:root {
  color-scheme: dark;
  --bg: #07111f;
  --surface: rgba(13, 25, 43, 0.88);
  --surface-strong: rgba(17, 32, 52, 0.96);
  --border: rgba(131, 151, 177, 0.22);
  --text: #f6fbff;
  --muted: #a8b5c7;
  --soft: #d9e6f6;
  --accent: #35efd0;
  --accent-blue: #52b7ff;
  --accent-warm: #f6c35b;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  background:
    linear-gradient(135deg, rgba(53, 239, 208, 0.1), transparent 36%),
    linear-gradient(215deg, rgba(82, 183, 255, 0.12), transparent 44%),
    linear-gradient(180deg, #0d1b2e 0%, var(--bg) 56%, #030814 100%);
  color: var(--text);
  font-family: Inter, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

a {
  color: inherit;
}

.seo-shell {
  width: min(1120px, calc(100% - 32px));
  margin: 0 auto;
  padding: 26px 0 44px;
}

.seo-nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 34px;
}

.seo-brand {
  font-size: 28px;
  font-weight: 900;
  letter-spacing: 0;
  text-decoration: none;
}

.seo-brand span {
  background: linear-gradient(135deg, var(--accent) 0%, var(--accent-blue) 58%, var(--accent-warm) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.seo-nav-links {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 8px;
}

.seo-nav-links a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 38px;
  padding: 0 14px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: rgba(12, 22, 38, 0.7);
  color: #dce9f8;
  font-size: 14px;
  font-weight: 750;
  text-decoration: none;
}

.seo-nav-links a:hover,
.seo-nav-links a:focus-visible {
  border-color: rgba(53, 239, 208, 0.52);
  color: #f8ffff;
  outline: none;
}

.seo-hero {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(280px, 0.72fr);
  gap: 24px;
  align-items: stretch;
  margin-bottom: 28px;
}

.seo-hero-main,
.seo-panel,
.seo-section,
.seo-card,
.seo-faq details {
  border: 1px solid var(--border);
  border-radius: 8px;
  background:
    linear-gradient(180deg, rgba(17, 32, 52, 0.95), rgba(8, 18, 33, 0.91)),
    var(--surface);
  box-shadow: 0 22px 60px rgba(0, 0, 0, 0.24);
}

.seo-hero-main,
.seo-panel {
  padding: clamp(22px, 3.2vw, 34px);
}

.seo-kicker {
  display: inline-flex;
  align-items: center;
  min-height: 30px;
  padding: 0 10px;
  border: 1px solid rgba(53, 239, 208, 0.34);
  border-radius: 999px;
  background: rgba(53, 239, 208, 0.08);
  color: #bafff2;
  font-size: 12px;
  font-weight: 900;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  max-width: 17ch;
  margin: 16px 0 16px;
  font-size: clamp(32px, 4.8vw, 54px);
  line-height: 1.06;
  letter-spacing: 0;
}

.seo-lead {
  max-width: 65ch;
  color: #c8d8ec;
  font-size: clamp(15.5px, 1.55vw, 18px);
  line-height: 1.7;
}

.seo-panel {
  display: grid;
  align-content: center;
  gap: 18px;
}

.seo-panel-item strong {
  display: block;
  margin-bottom: 5px;
  color: #f8fafc;
  font-size: 16px;
}

.seo-panel-item span {
  color: var(--muted);
  font-size: 14.5px;
  line-height: 1.6;
}

.seo-section {
  margin-top: 18px;
  padding: clamp(22px, 3vw, 34px);
}

.seo-section h2 {
  margin-bottom: 12px;
  font-size: clamp(23px, 3vw, 32px);
  line-height: 1.16;
}

.seo-section > p {
  color: var(--muted);
  font-size: 15.5px;
  line-height: 1.72;
}

.seo-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
  margin-top: 20px;
}

.seo-grid.two {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.seo-card {
  padding: 18px;
  box-shadow: none;
}

.seo-card strong {
  display: block;
  margin-bottom: 8px;
  color: #f8fafc;
  font-size: 16px;
}

.seo-card p,
.seo-card li {
  color: var(--muted);
  font-size: 14.5px;
  line-height: 1.62;
}

.seo-card ul,
.seo-list {
  margin: 0;
  padding-left: 20px;
}

.alphabet-table {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 8px;
  margin-top: 20px;
}

.letter-tile {
  min-height: 74px;
  padding: 12px;
  border: 1px solid rgba(131, 151, 177, 0.2);
  border-radius: 8px;
  background: rgba(5, 13, 25, 0.56);
}

.letter-tile b {
  display: block;
  color: var(--accent);
  font-size: 26px;
  line-height: 1;
}

.letter-tile span {
  display: block;
  margin-top: 8px;
  color: #b8c7da;
  font-size: 13px;
}

.seo-phrase {
  display: grid;
  gap: 6px;
  padding: 12px 0;
  border-bottom: 1px solid rgba(131, 151, 177, 0.14);
}

.seo-phrase:last-child {
  border-bottom: 0;
}

.seo-phrase b {
  color: var(--accent);
  font-size: 18px;
}

.seo-phrase span {
  color: var(--soft);
}

.seo-faq {
  display: grid;
  gap: 10px;
  margin-top: 18px;
}

.seo-faq details {
  padding: 16px 18px;
  box-shadow: none;
}

.seo-faq summary {
  cursor: pointer;
  color: #f8fafc;
  font-weight: 850;
}

.seo-faq p {
  margin: 12px 0 0;
  color: var(--muted);
  line-height: 1.7;
}

.seo-footer {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
  margin-top: 28px;
  padding-top: 22px;
  border-top: 1px solid rgba(131, 151, 177, 0.16);
  color: #8190a5;
  font-size: 13px;
}

.seo-footer a {
  color: #b9f8ef;
  text-decoration: none;
}

@media (max-width: 840px) {
  .seo-nav {
    align-items: flex-start;
    flex-direction: column;
  }

  .seo-nav-links {
    justify-content: flex-start;
  }

  .seo-hero,
  .seo-grid,
  .seo-grid.two {
    grid-template-columns: 1fr;
  }

  .alphabet-table {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (max-width: 520px) {
  .seo-shell {
    width: min(100% - 20px, 1120px);
    padding-top: 18px;
  }

  .seo-hero-main,
  .seo-panel,
  .seo-section {
    padding: 20px;
  }

  .seo-nav-links a {
    width: 100%;
  }

  .alphabet-table {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}