body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
}

.fade-in {
    animation: fadeIn 0.5s ease-in-out;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

.pulse-slow {
    animation: pulse 3s infinite;
}

.video-container {
    position: relative;
    width: 100%;
    height: 0;
    padding-bottom: 56.25%;
    overflow: hidden;
}

.video-container iframe,
.video-container video {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

.progress-bar {
    transition: width 0.3s ease;
}

.course-card:hover {
    transform: translateY(-5px);
}

.btn-loading {
    position: relative;
}

.btn-loading:disabled {
    color: transparent;
}

.btn-loading:disabled::after {
    content: '';
    position: absolute;
    width: 16px;
    height: 16px;
    top: 50%;
    left: 50%;
    margin-left: -8px;
    margin-top: -8px;
    border: 2px solid #ffffff;
    border-radius: 50%;
    border-top-color: transparent;
    animation: spin 1s ease-in-out infinite;
}

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

.dropdown-menu {
    transform: translateY(-10px);
    opacity: 0;
    visibility: hidden;
    transition: all 0.2s ease;
}

.dropdown:hover .dropdown-menu {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
}

.alert {
    animation: slideDown 0.3s ease;
}

@keyframes slideDown {
    from { transform: translateY(-100%); }
    to { transform: translateY(0); }
}

.modal-overlay {
    background-color: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
}

.sidebar-enter {
    transform: translateX(-100%);
}

.sidebar-enter-active {
    transform: translateX(0);
    transition: transform 0.3s ease;
}

.mobile-menu-enter {
    max-height: 0;
    overflow: hidden;
}

.mobile-menu-enter-active {
    max-height: 500px;
    transition: max-height 0.3s ease;
}

@media (max-width: 768px) {
    .hero-title {
        font-size: 2.5rem;
    }
    
    .course-grid {
        grid-template-columns: 1fr;
    }
}

.text-gradient {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    background-clip: text;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.scrollbar-hide {
    -ms-overflow-style: none;
    scrollbar-width: none;
}

.scrollbar-hide::-webkit-scrollbar {
    display: none;
}

.glass-effect {
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.floating-action {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    z-index: 1000;
}