:root {
  color-scheme: light;
  --blue: #006aa7;
  --blue-dark: #103e83;
  --yellow: #fecc00;
  --ink: #172033;
  --muted: #53657b;
  --line: #d7e3f1;
  --soft: #eef6ff;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: linear-gradient(180deg, #eef6ff 0%, #ffffff 420px);
  color: var(--ink);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.65;
}

a {
  color: var(--blue);
  font-weight: 800;
}

.page {
  width: min(1040px, calc(100% - 32px));
  margin: 0 auto;
}

.topbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 24px 0;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  font-size: 1.05rem;
  font-weight: 950;
  text-decoration: none;
}

.brand-mark {
  display: grid;
  width: 40px;
  height: 40px;
  place-items: center;
  border-radius: 8px;
  background: linear-gradient(135deg, var(--blue) 0 49%, var(--yellow) 50% 100%);
  color: #ffffff;
}

.nav {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
}

.nav a {
  color: #334155;
  text-decoration: none;
}

.hero {
  display: grid;
  gap: 18px;
  padding: 56px 0 40px;
}

.eyebrow {
  margin: 0;
  color: var(--blue);
  font-weight: 950;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

h1,
h2,
h3 {
  margin: 0;
  color: #111827;
  line-height: 1.12;
}

h1 {
  max-width: 880px;
  font-size: clamp(2.25rem, 6vw, 4.6rem);
}

h2 {
  margin-top: 38px;
  font-size: clamp(1.55rem, 3vw, 2.25rem);
}

h3 {
  margin-top: 22px;
  font-size: 1.18rem;
}

p,
li {
  color: var(--muted);
  font-size: 1.04rem;
}

.lead {
  max-width: 760px;
  margin: 0;
  color: #334155;
  font-size: 1.22rem;
  font-weight: 700;
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 10px;
}

.button {
  display: inline-flex;
  min-height: 48px;
  align-items: center;
  justify-content: center;
  border-radius: 8px;
  padding: 0 18px;
  background: var(--yellow);
  color: #172033;
  font-weight: 950;
  text-decoration: none;
}

.button.secondary {
  border: 1px solid var(--line);
  background: #ffffff;
  color: var(--blue-dark);
}

.content {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 300px;
  gap: 36px;
  align-items: start;
  padding-bottom: 56px;
}

.article,
.sidebar {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.9);
  box-shadow: 0 18px 42px rgba(15, 23, 42, 0.08);
}

.article {
  padding: clamp(22px, 4vw, 38px);
}

.article p:first-child {
  margin-top: 0;
}

.sidebar {
  display: grid;
  gap: 14px;
  padding: 20px;
}

.sidebar h2 {
  margin-top: 0;
  font-size: 1.25rem;
}

.fact-list {
  display: grid;
  gap: 12px;
  margin: 22px 0;
  padding: 0;
  list-style: none;
}

.fact-list li {
  border-left: 4px solid var(--yellow);
  background: #fffaf0;
  padding: 12px 14px;
  color: #35465c;
  font-weight: 750;
}

.chapter-list {
  columns: 2;
  column-gap: 28px;
}

.chapter-list li {
  break-inside: avoid;
  margin-bottom: 8px;
}

.note {
  border: 1px solid #f3d27a;
  border-radius: 8px;
  background: #fff9e6;
  padding: 16px;
  color: #624000;
  font-weight: 750;
}

.footer {
  border-top: 1px solid var(--line);
  padding: 26px 0 38px;
  color: var(--muted);
}

@media (max-width: 800px) {
  .content {
    grid-template-columns: 1fr;
  }

  .chapter-list {
    columns: 1;
  }
}