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

ul, ol {
  list-style: none;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Hiragino Sans', 'Hiragino Kaku Gothic ProN', Meiryo, sans-serif;
  line-height: 1.6;
  color: #333;
  background: #f8f9fa;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1rem;
}

/* Header */
.site-header {
  background: linear-gradient(135deg, #1a5f7a 0%, #2e8b57 100%);
  color: #fff;
  padding: 1.5rem 0;
  margin-bottom: 2rem;
}

.site-title {
  font-size: 1.5rem;
  margin-bottom: 0.5rem;
}

.site-title a {
  color: #fff;
  text-decoration: none;
}

.site-description {
  font-size: 0.9rem;
  opacity: 0.9;
  margin-bottom: 1rem;
}

.main-nav {
  display: flex;
  gap: 1.5rem;
}

.main-nav a {
  color: #fff;
  text-decoration: none;
  font-size: 0.9rem;
}

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

/* Breadcrumb */
.breadcrumb {
  margin-bottom: 1.5rem;
  padding: 0.75rem 1rem;
  background: #fff;
  border-radius: 6px;
  font-size: 0.85rem;
  box-shadow: 0 1px 3px rgba(0,0,0,0.05);
}

.breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem;
  list-style: none;
}

.breadcrumb li {
  display: flex;
  align-items: center;
}

.breadcrumb li:not(:last-child)::after {
  content: "›";
  margin-left: 0.5rem;
  color: #999;
  font-weight: bold;
}

.breadcrumb a {
  color: #1a5f7a;
  text-decoration: none;
  transition: color 0.2s;
}

.breadcrumb a:hover {
  color: #2e8b57;
  text-decoration: underline;
}

.breadcrumb li[aria-current="page"] {
  color: #666;
}

/* Two Column Layout */
.layout-two-column {
  display: grid;
  grid-template-columns: 1fr 320px;
  gap: 2rem;
  align-items: start;
}

.main-content {
  min-width: 0;
}

/* Sidebar */
.sidebar {
  position: sticky;
  top: 1rem;
}

.sidebar-section {
  background: #fff;
  padding: 1.5rem;
  border-radius: 8px;
  margin-bottom: 1.5rem;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.sidebar-section h3 {
  font-size: 1.1rem;
  margin-bottom: 1rem;
  color: #1a5f7a;
  padding-bottom: 0.75rem;
  border-bottom: 2px solid #e8f4f8;
}

.sidebar-section .category-list {
  list-style: none;
}

.sidebar-section .category-list li {
  margin-bottom: 0.5rem;
}

.sidebar-section .category-list a {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.5rem 0.75rem;
  background: #f8f9fa;
  color: #333;
  text-decoration: none;
  border-radius: 6px;
  font-size: 0.9rem;
  transition: all 0.2s;
}

.sidebar-section .category-list a:hover {
  background: #1a5f7a;
  color: #fff;
}

.sidebar-section .category-list .count {
  font-size: 0.8rem;
  opacity: 0.7;
}

.sidebar-section .channel-list {
  list-style: none;
}

.sidebar-section .channel-list li {
  margin-bottom: 0.75rem;
}

.sidebar-section .channel-list a {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.5rem;
  background: #f8f9fa;
  color: #333;
  text-decoration: none;
  border-radius: 6px;
  font-size: 0.85rem;
  transition: all 0.2s;
}

.sidebar-section .channel-list a:hover {
  background: #e8f4f8;
  transform: translateX(4px);
}

.sidebar-section .channel-list img {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  object-fit: cover;
  flex-shrink: 0;
}

.sidebar-section .recent-videos-list {
  list-style: none;
}

.sidebar-section .recent-videos-list li {
  margin-bottom: 1rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid #f0f0f0;
}

.sidebar-section .recent-videos-list li:last-child {
  border-bottom: none;
  margin-bottom: 0;
  padding-bottom: 0;
}

.sidebar-section .recent-videos-list a {
  display: flex;
  gap: 0.75rem;
  text-decoration: none;
  color: #333;
  transition: all 0.2s;
}

.sidebar-section .recent-videos-list a:hover {
  transform: translateX(2px);
}

.sidebar-section .recent-videos-list img {
  width: 80px;
  height: 45px;
  border-radius: 4px;
  object-fit: cover;
  flex-shrink: 0;
}

.sidebar-section .recent-video-info {
  flex: 1;
  min-width: 0;
}

.sidebar-section .recent-video-info h4 {
  font-size: 0.8rem;
  line-height: 1.4;
  margin-bottom: 0.25rem;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
  font-weight: 500;
}

.sidebar-section .recent-video-info .meta {
  font-size: 0.7rem;
  color: #666;
}

.sidebar-section .recent-video-info .channel {
  color: #2e8b57;
  font-weight: 500;
}

.sidebar-section .menu-list {
  list-style: none;
}

.sidebar-section .menu-list li {
  margin-bottom: 0.5rem;
}

.sidebar-section .menu-list a {
  display: block;
  padding: 0.5rem 0.75rem;
  background: #f8f9fa;
  color: #333;
  text-decoration: none;
  border-radius: 6px;
  font-size: 0.9rem;
  transition: all 0.2s;
}

.sidebar-section .menu-list a:hover {
  background: #1a5f7a;
  color: #fff;
}

/* Video List */
.video-list h2 {
  font-size: 1.3rem;
  margin-bottom: 1.5rem;
  color: #333;
}

.videos {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 1.5rem;
}

.video-card {
  background: #fff;
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
  transition: transform 0.2s, box-shadow 0.2s;
}

.video-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}

.video-card a {
  text-decoration: none;
  color: inherit;
}

.video-card img {
  width: 100%;
  aspect-ratio: 16/9;
  object-fit: cover;
}

.video-info {
  padding: 1rem;
}

.video-info h3 {
  font-size: 0.95rem;
  line-height: 1.4;
  margin-bottom: 0.5rem;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.meta {
  font-size: 0.8rem;
  color: #666;
}

.meta .channel {
  color: #2e8b57;
  font-weight: 500;
}

.meta .date {
  margin-left: 0.5rem;
}

.category {
  font-size: 0.75rem;
  color: #1a5f7a;
  margin-top: 0.5rem;
}

/* Single Post */
.single-post {
  background: #fff;
  padding: 2rem;
  border-radius: 8px;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
  margin-bottom: 2rem;
}

.post-header h2 {
  font-size: 1.4rem;
  margin-bottom: 1rem;
}

.post-header .meta {
  margin-bottom: 1.5rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid #eee;
}

.category-tag {
  display: inline-block;
  padding: 0.25rem 0.75rem;
  background: #e8f4f8;
  color: #1a5f7a;
  text-decoration: none;
  border-radius: 4px;
  font-size: 0.8rem;
  margin-left: 0.5rem;
}

.post-content {
  margin-bottom: 2rem;
}

.post-content iframe {
  max-width: 100%;
  margin: 1rem 0;
}

.post-content h2 {
  font-size: 1.2rem;
  margin: 1.5rem 0 1rem;
  color: #1a5f7a;
}

.post-nav {
  display: flex;
  justify-content: space-between;
  padding-top: 1rem;
  border-top: 1px solid #eee;
}

.post-nav a {
  color: #1a5f7a;
  text-decoration: none;
  font-size: 0.9rem;
}

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

/* Related */
.related {
  background: #fff;
  padding: 1.5rem;
  border-radius: 8px;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
  margin-top: 2rem;
}

.related h3 {
  font-size: 1.3rem;
  margin-bottom: 1.5rem;
  color: #1a5f7a;
  padding-bottom: 0.75rem;
  border-bottom: 2px solid #e8f4f8;
}

.related-videos {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 1.5rem;
}

.related ul {
  list-style: none;
}

.related li {
  padding: 0.5rem 0;
  border-bottom: 1px solid #eee;
}

.related li:last-child {
  border-bottom: none;
}

.related a {
  color: #333;
  text-decoration: none;
}

.related a:hover {
  color: #1a5f7a;
}

/* Pagination */
.pagination {
  display: flex;
  justify-content: center;
  gap: 0.5rem;
  margin-top: 2rem;
  padding: 1rem 0;
}

.pagination a, .pagination span {
  padding: 0.5rem 1rem;
  background: #fff;
  border-radius: 4px;
  text-decoration: none;
  color: #333;
}

.pagination a:hover {
  background: #1a5f7a;
  color: #fff;
}

.pagination .active {
  background: #1a5f7a;
  color: #fff;
}

/* Footer */
.site-footer {
  background: #333;
  color: #fff;
  padding: 2rem 0;
  margin-top: 3rem;
  text-align: center;
  font-size: 0.85rem;
}

.site-footer p {
  margin-bottom: 0.5rem;
  opacity: 0.8;
}

.footer-nav {
  margin-top: 1rem;
}

.footer-nav a {
  color: #fff;
  text-decoration: none;
  opacity: 0.8;
}

.footer-nav a:hover {
  text-decoration: underline;
  opacity: 1;
}

/* Channels Page */
.channels-page {
  max-width: 1200px;
  margin: 0 auto;
}

.page-header {
  text-align: center;
  margin-bottom: 3rem;
  padding: 2rem;
  background: linear-gradient(135deg, #1a5f7a 0%, #2e8b57 100%);
  border-radius: 12px;
  color: #fff;
  box-shadow: 0 4px 20px rgba(26, 95, 122, 0.2);
}

.page-header h1 {
  font-size: 2.2rem;
  margin-bottom: 0.75rem;
  font-weight: 700;
}

.page-header .page-description {
  font-size: 1rem;
  opacity: 0.95;
  line-height: 1.6;
}

.channels-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 2rem;
}

.channel-card {
  background: #fff;
  border-radius: 12px;
  overflow: hidden;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
  transition: all 0.3s ease;
  border: 1px solid #f0f0f0;
}

.channel-card:hover {
  transform: translateY(-8px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.15);
  border-color: #1a5f7a;
}

.channel-thumbnail {
  position: relative;
  background: linear-gradient(135deg, #f8f9fa 0%, #e9ecef 100%);
  padding: 1.5rem;
  display: flex;
  justify-content: center;
  align-items: center;
}

.channel-thumbnail img {
  width: 80px;
  height: 80px;
  border-radius: 50%;
  object-fit: cover;
  border: 3px solid #fff;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
  transition: transform 0.3s ease;
}

.channel-card:hover .channel-thumbnail img {
  transform: scale(1.05);
}

.category-badge {
  position: absolute;
  top: 1rem;
  right: 1rem;
  display: inline-block;
  padding: 0.35rem 0.85rem;
  background: rgba(255, 255, 255, 0.95);
  color: #1a5f7a;
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 600;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.1);
  backdrop-filter: blur(10px);
}

.channel-content {
  padding: 1.5rem;
}

.channel-name {
  font-size: 1.15rem;
  margin-bottom: 0.75rem;
  font-weight: 600;
  line-height: 1.4;
}

.channel-name a {
  color: #333;
  text-decoration: none;
  transition: color 0.2s;
}

.channel-name a:hover {
  color: #1a5f7a;
}

.channel-description {
  font-size: 0.9rem;
  color: #666;
  line-height: 1.6;
  margin-bottom: 1.25rem;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
  min-height: 4rem;
}

.channel-actions {
  display: flex;
  gap: 0.75rem;
  margin-top: auto;
}

.btn {
  flex: 1;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.65rem 1rem;
  text-align: center;
  text-decoration: none;
  border-radius: 6px;
  font-size: 0.85rem;
  font-weight: 600;
  transition: all 0.2s ease;
  border: none;
}

.btn-youtube {
  background: #ff0000;
  color: #fff;
}

.btn-youtube:hover {
  background: #cc0000;
  transform: translateY(-2px);
  box-shadow: 0 4px 8px rgba(255, 0, 0, 0.3);
}

.btn-youtube svg {
  fill: currentColor;
}

.btn-archive {
  background: #f8f9fa;
  color: #1a5f7a;
  border: 2px solid #1a5f7a;
}

.btn-archive:hover {
  background: #1a5f7a;
  color: #fff;
  transform: translateY(-2px);
  box-shadow: 0 4px 8px rgba(26, 95, 122, 0.3);
}

/* Responsive */
@media (max-width: 1024px) {
  .layout-two-column {
    grid-template-columns: 1fr;
  }

  .sidebar {
    position: static;
    order: -1;
  }

  .sidebar-section .channel-list a {
    font-size: 0.8rem;
  }

  .sidebar-section .channel-list img {
    width: 28px;
    height: 28px;
  }
}

@media (max-width: 768px) {
  .site-title {
    font-size: 1.2rem;
  }

  .main-nav {
    flex-wrap: wrap;
    gap: 1rem;
  }

  .videos {
    grid-template-columns: 1fr;
  }

  .single-post {
    padding: 1rem;
  }

  .page-header {
    padding: 1.5rem;
  }

  .page-header h1 {
    font-size: 1.6rem;
  }

  .channels-grid {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }

  .channel-thumbnail img {
    width: 70px;
    height: 70px;
  }

  .channel-actions {
    flex-direction: column;
  }

  .btn {
    width: 100%;
  }

  .sidebar-section {
    padding: 1rem;
  }

  .sidebar-section .channel-list {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 0.5rem;
  }

  .related-videos {
    grid-template-columns: 1fr;
  }

  .related {
    padding: 1rem;
  }
}