/* 三站共用帳號：黑白、清楚的層次與充足留白。 */
:root { color-scheme: light; --bg:#fff; --surface:#fff; --ink:#111; --ink-soft:#666; --line:#dedede; --accent:#111; --font:-apple-system,BlinkMacSystemFont,"Segoe UI","Noto Sans TC","PingFang TC","Microsoft JhengHei",sans-serif; }
* { box-sizing:border-box; }
body { margin:0; min-height:100svh; display:grid; place-items:start center; padding:clamp(36px,10vh,100px) 24px 64px; background:var(--bg); color:var(--ink); font:15px/1.7 var(--font); -webkit-font-smoothing:antialiased; }
.card { width:100%; max-width:420px; }
.head { margin-bottom:36px; }
.kicker { display:flex; align-items:center; gap:12px; margin:0 0 24px; font-size:11px; font-weight:600; letter-spacing:.16em; color:var(--ink-soft); }
.kicker::before { content:""; width:24px; height:2px; background:var(--ink); }
h1 { margin:0 0 12px; font-size:clamp(26px,6vw,32px); font-weight:600; line-height:1.35; letter-spacing:-.035em; }
h2 { margin:32px 0 14px; padding-top:24px; border-top:1px solid var(--line); font-size:14px; font-weight:600; }
p { margin:0 0 16px; }
.muted { color:var(--ink-soft); font-size:13px; }
.fine { font-size:12px; color:var(--ink-soft); margin:10px 0 0; }
.center { text-align:center; }
.alert { padding:12px 14px; border:1px solid var(--line); border-left:3px solid var(--ink); margin-bottom:24px; font-size:13px; background:#f7f7f7; }
.alert.bad { border-color:var(--ink); }
.alert.ok { background:#f7f7f7; }
.tabs { display:grid; grid-template-columns:repeat(3,1fr); border-bottom:1px solid var(--line); margin-bottom:28px; }
.tab { font:inherit; font-size:13px; background:transparent; color:var(--ink-soft); border:0; border-bottom:2px solid transparent; margin-bottom:-1px; padding:12px 4px; cursor:pointer; }
.tab[aria-selected="true"] { color:var(--ink); border-bottom-color:var(--ink); font-weight:600; }
.form { display:grid; gap:20px; }
.form.inline { grid-template-columns:minmax(0,1fr) auto; align-items:end; gap:12px; }
.field { display:grid; gap:8px; font-size:12px; font-weight:600; }
.field input { font:inherit; font-size:16px; font-weight:400; width:100%; height:48px; padding:12px 14px; border:1px solid #c9c9c9; border-radius:3px; background:var(--surface); color:var(--ink); }
.field input::placeholder { color:#888; }
.field input:hover { border-color:#888; }
.field input:focus-visible { outline:2px solid var(--ink); outline-offset:2px; border-color:var(--ink); }
.btn { font:inherit; font-size:13px; font-weight:500; display:inline-flex; align-items:center; justify-content:center; gap:10px; min-height:46px; padding:11px 18px; border-radius:3px; border:1px solid var(--line); background:var(--surface); color:var(--ink); cursor:pointer; text-decoration:none; transition:background .15s,border-color .15s; }
.btn:hover:not(:disabled) { background:#f5f5f5; border-color:#999; }
.btn.primary { background:var(--ink); border-color:var(--ink); color:var(--surface); font-weight:600; }
.btn.primary:hover:not(:disabled) { background:#333; border-color:#333; }
.btn.danger { border-color:#999; }
.btn:disabled { opacity:.45; cursor:not-allowed; }
.btn:focus-visible,.tab:focus-visible,.linkish:focus-visible { outline:2px solid var(--ink); outline-offset:4px; }
.btn.google,.btn.site { width:100%; }
.btn.site { justify-content:space-between; padding:14px 16px; }
.linkish { font:inherit; font-size:12px; background:none; border:0; padding:0; color:var(--ink-soft); text-decoration:underline; text-underline-offset:4px; cursor:pointer; justify-self:start; }
.linkish:hover { color:var(--ink); }
.or { display:flex; align-items:center; gap:16px; margin:28px 0; color:#888; font-size:11px; }
.or::before,.or::after { content:""; flex:1; height:1px; background:var(--line); }
.sites { display:grid; gap:10px; }
.row { display:flex; gap:10px; flex-wrap:wrap; }
[hidden] { display:none !important; }
@media (max-width:420px) { body { padding:40px 22px; } .head { margin-bottom:28px; } .form.inline { grid-template-columns:1fr; } .row>.btn { flex:1 1 auto; } }
@media (prefers-reduced-motion:reduce) { .btn { transition:none; } }