:root {
  --blue: #2563eb;
  --blue-dark: #1d4ed8;
  --navy: #0f172a;
  --text: #1e293b;
  --muted: #64748b;
  --line: #e2e8f0;
  --bg: #f8fafc;
  --white: #ffffff;
  --teal: #0d9488;
  --soft: #eff6ff;
  --header: 64px;
  --max: 1080px;
  --radius: 12px;
  --shadow: 0 1px 2px rgba(15, 23, 42, 0.06), 0 8px 24px rgba(15, 23, 42, 0.04);
  --font: "Segoe UI", system-ui, -apple-system, Roboto, "Helvetica Neue", Arial, sans-serif;
}
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.6;
  color: var(--text);
  background: var(--white);
}
img { max-width: 100%; display: block; }
a { color: var(--blue); }
h1, h2, h3, h4 { color: var(--navy); margin: 0 0 12px; line-height: 1.2; letter-spacing: -0.02em; }
h1 { font-size: clamp(28px, 4vw, 42px); font-weight: 700; }
h2 { font-size: clamp(24px, 3vw, 32px); font-weight: 700; }
h3 { font-size: 18px; font-weight: 650; }
p { margin: 0 0 12px; }
.skip { position: absolute; left: -999px; }
.skip:focus { left: 12px; top: 12px; background: var(--navy); color: #fff; padding: 8px 12px; z-index: 99; }
.visually-hidden { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0,0,0,0); }
.wrap { width: min(var(--max), calc(100% - 40px)); margin: 0 auto; }
.muted { color: var(--muted); }

.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  height: var(--header);
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--line);
}
.header-inner {
  height: var(--header);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--navy);
  font-weight: 700;
  font-size: 17px;
  letter-spacing: -0.02em;
}
.brand svg { width: 32px; height: 32px; flex-shrink: 0; }
.nav { display: flex; align-items: center; gap: 4px; }
.nav a {
  text-decoration: none;
  color: var(--muted);
  font-size: 14px;
  font-weight: 600;
  padding: 8px 12px;
  border-radius: 8px;
}
.nav a:hover, .nav a[aria-current="page"] { color: var(--navy); background: var(--bg); }
.nav .btn { margin-left: 8px; color: #fff; }
.nav .btn:hover { color: #fff; background: var(--blue-dark); }
.nav-toggle {
  display: none;
  width: 40px; height: 40px;
  border: 1px solid var(--line);
  background: #fff;
  border-radius: 8px;
  cursor: pointer;
}
.nav-toggle span, .nav-toggle span::before, .nav-toggle span::after {
  display: block; width: 16px; height: 2px; background: var(--navy); margin: 0 auto; position: relative;
}
.nav-toggle span::before, .nav-toggle span::after { content: ""; position: absolute; left: 0; }
.nav-toggle span::before { top: -5px; }
.nav-toggle span::after { top: 5px; }

.btn {
  display: inline-flex; align-items: center; justify-content: center;
  text-decoration: none; font-weight: 650; font-size: 14px;
  padding: 10px 16px; border-radius: 8px; border: 1px solid transparent; cursor: pointer;
}
.btn-primary { background: var(--blue); color: #fff; }
.btn-primary:hover { background: var(--blue-dark); color: #fff; }
.btn-secondary { background: #fff; color: var(--navy); border-color: var(--line); }
.btn-secondary:hover { background: var(--bg); color: var(--navy); }
.hero-actions { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 24px; }

.hero {
  background: linear-gradient(180deg, var(--soft) 0%, var(--white) 100%);
  padding: 56px 0 48px;
  border-bottom: 1px solid var(--line);
}
.hero-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 48px;
  align-items: center;
}
.badge {
  display: inline-block;
  background: #dbeafe;
  color: var(--blue-dark);
  font-size: 12px;
  font-weight: 700;
  padding: 4px 10px;
  border-radius: 999px;
  margin-bottom: 14px;
}
.lede { font-size: 18px; color: var(--muted); max-width: 36rem; }
.hero-note { margin-top: 16px; font-size: 14px; color: var(--teal); font-weight: 600; }
.stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin-top: 32px;
  padding-top: 24px;
  border-top: 1px solid var(--line);
}
.stats strong { display: block; color: var(--navy); font-size: 15px; }
.stats span { font-size: 13px; color: var(--muted); }

.device {
  background: var(--navy);
  border-radius: 28px;
  padding: 12px;
  box-shadow: 0 20px 50px rgba(15, 23, 42, 0.18);
  max-width: 320px;
  margin: 0 auto;
}
.device-screen {
  background: #fff;
  border-radius: 20px;
  padding: 20px 18px 22px;
  min-height: 360px;
}
.device-bar { width: 48px; height: 5px; background: #e2e8f0; border-radius: 99px; margin: 0 auto 16px; }
.device-kicker { font-size: 11px; font-weight: 700; letter-spacing: 0.06em; text-transform: uppercase; color: var(--blue); }
.role {
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 12px 14px;
  margin-top: 10px;
}
.role b { display: block; color: var(--navy); font-size: 14px; }
.role span { font-size: 13px; color: var(--muted); }
.codebox {
  margin-top: 12px;
  background: var(--soft);
  border-radius: 10px;
  text-align: center;
  padding: 12px;
  font-size: 28px;
  font-weight: 700;
  letter-spacing: 0.12em;
  color: var(--navy);
}

.section { padding: 72px 0; }
.section-alt { background: var(--bg); border-block: 1px solid var(--line); }
.section-head { max-width: 640px; margin-bottom: 32px; }

.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px; }
.card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 22px;
  box-shadow: var(--shadow);
}
.card ul { margin: 0; padding-left: 18px; }
.card li { margin: 6px 0; }
.check { color: var(--teal); font-weight: 700; }
.cross { color: #be123c; font-weight: 700; }

.steps { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
.step {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 20px;
}
.step .n {
  width: 28px; height: 28px; border-radius: 8px;
  background: var(--soft); color: var(--blue);
  display: grid; place-items: center;
  font-size: 13px; font-weight: 800; margin-bottom: 12px;
}
.step p { color: var(--muted); font-size: 14px; margin: 0; }

.feat { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.feat article {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 18px 20px;
}
.feat h3 { margin-bottom: 6px; }
.feat p { margin: 0; color: var(--muted); font-size: 14px; }

.chip {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 14px 16px;
  font-weight: 650;
  color: var(--navy);
  font-size: 14px;
}

.compare { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.compare .card h3 { font-size: 16px; }
.compare.bad { opacity: 0.85; }
.compare .yes { border-color: #bfdbfe; background: #f8fbff; }

.cta {
  background: var(--navy);
  color: #fff;
  border-radius: 16px;
  padding: 40px;
}
.cta h2, .cta p { color: #fff; }
.cta p { color: #94a3b8; max-width: 36rem; }
.cta .btn-secondary { background: transparent; color: #fff; border-color: #334155; }
.cta .btn-secondary:hover { background: #1e293b; color: #fff; }

.site-footer {
  background: var(--navy);
  color: #94a3b8;
  padding: 40px 0 24px;
  font-size: 14px;
}
.footer-grid { display: grid; grid-template-columns: 1.5fr 1fr 1fr; gap: 24px; margin-bottom: 24px; }
.site-footer a { color: #e2e8f0; text-decoration: none; display: inline-block; margin: 4px 0; }
.site-footer a:hover { color: #fff; }
.site-footer .brand { color: #fff; }
.legal-tiny { border-top: 1px solid #1e293b; padding-top: 16px; font-size: 12px; }

.page-hero { padding: 40px 0 8px; }
.help-layout { display: grid; grid-template-columns: 240px 1fr; gap: 32px; padding: 24px 0 80px; align-items: start; }
.toc {
  position: sticky; top: calc(var(--header) + 16px);
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 16px;
  max-height: calc(100vh - var(--header) - 32px); overflow: auto;
}
.toc h2 { font-size: 12px; text-transform: uppercase; letter-spacing: 0.06em; color: var(--muted); }
.toc input {
  width: 100%; border: 1px solid var(--line); border-radius: 8px; padding: 8px 10px;
  font: inherit; margin: 8px 0 10px;
}
.toc a { display: block; text-decoration: none; color: var(--muted); font-size: 13px; font-weight: 600; padding: 6px 0; }
.toc a:hover, .toc a.active { color: var(--blue); }
.help-article { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 32px 36px 48px; }
.help-article h2 { margin-top: 40px; scroll-margin-top: calc(var(--header) + 16px); }
.help-article h2:first-of-type { margin-top: 0; }
.help-article li { margin: 6px 0; }
.callout { background: var(--bg); border: 1px solid var(--line); border-radius: 10px; padding: 14px 16px; margin: 16px 0; }
.callout.warn { background: #fffbeb; border-color: #fde68a; }
.callout.safe { background: #f0fdfa; border-color: #99f6e4; }
.callout strong { display: block; margin-bottom: 4px; }
.pill-list { display: flex; flex-wrap: wrap; gap: 8px; }
.pill { border: 1px solid var(--line); border-radius: 999px; padding: 6px 12px; font-size: 13px; font-weight: 600; }

.policy { max-width: 760px; margin: 0 auto; padding: 16px 0 80px; }
.policy h2 { margin-top: 36px; scroll-margin-top: calc(var(--header) + 16px); }
.policy-meta {
  display: grid; grid-template-columns: 1fr 1fr; gap: 10px 24px;
  background: var(--bg); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 16px 20px; margin: 20px 0 8px; font-size: 14px;
}
.policy-meta dt { color: var(--muted); font-size: 12px; font-weight: 700; }
.policy-meta dd { margin: 2px 0 0; font-weight: 650; color: var(--navy); }
.table-wrap { overflow: auto; border: 1px solid var(--line); border-radius: 10px; }
table { width: 100%; border-collapse: collapse; }
th, td { text-align: left; padding: 10px 12px; border-bottom: 1px solid var(--line); vertical-align: top; }
th { background: var(--bg); font-size: 12px; color: var(--muted); }

@media (max-width: 860px) {
  .hero-grid, .grid-2, .grid-3, .grid-4, .steps, .feat, .compare, .footer-grid, .help-layout, .policy-meta, .stats { grid-template-columns: 1fr; }
  .nav-toggle { display: inline-grid; place-items: center; }
  .nav {
    display: none; position: absolute; left: 20px; right: 20px; top: 56px;
    background: #fff; border: 1px solid var(--line); border-radius: 12px;
    padding: 10px; flex-direction: column; align-items: stretch;
    box-shadow: var(--shadow);
  }
  .nav.open { display: flex; }
  .toc { position: static; max-height: none; }
  .help-article { padding: 20px; }
  .cta { padding: 24px; }
  .section { padding: 48px 0; }
}