:root {
  --primary-color: #2563eb;
  --primary-hover: #1d4ed8;
  --secondary-color: #64748b;
  --text-color: #1f2937;
  --text-light: #6b7280;
  --bg-color: #ffffff;
  --bg-light: #f9fafb;
  --border-color: #e5e7eb;
  --sidebar-width: 280px;
  --header-height: 64px;
  --transition: all 0.3s ease;
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.1);
  --card-bg: #ffffff;
}

/* Dark mode */
@media (prefers-color-scheme: dark) {
  :root {
    --primary-color: #3b82f6;
    --primary-hover: #2563eb;
    --secondary-color: #94a3b8;
    --text-color: #f9fafb;
    --text-light: #d1d5db;
    --bg-color: #111827;
    --bg-light: #1f2937;
    --border-color: #374151;
    --card-bg: #1f2937;
  }

  .card {
    background-color: var(--card-bg);
  }

  .logo-dark {
    display: block;
  }

  .logo-light {
    display: none;
  }

  .search-input {
    background-color: var(--bg-color);
    color: var(--text-color);
  }

  .topic-content {
    background-color: var(--card-bg);
  }

  .btn {
    background-color: var(--bg-color);
    color: var(--text-color);
  }

  .btn:hover {
    background-color: var(--bg-light);
  }

  .btn-primary {
    background-color: var(--primary-color);
    color: white;
  }

  .btn-primary:hover {
    background-color: var(--primary-hover);
  }

  /* Bootstrap overrides for dark mode */
  .card-body {
    background-color: var(--card-bg);
    color: var(--text-color);
  }

  .form-control {
    background-color: var(--bg-color);
    color: var(--text-color);
    border-color: var(--border-color);
  }

  .form-control:focus {
    background-color: var(--bg-color);
    color: var(--text-color);
  }

  .form-label {
    color: var(--text-color);
  }
}

/* Light mode explicitly set */
.light-mode {
  --primary-color: #2563eb;
  --primary-hover: #1d4ed8;
  --secondary-color: #64748b;
  --text-color: #1f2937;
  --text-light: #6b7280;
  --bg-color: #ffffff;
  --bg-light: #f9fafb;
  --border-color: #e5e7eb;
  --card-bg: #ffffff;
}

/* Dark mode explicitly set */
.dark-mode {
  --primary-color: #3b82f6;
  --primary-hover: #2563eb;
  --secondary-color: #94a3b8;
  --text-color: #f9fafb;
  --text-light: #d1d5db;
  --bg-color: #111827;
  --bg-light: #1f2937;
  --border-color: #374151;
  --card-bg: #1f2937;
}

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

body {
  font-family: "Inter", -apple-system, BlinkMacSystemFont, sans-serif;
  background-color: var(--bg-light);
  color: var(--text-color);
  line-height: 1.6;
  transition: background-color 0.3s ease, color 0.3s ease;
}

/* Typography */
h1,
h2,
h3,
h4,
h5,
h6 {
  font-weight: 600;
  line-height: 1.25;
}

h1 {
  font-size: 1.5rem;
}
h2 {
  font-size: 1.25rem;
}
h3 {
  font-size: 1.125rem;
}

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

/* Layout */
.layout {
  display: flex;
  min-height: 100vh;
}

/* Sidebar */
.sidebar {
  width: var(--sidebar-width);
  background: var(--bg-color);
  border-right: 1px solid var(--border-color);
  position: fixed;
  height: 100vh;
  left: 0;
  top: 0;
  transform: translateX(-100%);
  transition: var(--transition);
  z-index: 50;
  display: flex;
  flex-direction: column;
}

.sidebar.open {
  transform: translateX(0);
}

.sidebar-header {
  height: var(--header-height);
  padding: 0 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--border-color);
}

.logo {
  height: 78px;
  width: auto;
  object-fit: contain;
}

.sidebar-search {
  padding: 1rem 1.5rem;
  border-bottom: 1px solid var(--border-color);
}

.search-input {
  width: 100%;
  padding: 0.5rem 1rem;
  border-radius: 0.5rem;
  border: 1px solid var(--border-color);
  background: var(--bg-light);
  transition: var(--transition);
}

.search-input:focus {
  outline: none;
  border-color: var(--primary-color);
  box-shadow: 0 0 0 2px rgba(37, 99, 235, 0.1);
}

.sidebar-menu {
  padding: 1rem 0;
  flex: 1;
  overflow-y: auto;
}

.menu-item {
  padding: 0.75rem 1.5rem;
  display: flex;
  align-items: center;
  color: var(--text-color);
  transition: var(--transition);
}

.menu-item:hover {
  background: var(--bg-light);
  color: var(--primary-color);
}

.menu-item i {
  width: 1.5rem;
  margin-right: 0.75rem;
  color: var(--text-light);
  font-size: 1.25rem;
}

.menu-item:hover i {
  color: var(--primary-color);
}

.menu-item.active {
  background: var(--bg-light);
  color: var(--primary-color);
  font-weight: 500;
}

.menu-item.active i {
  color: var(--primary-color);
}

/* Categories in sidebar */
.category-section {
  margin-top: 1rem;
  padding: 0 1.5rem;
}

.category-title {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-light);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.5rem;
}

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

.category-item {
  padding: 0.5rem 0;
  font-size: 0.875rem;
  color: var(--text-color);
  cursor: pointer;
  transition: var(--transition);
  display: flex;
  align-items: center;
}

.category-item:hover {
  color: var(--primary-color);
}

.category-item i {
  margin-right: 0.5rem;
  font-size: 0.75rem;
  color: var(--text-light);
}

.category-item:hover i {
  color: var(--primary-color);
}

/* Header */
.header {
  height: var(--header-height);
  background: var(--bg-color);
  border-bottom: 1px solid var(--border-color);
  position: fixed;
  top: 0;
  right: 0;
  left: var(--sidebar-width);
  z-index: 40;
  padding: 0 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  transition: var(--transition);
}

.header-mobile {
  left: 0;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.theme-toggle {
  background: none;
  border: none;
  color: var(--text-color);
  cursor: pointer;
  padding: 0.5rem;
  border-radius: 0.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
}

.theme-toggle:hover {
  background: var(--bg-light);
}

.language-selector {
  position: relative;
}

.language-toggle {
  background: none;
  border: none;
  color: var(--text-color);
  cursor: pointer;
  padding: 0.5rem;
  border-radius: 0.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
}

.language-toggle:hover {
  background: var(--bg-light);
}

.language-dropdown {
  position: absolute;
  top: 100%;
  right: 0;
  background: var(--bg-color);
  border: 1px solid var(--border-color);
  border-radius: 0.5rem;
  box-shadow: var(--shadow);
  padding: 0.5rem;
  min-width: 120px;
  z-index: 50;
  display: none;
}

.language-dropdown.show {
  display: block;
}

.language-option {
  padding: 0.5rem;
  cursor: pointer;
  border-radius: 0.25rem;
  transition: var(--transition);
  display: flex;
  align-items: center;
}

.language-option:hover {
  background: var(--bg-light);
}

.language-option i {
  margin-right: 0.5rem;
}

/* Main Content */
.main {
  flex: 1;
  margin-left: var(--sidebar-width);
  padding: calc(var(--header-height) + 2rem) 2rem 2rem;
  transition: var(--transition);
}

.main-mobile {
  margin-left: 0;
}

/* Cards */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.5rem;
}

.card {
  background: var(--card-bg);
  border-radius: 0.75rem;
  border: 1px solid var(--border-color);
  padding: 1.5rem;
  transition: var(--transition);
}

.card:hover {
  box-shadow: var(--shadow);
  transform: translateY(-2px);
}

.card-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 1rem;
}

.card-title {
  color: var(--text-color);
  font-weight: 600;
  font-size: 1.125rem;
  line-height: 1.4;
}

.card-content {
  color: var(--text-light);
  margin-bottom: 1rem;
}

.card-actions {
  display: flex;
  gap: 0.5rem;
}

.card-category {
  display: inline-block;
  padding: 0.25rem 0.5rem;
  background: var(--bg-light);
  color: var(--text-light);
  border-radius: 0.25rem;
  font-size: 0.75rem;
  margin-bottom: 0.5rem;
}

/* Topic View */
.topic-view {
  max-width: 800px;
  margin: 0 auto;
}

.topic-header {
  margin-bottom: 2rem;
}

.topic-content {
  background: var(--card-bg);
  padding: 2rem;
  border-radius: 0.75rem;
  border: 1px solid var(--border-color);
}

.topic-content img {
  max-width: 100%;
  height: auto;
  border-radius: 0.5rem;
  margin: 1rem 0;
  cursor: pointer;
}

.topic-content iframe {
  width: 100%;
  aspect-ratio: 16 / 9;
  border-radius: 0.5rem;
  margin: 1rem 0;
}

.topic-meta {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 1rem;
  color: var(--text-light);
  font-size: 0.875rem;
}

.topic-meta i {
  margin-right: 0.25rem;
}

.topic-categories {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1rem;
}

.topic-category {
  padding: 0.25rem 0.5rem;
  background: var(--bg-light);
  color: var(--text-light);
  border-radius: 0.25rem;
  font-size: 0.75rem;
}

.related-topics {
  margin-top: 2rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border-color);
}

.related-topics-title {
  margin-bottom: 1rem;
  font-size: 1.25rem;
}

.related-topics-list {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  gap: 1rem;
}

.related-topic-item {
  background: var(--bg-light);
  padding: 1rem;
  border-radius: 0.5rem;
  transition: var(--transition);
}

.related-topic-item:hover {
  background: var(--bg-color);
  box-shadow: var(--shadow-sm);
}

.related-topic-title {
  font-weight: 500;
  margin-bottom: 0.5rem;
}

.related-topic-views {
  font-size: 0.75rem;
  color: var(--text-light);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  padding: 0.5rem 1rem;
  border-radius: 0.5rem;
  border: 1px solid var(--border-color);
  background: var(--bg-color);
  color: var(--text-color);
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition);
}

.btn:hover {
  background: var(--bg-light);
}

.btn i {
  margin-right: 0.5rem;
}

.btn-icon {
  padding: 0.5rem;
}

.btn-icon i {
  margin: 0;
}

.btn-primary {
  background: var(--primary-color);
  color: white;
  border: none;
}

.btn-primary:hover {
  background: var(--primary-hover);
}

/* Notification */
.notification {
  position: fixed;
  bottom: 1rem;
  right: 1rem;
  background: var(--text-color);
  color: white;
  padding: 0.75rem 1.5rem;
  border-radius: 0.5rem;
  box-shadow: var(--shadow);
  transform: translateY(100%);
  opacity: 0;
  transition: var(--transition);
  z-index: 100;
}

.notification.show {
  transform: translateY(0);
  opacity: 1;
}

/* Contact section */
.contact-section {
  padding: 1.5rem;
  border-top: 1px solid var(--border-color);
  margin-top: auto;
}

.contact-title {
  color: var(--text-color);
  font-size: 1rem;
  margin-bottom: 1rem;
}

.social-links {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.social-link {
  display: flex;
  align-items: center;
  padding: 0.5rem;
  color: var(--text-color);
  transition: var(--transition);
  border-radius: 0.5rem;
}

.social-link:hover {
  background: var(--bg-light);
  color: var(--primary-color);
}

.social-link i {
  width: 1.5rem;
  margin-right: 0.75rem;
  font-size: 1.25rem;
}

/* Bookmark button styling */
.btn-icon .fa-bookmark {
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  font-size: 1.2rem;
}

/* Default state */
.btn-icon .fa-bookmark {
  color: var(--text-light);
  transform: scale(1);
}

/* Hover effect */
.btn-icon:hover .fa-bookmark:not(.saved) {
  color: #ff4d4d;
  transform: scale(1.1);
}

/* Saved state */
.btn-icon .fa-bookmark.saved {
  color: #ff4d4d;
  animation: saveAnimation 0.5s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

/* Animation when clicking save */
@keyframes saveAnimation {
  0% {
    transform: scale(1);
  }
  50% {
    transform: scale(1.4);
  }
  100% {
    transform: scale(1);
  }
}

/* Optional: Add a heart animation when hovering saved items */
.btn-icon:hover .fa-bookmark.saved {
  animation: pulseHeart 1s infinite;
}

@keyframes pulseHeart {
  0% {
    transform: scale(1);
  }
  50% {
    transform: scale(1.1);
  }
  100% {
    transform: scale(1);
  }
}

/* Search form */
.search-form {
  width: 100%;
}

.search-input-group {
  position: relative;
  display: flex;
  align-items: center;
}

.search-input {
  width: 100%;
  padding: 0.5rem 2.5rem 0.5rem 1rem;
  border-radius: 0.5rem;
  border: 1px solid var(--border-color);
  background: var(--bg-light);
  transition: var(--transition);
}

.search-input:focus {
  outline: none;
  border-color: var(--primary-color);
  box-shadow: 0 0 0 2px rgba(37, 99, 235, 0.1);
}

.search-btn {
  position: absolute;
  right: 0.5rem;
  padding: 0.25rem;
  color: var(--text-light);
}

.search-btn:hover {
  color: var(--primary-color);
}

/* For enlarged view */
.image-modal {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.8);
  justify-content: center;
  align-items: center;
  z-index: 1000;
}

.image-modal img {
  max-width: 90%;
  max-height: 90%;
  border-radius: 8px;
}

/* Responsive */
@media (min-width: 769px) {
  .sidebar {
    transform: none !important;
  }

  .close-btn {
    display: none !important;
  }
}

@media (max-width: 768px) {
  .sidebar {
    width: 100%;
    transform: translateX(-100%);
  }

  .sidebar.open {
    transform: translateX(0);
  }

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

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

/* Utilities */
.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}

/* Loading spinner */
.loading {
  display: inline-block;
  width: 1.5rem;
  height: 1.5rem;
  border: 2px solid var(--bg-light);
  border-radius: 50%;
  border-top-color: var(--primary-color);
  animation: spin 1s linear infinite;
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

/* Skeleton loading */
.skeleton {
  background: linear-gradient(90deg, var(--bg-light) 25%, var(--border-color) 50%, var(--bg-light) 75%);
  background-size: 200% 100%;
  animation: skeleton-loading 1.5s infinite;
  border-radius: 0.25rem;
}

@keyframes skeleton-loading {
  0% {
    background-position: 200% 0;
  }
  100% {
    background-position: -200% 0;
  }
}

.skeleton-title {
  height: 1.5rem;
  margin-bottom: 1rem;
  width: 80%;
}

.skeleton-text {
  height: 1rem;
  margin-bottom: 0.5rem;
}

.skeleton-text:last-child {
  width: 60%;
}