/* 契约 G9:50+ 适老化 — 正文≥18px、标题≥24px、按钮≥56px、对比≥4.5:1、375×667 一屏 */
:root {
  --bg: #fbf7f0;
  --ink: #2b1d0e;
  --brand: #8a4b12;
  --brand-ink: #ffffff;
  --muted: #6b5a48;
  --line: #e5d9c8;
}
* { box-sizing: border-box; }
html, body { margin: 0; height: 100%; }
body {
  font: 18px/1.5 -apple-system, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  color: var(--ink);
  background: var(--bg);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 24px 16px;
  min-height: 100%;
}
main { width: 100%; max-width: 420px; text-align: center; }
.logo {
  width: 88px; height: 88px; margin: 0 auto 12px;
  border-radius: 50%; background: var(--brand); color: var(--brand-ink);
  display: flex; align-items: center; justify-content: center;
  font-size: 40px; font-weight: 700;
}
h1 { font-size: 30px; line-height: 1.2; margin: 0 0 8px; color: var(--brand); }
.slogan { font-size: 20px; margin: 0 0 4px; }
.sub { font-size: 18px; color: var(--muted); margin: 0 0 24px; }
.actions { display: flex; flex-direction: column; gap: 14px; margin-bottom: 20px; }
.btn {
  display: flex; align-items: center; justify-content: center;
  min-height: 56px; padding: 0 20px;
  font-size: 20px; font-weight: 600; text-decoration: none;
  color: var(--brand-ink); background: var(--brand);
  border-radius: 14px;
}
.btn:active { opacity: .9; }
.btn-disabled { background: #b9a892; color: #fff; }
.aside { margin-bottom: 8px; }
.code { width: 180px; height: 180px; border: 1px solid var(--line); background: #fff; border-radius: 12px; }
.hint { font-size: 18px; color: var(--muted); margin: 8px 0 0; }
.meta { font-size: 14px; color: #8c7b68; margin-top: 12px; }
.mask {
  position: fixed; inset: 0; background: rgba(0,0,0,.82); color: #fff;
  display: flex; flex-direction: column; align-items: flex-end; padding: 24px 20px;
  font-size: 22px; line-height: 1.5; z-index: 10;
}
.mask .arrow { font-size: 48px; line-height: 1; margin-bottom: 8px; }
.mask p { margin: 0; text-align: right; }
.mask[hidden] { display: none; }
@media (max-height: 640px) {
  .logo { width: 64px; height: 64px; font-size: 30px; }
  .code { width: 140px; height: 140px; }
  .sub { margin-bottom: 16px; }
}