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

:root {
  --bg: #f5f7fb;
  --surface: #ffffff;
  --text-primary: #1a1f2e;
  --text-secondary: #64748b;
  --border: #e2e8f0;
  --accent: #1a73e8;
  --accent-dark: #1a56db;
  --accent-light: #e8f0fe;
  --navy: #1e3a5f;
  --green: #34a853;
  --green-bg: #ecfdf3;
  --green-border: #bbf7d0;
  --green-text: #166534;
  --yellow-bg: #fff7ed;
  --yellow-border: #fed7aa;
  --yellow-text: #9a3412;
  --radius: 16px;
  --shadow: 0 8px 24px rgba(15, 23, 42, 0.06);
  --max-w: 1100px;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Nunito', Arial, sans-serif;
  background: var(--bg);
  color: var(--text-primary);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  line-height: 1.7;
}

.container {
  width: 100%;
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 20px;
}

.topbar {
  background: var(--navy);
  padding: 12px 0;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 2px 10px rgba(0,0,0,0.18);
}

.topbar-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
}

.logo-box {
  width: 36px;
  height: 36px;
  background: #fff;
  border-radius: 8px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4px;
  padding: 6px;
}

.logo-box span {
  border-radius: 2px;
}

.logo-box .b1,
.logo-box .b2,
.logo-box .b3 {
  background: var(--accent);
}

.logo-box .b4 {
  background: var(--green);
}

.logo-text {
  color: #fff;
  font-size: 1.08rem;
  font-weight: 800;
  white-space: nowrap;
}

.back-btn {
  color: rgba(255,255,255,0.9);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 700;
  padding: 8px 14px;
  border-radius: 8px;
  background: rgba(255,255,255,0.08);
}

.back-btn:hover {
  background: rgba(255,255,255,0.14);
}

.hero {
  background: linear-gradient(160deg, #1e3a5f 0%, #1a4f8a 55%, #1e5ea8 100%);
  padding: 34px 0 30px;
  text-align: center;
  border-bottom: 4px solid #2563c8;
}

.hero-badge {
  display: inline-block;
  background: rgba(255,255,255,0.12);
  border: 1px solid rgba(255,255,255,0.2);
  color: #fff;
  border-radius: 999px;
  padding: 6px 14px;
  font-size: 0.82rem;
  font-weight: 700;
  margin-bottom: 14px;
}

.hero h1 {
  color: #fff;
  font-size: clamp(1.9rem, 5vw, 2.8rem);
  font-weight: 800;
  line-height: 1.15;
  margin-bottom: 12px;
}

.hero p {
  color: rgba(255,255,255,0.82);
  max-width: 560px;
  margin: 0 auto 22px;
  font-size: 1rem;
}

.hero-chips {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
}

.chip {
  background: rgba(255,255,255,0.1);
  border: 1px solid rgba(255,255,255,0.18);
  border-radius: 999px;
  padding: 6px 14px;
  font-size: 0.8rem;
  color: rgba(255,255,255,0.92);
}

.page-wrap {
  width: 100%;
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 44px 24px 80px;
}

.intro-card,
.sec,
.toc {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.intro-card {
  padding: 28px 30px;
  margin-bottom: 34px;
  color: var(--text-secondary);
}

.intro-card strong {
  color: var(--text-primary);
}

.intro-card a {
  color: var(--accent);
  text-decoration: none;
  font-weight: 700;
}

.toc {
  padding: 24px 28px;
  margin-bottom: 40px;
  background: var(--accent-light);
  border-color: #bfdbfe;
}

.toc-title {
  font-size: 0.78rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--accent-dark);
  margin-bottom: 14px;
}

.toc-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px 24px;
}

.toc-grid a {
  font-size: 0.9rem;
  color: var(--accent-dark);
  text-decoration: none;
  font-weight: 700;
}

.toc-grid a:hover {
  text-decoration: underline;
}

.sec {
  padding: 30px;
  margin-bottom: 18px;
  scroll-margin-top: 90px;
}

.sec-head {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 18px;
}

.sec-num {
  width: 34px;
  height: 34px;
  background: var(--accent);
  color: #fff;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.8rem;
  font-weight: 800;
  flex-shrink: 0;
}

.sec h2 {
  font-size: 1.18rem;
  font-weight: 800;
}

.sec p {
  color: var(--text-secondary);
  margin-bottom: 12px;
}

.pill-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 14px 0;
}

.pill {
  background: #f8fafc;
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 6px 14px;
  font-size: 0.86rem;
  color: var(--text-secondary);
  font-weight: 700;
}

.icon-list {
  list-style: none;
  margin: 12px 0;
}

.icon-list li {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  padding: 8px 0;
  border-bottom: 1px solid var(--border);
  color: var(--text-secondary);
}

.icon-list li:last-child {
  border-bottom: none;
}

.ico {
  width: 22px;
  height: 22px;
  border-radius: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.76rem;
  flex-shrink: 0;
  margin-top: 2px;
  font-weight: 800;
}

.ico.green { background: var(--green-bg); color: var(--green-text); }
.ico.red { background: #fef2f2; color: #b91c1c; }
.ico.blue { background: var(--accent-light); color: var(--accent-dark); }

.zero-row {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  margin: 16px 0;
}

.zero-badge {
  background: var(--green-bg);
  border: 1px solid var(--green-border);
  color: var(--green-text);
  border-radius: 8px;
  padding: 8px 14px;
  font-size: 0.84rem;
  font-weight: 800;
}

.callout {
  border-radius: 10px;
  padding: 14px 18px;
  font-size: 0.92rem;
  margin: 16px 0;
}

.callout.warn {
  background: var(--yellow-bg);
  border: 1px solid var(--yellow-border);
  color: var(--yellow-text);
}

.callout.secure {
  background: var(--green-bg);
  border: 1px solid var(--green-border);
  color: var(--green-text);
}

.callout.info {
  background: var(--accent-light);
  border: 1px solid #bfdbfe;
  color: #1e40af;
}

.callout strong {
  display: block;
  margin-bottom: 4px;
  font-size: 0.76rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.owner-row {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  margin: 14px 0;
}

.owner-card {
  flex: 1;
  min-width: 220px;
  border-radius: 10px;
  padding: 14px 18px;
  font-size: 0.92rem;
  font-weight: 800;
}

.owner-card.theirs {
  background: #fef2f2;
  border: 1px solid #fecaca;
  color: #b91c1c;
}

.owner-card.yours {
  background: var(--green-bg);
  border: 1px solid var(--green-border);
  color: var(--green-text);
}

.owner-card span {
  display: block;
  margin-top: 4px;
  font-size: 0.78rem;
  font-weight: 600;
  opacity: 0.85;
}

.flow {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 6px;
  margin: 18px 0;
}

.flow-step {
  background: #f8fafc;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 10px 14px;
  font-size: 0.84rem;
  font-weight: 800;
  color: var(--text-secondary);
}

.flow-arrow {
  color: var(--accent-dark);
  font-weight: 800;
}

.flow-step.last {
  background: var(--green-bg);
  border-color: var(--green-border);
  color: var(--green-text);
}

.contact-card {
  background: linear-gradient(145deg, #1e40af, #2563eb);
  border-radius: 16px;
  padding: 42px 30px;
  text-align: center;
  color: #fff;
  margin-top: 40px;
}

.contact-card h2 {
  font-size: 1.5rem;
  font-weight: 800;
  margin-bottom: 10px;
}

.contact-card p {
  color: rgba(255,255,255,0.85);
  margin-bottom: 22px;
}

.contact-btn {
  display: inline-block;
  background: #fff;
  color: var(--accent-dark);
  font-weight: 800;
  font-size: 0.9rem;
  padding: 12px 28px;
  border-radius: 999px;
  text-decoration: none;
}

.site-footer {
  background: var(--navy);
  padding: 18px 0;
  margin-top: auto;
}

.footer-inner {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

.footer-logo {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.9rem;
  font-weight: 800;
  color: #fff;
}

.footer-logo-box {
  width: 26px;
  height: 26px;
  background: rgba(255,255,255,0.15);
  border-radius: 6px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3px;
  padding: 4px;
}

.footer-logo-box span {
  border-radius: 1px;
}

.footer-logo-box .b1,
.footer-logo-box .b2,
.footer-logo-box .b3 {
  background: rgba(255,255,255,0.9);
}

.footer-logo-box .b4 {
  background: var(--green);
}

.footer-nav {
  display: flex;
  gap: 20px;
}

.footer-nav a {
  color: rgba(255,255,255,0.7);
  text-decoration: none;
  font-size: 0.82rem;
  font-weight: 700;
}

.footer-nav a:hover {
  color: #fff;
}

.footer-copy {
  margin-left: auto;
  font-size: 0.78rem;
  color: rgba(255,255,255,0.45);
}

@media (min-width: 768px) {
  .site-footer {
    padding: 26px 0;
  }

  .footer-inner {
    display: grid;
    grid-template-columns: auto 1fr auto;
    align-items: center;
    gap: 24px;
  }

  .footer-nav {
    justify-self: end;
    display: flex;
    gap: 24px;
    flex-wrap: nowrap;
  }

  .footer-copy {
    grid-column: 1 / -1;
    text-align: center;
    margin-top: 10px;
    width: 100%;
  }
}