@import url('https://fonts.googleapis.com/css2?family=Kaisei+Tokumin:wght@400;700&family=Zen+Kaku+Gothic+New:wght@400;500;700&display=swap');

:root {
  --ink: #1f2a2e;
  --muted: #5a6a6f;
  --accent: #1f6f8b;
  --accent-2: #e4a95b;
  --bg: #f5f1e9;
  --card: rgba(255, 255, 255, 0.75);
  --line: rgba(31, 42, 46, 0.12);
  --shadow: 0 18px 45px rgba(31, 42, 46, 0.12);
}

* {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  padding: 0;
}

body {
  font-family: 'Zen Kaku Gothic New', sans-serif;
  color: var(--ink);
  background: radial-gradient(1200px 600px at 10% 0%, #ffffff 0%, #f6f2ea 40%, #eef3f4 100%);
  min-height: 100vh;
}

body::before {
  content: '';
  position: fixed;
  inset: 0;
  background-image:
    radial-gradient(circle at 15% 20%, rgba(31, 111, 139, 0.08), transparent 45%),
    radial-gradient(circle at 80% 10%, rgba(228, 169, 91, 0.08), transparent 40%),
    radial-gradient(circle at 70% 80%, rgba(31, 111, 139, 0.06), transparent 45%);
  pointer-events: none;
  z-index: 0;
}

main {
  position: relative;
  z-index: 1;
}

a {
  color: inherit;
  text-decoration: none;
}

.container {
  max-width: 1080px;
  margin: 0 auto;
  padding: 40px 24px 80px;
}

.site-header {
  display: grid;
  gap: 12px;
  padding: 24px 0 12px;
}

.site-header .eyebrow {
  font-size: 12px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--muted);
}

.site-header h1 {
  font-family: 'Kaisei Tokumin', serif;
  font-size: clamp(28px, 5vw, 44px);
  margin: 0;
}

.site-header p {
  margin: 0;
  color: var(--muted);
  max-width: 620px;
  line-height: 1.7;
}

.grid {
  display: grid;
  gap: 20px;
}

.grid.two {
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
}

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 18px;
  padding: 22px;
  box-shadow: var(--shadow);
  backdrop-filter: blur(8px);
  transition: transform 0.25s ease, box-shadow 0.25s ease;
}

.card:hover {
  transform: translateY(-6px);
  box-shadow: 0 24px 60px rgba(31, 42, 46, 0.16);
}

.card h2, .card h3 {
  font-family: 'Kaisei Tokumin', serif;
  margin: 0 0 8px;
}

.card p {
  margin: 0;
  color: var(--muted);
  line-height: 1.6;
}

.section-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin: 24px 0 12px;
}

.search {
  flex: 1 1 260px;
  display: flex;
  align-items: center;
  gap: 12px;
  background: #ffffff;
  border-radius: 999px;
  border: 1px solid var(--line);
  padding: 10px 16px;
  box-shadow: 0 12px 30px rgba(31, 42, 46, 0.1);
}

.search input {
  border: none;
  outline: none;
  font-size: 15px;
  flex: 1;
  background: transparent;
  color: var(--ink);
}

.badge {
  padding: 6px 12px;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.65);
  font-size: 12px;
  color: var(--muted);
}

.lesson-grid {
  display: grid;
  gap: 16px;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  list-style: none;
  padding: 0;
  margin: 0;
}

.lesson-card {
  padding: 18px;
  border-radius: 16px;
  border: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.8);
  box-shadow: 0 12px 30px rgba(31, 42, 46, 0.08);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.lesson-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 18px 36px rgba(31, 42, 46, 0.12);
}

.lesson-card h3 {
  font-size: 18px;
  margin: 0 0 6px;
}

.lesson-card .meta {
  font-size: 12px;
  color: var(--muted);
}

.footer {
  margin-top: 48px;
  font-size: 12px;
  color: var(--muted);
}

.back-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  color: var(--muted);
}

@media (max-width: 600px) {
  .container {
    padding: 32px 18px 64px;
  }
  .card {
    padding: 18px;
  }
}