:root {
  --bg-primary: #0a0a0a;
  --bg-secondary: #111111;
  --bg-card: rgba(26, 26, 26, 0.6);
  --border-color: #1a3d1a;
  --border-light: #2a4d2a;
  --text-primary: #e0e0e0;
  --text-secondary: #a0a0a0;
  --accent-green: #00aa55;
  --accent-green-hover: #00cc66;
  --accent-green-dim: rgba(0, 170, 85, 0.1);
}

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

body {
  font-family: 'Noto Sans Devanagari', sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  overflow-x: hidden;
  line-height: 1.6;
}

/* Interactive Background */
#bg-canvas {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: -1;
  pointer-events: none;
}

/* Navigation */
.learning-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 60px;
  background: rgba(10, 10, 10, 0.95);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border-color);
  z-index: 1000;
}

.nav-container {
  max-width: 1600px;
  margin: 0 auto;
  padding: 0 2rem;
  height: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.brand-logo a {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--accent-green);
  text-decoration: none;
  transition: opacity 0.2s;
}

.brand-logo a:hover {
  opacity: 0.8;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 2rem;
}

.nav-link {
  color: var(--text-primary);
  text-decoration: none;
  transition: color 0.2s;
}

.nav-link:hover {
  color: var(--accent-green);
}

.btn-logout {
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  padding: 0.5rem 1rem;
  border-radius: 4px;
  cursor: pointer;
  transition: all 0.2s;
  font-family: inherit;
}

.btn-logout:hover {
  border-color: var(--accent-green);
  color: var(--accent-green);
}

/* Main Layout */
.learning-container {
  display: flex;
  margin-top: 60px;
  min-height: calc(100vh - 60px);
}

.learning-sidebar {
  width: 340px;
  background: var(--bg-secondary);
  border-right: 1px solid var(--border-color);
  overflow-y: auto;
  padding: 0;
  position: sticky;
  top: 60px;
  height: calc(100vh - 60px);
}

.learning-main {
  flex: 1;
  padding: 3rem;
  max-width: 900px;
  margin: 0 auto;
}

/* Tab Switcher */
.tab-switcher {
  display: flex;
  padding: 1rem;
  gap: 0.5rem;
  border-bottom: 1px solid var(--border-color);
  background: var(--bg-primary);
  position: sticky;
  top: 0;
  z-index: 10;
}

.tab-btn {
  flex: 1;
  padding: 0.75rem 1rem;
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  cursor: pointer;
  border-radius: 4px;
  font-weight: 500;
  transition: all 0.2s;
  font-family: inherit;
}

.tab-btn:hover {
  border-color: var(--border-light);
  color: var(--text-primary);
}

.tab-btn.active {
  background: var(--accent-green-dim);
  border-color: var(--accent-green);
  color: var(--accent-green);
}

/* Sidebar Content */
.sidebar-content {
  display: none;
  padding: 1.5rem;
}

.sidebar-content.active {
  display: block;
}

/* Course Cards */
.course-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 1.5rem;
  margin-bottom: 1rem;
  transition: all 0.2s;
  cursor: pointer;
}

.course-card:hover {
  transform: translateY(-2px);
  border-color: var(--accent-green);
  box-shadow: 0 4px 12px rgba(0, 170, 85, 0.1);
}

.course-icon {
  font-size: 2rem;
  margin-bottom: 0.75rem;
}

.course-info h3 {
  font-size: 1.1rem;
  margin-bottom: 0.5rem;
  color: var(--text-primary);
}

.course-info p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-bottom: 0.75rem;
  line-height: 1.5;
}

.course-meta {
  display: flex;
  gap: 0.75rem;
  align-items: center;
  font-size: 0.85rem;
}

.badge {
  background: var(--accent-green-dim);
  border: 1px solid var(--accent-green);
  color: var(--accent-green);
  padding: 0.25rem 0.5rem;
  border-radius: 3px;
  font-weight: 500;
  text-transform: capitalize;
}

.duration {
  color: var(--text-secondary);
}

.btn-start {
  width: 100%;
  margin-top: 1rem;
  padding: 0.75rem;
  background: var(--accent-green);
  border: none;
  color: white;
  border-radius: 4px;
  cursor: pointer;
  font-weight: 600;
  transition: all 0.2s;
  font-family: inherit;
}

.btn-start:hover {
  background: var(--accent-green-hover);
  transform: translateY(-1px);
}

/* Course View (after opening a course) */
.btn-back {
  width: 100%;
  padding: 0.75rem;
  margin-bottom: 1.5rem;
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  border-radius: 4px;
  cursor: pointer;
  transition: all 0.2s;
  font-family: inherit;
}

.btn-back:hover {
  border-color: var(--accent-green);
  color: var(--accent-green);
}

.course-title {
  font-size: 1.3rem;
  margin-bottom: 1.5rem;
  color: var(--accent-green);
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--border-color);
}

.modules-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.module {
  border: 1px solid var(--border-color);
  border-radius: 6px;
  padding: 1rem;
  background: var(--bg-card);
}

.module-title {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 1rem;
  margin-bottom: 0.75rem;
  color: var(--text-primary);
}

.module-number {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  background: var(--accent-green-dim);
  border: 1px solid var(--accent-green);
  border-radius: 50%;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--accent-green);
}

.lessons-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.lesson-item {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.75rem;
  border-radius: 4px;
  cursor: pointer;
  transition: all 0.2s;
  border: 1px solid transparent;
}

.lesson-item:hover {
  background: rgba(255, 255, 255, 0.05);
  border-color: var(--border-light);
}

.lesson-item.active {
  background: var(--accent-green-dim);
  border-color: var(--accent-green);
  color: var(--accent-green);
}

.lesson-item.completed {
  opacity: 0.7;
}

.lesson-item.completed .lesson-icon {
  color: var(--accent-green);
}

.lesson-icon {
  font-size: 1.2rem;
}

.lesson-duration {
  margin-left: auto;
  font-size: 0.8rem;
  color: var(--text-secondary);
}

/* Research Filters */
.research-filters {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  margin-bottom: 1.5rem;
}

#research-search,
#research-tags {
  width: 100%;
  padding: 0.75rem;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  border-radius: 4px;
  font-family: inherit;
  transition: border-color 0.2s;
}

#research-search:focus,
#research-tags:focus {
  outline: none;
  border-color: var(--accent-green);
}

/* Research Cards */
.research-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 1.25rem;
  margin-bottom: 1rem;
  transition: all 0.2s;
}

.research-card:hover {
  border-color: var(--border-light);
  transform: translateY(-1px);
}

.research-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.75rem;
  font-size: 0.85rem;
}

.research-date {
  color: var(--text-secondary);
}

.verified-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  background: var(--accent-green-dim);
  border: 1px solid var(--accent-green);
  border-radius: 12px;
  padding: 0.2rem 0.5rem;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--accent-green);
}

.research-card h3 {
  font-size: 1.05rem;
  margin-bottom: 0.5rem;
  color: var(--text-primary);
}

.research-excerpt {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.5;
  margin-bottom: 0.75rem;
}

.research-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 0.75rem;
}

.tag {
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border-color);
  padding: 0.25rem 0.5rem;
  border-radius: 3px;
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.btn-read {
  width: 100%;
  padding: 0.6rem;
  background: transparent;
  border: 1px solid var(--accent-green);
  color: var(--accent-green);
  border-radius: 4px;
  cursor: pointer;
  font-weight: 500;
  transition: all 0.2s;
  font-family: inherit;
}

.btn-read:hover {
  background: var(--accent-green);
  color: white;
}

/* Main Content Area */
.welcome-screen {
  text-align: center;
  padding: 4rem 2rem;
}

.welcome-screen h1 {
  font-size: 2.5rem;
  margin-bottom: 1rem;
  color: var(--accent-green);
}

.welcome-screen > p {
  font-size: 1.2rem;
  color: var(--text-secondary);
  margin-bottom: 3rem;
}

.welcome-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 2rem;
  margin-top: 3rem;
}

.welcome-card {
  padding: 2rem;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  transition: all 0.2s;
}

.welcome-card:hover {
  border-color: var(--accent-green);
  transform: translateY(-4px);
}

.card-icon {
  font-size: 3rem;
  margin-bottom: 1rem;
}

.welcome-card h3 {
  font-size: 1.2rem;
  margin-bottom: 0.75rem;
  color: var(--text-primary);
}

.welcome-card p {
  color: var(--text-secondary);
  line-height: 1.6;
}

/* Lesson Display */
.lesson-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 2rem;
  padding-bottom: 1rem;
  border-bottom: 2px solid var(--border-color);
}

.lesson-header h1 {
  font-size: 2.2rem;
  color: var(--text-primary);
}

.lesson-header .lesson-duration {
  background: var(--accent-green-dim);
  border: 1px solid var(--accent-green);
  color: var(--accent-green);
  padding: 0.5rem 1rem;
  border-radius: 4px;
  font-weight: 600;
}

/* Markdown Content */
.markdown-body {
  line-height: 1.8;
  font-size: 1.05rem;
  color: var(--text-primary);
}

.markdown-body h1 {
  font-size: 2.5rem;
  margin-bottom: 1rem;
  color: var(--accent-green);
}

.markdown-body h2 {
  font-size: 1.8rem;
  margin: 2rem 0 1rem;
  color: var(--text-primary);
}

.markdown-body h3 {
  font-size: 1.4rem;
  margin: 1.5rem 0 0.75rem;
  color: var(--text-primary);
}

.markdown-body p {
  margin-bottom: 1rem;
}

.markdown-body ul,
.markdown-body ol {
  margin-left: 2rem;
  margin-bottom: 1rem;
}

.markdown-body li {
  margin-bottom: 0.5rem;
}

.markdown-body code {
  background: var(--accent-green-dim);
  padding: 0.2rem 0.4rem;
  border-radius: 3px;
  font-family: 'Courier New', monospace;
  font-size: 0.95em;
  color: var(--accent-green);
}

.markdown-body pre {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 6px;
  padding: 1rem;
  overflow-x: auto;
  margin-bottom: 1rem;
}

.markdown-body pre code {
  background: none;
  padding: 0;
  color: var(--text-primary);
}

.markdown-body blockquote {
  border-left: 3px solid var(--accent-green);
  padding-left: 1rem;
  margin: 1rem 0;
  color: var(--text-secondary);
  font-style: italic;
}

.markdown-body table {
  width: 100%;
  border-collapse: collapse;
  margin: 1rem 0;
}

.markdown-body th,
.markdown-body td {
  border: 1px solid var(--border-color);
  padding: 0.75rem;
  text-align: left;
}

.markdown-body th {
  background: var(--bg-secondary);
  font-weight: 600;
}

.markdown-body strong {
  color: var(--accent-green);
  font-weight: 600;
}

.markdown-body em {
  color: var(--text-secondary);
  font-style: italic;
}

/* Lesson Footer */
.lesson-footer {
  display: flex;
  gap: 1rem;
  margin-top: 3rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border-color);
}

.btn-complete {
  flex: 1;
  padding: 1rem;
  background: var(--accent-green);
  border: none;
  color: white;
  border-radius: 4px;
  cursor: pointer;
  font-weight: 600;
  font-size: 1rem;
  transition: all 0.2s;
  font-family: inherit;
}

.btn-complete:hover {
  background: var(--accent-green-hover);
  transform: translateY(-1px);
}

.btn-next {
  flex: 1;
  padding: 1rem;
  background: transparent;
  border: 1px solid var(--accent-green);
  color: var(--accent-green);
  border-radius: 4px;
  cursor: pointer;
  font-weight: 600;
  font-size: 1rem;
  transition: all 0.2s;
  font-family: inherit;
}

.btn-next:hover {
  background: var(--accent-green);
  color: white;
}

/* Article Display */
.article-header {
  margin-bottom: 2rem;
  padding-bottom: 1rem;
  border-bottom: 2px solid var(--border-color);
}

.article-header h1 {
  font-size: 2.2rem;
  margin-bottom: 1rem;
  color: var(--text-primary);
}

.article-meta {
  display: flex;
  gap: 1.5rem;
  align-items: center;
  font-size: 0.95rem;
  color: var(--text-secondary);
  margin-bottom: 1rem;
}

.article-meta .verified {
  color: var(--accent-green);
  font-weight: 600;
}

.article-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

/* Loading/Error States */
.loading,
.error {
  text-align: center;
  padding: 3rem;
  color: var(--text-secondary);
  font-size: 1.1rem;
}

.error {
  color: #ff5555;
}

/* Scrollbar Styles */
.learning-sidebar::-webkit-scrollbar {
  width: 8px;
}

.learning-sidebar::-webkit-scrollbar-track {
  background: var(--bg-primary);
}

.learning-sidebar::-webkit-scrollbar-thumb {
  background: var(--border-color);
  border-radius: 4px;
}

.learning-sidebar::-webkit-scrollbar-thumb:hover {
  background: var(--border-light);
}

/* Responsive Design */
@media (max-width: 1024px) {
  .learning-sidebar {
    width: 280px;
  }
  
  .learning-main {
    padding: 2rem;
  }
}

@media (max-width: 768px) {
  .learning-container {
    flex-direction: column;
  }
  
  .learning-sidebar {
    width: 100%;
    position: relative;
    height: auto;
    max-height: 50vh;
  }
  
  .learning-main {
    padding: 1.5rem;
  }
  
  .welcome-screen h1 {
    font-size: 2rem;
  }
  
  .welcome-cards {
    grid-template-columns: 1fr;
  }
}