/* ============================================
   Virtual Simulation Software Platform
   Design: Premium Academic + Elegant + Refined
   ============================================ */

/* --- Reset & Base --- */
*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: 'Noto Sans SC', 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  color: #1E293B;
  background-color: #F0F2F7;
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

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

ul {
  list-style: none;
}

button {
  border: none;
  background: none;
  cursor: pointer;
  font: inherit;
  color: inherit;
}

/* ============================================
   Banner
   ============================================ */
.banner {
  position: relative;
  background: linear-gradient(135deg, #0F2640 0%, #1B3A5C 40%, #234B73 70%, #1B3A5C 100%);
  width: 100%;
  flex-shrink: 0;
  overflow: hidden;
}

.banner-bg-pattern {
  position: absolute;
  inset: 0;
  pointer-events: none;
  opacity: 0.6;
}

.banner-glow {
  position: absolute;
  top: -40%;
  left: 50%;
  transform: translateX(-50%);
  width: 600px;
  height: 300px;
  background: radial-gradient(ellipse, rgba(59, 111, 160, 0.2) 0%, transparent 70%);
  pointer-events: none;
}

.banner-inner {
  position: relative;
  z-index: 1;
  max-width: 1200px;
  margin: 0 auto;
  padding: 56px 24px 48px;
  text-align: center;
}

.banner-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 16px;
  border: 1px solid rgba(255, 255, 255, 0.15);
  border-radius: 20px;
  color: rgba(255, 255, 255, 0.6);
  font-family: 'Inter', sans-serif;
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.06em;
  margin-bottom: 20px;
  backdrop-filter: blur(4px);
  background: rgba(255, 255, 255, 0.04);
}

.banner-title {
  font-size: 34px;
  font-weight: 700;
  color: #FFFFFF;
  letter-spacing: 0.08em;
  margin-bottom: 10px;
  text-shadow: 0 2px 12px rgba(0, 0, 0, 0.15);
}

.banner-subtitle {
  font-family: 'Inter', sans-serif;
  font-size: 14px;
  font-weight: 300;
  color: rgba(255, 255, 255, 0.45);
  letter-spacing: 0.06em;
  margin-bottom: 28px;
}

.banner-divider {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  margin-bottom: 28px;
}

.banner-divider span {
  display: block;
  width: 48px;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.25), transparent);
}

.divider-diamond {
  width: 6px !important;
  height: 6px !important;
  background: rgba(255, 255, 255, 0.25);
  transform: rotate(45deg);
}

.banner-stats {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 32px;
}

.stat-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
}

.stat-number {
  font-family: 'Inter', sans-serif;
  font-size: 26px;
  font-weight: 700;
  color: #FFFFFF;
  letter-spacing: 0.02em;
}

.stat-label {
  font-size: 12px;
  color: rgba(255, 255, 255, 0.45);
  letter-spacing: 0.04em;
}

.stat-divider {
  width: 1px;
  height: 32px;
  background: rgba(255, 255, 255, 0.12);
}

/* ============================================
   Content Area
   ============================================ */
.content {
  flex: 1;
  width: 100%;
}

.content-inner {
  max-width: 1080px;
  margin: 0 auto;
  padding: 40px 24px 60px;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

/* ============================================
   Course Card
   ============================================ */
.course-card {
  background: #FFFFFF;
  border-radius: 8px;
  border: 1px solid rgba(226, 232, 240, 0.8);
  overflow: hidden;
  position: relative;
  transition: box-shadow 0.3s ease, transform 0.3s ease, border-color 0.3s ease;
}

.course-card::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 4px;
  background: linear-gradient(180deg, #1B3A5C, #3B6FA0);
  border-radius: 8px 0 0 8px;
  opacity: 0.7;
  transition: opacity 0.3s ease;
}

.course-card:hover {
  box-shadow: 0 8px 30px rgba(27, 58, 92, 0.1), 0 2px 8px rgba(27, 58, 92, 0.06);
  transform: translateY(-2px);
  border-color: rgba(59, 111, 160, 0.2);
}

.course-card:hover::before {
  opacity: 1;
}

.course-card.is-open {
  border-color: rgba(59, 111, 160, 0.25);
  box-shadow: 0 4px 20px rgba(27, 58, 92, 0.08);
}

.course-card.is-open::before {
  opacity: 1;
}

/* ============================================
   Course Header
   ============================================ */
.course-header {
  display: flex;
  align-items: center;
  width: 100%;
  padding: 22px 24px;
  gap: 16px;
  text-align: left;
  transition: background-color 0.2s ease;
}

.course-header:hover {
  background-color: #F8FAFC;
}

/* --- Course Info --- */
.course-info {
  flex: 1;
  min-width: 0;
}

.course-name {
  font-size: 18px;
  font-weight: 600;
  color: #1E293B;
  line-height: 1.4;
}

.course-desc {
  font-size: 13px;
  color: #64748B;
  margin-top: 3px;
  line-height: 1.5;
}

/* --- Course Meta --- */
.course-meta {
  flex-shrink: 0;
}

.course-count {
  display: inline-block;
  padding: 4px 12px;
  border-radius: 4px;
  background: #F1F5F9;
  color: #64748B;
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.02em;
  transition: background 0.2s ease, color 0.2s ease;
}

.course-card.is-open .course-count {
  background: #EFF4F9;
  color: #3B6FA0;
}

/* --- Chevron --- */
.chevron {
  flex-shrink: 0;
  color: #94A3B8;
  transition: transform 0.35s cubic-bezier(0.4, 0, 0.2, 1), color 0.2s ease;
}

.course-header:hover .chevron {
  color: #3B6FA0;
}

.course-card.is-open .chevron {
  transform: rotate(180deg);
  color: #3B6FA0;
}

/* ============================================
   Course Body (expandable)
   ============================================ */
.course-body {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.course-card.is-open .course-body {
  max-height: 600px;
}

/* ============================================
   Software Grid & Cards
   ============================================ */
.software-grid {
  padding: 4px 24px 24px 24px;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
}

.software-card {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 16px;
  border-radius: 6px;
  border: 1px solid transparent;
  background: #FAFBFC;
  transition: all 0.25s ease;
}

.software-card:hover {
  background: #FFFFFF;
  border-color: rgba(59, 111, 160, 0.15);
  box-shadow: 0 2px 8px rgba(27, 58, 92, 0.06);
  transform: translateX(2px);
}

.software-card-info {
  flex: 1;
  min-width: 0;
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.software-name {
  font-size: 15px;
  font-weight: 500;
  color: #1E293B;
  line-height: 1.3;
  transition: color 0.2s ease;
}

.software-card:hover .software-name {
  color: #1B3A5C;
}

.software-tag {
  font-size: 12px;
  color: #94A3B8;
  line-height: 1.3;
  transition: color 0.2s ease;
}

.software-card:hover .software-tag {
  color: #3B6FA0;
}

.arrow {
  flex-shrink: 0;
  color: #CBD5E1;
  transition: transform 0.25s ease, color 0.25s ease;
}

.software-card:hover .arrow {
  transform: translateX(4px);
  color: #3B6FA0;
}

/* ============================================
   Footer
   ============================================ */
.footer {
  background: linear-gradient(135deg, #0F2640 0%, #1B3A5C 100%);
  border-top: 1px solid rgba(59, 111, 160, 0.15);
  flex-shrink: 0;
}

.footer-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 28px 24px;
  text-align: center;
}

.footer-text {
  font-size: 14px;
  color: rgba(255, 255, 255, 0.7);
  font-weight: 500;
  letter-spacing: 0.04em;
  margin-bottom: 4px;
}

.footer-copy {
  font-family: 'Inter', sans-serif;
  font-size: 12px;
  color: rgba(255, 255, 255, 0.3);
  letter-spacing: 0.04em;
}

/* ============================================
   Responsive
   ============================================ */
@media (max-width: 768px) {
  .banner-inner {
    padding: 40px 20px 36px;
  }

  .banner-title {
    font-size: 26px;
    letter-spacing: 0.04em;
  }

  .banner-subtitle {
    font-size: 12px;
    margin-bottom: 20px;
  }

  .banner-stats {
    gap: 20px;
  }

  .stat-number {
    font-size: 22px;
  }

  .stat-label {
    font-size: 11px;
  }

  .content-inner {
    padding: 24px 16px 40px;
    gap: 12px;
  }

  .course-header {
    padding: 16px;
    gap: 12px;
  }

  .course-name {
    font-size: 16px;
  }

  .course-desc {
    font-size: 12px;
  }

  .course-meta {
    display: none;
  }

  .software-grid {
    grid-template-columns: 1fr;
    padding: 4px 16px 16px;
    gap: 8px;
  }

  .software-card {
    padding: 12px 14px;
  }

  .software-name {
    font-size: 14px;
  }
}

@media (max-width: 480px) {
  .banner-title {
    font-size: 22px;
  }

  .banner-badge {
    font-size: 11px;
    padding: 5px 12px;
  }

  .banner-stats {
    gap: 16px;
  }

  .stat-number {
    font-size: 20px;
  }

  .course-name {
    font-size: 15px;
  }
}