@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&display=swap');

:root {
  --primary: #0b5cff;
  --primary-hover: #0046d1;
  --primary-light: #e0edff;
  --secondary: #ffffff;
  --bg-color: #f4f7fb;
  --text-dark: #1e293b;
  --text-muted: #64748b;
  --border: #e2e8f0;
  --success: #10b981;
  --warning: #f59e0b;
  --danger: #ef4444;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Inter', sans-serif;
}

body {
  background-color: var(--bg-color);
  color: var(--text-dark);
  line-height: 1.6;
}

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

ul {
  list-style: none;
}

/* Typography */
h1, h2, h3, h4 {
  color: var(--text-dark);
  font-weight: 700;
  margin-bottom: 1rem;
}

/* Helper Classes */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 5%;
}

.btn {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  border-radius: 8px;
  font-weight: 600;
  text-align: center;
  cursor: pointer;
  transition: all 0.3s ease;
  border: none;
}

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

.btn-primary:hover {
  background-color: var(--primary-hover);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(11, 92, 255, 0.2);
}

.btn-outline {
  border: 2px solid var(--primary);
  color: var(--primary);
  background: transparent;
}

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

.btn-sm {
  padding: 0.5rem 1rem;
  font-size: 0.875rem;
}

.card {
  background: white;
  border-radius: 16px;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
  padding: 2rem;
  border: 1px solid var(--border);
}

.grid {
  display: grid;
  gap: 2rem;
}

.grid-cols-2 { grid-template-columns: repeat(2, 1fr); }
.grid-cols-3 { grid-template-columns: repeat(3, 1fr); }
.grid-cols-4 { grid-template-columns: repeat(4, 1fr); }

/* Navigation */
header {
  background-color: white;
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 1000;
}

.navbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 80px;
}

.navbar .logo {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--primary);
}

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

.nav-links a {
  font-weight: 500;
  color: var(--text-muted);
  transition: color 0.3s;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--primary);
}

/* Hero Section */
.hero {
  padding: 6rem 0;
  text-align: center;
  background: linear-gradient(135deg, white 0%, var(--primary-light) 100%);
  border-bottom: 1px solid var(--border);
}

.hero h1 {
  font-size: 3.5rem;
  letter-spacing: -1px;
  margin-bottom: 1.5rem;
}

.hero h1 span {
  color: var(--primary);
}

.hero p {
  font-size: 1.25rem;
  color: var(--text-muted);
  max-width: 600px;
  margin: 0 auto 2.5rem;
}

/* Stats */
.hero-stats {
  display: flex;
  justify-content: center;
  gap: 3rem;
  margin-top: 3rem;
}

.stat-item {
  text-align: center;
}

.stat-item h4 {
  font-size: 1.5rem;
  margin-bottom: 0.25rem;
  color: var(--primary);
}

.stat-item p {
  font-size: 0.875rem;
  color: var(--text-muted);
  margin: 0;
}

/* Sections */
section {
  padding: 5rem 0;
}

.section-title {
  text-align: center;
  margin-bottom: 3rem;
}

.topic-card {
  transition: transform 0.3s, box-shadow 0.3s;
}

.topic-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 25px rgba(0,0,0,0.1);
}

.topic-icon {
  width: 60px;
  height: 60px;
  background: var(--primary-light);
  color: var(--primary);
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  font-weight: bold;
  margin-bottom: 1.5rem;
}

/* Course Page Layout */
.course-layout {
  display: flex;
  gap: 2rem;
  padding: 2rem 5%;
  max-width: 1400px;
  margin: 0 auto;
}

.course-sidebar {
  width: 300px;
  flex-shrink: 0;
  height: calc(100vh - 120px);
  position: sticky;
  top: 100px;
  overflow-y: auto;
}

.accordion {
  border: 1px solid var(--border);
  border-radius: 12px;
  background: white;
  overflow: hidden;
}

.accordion-item {
  border-bottom: 1px solid var(--border);
}

.accordion-item:last-child {
  border-bottom: none;
}

.accordion-header {
  padding: 1rem 1.5rem;
  background: var(--bg-color);
  font-weight: 600;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
}

.accordion-body {
  padding: 0;
}

.accordion-body a {
  display: block;
  padding: 0.75rem 1.5rem 0.75rem 2.5rem;
  color: var(--text-muted);
  border-left: 3px solid transparent;
}

.accordion-body a:hover,
.accordion-body a.active {
  background: var(--primary-light);
  color: var(--primary);
  border-left-color: var(--primary);
}

.course-content {
  flex-grow: 1;
  background: white;
  border-radius: 16px;
  padding: 2rem;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
  border: 1px solid var(--border);
}

.video-container {
  width: 100%;
  aspect-ratio: 16 / 9;
  background: black;
  border-radius: 12px;
  margin-bottom: 2rem;
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
}

pre {
  background: #1e1e1e;
  color: #d4d4d4;
  padding: 1.5rem;
  border-radius: 8px;
  overflow-x: auto;
  margin: 1.5rem 0;
  font-family: monospace;
}

/* Dashboard */
.dashboard-grid {
  display: grid;
  grid-template-columns: 250px 1fr;
  gap: 2rem;
  padding: 2rem 5%;
  max-width: 1400px;
  margin: 0 auto;
}

.user-profile {
  text-align: center;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--border);
  margin-bottom: 1.5rem;
}

.avatar {
  width: 100px;
  height: 100px;
  background: var(--primary-light);
  border-radius: 50%;
  margin: 0 auto 1rem;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
  color: var(--primary);
  font-weight: 700;
}

.dash-menu a {
  display: block;
  padding: 1rem;
  border-radius: 8px;
  color: var(--text-muted);
  margin-bottom: 0.5rem;
}

.dash-menu a:hover,
.dash-menu a.active {
  background: var(--primary);
  color: white;
}

.progress-container {
  margin-bottom: 1.5rem;
}

.progress-header {
  display: flex;
  justify-content: space-between;
  margin-bottom: 0.5rem;
  font-size: 0.875rem;
  font-weight: 600;
}

.progress-bar {
  width: 100%;
  height: 8px;
  background: var(--border);
  border-radius: 4px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: var(--primary);
  border-radius: 4px;
}

/* Forum */
.forum-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 2rem;
}

.forum-post {
  display: flex;
  gap: 1.5rem;
  padding: 1.5rem;
  border-bottom: 1px solid var(--border);
}

.forum-post:last-child {
  border-bottom: none;
}

.post-stats {
  text-align: center;
  flex-shrink: 0;
  width: 60px;
}

.post-stats .votes {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--primary);
}

.post-content h4 {
  margin-bottom: 0.5rem;
}

.post-meta {
  font-size: 0.875rem;
  color: var(--text-muted);
  margin-top: 1rem;
}

/* Forms & Quiz */
.form-group {
  margin-bottom: 1.5rem;
}

.form-group label {
  display: block;
  font-weight: 500;
  margin-bottom: 0.5rem;
}

.form-control {
  width: 100%;
  padding: 0.75rem 1rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  transition: border-color 0.3s;
}

.form-control:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--primary-light);
}

.quiz-question {
  margin-bottom: 2rem;
  padding: 1.5rem;
  background: var(--bg-color);
  border-radius: 12px;
}

.quiz-options label {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1rem;
  background: white;
  border: 1px solid var(--border);
  border-radius: 8px;
  margin-bottom: 0.5rem;
  cursor: pointer;
  transition: all 0.2s;
}

.quiz-options label:hover {
  border-color: var(--primary);
  background: var(--primary-light);
}

/* Admin Panel Table */
.table-responsive {
  overflow-x: auto;
}

table {
  width: 100%;
  border-collapse: collapse;
}

th, td {
  padding: 1rem;
  text-align: left;
  border-bottom: 1px solid var(--border);
}

th {
  background: var(--bg-color);
  font-weight: 600;
  color: var(--text-muted);
}

.badge {
  padding: 0.25rem 0.75rem;
  border-radius: 99px;
  font-size: 0.75rem;
  font-weight: 600;
}

.badge-success { background: #d1fae5; color: #065f46; }
.badge-warning { background: #fef3c7; color: #92400e; }

/* Responsive */
@media (max-width: 768px) {
  .navbar { padding: 1rem; }
  .nav-links { display: none; } /* Could be toggleable via CSS :target if needed */
  .grid-cols-2, .grid-cols-3, .grid-cols-4 { grid-template-columns: 1fr; }
  .course-layout, .dashboard-grid { flex-direction: column; display: flex; }
  .course-sidebar { width: 100%; height: auto; position: static; }
}

/* Footer */
footer {
  background: white;
  border-top: 1px solid var(--border);
  padding: 3rem 5% 1.5rem;
  margin-top: 4rem;
}

.footer-bottom {
  text-align: center;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
  margin-top: 3rem;
  color: var(--text-muted);
}