:root {
  --white: #ffffff;
  --bg: #f7f9fc;
  --ink: #172033;
  --muted: #657386;
  --line: #dbe3ec;
  --blue: #2f5f9f;
  --blue-soft: #eef5ff;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: Arial, Helvetica, sans-serif;
  line-height: 1.55;
}

a {
  color: inherit;
}

.wrap {
  width: min(980px, calc(100% - 36px));
  margin: 0 auto;
}

.site-header {
  border-bottom: 1px solid var(--line);
  background: var(--white);
}

.nav {
  min-height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand {
  color: var(--blue);
  font-size: 20px;
  font-weight: 700;
  text-decoration: none;
}

nav {
  display: flex;
  gap: 18px;
}

nav a {
  color: var(--muted);
  font-size: 14px;
  font-weight: 700;
  text-decoration: none;
}

nav a:hover,
nav a:focus-visible {
  color: var(--blue);
}

.intro {
  padding: 56px 0 26px;
}

.eyebrow {
  margin: 0 0 8px;
  color: var(--blue);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

h1 {
  margin: 0;
  font-size: clamp(42px, 7vw, 68px);
  line-height: 1;
  letter-spacing: 0;
}

.intro p:last-child {
  max-width: 600px;
  margin: 18px 0 0;
  color: var(--muted);
  font-size: 18px;
}

.search-label {
  display: block;
  margin: 0 0 8px;
  color: var(--muted);
  font-size: 14px;
  font-weight: 700;
}

.search {
  width: 100%;
  min-height: 48px;
  padding: 12px 14px;
  border: 1px solid var(--line);
  background: var(--white);
  color: var(--ink);
  font: inherit;
}

.search:focus-visible,
a:focus-visible {
  outline: 3px solid rgba(47, 95, 159, 0.28);
  outline-offset: 3px;
}

.lesson-section {
  margin-top: 38px;
  padding: 28px;
  border: 1px solid var(--line);
  background: var(--white);
}

h2 {
  margin: 0 0 18px;
  color: var(--blue);
  font-size: 26px;
  line-height: 1.15;
}

.lesson-list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.lesson-list li {
  border-bottom: 1px solid var(--line);
}

.lesson-list a {
  min-height: 48px;
  padding: 13px 4px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  color: var(--ink);
  font-weight: 700;
  text-decoration: none;
}

.lesson-list a::after {
  content: "PDF";
  flex: 0 0 auto;
  padding: 4px 8px;
  border: 1px solid var(--line);
  background: var(--blue-soft);
  color: var(--blue);
  font-size: 12px;
}

.lesson-list a:hover,
.lesson-list a:focus-visible {
  color: var(--blue);
}

[hidden] {
  display: none !important;
}

.footer {
  padding: 34px 0 46px;
  color: var(--muted);
  font-size: 14px;
}

@media (max-width: 640px) {
  .nav {
    align-items: flex-start;
    flex-direction: column;
    padding: 16px 0;
  }

  nav {
    width: 100%;
    overflow-x: auto;
  }

  .lesson-section {
    padding: 20px;
  }
}