body {
  margin: 0;
  margin-top: 64px;
  font-family: 'Arial', sans-serif;
}

.main-content {
  min-height: calc(100vh - 140px);
}

.lecture-section .lecture-body {
  margin: 24px;
}

.lecture-section {
  margin-bottom: 80px;
}

.lecture-title {
  width: 500px;
  height: 110px;
  background: linear-gradient(to right, #192437 20px, transparent 20px), none;
  line-height: 110px;
  margin: 40px 0;
}

.lecture-title .title-text {
  margin-left: 97px;
  font-size: 50px;
  font-weight: bold;
  color: #192437;
}

.lecture-content {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 30px;
  margin: 40px 0;
  align-items: stretch;
}

.lecture-card {
  display: flex;
  flex-direction: column;
  height: 100%;
  background-color: white;
  border: 1px solid #e0e0e0;
  border-radius: 20px;
  overflow: hidden;
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.1);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  cursor: pointer;
}

.lecture-intro {
  margin: 0 24px 8px;
  font-size: 16px;
  line-height: 1.8;
  color: #444;
  font-weight: 600;
}

.lecture-card:hover {
  transform: translateY(-8px);
  box-shadow: 0 12px 30px rgba(0, 0, 0, 0.15);
}

.lecture-image {
  flex: 1;
  width: 100%;
  min-height: 220px;
  background: linear-gradient(135deg, var(--banner-color));
  display: flex;
  flex-direction: column;
  align-items: stretch;
  justify-content: stretch;
  position: relative;
  border-radius: 20px 20px 0 0;
}

.lecture-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.lecture-image::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: none;
  z-index: 1;
}

.lecture-text {
  flex: 1;
  display: flex;
  flex-direction: column;
  padding: 30px;
  position: relative;
  z-index: 2;
  width: 100%;
  box-sizing: border-box;
  background-color: rgba(255, 255, 255, 0.96);
  border-radius: 0 0 15px 15px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
  overflow: hidden;
}

.lecture-text h3 {
  margin: 0 0 20px 0;
  font-size: 28px;
  color: #192437;
  font-weight: bold;
  border-bottom: 3px solid var(--banner-color);
  padding-bottom: 10px;
}

.lecture-description {
  flex: 1;
  margin: 0;
  font-size: 16px;
  line-height: 1.6;
  color: #666;
  background-color: #f8f9fa;
  padding: 15px;
  border-radius: 8px;
  border-left: 4px solid var(--banner-color);
}

.lecture-details {
  margin-top: auto;
}

.lecture-details-body {
  display: none;
}

.lecture-modal-body .lecture-details-body {
  display: block;
}

.lecture-details h4 {
  margin: 0 0 15px 0;
  font-size: 20px;
  color: #192437;
  font-weight: bold;
}

.lecture-details ul {
  margin: 0;
  padding-left: 20px;
  list-style: none;
}

.lecture-details li {
  position: relative;
  margin-bottom: 8px;
  font-size: 14px;
  color: #555;
  padding-left: 20px;
}

.lecture-details li::before {
  content: '▶';
  position: absolute;
  left: 0;
  color: var(--banner-color);
  font-size: 12px;
}

.lecture-details-sub {
  margin-top: 14px;
}

.lecture-details-sub:first-of-type {
  margin-top: 0;
}

.lecture-details-sub h5 {
  margin: 0 0 8px 0;
  font-size: 15px;
  color: #192437;
  font-weight: bold;
  padding-left: 0;
}

.lecture-details-sub ul {
  margin: 0 0 0 0;
  padding-left: 20px;
}

.lecture-photo {
  margin-top: 15px;
  border-radius: 10px;
  overflow: hidden;
  display: none;
  max-height: 200px;
}

.lecture-photo img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.lecture-photo.is-visible {
  display: block;
}

.lecture-custom-contact {
  margin: 60px 24px 40px;
  padding: 30px 40px;
  border-radius: 16px;
  background: linear-gradient(135deg, var(--banner-color) 0%, #192437 100%);
  color: #fff;
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.18);
  text-align: center;
}

.lecture-custom-inner {
  max-width: 960px;
  margin: 0 auto;
}

.lecture-custom-message {
  margin: 0 0 12px;
  font-size: 20px;
  font-weight: 600;
}

.lecture-custom-sub {
  margin: 0;
  font-size: 16px;
}

.lecture-custom-link {
  display: inline-block;
  margin-left: 8px;
  padding: 8px 18px;
  border-radius: 999px;
  background-color: #fff;
  color: #192437;
  font-weight: 600;
  text-decoration: none;
  transition: background-color 0.2s ease, transform 0.2s ease, box-shadow 0.2s ease;
}

.lecture-custom-link:hover {
  background-color: #e8ebff;
  transform: translateY(-1px);
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.18);
}

.nav-link.active {
  background-color: var(--banner-color);
  color: white;
}

.lecture-modal {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 2000;
  align-items: center;
  justify-content: center;
  padding: 24px;
  box-sizing: border-box;
}

.lecture-modal.active {
  display: flex;
}

.lecture-modal-overlay {
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, 0.6);
}

.lecture-modal-panel {
  position: relative;
  z-index: 1;
  width: min(640px, 100%);
  max-height: min(80vh, 720px);
  overflow-y: auto;
  background: #fff;
  border-radius: 16px;
  padding: 28px 32px 32px;
  box-shadow: 0 16px 40px rgba(0, 0, 0, 0.2);
}

.lecture-modal-close {
  position: absolute;
  top: 12px;
  right: 16px;
  border: none;
  background: none;
  font-size: 28px;
  line-height: 1;
  color: #666;
  cursor: pointer;
  padding: 4px 8px;
}

.lecture-modal-close:hover {
  color: #192437;
}

.lecture-modal-label {
  margin: 0 48px 6px 0;
  font-size: 14px;
  font-weight: bold;
  color: var(--banner-color);
  letter-spacing: 0.05em;
}

.lecture-modal-title {
  margin: 0 48px 20px 0;
  font-size: 24px;
  color: #192437;
  border-bottom: 3px solid var(--banner-color);
  padding-bottom: 10px;
}

.lecture-modal-body ul {
  margin: 0;
  padding-left: 20px;
  list-style: none;
}

@media (max-width: 768px) {
  body {
    margin: 0;
    margin-top: 56px;
  }

  .lecture-section .lecture-body {
    margin: 16px;
  }

  .lecture-section {
    margin-bottom: 60px;
  }

  .lecture-title {
    height: 60px;
    background: linear-gradient(to right, #192437 15px, transparent 15px), none;
    display: flex;
    align-items: center;
    width: auto;
    margin: 20px 0;
  }

  .lecture-title .title-text {
    margin-left: 35px;
    font-size: 32px;
    font-weight: bold;
  }

  .lecture-content {
    grid-template-columns: 1fr;
    gap: 20px;
    margin: 30px 0;
  }

  .lecture-card {
    margin-bottom: 20px;
  }

  .lecture-text {
    padding: 20px;
  }

  .lecture-text h3 {
    font-size: 24px;
    margin-bottom: 15px;
  }

  .lecture-description {
    font-size: 14px;
    padding: 12px;
  }

  .lecture-intro {
    margin: 0 16px 4px;
    font-size: 14px;
  }

  .lecture-details h4 {
    font-size: 18px;
    margin-bottom: 12px;
  }

  .lecture-modal-panel {
    padding: 24px 20px 28px;
  }

  .lecture-modal-title {
    font-size: 20px;
  }

  .lecture-details li {
    font-size: 13px;
  }
}

@media (max-width: 480px) {
  .lecture-content {
    grid-template-columns: 1fr;
    gap: 15px;
  }
}