:root {
  --accent: #0b4f6c;
  --accent-dark: #07384d;
  --text: #17212b;
  --muted: #5b6673;
  --line: #d8e1e8;
  --paper: #ffffff;
  --soft: #f6f9fb;
  --content-width: 880px;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--soft);
  color: var(--text);
  font-family: Georgia, "Times New Roman", serif;
  font-size: 18px;
  line-height: 1.7;
}

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover,
a:focus {
  color: var(--accent-dark);
  text-decoration: underline;
}

.page {
  max-width: calc(var(--content-width) + 48px);
  margin: 0 auto;
  padding: 36px 24px 64px;
}

.top-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 12px;
  margin-bottom: 36px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--line);
  font-family: Arial, Helvetica, sans-serif;
  font-size: 14px;
}

.top-nav a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 38px;
  padding: 8px 13px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--paper);
  color: var(--accent);
  text-decoration: none;
}

.top-nav a:hover,
.top-nav a:focus {
  background: #eef6f9;
  color: var(--accent-dark);
  text-decoration: none;
}

.hero,
.content-section,
.page-nav,
.program-footer {
  max-width: var(--content-width);
  margin-left: auto;
  margin-right: auto;
}

.hero {
  margin-bottom: 36px;
}

.eyebrow {
  margin: 0 0 8px;
  color: var(--muted);
  font-family: Arial, Helvetica, sans-serif;
  font-size: 14px;
  letter-spacing: 0.02em;
  text-transform: uppercase;
}

h1,
h2,
h3 {
  color: var(--accent-dark);
  line-height: 1.2;
}

h1 {
  margin: 0;
  font-size: 42px;
  font-weight: 600;
}

.subtitle {
  margin: 8px 0 24px;
  color: var(--muted);
  font-family: Arial, Helvetica, sans-serif;
  font-size: 18px;
}

.question {
  margin: 22px 0 10px;
  color: var(--text);
  font-size: 27px;
  line-height: 1.35;
}

.framing {
  margin: 0 0 24px;
  color: var(--muted);
  font-family: Arial, Helvetica, sans-serif;
  font-size: 16px;
}

.content-section {
  padding: 28px 0;
  border-top: 1px solid var(--line);
}

.content-section:first-of-type {
  border-top: 0;
}

.content-section h2 {
  margin: 0 0 18px;
  font-size: 27px;
}

.content-section h3 {
  margin: 24px 0 10px;
  font-size: 21px;
}

.content-section p {
  margin: 0 0 16px;
}

.content-section ul,
.content-section ol {
  margin: 0 0 18px;
  padding-left: 24px;
}

.content-section li {
  margin: 6px 0;
}

.editorial-note {
  padding: 18px 20px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--paper);
  font-family: Arial, Helvetica, sans-serif;
}

.editorial-note h2 {
  margin-bottom: 8px;
  font-size: 18px;
}

.editorial-note p {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.55;
}

.note,
.related,
.download-box {
  margin: 24px 0;
  padding: 18px 20px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--paper);
}

.note p,
.related p,
.download-box p {
  margin-bottom: 10px;
}

.related ul {
  margin-bottom: 0;
}

.program-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
  margin-top: 22px;
}

.program-card {
  display: block;
  min-height: 150px;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--paper);
  color: inherit;
  text-decoration: none;
}

.program-card:hover,
.program-card:focus {
  background: #eef6f9;
  text-decoration: none;
}

.program-card h2,
.program-card h3 {
  margin: 0 0 8px;
  font-family: Arial, Helvetica, sans-serif;
  font-size: 18px;
}

.program-card p {
  margin: 0;
  color: var(--muted);
  font-family: Arial, Helvetica, sans-serif;
  font-size: 14px;
  line-height: 1.55;
}

.button-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 22px 0 0;
}

.button-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 38px;
  padding: 8px 13px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--paper);
  color: var(--accent);
  font-family: Arial, Helvetica, sans-serif;
  font-size: 14px;
  text-decoration: none;
}

.button-link:hover,
.button-link:focus {
  background: #eef6f9;
  text-decoration: none;
}

.equation {
  overflow-x: auto;
  margin: 20px 0;
  padding: 14px 0;
}

.page-nav {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: 12px;
  margin-top: 36px;
  padding-top: 20px;
  border-top: 1px solid var(--line);
  font-family: Arial, Helvetica, sans-serif;
  font-size: 14px;
}

.page-nav a {
  display: inline-flex;
  align-items: center;
}

.page-nav .index-link {
  justify-content: center;
}

.page-nav .next-link {
  justify-content: flex-end;
}

.program-footer {
  margin-top: 28px;
  color: var(--muted);
  font-family: Arial, Helvetica, sans-serif;
  font-size: 13px;
  text-align: center;
}

@media (max-width: 720px) {
  body {
    font-size: 17px;
  }

  .page {
    padding: 28px 18px 52px;
  }

  h1 {
    font-size: 34px;
  }

  .question {
    font-size: 23px;
  }

  .program-grid {
    grid-template-columns: 1fr;
  }

  .page-nav {
    grid-template-columns: 1fr;
  }

  .page-nav .index-link,
  .page-nav .next-link {
    justify-content: flex-start;
  }
}