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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: linear-gradient(135deg, #0f0c29 0%, #1a1a2e 50%, #16213e 100%);
    color: #e0e0e0;
    line-height: 1.6;
    min-height: 100vh;
}

.container, .course-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 20px;
}

/* Header */
.course-header {
    background: linear-gradient(135deg, rgba(247, 147, 26, 0.1), rgba(255, 215, 0, 0.05));
    border-radius: 20px;
    padding: 40px;
    margin-bottom: 30px;
    text-align: center;
    border: 1px solid rgba(247, 147, 26, 0.2);
}

.course-header h1 {
    font-size: 2.5rem;
    background: linear-gradient(135deg, #f7931a, #ffd700);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    margin-bottom: 15px;
}

.course-header h1 i {
    background: none;
    -webkit-background-clip: unset;
    background-clip: unset;
    color: #f7931a;
}

/* Stats Bar */
.stats-bar {
    display: flex;
    justify-content: center;
    gap: 40px;
    margin: 30px 0;
    flex-wrap: wrap;
}

.stat {
    text-align: center;
}

.stat-number {
    display: block;
    font-size: 2rem;
    font-weight: bold;
    color: #f7931a;
}

.stat-label {
    font-size: 0.85rem;
    color: #aaa;
}

/* Search Bar */
.search-bar {
    max-width: 600px;
    margin: 0 auto;
}

.search-bar form {
    display: flex;
    background: rgba(0, 0, 0, 0.4);
    border-radius: 50px;
    border: 1px solid rgba(255, 255, 255, 0.1);
    overflow: hidden;
}

.search-bar i {
    position: relative;
    left: 20px;
    top: 50%;
    transform: translateY(50%);
    color: #888;
}

.search-bar input {
    flex: 1;
    background: transparent;
    border: none;
    padding: 15px 20px 15px 45px;
    color: #fff;
    font-size: 1rem;
}

.search-bar input:focus {
    outline: none;
}

.search-bar button {
    background: #f7931a;
    border: none;
    padding: 0 25px;
    color: #000;
    font-weight: 600;
    cursor: pointer;
    transition: opacity 0.3s;
}

.search-bar button:hover {
    opacity: 0.9;
}

/* Filter Tabs */
.filter-tabs {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-bottom: 30px;
    flex-wrap: wrap;
}

.filter-btn {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    padding: 10px 25px;
    border-radius: 30px;
    color: #e0e0e0;
    cursor: pointer;
    transition: all 0.3s;
    font-size: 0.9rem;
}

.filter-btn:hover, .filter-btn.active {
    background: #f7931a;
    color: #000;
    border-color: #f7931a;
}

/* Module Cards */
.module-card {
    background: rgba(255, 255, 255, 0.05);
    border-radius: 15px;
    margin-bottom: 20px;
    overflow: hidden;
    transition: all 0.3s;
}

.module-card:hover {
    background: rgba(255, 255, 255, 0.08);
}

.module-header {
    padding: 25px;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: background 0.3s;
}

.module-header:hover {
    background: rgba(247, 147, 26, 0.1);
}

.module-info {
    flex: 1;
}

.module-number {
    display: inline-block;
    background: rgba(247, 147, 26, 0.2);
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 0.75rem;
    color: #f7931a;
    margin-bottom: 10px;
}

.module-header h2 {
    font-size: 1.5rem;
    margin-bottom: 10px;
}

.module-meta {
    display: flex;
    gap: 15px;
    flex-wrap: wrap;
}

.badge {
    display: inline-flex;
    align-items: center;
    gap: 5px;
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 0.75rem;
    background: rgba(255, 255, 255, 0.1);
}

.difficulty-beginner { background: rgba(0, 255, 136, 0.2); color: #00ff88; }
.difficulty-intermediate { background: rgba(255, 215, 0, 0.2); color: #ffd700; }
.difficulty-advanced { background: rgba(255, 68, 68, 0.2); color: #ff8888; }

.module-toggle i {
    font-size: 1.2rem;
    transition: transform 0.3s;
    color: #888;
}

.module-toggle .rotated {
    transform: rotate(180deg);
}

.module-body {
    padding: 0 25px 25px 25px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

/* Sections Container */
.sections-container {
    margin-top: 20px;
}

.section-item {
    background: rgba(0, 0, 0, 0.3);
    border-radius: 12px;
    margin-bottom: 15px;
    overflow: hidden;
}

.section-header {
    padding: 15px 20px;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: background 0.3s;
}

.section-header:hover {
    background: rgba(247, 147, 26, 0.05);
}

.section-number {
    color: #f7931a;
    font-weight: bold;
    margin-right: 10px;
}

.section-title {
    font-weight: 500;
}

.beginner-badge {
    background: rgba(247, 147, 26, 0.2);
    color: #f7931a;
    padding: 2px 8px;
    border-radius: 5px;
    font-size: 0.7rem;
    margin-left: 10px;
}

.section-content {
    padding: 0 20px;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease-out;
}

.section-content.open {
    max-height: 2000px;
    padding: 20px;
}

/* Units List */
.units-list {
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin-top: 15px;
}

.unit-item {
    background: rgba(0, 0, 0, 0.2);
    border-radius: 8px;
    padding: 12px 15px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: all 0.3s;
    cursor: pointer;
}

.unit-item:hover {
    background: rgba(247, 147, 26, 0.1);
    transform: translateX(5px);
}

.unit-number {
    font-family: monospace;
    color: #f7931a;
    font-size: 0.85rem;
    min-width: 70px;
}

.unit-title {
    flex: 1;
    margin-left: 15px;
}

.unit-duration {
    font-size: 0.75rem;
    color: #888;
    margin-left: 15px;
}

/* Breadcrumb */
.breadcrumb {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 30px;
    font-size: 0.85rem;
    flex-wrap: wrap;
}

.breadcrumb a {
    color: #aaa;
    text-decoration: none;
}

.breadcrumb a:hover {
    color: #f7931a;
}

.breadcrumb i {
    font-size: 0.7rem;
    color: #555;
}

.breadcrumb .current {
    color: #f7931a;
}

/* Section Header */
.section-header-page {
    margin-bottom: 30px;
}

.section-badge {
    display: flex;
    gap: 10px;
    margin-bottom: 15px;
}

.section-header-page h1 {
    font-size: 2rem;
    margin-bottom: 15px;
}

.section-meta {
    display: flex;
    gap: 20px;
    color: #888;
    font-size: 0.85rem;
}

/* Unit Card (for section page) */
.unit-card {
    background: rgba(0, 0, 0, 0.3);
    border-radius: 12px;
    padding: 15px 20px;
    margin-bottom: 12px;
    display: flex;
    align-items: center;
    gap: 15px;
    cursor: pointer;
    transition: all 0.3s;
}

.unit-card:hover {
    background: rgba(247, 147, 26, 0.1);
    transform: translateX(5px);
}

.unit-number {
    font-family: monospace;
    background: rgba(247, 147, 26, 0.2);
    padding: 5px 10px;
    border-radius: 6px;
    font-size: 0.8rem;
    min-width: 60px;
    text-align: center;
}

.unit-info {
    flex: 1;
}

.unit-info h3 {
    margin-bottom: 5px;
}

.unit-meta {
    display: flex;
    gap: 15px;
    font-size: 0.75rem;
    color: #888;
}

.unit-arrow i {
    color: #f7931a;
}

/* Loading Spinner */
.loading-spinner {
    text-align: center;
    padding: 40px;
    color: #888;
}

/* Footer */
.course-footer {
    margin-top: 50px;
    padding: 30px;
    background: rgba(0, 0, 0, 0.3);
    border-radius: 15px;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
}

.footer-section h4 {
    color: #f7931a;
    margin-bottom: 10px;
}

.footer-section p {
    font-size: 0.85rem;
    color: #aaa;
}

/* Navigation Buttons */
.section-navigation, .unit-navigation {
    display: flex;
    justify-content: space-between;
    margin-top: 40px;
    padding-top: 20px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.nav-btn {
    background: rgba(255, 255, 255, 0.1);
    padding: 12px 24px;
    border-radius: 8px;
    text-decoration: none;
    color: #e0e0e0;
    transition: all 0.3s;
}

.nav-btn:hover {
    background: #f7931a;
    color: #000;
}

/* Responsive */
@media (max-width: 768px) {
    .course-header {
        padding: 20px;
    }
    
    .course-header h1 {
        font-size: 1.5rem;
    }
    
    .stats-bar {
        gap: 20px;
    }
    
    .stat-number {
        font-size: 1.5rem;
    }
    
    .module-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 15px;
    }
    
    .module-meta {
        flex-wrap: wrap;
    }
    
    .unit-item {
        flex-wrap: wrap;
    }
    
    .unit-title {
        margin-left: 0;
        margin-top: 5px;
        width: 100%;
    }
    
    .unit-card {
        flex-wrap: wrap;
    }
    
    .unit-info {
        width: 100%;
    }
}