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

body {
    font-family: 'Inter', sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
    color: #333;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
}

/* Header Styles */
.header {
    background: rgba(255, 255, 255, 0.98);
    border-radius: 24px;
    padding: 40px;
    margin-bottom: 40px;
    box-shadow: 0 15px 50px rgba(0, 0, 0, 0.2);
    backdrop-filter: blur(10px);
    text-align: center;
}

.header-content {
    animation: fadeInDown 0.8s ease;
}

.header-top {
    margin-bottom: 1rem;
}

.back-link {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    color: #667eea;
    text-decoration: none;
    font-weight: 600;
    font-size: 0.95rem;
    padding: 0.5rem 1rem;
    border-radius: 0.5rem;
    background: rgba(102, 126, 234, 0.1);
    transition: all 0.3s ease;
}

.back-link:hover {
    background: rgba(102, 126, 234, 0.2);
    color: #764ba2;
    transform: translateX(-3px);
}

@keyframes fadeInDown {
    from {
        opacity: 0;
        transform: translateY(-30px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.main-title {
    font-size: 3rem;
    font-weight: 800;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 10px;
}

.subtitle {
    font-size: 1.2rem;
    color: #666;
    font-weight: 500;
}

/* Courses Container */
.courses-container {
    animation: fadeInUp 0.8s ease 0.2s backwards;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.section-title {
    font-size: 2rem;
    font-weight: 700;
    color: white;
    margin-bottom: 30px;
    text-align: center;
    text-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
}

/* Course Card */
.course-card {
    background: rgba(255, 255, 255, 0.98);
    border-radius: 20px;
    padding: 35px;
    margin-bottom: 30px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.15);
    transition: all 0.3s ease;
}

.course-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 50px rgba(0, 0, 0, 0.2);
}

.course-card.disabled-course {
    opacity: 0.6;
    cursor: not-allowed;
}

.course-card.disabled-course:hover {
    transform: none;
}

.course-header {
    display: flex;
    align-items: center;
    gap: 20px;
    margin-bottom: 30px;
    padding-bottom: 20px;
    border-bottom: 2px solid #e9ecf5;
}

.course-icon {
    font-size: 3.5rem;
    width: 80px;
    height: 80px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 20px;
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.4);
}

.course-info {
    flex: 1;
}

.course-name {
    font-size: 2rem;
    font-weight: 700;
    color: #2d3748;
    margin-bottom: 5px;
}

.course-description {
    font-size: 1.1rem;
    color: #718096;
    font-weight: 500;
}

/* Units Section */
.units-container {
    margin-top: 20px;
}

.units-title {
    font-size: 1.3rem;
    font-weight: 600;
    color: #4a5568;
    margin-bottom: 20px;
}

.units-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 20px;
}

/* Unit Card */
.unit-card {
    background: linear-gradient(135deg, #f6f8fc 0%, #e9ecf5 100%);
    border: 2px solid #e2e8f0;
    border-radius: 16px;
    padding: 25px;
    transition: all 0.3s ease;
    cursor: pointer;
    text-decoration: none;
    color: inherit;
    display: flex;
    flex-direction: column;
    gap: 12px;
    position: relative;
    overflow: hidden;
}

.unit-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    transform: scaleX(0);
    transform-origin: left;
    transition: transform 0.3s ease;
}

.unit-card:hover::before {
    transform: scaleX(1);
}

.unit-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(102, 126, 234, 0.3);
    border-color: #667eea;
}

.unit-card.disabled {
    cursor: not-allowed;
    opacity: 0.6;
}

.unit-card.disabled:hover {
    transform: none;
    box-shadow: none;
    border-color: #e2e8f0;
}

.unit-card.disabled::before {
    display: none;
}

.unit-number {
    font-size: 0.9rem;
    font-weight: 600;
    color: #667eea;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.unit-name {
    font-size: 1.3rem;
    font-weight: 700;
    color: #2d3748;
    line-height: 1.3;
}

.unit-meta {
    display: flex;
    flex-direction: column;
    gap: 8px;
    margin-top: 10px;
}

.questions-count,
.duration {
    font-size: 0.9rem;
    color: #718096;
    font-weight: 500;
}

.start-button {
    margin-top: auto;
    padding: 12px 24px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border-radius: 10px;
    font-weight: 600;
    text-align: center;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.3);
}

.unit-card:hover .start-button {
    box-shadow: 0 6px 20px rgba(102, 126, 234, 0.5);
    transform: translateY(-2px);
}

.coming-soon-badge {
    margin-top: auto;
    padding: 10px 20px;
    background: linear-gradient(135deg, #ffeaa7 0%, #fdcb6e 100%);
    color: #856404;
    border-radius: 10px;
    font-weight: 600;
    text-align: center;
    font-size: 0.9rem;
}

/* Footer */
.footer {
    text-align: center;
    margin-top: 50px;
    padding: 30px;
    color: white;
    text-shadow: 0 2px 5px rgba(0, 0, 0, 0.2);
}

.footer p {
    margin-bottom: 10px;
    font-size: 1.1rem;
    font-weight: 500;
}

.footer-note {
    font-size: 0.95rem;
    opacity: 0.9;
    font-weight: 400;
}

/* Responsive Design */
@media (max-width: 768px) {
    body {
        padding: 10px;
    }

    .header {
        padding: 25px;
    }

    .main-title {
        font-size: 2rem;
    }

    .subtitle {
        font-size: 1rem;
    }

    .section-title {
        font-size: 1.5rem;
    }

    .course-card {
        padding: 25px;
    }

    .course-icon {
        width: 60px;
        height: 60px;
        font-size: 2.5rem;
    }

    .course-name {
        font-size: 1.5rem;
    }

    .course-description {
        font-size: 1rem;
    }

    .units-grid {
        grid-template-columns: 1fr;
    }

    .footer {
        margin-top: 30px;
        padding: 20px;
    }

    .footer p {
        font-size: 1rem;
    }

    .footer-note {
        font-size: 0.85rem;
    }
}

@media (max-width: 480px) {
    .main-title {
        font-size: 1.8rem;
    }

    .subtitle {
        font-size: 0.9rem;
    }

    .course-header {
        flex-direction: column;
        text-align: center;
    }

    .unit-name {
        font-size: 1.1rem;
    }
}