:root {
    --primary-color: #3B8BEB;
    --secondary-color: #B23850;
    --accent-color: #E7E334;
    --light-bg: #C4DBF6;
    --muted-text: #8590AA;
    --white: #ffffff;
    --card-bg: #F7FAFC;
    --hover-bg: #D0E7FF;
    --text-main: #2c3e50;
    --text-muted: #34495e;
}

.banner {
    width: 100%;
    padding: 20px 0;
    overflow: hidden;
    border-radius: 16px;
    margin-bottom: 30px;
    position: relative;
}

.video-banner {
    width: 100%;
    height: auto;
    display: block;
    object-fit: cover;
    border-radius: 16px;
    transition: transform 0.3s ease;
    filter: brightness(0.95) contrast(1.05);
}

.banner:hover .video-banner {
    transform: scale(1.02);
}


.courses {
    padding: 30px 0 80px;
    background-color: var(--white);
}

.courses .container {
    padding-top: 20px;
    padding-bottom: 10px;
    background-color: var(--card-bg);
    border-radius: 16px;
}

.course-title-wrap {
    margin-bottom: 30px;
}

.course-title {
    padding: 10px;
    font-size: 32px;
    font-weight: bold;
    border-radius: 10px;
    /*background-color: var(--light-bg);*/
    color: var(--secondary-color);
}

.tabs {
    padding: 10px;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    margin-bottom: 30px;
    gap: 10px;
    border-radius: 10px;
}

.course-option-item,
.test-option-item,
.document-option-item {
    padding: 10px 20px;
    background-color: var(--white);
    border-radius: 15px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: 500;
    color: var(--text-muted);
    letter-spacing: 0.5px;
}

.course-option-item:hover,
.test-option-item:hover,
.document-option-item:hover {
    transform: scale(1.05);
    background-color: var(--hover-bg);
    color: var(--primary-color);
}

.course-option-item.active,
.test-option-item.active,
.document-option-item.active {
    background: linear-gradient(135deg, var(--primary-color) 0%, #2A64BA 100%);
    box-shadow: 0 4px 12px rgba(59, 139, 235, 0.25);
    color: var(--white);
    font-weight: 600;
}

.tab-contents .tab-course-content,
.tab-contents .tab-test-content,
.tab-contents .tab-document-content {
    display: none;
}

.tab-contents .tab-course-content.active,
.tab-contents .tab-test-content.active,
.tab-contents .tab-document-content.active {
    display: block;
}

.course-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 20px;
    margin: 20px;
}

.course-item {
    padding: 10px;
    background: var(--white);
    border-radius: 12px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
    overflow: hidden;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.course-item:hover {
    transform: translateY(-10px);
    box-shadow: 2px 4px 10px 0 rgba(0, 0, 0, .2);
}

.course-card-body {
    display: flex;
    flex-direction: column;
    text-decoration: none;
    color: inherit;
    height: 100%;
}

.course-item-avatar img {
    width: 100%;
    height: 180px;
    object-fit: cover;
    display: block;
    border-radius: 10px;
    border: 1px solid #eee;
}

.course-item-info {
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    flex-grow: 1;
    padding: 15px 10px 10px;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

.course-item-title span {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-main);
    line-height: 1.4;
    min-height: 44px;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
    text-overflow: ellipsis;
}

.course-card-price-border {
    text-align: end;
    margin-top: 10px;
    border-top: 1px solid #f0f0f0;
    padding-top: 10px;
}

.course-card-price-left h5 {
    font-size: 1rem;
    font-weight: 700;
    color: var(--primary-color);
    margin: 0;
}

.course-card-price-left p del {
    color: #bdc3c7;
    font-size: 0.9rem;
}

.popover-btns .purchase-btn {
    padding: 8px 10px;
    gap: 3px;
    background-color: var(--primary-color);
    color: var(--white);
    border: none;
    border-radius: 6px;
    transition: background-color 0.3s ease;
}

.popover-btns .purchase-btn:hover {
    background-color: #2A64BA;
}