:root {
  --bg: #0f172a;
  --bg-soft: #111827;
  --surface: #ffffff;
  --surface-alt: #f8fafc;
  --text: #1f2937;
  --text-light: #e5e7eb;
  --primary: #10b981;
  --primary-dark: #059669;
  --shadow: 0 10px 25px rgba(2, 6, 23, 0.1);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Inter", "Segoe UI", Roboto, sans-serif;
  background: var(--surface);
  color: var(--text);
  line-height: 1.6;
}

.container {
  width: min(1000px, 92%);
  margin: 0 auto;
}

.hero {
  background: linear-gradient(120deg, var(--bg), var(--bg-soft));
  color: var(--text-light);
  padding: 96px 0 88px;
}

.domain {
  display: inline-block;
  margin: 0 0 14px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: #86efac;
}

h1,
h2,
h3 {
  margin-top: 0;
  line-height: 1.25;
}

h1 {
  font-size: clamp(1.9rem, 3vw, 2.7rem);
  max-width: 780px;
}

.hero p {
  max-width: 760px;
  font-size: 1.06rem;
}

.btn {
  display: inline-block;
  margin-top: 22px;
  padding: 12px 22px;
  border-radius: 10px;
  background: var(--primary);
  color: #052e16;
  text-decoration: none;
  font-weight: 700;
  transition: background 0.2s ease;
}

.btn:hover {
  background: var(--primary-dark);
  color: #ecfdf5;
}

.section {
  padding: 74px 0;
}

.section.alt {
  background: var(--surface-alt);
}

h2 {
  font-size: clamp(1.5rem, 2.3vw, 2rem);
  margin-bottom: 14px;
}

.subtitle {
  margin-top: 0;
  margin-bottom: 24px;
  color: #4b5563;
}

.card-list,
.book-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.card-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 18px;
}

.card-list li {
  background: var(--surface);
  border-radius: 14px;
  padding: 18px;
  box-shadow: var(--shadow);
}

.card-list h3 {
  margin-bottom: 8px;
  font-size: 1.06rem;
}

.card-list p {
  margin: 0;
  color: #374151;
}

.book-list li {
  padding: 13px 14px;
  margin-bottom: 10px;
  border-radius: 10px;
  background: #f3f4f6;
}

.footer {
  background: #020617;
  color: #cbd5e1;
  text-align: center;
  padding: 24px 0;
  font-size: 0.93rem;
}

@media (max-width: 640px) {
  .hero {
    padding: 74px 0 64px;
  }

  .section {
    padding: 58px 0;
  }
}