hidden}
.progress>div{height:100%;background:var(--accent);width:0;transition:width .2s}
.group{display:flex;flex-direction:column;gap:8px}
.group h3{font-size:18px}
ul.check{list-style:none;margin:0;padding:0;display:flex;flex-direction:column;gap:4px}
ul.check label{display:flex;gap:12px;align-items:flex-start;padding:8px 0;cursor:pointer}
ul.check input{width:20px;height:20px;margin-top:3px;flex:0 0 auto;accent-color:var(--accent)}
ul.check small{display:block;color:var(--muted);font-size:14px}
ul.check input:checked+span{color:var(--muted);text-decoration:line-through}
.aff{border:1px dashed var(--line);border-radius:8px;padding:10px 12px;font-size:15px;color:var(--muted)}
.aff b{color:var(--ink)}

/* Article */
.article{max-width:70ch;display:flex;flex-direction:column;gap:18px}
.article h2{font-size:28px;margin-top:20px}
.article ul{margin:0;padding-left:22px;display:flex;flex-direction:column;gap:6px}
.evidence{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:12px}
.evidence .box{background:var(--surface);border:1px solid var(--line);border-radius:10px;padding:16px 18px;display:flex;flex-direction:column;gap:8px}
.evidence .box strong{font:500 12px var(--mono);letter-spacing:.06em;text-transform:uppercase}
.evidence .strong strong{color:var(--good)}
.evidence .weak strong{color:var(--muted)}
.evidence ul{font-size:16px}
.mistake{background:var(--stamp-soft);border-radius:10px;padding:16px 18px;display:flex;flex-direction:column;gap:4px}
.mistake b{color:var(--stamp);font:500 12px var(--mono);letter-spacing:.06em;text-transform:uppercase}
.byline{display:flex;flex-wrap:wrap;gap:6px 16px;font-size:15px;color:var(--muted)}

/* Kit */
.price{background:var(--surface);border:1px solid var(--line);border-radius:12px;padding:28px;display:flex;flex-direction:column;gap:16px;box-shadow:0 12px 32px rgba(19,48,47,.08)}
.price .amt{font:800 46px/1.05 var(--display)}
.price ul{margin:0;padding-left:20px;display:flex;flex-direction:column;gap:6px;font-size:16px}
.toc{list-style:none;margin:0;padding:0;display:grid;grid-template-columns:repeat(auto-fit,minmax(300px,1fr));gap:12px}
.toc li{background:var(--surface);border:1px solid var(--line);border-radius:10px;padding:18px;display:flex;gap:14px}
.toc .n{font:500 15px var(--mono);color:var(--accent);flex:0 0 auto}
.toc span{color:var(--muted);font-size:16px;display:block}
.sheet{background:var(--surface);border-radius:6px;padding:32px;box-shadow:0 18px 40px rgba(19,48,47,.14);display:flex;flex-direction:column;gap:14px;transform:rotate(.6deg)}
@media (max-width:600px){.sheet{transform:none;padding:22px}}
.faq{display:flex;flex-direction:column}
.faq details{border-top:1px solid var(--line);padding-block:14px}
.faq summary{font-weight:600;cursor:pointer;font-size:18px;min-height:32px}
.faq details p{margin-top:8px;color:var(--muted)}

/* Email sign-up */
.signup{display:flex;flex-wrap:wrap;gap:10px}
.signup input{flex:1 1 240px;min-width:0;min-height:48px;padding:10px 14px;font:16px var(--body);border:1px solid var(--line);border-radius:8px;background:var(--surface);color:var(--ink)}
.author{display:flex;flex-wrap:wrap;gap:24px;align-items:center}
.photo{width:104px;height:104px;border-radius:50%;background:var(--tint);border:1px dashed var(--muted);display:flex;align-items:center;justify-content:center;font-size:13px;color:var(--muted);flex:0 0 104px}
.author>div:last-child{flex:1 1 360px;min-width:0;display:flex;flex-direction:column;gap:6px}

@media (prefers-reduced-motion:reduce){*{transition:none!important}}