body {
  font-family: "Inter", sans-serif;
  transition: background-color 0.3s ease, color 0.3s ease;
}

/* Dark mode default styles via class */
body.dark {
  background-color: #0f172a;
  color: #f8fafc;
}

/* Light mode styles */
body:not(.dark) {
  background-color: #f8fafc;
  color: #0f172a;
}

.glass-nav {
  backdrop-filter: blur(12px);
  transition: background-color 0.3s ease, border-color 0.3s ease;
}

.dark .glass-nav {
  background: rgba(15, 23, 42, 0.8);
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

body:not(.dark) .glass-nav {
  background: rgba(248, 250, 252, 0.8);
  border-bottom: 1px solid rgba(0, 0, 0, 0.1);
}

.course-card {
  transition: all 0.3s ease;
}

.course-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 25px -5px rgba(168, 85, 247, 0.2),
    0 8px 10px -6px rgba(236, 72, 153, 0.2);
}

/* Gradient text utility */
.text-gradient {
  background-clip: text;
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-image: linear-gradient(to right, #ec4899, #a855f7);
}

/* Gradient background for active filter */
.bg-gradient-active {
  background: linear-gradient(to right, #ec4899, #9333ea);
  color: white;
}

/* Hide scrollbar */
.hide-scrollbar::-webkit-scrollbar {
  display: none;
}
.hide-scrollbar {
  -ms-overflow-style: none;
  scrollbar-width: none;
}

/* Locked lesson styles */
.lesson-locked {
  opacity: 0.6;
  cursor: not-allowed;
  filter: grayscale(100%);
}

.auth-overlay {
  backdrop-filter: blur(8px);
  background: rgba(15, 23, 42, 0.95);
}

.telegram-btn {
  background-color: #2481cc;
  transition: background-color 0.3s ease, transform 0.2s ease;
}

.telegram-btn:hover {
  background-color: #1d69a6;
  transform: translateY(-2px);
}