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

body {
    font-family: 'Inter', sans-serif;
    background: #f5f7fa;
}

/* Navbar Container */
.navbar-lessons {
    background: white;
    border-radius: 12px;
    box-shadow: 0 2px 12px rgba(0, 0, 0, 0.08);
    position: sticky;
    top: 0px;
    transition: all 0.3s ease;
}

.navbar-lessons:hover {
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.12);
}

/* Header - Always Visible */
.navbar-lessons-header {
    padding: 1.25rem 1.5rem;
}

.navbar-lessons-header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.navbar-lessons-title {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    color: #1f2937;
    font-size: 1.25rem;
    font-weight: 700;
    margin: 0;
}

.navbar-lessons-title i {
    font-size: 1.4rem;
    color: #667eea;
}

/* Toggle Button */
.navbar-lessons-toggle-btn {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border: none;
    border-radius: 10px;
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.3);
}

.navbar-lessons-toggle-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(102, 126, 234, 0.4);
}

.navbar-lessons-toggle-btn.active {
    background: linear-gradient(135deg, #764ba2 0%, #667eea 100%);
}

.navbar-lessons-toggle-btn.active i {
    transform: rotate(180deg);
}

.navbar-lessons-toggle-btn i {
    transition: transform 0.3s ease;
}

/* Dropdown Menu */
.navbar-lessons-dropdown {
    max-height: 0;
    overflow: hidden;
    opacity: 0;
    transform: translateY(-10px);
    transition: all 0.4s cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

.navbar-lessons-dropdown.show {
    max-height: 800px;
    opacity: 1;
    transform: translateY(0);
}

/* Search */
.navbar-lessons-search {
    position: relative;
    padding: 1.25rem 1.5rem;
    background: #f9fafb;
    border-bottom: 1px solid #e5e7eb;
}

.navbar-lessons-search i {
    position: absolute;
    left: 2.25rem;
    top: 50%;
    transform: translateY(-50%);
    color: #9ca3af;
}

.navbar-lessons-search input {
    width: 100%;
    padding: 0.875rem 1rem 0.875rem 2.75rem;
    border: 2px solid #e5e7eb;
    border-radius: 10px;
    background: white;
    transition: all 0.3s ease;
}

.navbar-lessons-search input:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 4px rgba(102, 126, 234, 0.1);
}

/* Dropdown Content */
.navbar-lessons-content {
    padding: 1.5rem;
    max-height: 450px;
    overflow-y: auto;
}

.navbar-lessons-content::-webkit-scrollbar {
    width: 6px;
}

.navbar-lessons-content::-webkit-scrollbar-thumb {
    background: #d1d5db;
    border-radius: 10px;
}

.navbar-lessons-content::-webkit-scrollbar-thumb:hover {
    background: #9ca3af;
}

/* Categories */
.navbar-lessons-category {
    margin-bottom: 2rem;
}

.navbar-lessons-category-title {
    display: flex;
    align-items: center;
    gap: 0.625rem;
    font-size: 0.8rem;
    font-weight: 700;
    color: #667eea;
    text-transform: uppercase;
    letter-spacing: 0.8px;
    margin-bottom: 0.875rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid #e5e7eb;
}

/* Lesson List */
.navbar-lessons-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 0.375rem;
    padding: 0;
    margin: 0;
}

.navbar-lessons-item a {
    display: flex;
    align-items: center;
    gap: 0.875rem;
    padding: 0.875rem 1rem;
    text-decoration: none;
    color: #4b5563;
    border-radius: 10px;
    transition: all 0.2s ease;
    border: 1px solid transparent;
}

.navbar-lessons-item a:hover {
    background: linear-gradient(135deg, rgba(102,126,234,0.08), rgba(118,75,162,0.08));
    color: #667eea;
    transform: translateX(4px);
    border-color: rgba(102, 126, 234, 0.2);
}

/* Active Lesson */
.navbar-lessons-item.active a {
    background: linear-gradient(135deg, #667eea, #764ba2);
    color: white;
    font-weight: 600;
    box-shadow: 0 4px 12px rgba(102,126,234,0.3);
}

.navbar-lessons-item.active a:hover {
    transform: none;
}

.navbar-lessons-item-icon {
    width: 36px;
    height: 36px;
    background: #f3f4f6;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: 0.2s ease;
}

.navbar-lessons-item a:hover .navbar-lessons-item-icon {
    background: rgba(102, 126, 234, 0.15);
    transform: scale(1.1);
}

.navbar-lessons-item.active .navbar-lessons-item-icon {
    background: rgba(255,255,255,0.25);
    color: white;
}

.navbar-lessons-item-text {
    flex: 1;
}

.navbar-lessons-active-badge {
    color: #4ade80;
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.6;
    }
}

/* Progress Indicator */
.navbar-lessons-progress {
    padding: 1.5rem;
    background: linear-gradient(135deg, #f9fafb, #f3f4f6);
    border-top: 1px solid #e5e7eb;
}

.navbar-lessons-progress-info {
    display: flex;
    justify-content: space-between;
    margin-bottom: 0.875rem;
}

.navbar-lessons-progress-label {
    display: flex;
    align-items: center;
    font-size: 0.9rem;
    font-weight: 600;
    gap: 0.5rem;
}

.navbar-lessons-progress-label i {
    color: #667eea;
}

.navbar-lessons-progress-value {
    color: #667eea;
    font-weight: 700;
    background: white;
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
}

.navbar-lessons-progress-bar-container {
    height: 12px;
    background: #e5e7eb;
    border-radius: 10px;
    overflow: hidden;
}

.navbar-lessons-progress-bar-fill {
    height: 100%;
    background: linear-gradient(90deg, #667eea, #764ba2, #667eea);
    background-size: 200% 100%;
    transition: width 0.8s ease;
    animation: shimmer 2s infinite;
}

@keyframes shimmer {
    0% {
        background-position: -100% 0;
    }
    100% {
        background-position: 100% 0;
    }
}

.navbar-lessons-progress-percentage {
    margin-top: 0.625rem;
    font-size: 0.8rem;
    text-align: center;
    font-weight: 600;
    color: #6b7280;
}

/* Fade in animation */
.fade-in {
    animation: fadeIn 0.3s ease-in;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(-5px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Responsive */
@media (max-width: 992px) {
    .navbar-lessons {
        position: relative;
        top: 0;
        margin-bottom: 2rem;
    }
}

@media (max-width: 768px) {
    .navbar-lessons-header {
        padding: 1rem 1.25rem;
    }
    .navbar-lessons-title {
        font-size: 1.1rem;
    }
    .navbar-lessons-toggle-btn {
        width: 40px;
        height: 40px;
    }
}

@media (max-width: 576px) {
    .navbar-lessons-title span {
        font-size: 1rem;
    }
}