:root {
  --bg: #ffffff;
  --text: #1c1c1e;
  --secondary: #8e8e93;
  --accent: #007aff;
  --card-bg: #f2f2f7;
  --border: #c6c6c8;
  --section-header: #6e6e73;
  --kbd-bg: #e5e5ea;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #000000;
    --text: #f5f5f7;
    --secondary: #98989d;
    --accent: #0a84ff;
    --card-bg: #1c1c1e;
    --border: #38383a;
    --section-header: #98989d;
    --kbd-bg: #2c2c2e;
  }
}
* { margin: 0; padding: 0; box-sizing: border-box; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Helvetica Neue", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
  padding: 0 20px 60px;
  -webkit-text-size-adjust: 100%;
  padding-top: env(safe-area-inset-top);
}
h1 {
  font-size: 28px;
  font-weight: 700;
  margin: 32px 0 8px;
}
.subtitle {
  font-size: 15px;
  color: var(--secondary);
  margin-bottom: 28px;
}
h2 {
  font-size: 20px;
  font-weight: 600;
  margin: 32px 0 4px;
  color: var(--text);
}
.section-desc {
  font-size: 14px;
  color: var(--secondary);
  margin-bottom: 12px;
}
.card {
  background: var(--card-bg);
  border-radius: 12px;
  padding: 16px;
  margin-bottom: 12px;
}
.card h3 {
  font-size: 16px;
  font-weight: 600;
  margin-bottom: 8px;
  display: flex;
  align-items: center;
  gap: 8px;
}
.card p, .card li {
  font-size: 15px;
  color: var(--text);
  line-height: 1.55;
}
.card ul, .card ol {
  padding-left: 20px;
  margin-top: 6px;
}
.card li { margin-bottom: 4px; }
.icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border-radius: 6px;
  font-size: 15px;
  flex-shrink: 0;
}
.icon-blue { background: #007aff; color: white; }
.icon-green { background: #34c759; color: white; }
.icon-orange { background: #ff9500; color: white; }
.icon-purple { background: #af52de; color: white; }
.icon-red { background: #ff3b30; color: white; }
.icon-teal { background: #5ac8fa; color: white; }
.icon-indigo { background: #5856d6; color: white; }
.icon-pink { background: #ff2d55; color: white; }
.icon-gray { background: #8e8e93; color: white; }
.badge {
  display: inline-block;
  font-size: 11px;
  font-weight: 600;
  padding: 2px 7px;
  border-radius: 4px;
  vertical-align: middle;
  margin-left: 6px;
}
.badge-premium { background: #ff9500; color: white; }
.steps { counter-reset: step; list-style: none; padding-left: 0; }
.steps li {
  counter-increment: step;
  padding-left: 32px;
  position: relative;
  margin-bottom: 8px;
}
.steps li::before {
  content: counter(step);
  position: absolute;
  left: 0;
  top: 1px;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--accent);
  color: white;
  font-size: 13px;
  font-weight: 600;
  display: flex;
  align-items: center;
  justify-content: center;
}
.tip {
  background: var(--card-bg);
  border-left: 3px solid var(--accent);
  border-radius: 0 8px 8px 0;
  padding: 12px 14px;
  margin: 12px 0;
  font-size: 14px;
}
.tip strong { color: var(--accent); }
kbd {
  display: inline-block;
  background: var(--kbd-bg);
  border-radius: 4px;
  padding: 1px 6px;
  font-family: inherit;
  font-size: 13px;
}
.toc { margin-bottom: 24px; }
.toc a {
  display: block;
  padding: 10px 14px;
  color: var(--accent);
  text-decoration: none;
  font-size: 15px;
  border-bottom: 0.5px solid var(--border);
}
.toc a:last-child { border-bottom: none; }
.back-to-top {
  display: block;
  text-align: center;
  color: var(--accent);
  text-decoration: none;
  font-size: 14px;
  padding: 16px;
}
.formats-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
  margin-top: 8px;
}
.format-tag {
  background: var(--kbd-bg);
  border-radius: 8px;
  padding: 8px 12px;
  font-size: 14px;
  font-weight: 500;
  text-align: center;
}