/* RESET */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

/* PAGE */
body {
  font-family: Arial, Helvetica, sans-serif;
  background: #0f172a;
  color: #f8fafc;
  line-height: 1.6;
  text-align: center;
}

/* HEADER */
header {
  background: #111827;
  padding: 24px 16px;
  border-bottom: 1px solid #334155;
}

header h1 {
  font-size: 2rem;
  margin-bottom: 8px;
}

.site-tagline {
  font-size: 1rem;
  color: #cbd5e1;
  margin-bottom: 16px;
}

/* NAV */
nav {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 10px;
}

nav a {
  color: #ffffff;
  text-decoration: none;
  font-weight: bold;
  padding: 8px 14px;
  border: 1px solid #3b82f6;
  border-radius: 6px;
  transition: 0.2s ease;
}

nav a:hover {
  background: #3b82f6;
  color: #ffffff;
}

/* MAIN WRAPPER */
main {
  max-width: 820px;
  margin: 0 auto;
  padding: 28px 16px;
}

/* SECTIONS */
section {
  width: 100%;
  max-width: 760px;
  margin: 0 auto 28px auto;
}

/* HERO IMAGE */
.hero {
  text-align: center;
}

.hero img {
  display: block;
  width: 100%;
  max-width: 680px;
  height: auto;
  margin: 0 auto 22px auto;
  border-radius: 10px;
}

/* TEXT BLOCKS */
.intro,
.video-section,
.content-section,
.page-section,
.page-intro,
.books-video-section {
  max-width: 760px;
  margin: 0 auto 28px auto;
  text-align: center;
}

.page-intro h2,
.books-video-section h2,
.intro h2,
.video-section h2,
.page-section h2 {
  font-size: 1.6rem;
  margin-bottom: 12px;
  color: #ffffff;
}

p {
  max-width: 700px;
  margin: 0 auto 14px auto;
  color: #e2e8f0;
  font-size: 0.98rem;
}

/* VIDEO */
video {
  display: block;
  width: 100%;
  max-width: 680px;
  height: auto;
  margin: 16px auto;
  border-radius: 10px;
}

/* BUTTONS */
.video-buttons {
  margin-top: 12px;
}

.video-btn,
.book-button,
.cta-button {
  display: inline-block;
  padding: 9px 16px;
  background: #0b5cff;
  color: #ffffff;
  text-decoration: none;
  border-radius: 6px;
  margin: 6px 5px;
  font-size: 0.95rem;
}

.video-btn:hover,
.book-button:hover,
.cta-button:hover {
  background: #2563eb;
}

/* BOOK LIST */
.book-list {
  max-width: 760px;
  margin: 0 auto 24px auto;
}

/* BOOK CARDS */
.book-card {
  max-width: 520px;
  margin: 0 auto 22px auto;
  padding: 16px;
  background: #1e293b;
  border: 1px solid #334155;
  border-radius: 12px;
  text-align: center;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.book-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.35);
}

.book-card img {
  display: block;
  width: 150px;
  max-width: 100%;
  height: auto;
  margin: 0 auto 12px auto;
  border-radius: 8px;
}

.book-card h3 {
  margin-bottom: 8px;
  color: #ffffff;
  font-size: 1.1rem;
}

.book-card p {
  margin-bottom: 10px;
  max-width: 500px;
}

/* FOOTER */
footer {
  padding: 22px 16px;
  text-align: center;
  border-top: 1px solid #334155;
  color: #cbd5e1;
  background: #111827;
}

/* MOBILE */
@media (max-width: 768px) {
  header h1 {
    font-size: 1.7rem;
  }

  .page-intro h2,
  .books-video-section h2,
  .intro h2,
  .video-section h2,
  .page-section h2 {
    font-size: 1.4rem;
  }

  nav {
    flex-direction: column;
    align-items: center;
  }

  nav a {
    width: 220px;
    text-align: center;
  }

  .book-card {
    max-width: 100%;
    padding: 14px;
  }

  .book-card img {
    width: 140px;
  }
}@media (max-width: 768px) {
  section {
    margin: 0 auto 20px auto;
  }

  .book-card {
    margin-bottom: 18px;
  }

  p {
    margin-bottom: 10px;
  }
}