@import url('https://fonts.googleapis.com/css2?family=JetBrains+Mono:wght@600&family=Outfit:wght@400;500;600;700;800&display=swap');

:root {
  --bg: #06090f;
  --panel: #0d1320;
  --panel-soft: #111827;
  --border: rgba(148, 163, 184, 0.16);
  --text: #e8eef8;
  --muted: #a4b1c4;
  --gold: #e2c777;
  --blue: #62b8d1;
  --radius: 24px;
}

* { box-sizing: border-box; }
body {
  margin: 0;
  min-height: 100vh;
  color: var(--text);
  background:
    radial-gradient(circle at 10% 0%, rgba(226, 199, 119, 0.11), transparent 30%),
    radial-gradient(circle at 90% 30%, rgba(98, 184, 209, 0.08), transparent 28%),
    var(--bg);
  font-family: 'Outfit', sans-serif;
  line-height: 1.6;
}
a { color: inherit; }
.seo-shell { width: min(1160px, calc(100% - 32px)); margin: 0 auto; }
.seo-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding: 22px 0;
}
.seo-brand { display: flex; align-items: center; gap: 12px; text-decoration: none; font-weight: 800; font-size: 19px; }
.seo-brand img { width: 42px; height: 42px; border-radius: 12px; object-fit: cover; border: 1px solid var(--border); }
.seo-nav { display: flex; gap: 18px; color: var(--muted); font-weight: 600; }
.seo-nav a { text-decoration: none; }
.seo-nav a:hover { color: var(--text); }
.seo-hero {
  margin: 24px 0;
  padding: clamp(34px, 7vw, 76px);
  border: 1px solid rgba(226, 199, 119, 0.2);
  border-radius: 34px;
  background: linear-gradient(140deg, rgba(17, 24, 39, 0.98), rgba(9, 15, 25, 0.94));
  box-shadow: 0 30px 90px rgba(0, 0, 0, 0.3);
}
.seo-kicker { color: var(--gold); font-size: 12px; font-weight: 800; letter-spacing: .12em; text-transform: uppercase; }
h1 { max-width: 900px; margin: 16px 0; font-size: clamp(40px, 7vw, 72px); line-height: 1; letter-spacing: -.05em; }
.seo-lead { max-width: 780px; margin: 0; color: var(--muted); font-size: clamp(17px, 2vw, 21px); }
.seo-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 30px; }
.seo-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 50px;
  padding: 13px 20px;
  border: 1px solid var(--border);
  border-radius: 14px;
  text-decoration: none;
  font-weight: 800;
}
.seo-btn.primary { color: #111827; background: linear-gradient(135deg, #f1dea0, #c5a75b); border-color: rgba(241, 222, 160, .65); }
.seo-btn.secondary { background: rgba(98, 184, 209, .1); border-color: rgba(98, 184, 209, .3); }
.seo-section { padding: clamp(32px, 5vw, 58px) 0; }
.seo-section-head { max-width: 760px; margin-bottom: 22px; }
.seo-section h2 { margin: 0 0 8px; font-size: clamp(27px, 4vw, 40px); letter-spacing: -.035em; line-height: 1.1; }
.seo-section-head p, .seo-card p, .seo-list { color: var(--muted); }
.seo-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 16px; }
.seo-grid.two { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.seo-card {
  padding: 24px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: linear-gradient(180deg, rgba(255,255,255,.045), rgba(255,255,255,.018));
}
.seo-card h3 { margin: 0 0 8px; font-size: 21px; }
.seo-card p { margin: 0 0 18px; }
.seo-card-link { color: var(--gold); font-weight: 800; text-decoration: none; }
.seo-list + .seo-card-link { display: inline-block; margin-top: 18px; }
.seo-card-link:hover { text-decoration: underline; }
.seo-sample { font-family: Georgia, serif; font-size: 17px; }
.seo-number { display: grid; place-items: center; width: 34px; height: 34px; margin-bottom: 16px; border-radius: 50%; color: var(--gold); background: rgba(226,199,119,.11); font-family: 'JetBrains Mono', monospace; }
.seo-list { margin: 12px 0 0; padding-left: 20px; }
.seo-cta { margin: 30px 0 68px; padding: clamp(28px, 5vw, 50px); border: 1px solid rgba(98,184,209,.22); border-radius: 30px; background: rgba(98,184,209,.06); }
.seo-cta h2 { margin: 0; font-size: clamp(28px, 4vw, 42px); letter-spacing: -.04em; }
.seo-cta p { color: var(--muted); }
.seo-footer { padding: 24px 0 38px; border-top: 1px solid var(--border); color: var(--muted); font-size: 14px; }
.seo-related { display: flex; flex-wrap: wrap; gap: 12px 20px; }
.seo-related a { color: var(--muted); text-decoration: none; }
.seo-related a:hover { color: var(--text); }
.advanced-topic-dashboard {
  display: grid;
  grid-template-columns: minmax(280px, .85fr) minmax(360px, 1.15fr);
  gap: 22px;
  padding: clamp(20px, 4vw, 34px);
  border: 1px solid var(--border);
  border-radius: 30px;
  background: linear-gradient(145deg, rgba(17, 24, 39, .94), rgba(10, 16, 27, .88));
}
.advanced-chart-panel {
  display: grid;
  align-content: center;
  justify-items: center;
  gap: 18px;
  min-height: 360px;
  padding: 12px;
  border: 1px solid rgba(148, 163, 184, .1);
  border-radius: 24px;
  background: radial-gradient(circle at center, rgba(98, 184, 209, .05), transparent 62%);
}
.advanced-chart-title {
  margin: 0;
  color: var(--text);
  font-size: clamp(15px, 1.5vw, 18px);
  line-height: 1.35;
  text-align: center;
}
.advanced-chart-wrap { position: relative; width: min(100%, 340px); aspect-ratio: 1; }
.advanced-chart-centre {
  position: absolute;
  inset: 50% auto auto 50%;
  width: 118px;
  transform: translate(-50%, -50%);
  text-align: center;
  pointer-events: none;
}
.advanced-chart-centre strong { display: block; color: var(--gold); font-size: 30px; line-height: 1; }
.advanced-chart-centre span { display: block; margin-top: 7px; color: var(--muted); font-size: 12px; line-height: 1.25; }
.advanced-topic-legend { display: grid; gap: 9px; align-content: center; }
.advanced-topic-entry {
  border: 1px solid transparent;
  border-radius: 16px;
  background: rgba(255,255,255,.025);
  overflow: hidden;
}
.advanced-topic-entry.is-selected { border-color: rgba(226,199,119,.42); background: rgba(226,199,119,.075); }
.advanced-topic-option {
  display: grid;
  grid-template-columns: 12px minmax(0, 1fr) auto;
  gap: 12px;
  align-items: center;
  width: 100%;
  padding: 13px 14px;
  border: 1px solid transparent;
  border-radius: 16px;
  color: var(--text);
  background: transparent;
  font: inherit;
  text-align: left;
  cursor: pointer;
  transition: transform .16s ease, border-color .16s ease, background .16s ease;
}
.advanced-topic-option:hover { transform: translateX(2px); background: rgba(255,255,255,.045); }
.advanced-topic-dot { width: 10px; height: 10px; border-radius: 50%; background: var(--topic-colour); }
.advanced-topic-copy strong { display: block; font-size: 15px; line-height: 1.25; }
.advanced-topic-percentage { color: var(--gold); font-family: 'JetBrains Mono', monospace; font-size: 13px; }
.advanced-subtopic-list {
  display: grid;
  gap: 7px;
  margin: 0;
  padding: 2px 18px 16px 42px;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.35;
}
.advanced-subtopic-list li::marker { color: var(--topic-colour); }
.advanced-sample-card {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 26px;
  align-items: center;
  padding: clamp(24px, 5vw, 42px);
  border: 1px solid rgba(98,184,209,.22);
  border-radius: 30px;
  background: linear-gradient(140deg, rgba(98,184,209,.075), rgba(255,255,255,.025));
}
.advanced-sample-label { margin: 0 0 7px; color: var(--gold); font-size: 13px; font-weight: 800; letter-spacing: .08em; text-transform: uppercase; }
.advanced-sample-card h3 { margin: 0; font-size: clamp(25px, 4vw, 38px); letter-spacing: -.035em; }
.advanced-sample-description { margin: 8px 0 22px; color: var(--muted); }
.advanced-sample-question { margin: 0; font-family: Georgia, serif; font-size: clamp(18px, 2.4vw, 23px); line-height: 1.55; }
.advanced-sample-note { margin: 18px 0 0; color: var(--muted); font-size: 14px; }
.advanced-sample-actions { display: grid; gap: 10px; min-width: 230px; }
.advanced-worked-example {
  padding: clamp(24px, 5vw, 42px);
  border: 1px solid rgba(98,184,209,.22);
  border-radius: 30px;
  background: linear-gradient(140deg, rgba(98,184,209,.075), rgba(255,255,255,.025));
}
.advanced-example-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding-bottom: 20px;
  border-bottom: 1px solid var(--border);
}
.advanced-example-code { color: var(--gold); font-family: 'JetBrains Mono', monospace; font-size: 13px; font-weight: 800; }
.advanced-example-badge { padding: 6px 10px; border: 1px solid rgba(98,184,209,.25); border-radius: 999px; color: var(--muted); font-size: 12px; font-weight: 700; }
.advanced-example-block { padding-top: 24px; }
.advanced-example-block + .advanced-example-block { margin-top: 24px; border-top: 1px solid var(--border); }
.advanced-example-block h3 { margin: 0 0 14px; font-size: 20px; }
.advanced-example-block p { color: var(--muted); }
.advanced-example-block .katex-display { overflow-x: auto; overflow-y: hidden; padding: 5px 0; }
.advanced-answer-line { color: var(--gold) !important; font-weight: 800; }
@media (max-width: 820px) {
  .seo-grid, .seo-grid.two { grid-template-columns: 1fr; }
  .seo-header { align-items: flex-start; }
  .seo-nav { gap: 10px; font-size: 14px; flex-wrap: wrap; justify-content: flex-end; }
  .advanced-topic-dashboard, .advanced-sample-card { grid-template-columns: 1fr; }
  .advanced-chart-panel { min-height: 320px; }
  .advanced-sample-actions { min-width: 0; }
}
@media (max-width: 560px) {
  .seo-shell { width: min(100% - 24px, 1160px); }
  .seo-header { display: grid; }
  .seo-nav { justify-content: flex-start; }
  .seo-hero { padding: 34px 22px; border-radius: 24px; }
  .seo-actions { display: grid; }
  .seo-btn { width: 100%; }
  .advanced-topic-dashboard { padding: 14px; border-radius: 24px; }
  .advanced-chart-panel { min-height: 280px; padding: 6px; }
  .advanced-chart-wrap { width: min(100%, 270px); }
  .advanced-topic-option { grid-template-columns: 10px minmax(0, 1fr) auto; padding: 12px; }
  .advanced-subtopic-list { padding-left: 34px; }
}