.course-container {
    background-color: var(--bg-card);
    border-radius: 16px;
    box-shadow: 0 10px 30px -5px rgba(0, 0, 0, 0.05);
    overflow: hidden;
    min-height: 400px;
    border-top: 5px solid var(--primary-color);
    margin-bottom: 2rem; /* Added margin for multiple boxes */
}

/* Add colors to consecutive boxes */
.course-container:nth-child(2) { border-top-color: var(--card-1-color); }
.course-container:nth-child(3) { border-top-color: var(--card-2-color); }
.course-container:nth-child(4) { border-top-color: var(--card-3-color); }
.course-container:nth-child(5) { border-top-color: var(--card-4-color); }
.course-container:nth-child(6) { border-top-color: #2a9d8f; }

/* Document link hover effects analogous to topic-card */
.course-container:nth-child(2) .document-link:hover {
    background-color: #edf2ff;
    color: var(--card-1-color);
}
.course-container:nth-child(2) .document-list li:hover::before {
    background-color: var(--card-1-color);
    color: white;
}

.course-container:nth-child(3) .document-link:hover {
    background-color: #ffeff5;
    color: var(--card-2-color);
}
.course-container:nth-child(3) .document-list li:hover::before {
    background-color: var(--card-2-color);
    color: white;
}

.course-container:nth-child(4) .document-link:hover {
    background-color: #ecf8fd;
    color: #0077b6;
}
.course-container:nth-child(4) .document-list li:hover::before {
    background-color: #0077b6;
    color: white;
}

.course-container:nth-child(5) .document-link:hover {
    background-color: #fff8eb;
    color: #e85d04;
}
.course-container:nth-child(5) .document-list li:hover::before {
    background-color: #e85d04;
    color: white;
}

.course-container:nth-child(6) .document-link:hover {
    background-color: #e6f7f5;
    color: #2a9d8f;
}
.course-container:nth-child(6) .document-list li:hover::before {
    background-color: #2a9d8f;
    color: white;
}

.course-main-header {
    padding: 2rem 2.5rem;
    border-bottom: 1px solid #edf2f4;
    background-color: #ffffff;
}

.course-main-header h2 {
    font-size: 1.8rem;
    color: var(--text-main);
    margin: 0;
}

.course-main-header p {
    color: var(--text-muted);
    margin-top: 0.5rem;
}

.course-body {
    display: flex;
}

.course-sidebar {
    width: 30%;
    background-color: #f8f9fa;
    border-right: 1px solid #edf2f4;
    padding: 1rem 0;
}

.topic-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.topic-list li {
    padding: 1rem 2rem;
    cursor: pointer;
    font-size: 1.1rem;
    font-weight: 500;
    color: var(--text-main);
    border-left: 4px solid transparent;
    transition: all 0.3s ease;
}

.topic-list li:hover {
    background-color: #e9ecef;
}

.topic-list li.active {
    background-color: #edf2ff;
    color: var(--primary-color);
    border-left: 4px solid var(--primary-color);
}

/* Sidebar items hover and active states according to box colors */
.course-container:nth-child(2) .topic-list li:hover {
    color: var(--card-1-color);
}
.course-container:nth-child(2) .topic-list li.active {
    background-color: #edf2ff;
    color: var(--card-1-color);
    border-color: var(--card-1-color);
}

.course-container:nth-child(3) .topic-list li:hover {
    color: var(--card-2-color);
}
.course-container:nth-child(3) .topic-list li.active {
    background-color: #ffeff5;
    color: var(--card-2-color);
    border-color: var(--card-2-color);
}

.course-container:nth-child(4) .topic-list li:hover {
    color: #0077b6;
}
.course-container:nth-child(4) .topic-list li.active {
    background-color: #ecf8fd;
    color: #0077b6;
    border-color: #0077b6;
}

.course-container:nth-child(5) .topic-list li:hover {
    color: #e85d04;
}
.course-container:nth-child(5) .topic-list li.active {
    background-color: #fff8eb;
    color: #e85d04;
    border-color: #e85d04;
}

.course-container:nth-child(6) .topic-list li:hover {
    color: #2a9d8f;
}
.course-container:nth-child(6) .topic-list li.active {
    background-color: #e6f7f5;
    color: #2a9d8f;
    border-color: #2a9d8f;
}

.course-content {
    width: 70%;
    padding: 2.5rem;
    background-color: #ffffff;
}

.content-pane {
    display: none;
    animation: fadeIn 0.4s ease-in-out;
}

.content-pane.active {
    display: block;
}

.content-pane h2 {
    font-size: 1.5rem;
    color: var(--text-main);
    margin-bottom: 1.5rem;
    padding-bottom: 1rem;
    border-bottom: 2px dashed #edf2f4;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

@media (max-width: 768px) {
    .course-body {
        flex-direction: column;
    }
    .course-sidebar {
        width: 100%;
        border-right: none;
        border-bottom: 1px solid #edf2f4;
    }
    .course-content {
        width: 100%;
        padding: 1.5rem;
    }
    .topic-list {
        display: flex;
        overflow-x: auto;
    }
    .topic-list li {
        white-space: nowrap;
        border-left: none;
        border-bottom: 4px solid transparent;
    }
    .topic-list li.active {
        border-left: none;
        border-bottom: 4px solid var(--primary-color);
    }
}