/* Course Detail Styles */
.course-detail {
    background: #f8fafc;
}

.course-banner {
    background: linear-gradient(135deg, #0070f3, #6b46c1);
    padding: 4rem 0 2rem;
    color: white;
}

.back-button {
    color: white;
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 2rem;
    opacity: 0.8;
    transition: opacity 0.3s;
}

.back-button:hover {
    opacity: 1;
}

.course-nav {
    background: white;
    position: sticky;
    top: 60px;
    z-index: 10;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.nav-tabs {
    display: flex;
    list-style: none;
    padding: 0;
    margin: 0;
}

.nav-tab {
    padding: 1rem 2rem;
    color: #4b5563;
    text-decoration: none;
    border-bottom: 2px solid transparent;
    transition: all 0.3s;
}

.nav-tab.active {
    color: #0070f3;
    border-bottom-color: #0070f3;
}

.course-sections {
    padding: 3rem 0;
}

.section-grid {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 2rem;
}

.course-sidebar {
    position: sticky;
    top: 120px;
}

.info-card {
    background: white;
    border-radius: 0.5rem;
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.module {
    background: white;
    border-radius: 0.5rem;
    margin-bottom: 1rem;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.module-header {
    padding: 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
}

.lesson {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem 1.5rem;
    border-bottom: 1px solid #e5e7eb;
}

.lesson i {
    color: #0070f3;
}

.resource-card {
    display: flex;
    align-items: center;
    gap: 1.5rem;
    background: white;
    padding: 1.5rem;
    border-radius: 0.5rem;
    text-decoration: none;
    color: inherit;
    transition: transform 0.3s;
}

.resource-card:hover {
    transform: translateY(-2px);
}

.assignment-card {
    background: white;
    border-radius: 0.5rem;
    padding: 1.5rem;
    margin-bottom: 1rem;
}

.assignments-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
}

.btn-assignment {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    background: #0070f3;
    color: white;
    text-decoration: none;
    border-radius: 0.5rem;
    margin-top: 1rem;
}

@media (max-width: 768px) {
    .section-grid {
        grid-template-columns: 1fr;
    }

    .nav-tabs {
        overflow-x: auto;
        white-space: nowrap;
    }
}