/* =========================
   Reset & Base
========================= */
* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI",
               Roboto, "Noto Sans KR", Arial, sans-serif;
  color: #222;
  background: #fff;
}

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

img {
  max-width: 100%;
  display: block;
}

/* =========================
   Layout
========================= */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 16px;
}

main {
  padding: 40px 0;
}

.section {
  margin-bottom: 60px;
}

.section.bg-light {
  background: #f7f7f9;
  padding: 40px 0;
}

/* =========================
   Header / Nav
========================= */
.main-nav {
  display: flex;
  gap: 20px;
  padding: 16px 24px;
  border-bottom: 1px solid #eee;
  background: #fff;
}

.main-nav a {
  font-weight: 600;
  color: #0052cc;
}

.main-nav a:hover {
  text-decoration: underline;
}

/* =========================
   Titles
========================= */
.page-title,
.section h2 {
  font-size: 24px;
  margin-bottom: 20px;
}

/* =========================
   Hero (index)
========================= */
.hero {
  padding: 80px 16px;
  text-align: center;
}

.hero h1 {
  font-size: 36px;
  margin-bottom: 16px;
}

.hero p {
  font-size: 18px;
  color: #555;
}

/* =========================
   Grid (공통)
========================= */
.grid,
.lecture-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 20px;
}

/* =========================
   Card (공통)
========================= */
.card,
.lecture-card {
  border: 1px solid #eee;
  border-radius: 8px;
  overflow: hidden;
  background: #fff;
  transition: transform .15s ease, box-shadow .15s ease;
}

.card:hover,
.lecture-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 6px 20px rgba(0,0,0,0.08);
}

/* Thumbnail */
.card img,
.lecture-card img {
  width: 100%;
  height: 140px;
  object-fit: cover;
  background: #ddd;
}

/* Card info */
.card strong,
.lecture-card .title {
  display: block;
  font-size: 15px;
  margin: 12px;
}

.card span,
.lecture-card .price {
  display: block;
  margin: 0 12px 12px;
  font-weight: 600;
  color: #0052cc;
}

/* =========================
   Lecture View
========================= */
.lecture-header {
  display: flex;
  gap: 40px;
  margin-bottom: 40px;
}

.lecture-thumb img {
  width: 320px;
  border-radius: 8px;
}

.lecture-info h1 {
  font-size: 28px;
  margin-bottom: 16px;
}

.price {
  font-size: 20px;
  margin-bottom: 20px;
}

.btn-buy {
  padding: 12px 24px;
  background: #0052cc;
  color: #fff;
  border: none;
  border-radius: 6px;
  font-size: 16px;
  cursor: pointer;
}

.btn-buy:hover {
  background: #003d99;
}

/* =========================
   Responsive
========================= */
@media (max-width: 768px) {
  .hero h1 {
    font-size: 28px;
  }

  .lecture-header {
    flex-direction: column;
  }

  .lecture-thumb img {
    width: 100%;
  }
}
/* =========================
   Footer
========================= */
.site-footer {
  border-top: 1px solid #eee;
  margin-top: 80px;
  padding: 40px 0 20px;
  background: #fafafa;
  font-size: 14px;
  color: #555;
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 20px;
}

.footer-left strong {
  font-size: 16px;
  color: #222;
}

.footer-right a {
  margin-left: 16px;
  color: #555;
}

.footer-right a:hover {
  text-decoration: underline;
}

.footer-copy {
  text-align: center;
  color: #999;
  font-size: 13px;
}

@media (max-width: 768px) {
  .footer-inner {
    flex-direction: column;
    gap: 12px;
    text-align: center;
  }

  .footer-right a {
    margin: 0 8px;
  }
}
/* =========================
   Books (교재)
========================= */
.lecture-books {
  margin: 30px 0;
}

.lecture-books h3 {
  margin-bottom: 10px;
}

.lecture-books ul {
  list-style: none;
  padding: 0;
}

.lecture-books li {
  margin-bottom: 6px;
}

.included {
  color: #0a7;
  font-size: 13px;
}

.book-option {
  display: block;
  margin-bottom: 8px;
  cursor: pointer;
}

.total-price {
  margin: 30px 0;
  font-size: 18px;
}
.badge {
  display: inline-block;
  margin-top: 6px;
  padding: 4px 8px;
  font-size: 12px;
  border-radius: 4px;
  background: #0a7;
  color: #fff;
}