:root {
  --indigo: #4051b5;
  --indigo-dark: #2e3d9a;
  --indigo-soft: #eef0fa;
  --text: #161820;
  --muted: #4a4f5c;
  --line: #d8dbe6;
  --line-strong: #b7bdd0;
  --bg: #f4f5fa;
  --card: #fff;
  --guide: #ffe08a;
  --guide-border: #e8b02a;
  --guide-text: #1a1404;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  font-size: 18px;
  line-height: 1.75;
  min-height: 100vh;
}

a { color: var(--indigo-dark); }
.wrap {
  width: min(840px, calc(100% - 32px));
  margin: 0 auto;
}

header {
  position: sticky;
  top: 0;
  z-index: 20;
  background: var(--indigo);
  color: #fff;
}
header .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 60px;
  gap: 16px;
}
.logo {
  color: #fff;
  text-decoration: none;
  font-weight: 750;
  font-size: 20px;
  display: flex;
  align-items: center;
  gap: 8px;
  letter-spacing: .02em;
}
.logo svg { display: block; flex: none; }
header nav { display: flex; gap: 4px; }
header nav a {
  color: #fff;
  text-decoration: none;
  padding: 10px 12px;
  border-radius: 8px;
  font-size: 17px;
  font-weight: 600;
}
header nav a:hover,
header nav a:focus-visible { background: rgba(255,255,255,.16); }
header nav a[aria-current="page"] { background: rgba(255,255,255,.18); }

main { padding: 28px 0 56px; }

.page-title {
  margin: 0 0 8px;
  font-size: 32px;
  line-height: 1.25;
  letter-spacing: -.02em;
}
.lead {
  margin: 0 0 20px;
  color: var(--muted);
  font-size: 18px;
}

.guide {
  display: block;
  background: var(--guide);
  color: var(--guide-text);
  text-decoration: none;
  padding: 20px 22px;
  border-radius: 16px;
  border: 3px solid var(--guide-border);
  box-shadow: 0 5px 0 #d9a31c;
  font-size: 22px;
  font-weight: 800;
  line-height: 1.45;
  margin: 0 0 28px;
}
.guide:hover,
.guide:focus-visible { filter: brightness(1.03); }
.guide span { display: block; }
.guide .sub {
  font-size: 18px;
  font-weight: 650;
  margin-top: 2px;
}

.block {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 18px;
  padding: 26px 24px 22px;
  margin: 0 0 20px;
}
.block.current {
  border-color: var(--indigo);
  box-shadow: 0 0 0 3px rgba(64,81,181,.16);
}
.block-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  margin-bottom: 4px;
}
.block h2 {
  margin: 0;
  font-size: 28px;
  letter-spacing: -.02em;
}
.badge {
  flex: none;
  background: var(--indigo);
  color: #fff;
  font-size: 13px;
  font-weight: 700;
  padding: 3px 10px;
  border-radius: 999px;
  line-height: 1.5;
}
.meta {
  margin: 0 0 18px;
  color: var(--muted);
  font-size: 16px;
}

.item { padding: 6px 0 4px; }
.item + .item {
  margin-top: 16px;
  padding-top: 18px;
  border-top: 1px dashed var(--line-strong);
}
.item h3 {
  margin: 0 0 12px;
  font-size: 22px;
  font-weight: 700;
}
.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: stretch;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  text-decoration: none;
  border-radius: 12px;
  padding: 14px 22px;
  font-size: 18px;
  font-weight: 750;
  border: 2px solid transparent;
  line-height: 1.3;
  cursor: pointer;
  font-family: inherit;
  min-height: 54px;
}
.btn-primary {
  background: var(--indigo);
  color: #fff;
  flex: 1 1 220px;
}
.btn-primary:hover,
.btn-primary:focus-visible { background: var(--indigo-dark); color: #fff; }
.btn-secondary {
  background: #fff;
  color: var(--indigo-dark);
  border-color: #b8bee0;
  flex: 1 1 160px;
}
.btn-secondary:hover,
.btn-secondary:focus-visible { background: var(--indigo-soft); }

.ios-text {
  margin: 0;
  color: var(--text);
  font-size: 18px;
}

.guide.footer-guide { margin: 28px 0 0; }

footer {
  border-top: 1px solid var(--line);
  padding: 22px 0 36px;
  color: var(--muted);
  font-size: 16px;
}
footer .wrap {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 20px;
  justify-content: space-between;
}
footer a { color: var(--indigo-dark); font-weight: 650; text-decoration: none; }
footer a:hover { text-decoration: underline; }

/* help page */
.back {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-weight: 700;
  text-decoration: none;
  margin: 0 0 16px;
  font-size: 18px;
}
.remote {
  background: var(--indigo-soft);
  border-radius: 16px;
  padding: 22px 22px 20px;
  margin: 28px 0 0;
  border: 1px solid #d5daf3;
}
.remote h2 {
  margin: 0 0 8px;
  font-size: 26px;
}
.remote p {
  margin: 0 0 16px;
  font-size: 20px;
}
.steps h2 {
  margin: 0 0 6px;
  font-size: 26px;
}
.steps .hint {
  margin: 0 0 8px;
  color: var(--muted);
  font-size: 18px;
}
.step {
  display: grid;
  grid-template-columns: 44px 1fr;
  gap: 14px;
  padding: 22px 0;
  border-top: 2px solid var(--line);
}
.step:first-of-type { border-top: 0; }
.num {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--indigo);
  color: #fff;
  font-size: 18px;
  font-weight: 800;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-top: 4px;
}
.step h3 {
  margin: 0 0 8px;
  font-size: 24px;
  line-height: 1.35;
}
.step p {
  margin: 0;
  font-size: 20px;
  color: var(--text);
}
.step figure { margin: 14px 0 0; }
.step img {
  display: block;
  width: 100%;
  height: auto;
  border-radius: 12px;
  border: 1px solid var(--line);
  background: #111;
}
.help-card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 18px;
  padding: 22px 22px 10px;
}

@media (max-width: 640px) {
  body { font-size: 18px; }
  .page-title { font-size: 28px; }
  .guide { font-size: 20px; padding: 18px 16px; }
  .guide .sub { font-size: 17px; }
  .block { padding: 22px 16px 16px; }
  .block h2 { font-size: 26px; }
  .item h3 { font-size: 20px; }
  .actions { flex-direction: column; }
  .btn { width: 100%; flex: none; font-size: 18px; }
  .step { grid-template-columns: 36px 1fr; gap: 10px; }
  .step h3 { font-size: 22px; }
  .step p, .remote p { font-size: 19px; }
  header .wrap { min-height: 56px; }
  .logo { font-size: 18px; }
}