/* ============================================================
   Course Page — 课程体系页 V2 增强
   ============================================================ */

/* Hero Banner */
.v2-course-hero {
  background: var(--gradient-hero);
  padding: var(--space-4xl) 0 var(--space-3xl);
  position: relative;
  overflow: hidden;
}

.v2-course-hero::before {
  content: '';
  position: absolute;
  width: 300px;
  height: 300px;
  border-radius: 50%;
  background: rgba(255,255,255,0.06);
  top: -80px;
  right: -60px;
  pointer-events: none;
}

.v2-course-hero__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2xl);
  position: relative;
  z-index: 2;
  color: #fff;
}

.v2-course-hero__text h1 {
  font-size: var(--text-5xl);
  font-weight: 800;
  margin-bottom: var(--space-md);
}

.v2-course-hero__text p {
  font-size: var(--text-xl);
  opacity: 0.85;
  line-height: 1.8;
}

.v2-course-hero__badge {
  display: flex;
  gap: var(--space-md);
  margin-top: var(--space-lg);
}

.v2-course-hero__badge span {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: rgba(255,255,255,0.15);
  padding: 8px 16px;
  border-radius: var(--radius-full);
  font-size: var(--text-sm);
}

/* 翻转卡片增强 — flexbox 布局，最后一行自动居中 */
.v2-flip-cards {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--space-lg);
  margin-top: var(--space-2xl);
}

.v2-flip-card {
  flex: 0 0 calc(25% - 18px); /* 4列：1200px容器 / 4 = ~282px */
  min-width: 240px;
  perspective: 1000px;
  height: 220px;
}

.v2-flip-card__inner {
  position: relative;
  width: 100%;
  height: 100%;
  transition: transform 0.6s;
  -webkit-transform-style: preserve-3d;
  transform-style: preserve-3d;
}

.v2-flip-card:hover .v2-flip-card__inner {
  transform: rotateY(180deg);
}

.v2-flip-card__front,
.v2-flip-card__back {
  position: absolute;
  width: 100%;
  height: 100%;
  -webkit-backface-visibility: hidden;
  backface-visibility: hidden;
  border-radius: var(--radius-lg);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: var(--space-lg);
  text-align: center;
}

.v2-flip-card__front {
  background: var(--color-bg-white);
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-sm);
}

.v2-flip-card__front .v2-flip-card__icon {
  font-size: 48px;
  margin-bottom: var(--space-md);
}

.v2-flip-card__front .v2-flip-card__title {
  font-size: var(--text-xl);
  font-weight: 700;
  color: var(--color-heading);
}

.v2-flip-card__back {
  background: var(--gradient-hero);
  color: #fff;
  transform: rotateY(180deg);
}

.v2-flip-card__back span {
  font-size: var(--text-base);
  line-height: 1.8;
}

/* 课程类型卡片 — flexbox 布局 */
.v2-course-type-grid {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--space-lg);
  margin-top: var(--space-2xl);
}

.v2-course-type-card {
  flex: 0 0 calc(33.333% - 16px); /* 3列 */
  min-width: 280px;
  background: var(--color-bg-white);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--color-border);
  border-left: 3px solid var(--card-color, var(--color-primary));
  transition: all var(--transition-base);
}

.v2-course-type-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-4px);
}

.v2-course-type-card__header {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  margin-bottom: var(--space-md);
  padding-bottom: var(--space-md);
  border-bottom: 2px solid var(--color-border);
}

.v2-course-type-card__icon {
  width: 56px;
  height: 56px;
  border-radius: var(--radius-md);
  background: var(--card-color, var(--gradient-hero));
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  flex-shrink: 0;
  transition: transform var(--transition-base);
}

.v2-course-type-card:hover .v2-course-type-card__icon {
  transform: scale(1.1);
}

.v2-course-type-card__title {
  font-size: var(--text-lg);
  font-weight: 700;
  color: var(--color-heading);
  margin-bottom: 4px;
}

.v2-course-type-card__subtitle {
  display: inline-block;
  font-size: var(--text-xs);
  color: var(--card-color, var(--color-primary));
  font-weight: 600;
  background: color-mix(in srgb, var(--card-color, var(--color-primary)) 10%, transparent);
  padding: 2px 10px;
  border-radius: var(--radius-full);
  line-height: 1.6;
}

.v2-course-type-card__body {
  font-size: var(--text-sm);
  color: var(--color-body);
  line-height: 1.8;
  list-style: none;
  padding: 0;
  margin: 0;
}

.v2-course-type-card__body li {
  padding-left: 18px;
  position: relative;
  margin-bottom: 8px;
}

.v2-course-type-card__body li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 10px;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--card-color, var(--color-primary));
}

/* 响应式 */
@media (max-width: 1024px) {
  .v2-flip-card {
    flex: 0 0 calc(50% - 12px); /* 2列 */
    min-width: 220px;
  }

  .v2-course-type-card {
    flex: 0 0 calc(50% - 12px); /* 2列 */
    min-width: 240px;
  }
}

@media (max-width: 768px) {
  .v2-course-hero__inner {
    flex-direction: column;
    text-align: center;
  }

  .v2-course-hero__badge {
    justify-content: center;
  }

  .v2-flip-card {
    flex: 0 0 100%;
    max-width: 280px;
  }

  .v2-course-type-card {
    flex: 0 0 100%;
    max-width: 400px;
  }

  /* 移动端翻转改为点击 */
  .v2-flip-card:hover .v2-flip-card__inner {
    transform: none;
  }

  .v2-flip-card--flipped .v2-flip-card__inner {
    transform: rotateY(180deg);
  }
}