:root {
  --red: #c8102e;
  --red-dark: #9d0000;
  --gold: #b8860b;
  --gold-line: #d4b45a;
  --paper: #fff8f3;
  --card: #ffffff;
  --ink: #1a1212;
  --muted: #6a5555;
  --line: #f0e6e6;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html, body { min-height: 100%; }

body {
  color: var(--ink);
  font-family: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background:
    radial-gradient(900px 420px at 50% -120px, rgba(212, 180, 90, 0.28), transparent 60%),
    linear-gradient(180deg, #8f0b18 0%, #5c030b 46%, #3a0208 100%);
  padding: 20px 16px 48px;
}

button {
  font: inherit;
  appearance: none;
}

.wrap {
  width: min(440px, 100%);
  margin: 0 auto;
}

.top {
  display: flex;
  align-items: center;
  gap: 12px;
  color: #fff8f0;
  margin-bottom: 18px;
}

.logo {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  box-shadow: 0 8px 18px rgba(0, 0, 0, 0.22);
}

.top strong {
  display: block;
  font-size: 20px;
  letter-spacing: 0.08em;
}

.top small {
  color: rgba(255, 248, 240, 0.72);
  font-size: 12px;
}

.hero {
  position: relative;
  padding: 26px 22px 24px;
  border-radius: 24px;
  color: #fff8f0;
  background: linear-gradient(160deg, #d31433 0%, #a0091b 62%, #7a0614 100%);
  box-shadow: 0 16px 40px rgba(90, 3, 11, 0.28);
  border-bottom: 3px solid var(--gold);
}

.hero::after {
  content: "";
  position: absolute;
  inset: 10px;
  border: 1px solid rgba(212, 180, 90, 0.38);
  border-radius: 16px;
  pointer-events: none;
}

.seal {
  display: inline-block;
  padding: 3px 10px;
  border: 1px solid #f3e2a6;
  border-radius: 999px;
  color: #f3e2a6;
  font-size: 12px;
  letter-spacing: 0.14em;
}

.hero h1 {
  margin: 14px 0 10px;
  font-size: 28px;
  line-height: 1.3;
  letter-spacing: 0.04em;
}

.hero p {
  color: rgba(255, 248, 240, 0.88);
  line-height: 1.65;
  font-size: 14px;
}

.chips {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 16px;
  list-style: none;
}

.chips li {
  padding: 5px 10px;
  border-radius: 999px;
  background: rgba(255, 248, 240, 0.12);
  font-size: 12px;
}

.invite {
  margin-top: 14px;
  padding: 10px 12px;
  border-radius: 12px;
  background: rgba(255, 248, 240, 0.14);
  font-size: 13px;
}

.cards {
  display: grid;
  gap: 12px;
  margin-top: 16px;
}

.card {
  padding: 20px 18px 18px;
  border-radius: 20px;
  background: var(--card);
  box-shadow: 0 12px 32px rgba(58, 2, 8, 0.16);
}

.card.is-dim { opacity: 0.7; }

.os {
  color: var(--red);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.16em;
}

.card h2 {
  margin: 8px 0;
  font-size: 22px;
}

.card p,
.guide p {
  color: var(--muted);
  font-size: 14px;
  line-height: 1.6;
}

.hint {
  margin-top: 10px;
  color: #a15b12;
  font-size: 13px;
}

.btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  min-height: 48px;
  margin-top: 16px;
  border: 0;
  border-radius: 14px;
  background: linear-gradient(135deg, var(--red), var(--red-dark));
  color: #fff;
  font-size: 16px;
  font-weight: 650;
  cursor: pointer;
}

.btn:disabled {
  background: #c9b6b6;
  cursor: not-allowed;
}

.btn.ghost {
  margin-top: 10px;
  background: transparent;
  color: var(--red-dark);
  border: 1px solid rgba(200, 16, 46, 0.28);
}

.guide {
  margin-top: 16px;
  padding: 20px 18px;
  border-radius: 20px;
  background: var(--paper);
}

.guide h3 { font-size: 18px; margin-bottom: 14px; }
.guide h4 { font-size: 15px; margin-bottom: 8px; color: var(--red-dark); }

.cols { display: grid; gap: 16px; }

.guide ol {
  padding-left: 18px;
  color: var(--muted);
  display: grid;
  gap: 8px;
  font-size: 14px;
  line-height: 1.55;
}

.page-android .ios-steps { display: none; }

footer {
  margin-top: 22px;
  text-align: center;
  color: rgba(255, 248, 240, 0.58);
  font-size: 12px;
}

.mask,
.sheet {
  position: fixed;
  inset: 0;
  z-index: 30;
}

.mask {
  background: rgba(20, 4, 6, 0.78);
  padding: 24px 18px;
}

.mask-card,
.sheet-card {
  width: min(400px, 100%);
  margin: 72px auto 0;
  padding: 22px 18px 20px;
  border-radius: 20px;
  background: var(--paper);
}

.arrow {
  color: var(--gold);
  font-size: 13px;
  letter-spacing: 0.08em;
}

.mask h2,
.sheet h3 { margin: 10px 0; }

.sheet {
  display: flex;
  align-items: flex-end;
  background: rgba(20, 4, 6, 0.45);
}

.mask[hidden],
.sheet[hidden] {
  display: none !important;
}

.sheet-card {
  width: 100%;
  margin: 0;
  border-radius: 22px 22px 0 0;
}

.sheet-card ol {
  padding-left: 18px;
  color: var(--muted);
  display: grid;
  gap: 8px;
  font-size: 14px;
}

@media (min-width: 900px) {
  .wrap { width: min(920px, 100%); }
  .cards { grid-template-columns: 1fr 1fr; }
  .page-android .ios-steps,
  .page-ios .android-steps { display: block; }
  .cols { grid-template-columns: 1fr 1fr; }
}