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

:root {
  --bg: #f8fafb;
  --surface: #ffffff;
  --accent: #1a73e8;
  --accent-light: #e8f0fe;
  --text: #1f2937;
  --text-muted: #6b7280;
  --border: #e5e7eb;
  --green: #16a34a;
  --red: #dc2626;
  --amber: #d97706;
  --radius: 12px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  padding: 0 16px 60px;
  max-width: 720px;
  margin: 0 auto;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

/* Header / hero */
.hero {
  text-align: center;
  padding: 48px 0 32px;
}
.hero h1 {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 8px;
}
.hero p {
  color: var(--text-muted);
  font-size: 1.05rem;
}

/* Breadcrumb */
.breadcrumb {
  font-size: 0.85rem;
  color: var(--text-muted);
  padding: 20px 0 8px;
}

/* Cards grid on index */
.card-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
  margin-top: 24px;
}
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px 16px;
  transition: box-shadow .15s;
}
.card:hover { box-shadow: 0 4px 12px rgba(0,0,0,.06); }
.card .icon { font-size: 1.6rem; margin-bottom: 8px; }
.card h3 { font-size: 1rem; font-weight: 600; margin-bottom: 4px; }
.card p { font-size: 0.85rem; color: var(--text-muted); }

/* Content sections */
h2 {
  font-size: 1.4rem;
  font-weight: 700;
  margin: 36px 0 12px;
  padding-bottom: 6px;
  border-bottom: 2px solid var(--accent-light);
}
h3 {
  font-size: 1.1rem;
  font-weight: 600;
  margin: 24px 0 8px;
}
p, ul, ol { margin-bottom: 14px; }
ul, ol { padding-left: 22px; }
li { margin-bottom: 6px; }

/* Callout boxes */
.tip, .warning, .note {
  border-radius: var(--radius);
  padding: 14px 16px;
  margin: 18px 0;
  font-size: 0.92rem;
}
.tip     { background: #ecfdf5; border-left: 4px solid var(--green); }
.warning { background: #fef9c3; border-left: 4px solid var(--amber); }
.note    { background: var(--accent-light); border-left: 4px solid var(--accent); }

/* Key-value info list */
.info-list { list-style: none; padding: 0; }
.info-list li {
  display: flex;
  gap: 8px;
  padding: 8px 0;
  border-bottom: 1px solid var(--border);
  font-size: 0.92rem;
}
.info-list li strong { min-width: 130px; }

/* Keyboard shortcut style badges */
.badge {
  display: inline-block;
  background: var(--accent-light);
  color: var(--accent);
  font-size: 0.8rem;
  font-weight: 600;
  padding: 2px 8px;
  border-radius: 6px;
}
.badge.good { background: #dcfce7; color: var(--green); }
.badge.bad  { background: #fee2e2; color: var(--red); }

/* Step lists */
.steps { counter-reset: step; list-style: none; padding: 0; }
.steps li {
  counter-increment: step;
  padding: 10px 0 10px 40px;
  position: relative;
  border-bottom: 1px solid var(--border);
}
.steps li::before {
  content: counter(step);
  position: absolute;
  left: 0; top: 10px;
  width: 28px; height: 28px;
  background: var(--accent);
  color: #fff;
  border-radius: 50%;
  font-size: 0.85rem;
  font-weight: 700;
  display: flex; align-items: center; justify-content: center;
}

/* Nav footer */
.nav-footer {
  display: flex;
  justify-content: space-between;
  margin-top: 40px;
  padding-top: 16px;
  border-top: 1px solid var(--border);
  font-size: 0.9rem;
}

/* Responsive */
@media (max-width: 500px) {
  .card-grid { grid-template-columns: 1fr; }
  body { padding: 0 12px 40px; }
  .hero h1 { font-size: 1.5rem; }
}