:root {
  --bg-main: #f8fafc;
  --bg-card: #ffffff;
  --bg-subtle: #f1f5f9;
  --border-color: #e2e8f0;
  --border-focus: #3b82f6;
  
  --primary: #0284c7;
  --primary-hover: #0369a1;
  --primary-light: #e0f2fe;
  
  --text-title: #0f172a;
  --text-body: #334155;
  --text-muted: #64748b;
  
  --radius-lg: 12px;
  --radius-md: 8px;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.05), 0 2px 4px -1px rgba(0, 0, 0, 0.03);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.05), 0 4px 6px -2px rgba(0, 0, 0, 0.02);
}
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
}
body {
  background-color: var(--bg-main);
  color: var(--text-body);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}
header {
  background-color: var(--bg-card);
  border-bottom: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
  position: sticky;
  top: 0;
  z-index: 50;
}
.versalita {
    font-variant: small-caps;
	font-feature-settings: "smcp"; 
}
.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 1rem 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.logo {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--primary);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.nav-links {
  display: flex;
  gap: 1.5rem;
  list-style: none;
}
.nav-links a {
  text-decoration: none;
  color: var(--text-body);
  font-weight: 500;
  font-size: 0.95rem;
  transition: color 0.2s ease;
}
.nav-links a:hover,
.nav-links a.active {
  color: var(--primary);
}
.main-wrapper {
  max-width: 1200px;
  margin: 2rem auto;
  padding: 0 1.5rem;
  width: 100%;
  flex: 1;
}
.hero-card {
  background: linear-gradient(135deg, #ffffff 0%, #f0f9ff 100%);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 3rem 2rem;
  text-align: center;
  box-shadow: var(--shadow-md);
  margin-bottom: 2.5rem;
}
.hero-card h1 {
  font-size: 2.25rem;
  color: var(--text-title);
  margin-bottom: 1rem;
}
.hero-card p {
  font-size: 1.1rem;
  color: var(--text-muted);
  max-width: 700px;
  margin: 0 auto 1.5rem auto;
}
.btn-primary {
  display: inline-block;
  background-color: var(--primary);
  color: #ffffff;
  padding: 0.75rem 1.75rem;
  border-radius: var(--radius-md);
  text-decoration: none;
  font-weight: 600;
  transition: background-color 0.2s ease, transform 0.1s ease;
  border: none;
  cursor: pointer;
}
.btn-primary:hover {
  background-color: var(--primary-hover);
}
.grid-title {
  font-size: 1.5rem;
  color: var(--text-title);
  margin-bottom: 1.5rem;
}
.classes-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 1.5rem;
}
.course-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  box-shadow: var(--shadow-sm);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  display: flex;
  flex-direction: column;
}
.course-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
}
.card-badge {
  background-color: var(--primary-light);
  color: var(--primary);
  font-weight: 700;
  font-size: 0.8rem;
  padding: 0.25rem 0.6rem;
  border-radius: 20px;
  width: fit-content;
  margin-bottom: 0.75rem;
}
.course-card h3 {
  font-size: 1.15rem;
  color: var(--text-title);
  margin-bottom: 0.5rem;
}
.course-card p {
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-bottom: 1.25rem;
  flex: 1;
}
.course-card a {
  align-self: flex-start;
  color: var(--primary);
  text-decoration: none;
  font-weight: 600;
  font-size: 0.9rem;
  display: flex;
  align-items: center;
  gap: 0.3rem;
}
.course-card a:hover {
  text-decoration: underline;
}
.class-layout {
  display: flex;
  gap: 2rem;
  flex-wrap: wrap;
}
.class-main {
  flex: 1 1 640px;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}
.video-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-md);
}
.video-wrapper {
  background-color: #000;
  width: 100%;
  aspect-ratio: 16 / 9;
}
.video-wrapper video {
  width: 100%;
  height: 100%;
  object-fit: contain;
}
.class-info {
  padding: 1.5rem;
}
.class-info h1 {
  font-size: 1.6rem;
  color: var(--text-title);
  margin-bottom: 0.75rem;
}
.class-info p {
  color: var(--text-body);
  font-size: 1rem;
}
.comments-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  box-shadow: var(--shadow-md);
}
.comments-card h2 {
  font-size: 1.3rem;
  color: var(--text-title);
  margin-bottom: 1.25rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.comment-form {
  background-color: var(--bg-subtle);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  margin-bottom: 2rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}
.form-group {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}
.form-group label {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-muted);
}
.form-group input,
.form-group textarea {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 0.75rem;
  font-size: 0.95rem;
  color: var(--text-body);
  outline: none;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}
.form-group input:focus,
.form-group textarea:focus {
  border-color: var(--border-focus);
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.15);
}
.comments-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}
.comment-item {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-left: 4px solid var(--primary);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  padding: 1rem 1.25rem;
  box-shadow: var(--shadow-sm);
}
.comment-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.5rem;
}
.comment-author {
  font-weight: 700;
  color: var(--text-title);
  font-size: 0.95rem;
}

.comment-date {
  font-size: 0.75rem;
  color: var(--text-muted);
}
.comment-body {
  color: var(--text-body);
  font-size: 0.95rem;
  white-space: pre-wrap;
}
.no-comments {
  text-align: center;
  color: var(--text-muted);
  font-style: italic;
  padding: 1.5rem 0;
}
.sidebar {
  flex: 0 0 320px;
}
.sidebar-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 1.25rem;
  box-shadow: var(--shadow-md);
  position: sticky;
  top: 5.5rem;
}
.sidebar-card h3 {
  font-size: 1.1rem;
  color: var(--text-title);
  margin-bottom: 1rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--border-color);
}
.sidebar-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}
.sidebar-item a {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.75rem;
  border-radius: var(--radius-md);
  text-decoration: none;
  color: var(--text-body);
  border: 1px solid transparent;
  transition: all 0.2s ease;
}
.sidebar-item a:hover {
  background-color: var(--bg-subtle);
}
.sidebar-item.active a {
  background-color: var(--primary-light);
  border-color: var(--primary);
  color: var(--primary);
  font-weight: 600;
}
.num-badge {
  background-color: var(--bg-subtle);
  color: var(--text-muted);
  width: 26px;
  height: 26px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.8rem;
  font-weight: 700;
}
.sidebar-item.active .num-badge {
  background-color: var(--primary);
  color: #ffffff;
}
footer {
  background-color: var(--bg-card);
  border-top: 1px solid var(--border-color);
  text-align: center;
  padding: 1.5rem;
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-top: 3rem;
}
@media (max-width: 900px) {
  .class-layout {
    flex-direction: column;
  }
  .sidebar {
    width: 100%;
  }
  .sidebar-card {
    position: static;
  }
}