:root{color-scheme:light dark;--background:#f7fafd;--surface:#fff;--text:#183052;--muted:#355579;--border:#dde8f4;--accent:#5daaf7;--on-accent:#183052;font-family:system-ui,-apple-system,"Segoe UI","Microsoft YaHei",sans-serif;line-height:1.6;font-synthesis:none}
*{box-sizing:border-box}
body{margin:0;background:var(--background);color:var(--text);min-height:100svh}
main{max-width:32rem;margin:auto;padding:max(32px,env(safe-area-inset-top)) 20px max(32px,env(safe-area-inset-bottom))}
.brand{font-size:18px;font-weight:750;letter-spacing:.04em;margin:0 0 32px}
.brand span{display:inline-block;font-size:13px;font-weight:500;letter-spacing:0;color:var(--muted);margin-left:12px}
section{padding:28px 24px;background:var(--surface);border:1px solid var(--border);border-radius:20px}
h1{font-size:clamp(24px,6vw,30px);line-height:1.35;margin:0 0 16px;overflow-wrap:anywhere}
p{margin:0 0 20px;font-size:16px;overflow-wrap:anywhere}
.action{display:flex;align-items:center;justify-content:center;min-height:52px;padding:14px 18px;margin:24px 0;text-align:center;text-decoration:none;font-weight:700;background:var(--accent);color:var(--on-accent);border-radius:12px;touch-action:manipulation;cursor:pointer;transition:filter 140ms ease}
.action[hidden]{display:none}
.action:hover,.action:active{filter:brightness(.94)}
.action:focus-visible{outline:3px solid var(--text);outline-offset:4px}
.help{color:var(--muted);font-size:15px;margin-bottom:0}
.foot{font-size:14px;color:var(--muted);margin:24px 4px 0}
@media(prefers-color-scheme:dark){:root{--background:#0e1728;--surface:#17263d;--text:#f2f7fc;--muted:#b8c7da;--border:#324e6b;--accent:#9ccaff;--on-accent:#142238}}
@media(prefers-reduced-motion:reduce){.action{transition:none}}