/* Reset & Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', system-ui, sans-serif;
    background-color: #ffffff;
    color: #1f2937;
    line-height: 1.6;
}

/* Layout Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 3rem 2rem;
}

/* Typography */
.page-title {
    font-size: 2.25rem;
    font-weight: 800;
    text-align: center;
    margin-bottom: 0.5rem;
    color: #111827;
}

.page-subtitle {
    font-size: 1.125rem;
    text-align: center;
    color: #4b5563;
    margin-top: 2.5rem;
}

.section-title {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 3.5rem;
    color: #1f2937;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid #e5e7eb;
}

.group-title {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: #374151;
}

/* Video Grid */
.video-grid {
    display: grid;
    gap: 2rem;
    grid-template-columns: 1fr;
}

@media (min-width: 640px) {
    .video-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

/* Add spacing between sections */
section {
    margin-bottom: 6rem;
}

@media (min-width: 1024px) {
    .video-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

.video-group {
    background: white;
    border-radius: 1rem;
    padding: 1.5rem;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    transition: all 0.3s ease;
}

.video-group:hover {
    box-shadow: 0 10px 15px rgba(0, 0, 0, 0.1);
    transform: translateY(-2px);
}

.video-pair {
    display: flex;
    gap: 1rem;
    margin-bottom: 1rem;
}

@media (max-width: 639px) {
    .video-pair {
        flex-direction: column;
    }
}

.video-card {
    flex: 1;
    background: white;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-direction: column;
    border-radius: 1rem;
    padding: 1rem;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    transition: all 0.3s ease;
}

@media (max-width: 639px) {
    .video-card {
        flex: none;
    }
}

.video-card:hover {
    box-shadow: 0 10px 15px rgba(0, 0, 0, 0.1);
    transform: translateY(-2px);
}

.video-placeholder {
    aspect-ratio: 16 / 9;
    background: #f3f4f6;
    border: 2px solid #d1d5db;
    border-radius: 0.75rem;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #6b7280;
    font-weight: 600;
    font-size: 1.125rem;
    transition: all 0.3s ease;
    cursor: pointer;
    overflow: hidden;
    /* 防止视频溢出 */
}

.video-placeholder>video {
    width: 100%;
    height: 100%;
    object-fit: fill;
    /* 保持视频比例并填充容器 */
    border-radius: 0.75rem;
}

.video-placeholder:hover {
    border-color: #3b82f6;
    box-shadow: 0 8px 16px rgba(59, 130, 246, 0.15);
}

.video-placeholder.highlight {
    border-color: #3b82f6;
}

.video-placeholder.highlight span {
    color: #3b82f6;
}

.prompt-text {
    font-size: 0.875rem;
    color: #4b5563;
    margin-top: 0.5rem;
    text-align: center;
}

.prompt-text strong {
    color: #1f2937;
}

/* Questionnaire Section */
.questionnaire {
    background: #f3f4f6;
    border-radius: 1.5rem;
    padding: 2rem;
    margin: 3rem auto;
    /* Center horizontally */
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    text-align: center;
    /* Center content inside */
}

.questionnaire-title {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: #1f2937;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid #e5e7eb;
}

.questionnaire-desc {
    font-size: 1.125rem;
    color: #374151;
    margin-bottom: 1.5rem;
}

.btn-primary {
    display: inline-block;
    background: #3b82f6;
    color: white;
    font-weight: 600;
    padding: 0.75rem 1.5rem;
    border-radius: 0.75rem;
    text-decoration: none;
    transition: all 0.3s ease;
    box-shadow: 0 4px 6px rgba(59, 130, 246, 0.3);
}

.btn-primary:hover {
    background: #2563eb;
    box-shadow: 0 6px 12px rgba(59, 130, 246, 0.4);
    transform: translateY(-1px);
}

.btn-primary i {
    margin-right: 0.5rem;
}

/* Footer */
.footer {
    margin-top: 3rem;
    text-align: center;
    color: #6b7280;
    font-size: 0.875rem;
}

/* Video Modal */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.8);
    justify-content: center;
    align-items: center;
}

.modal-content {
    position: relative;
    background-color: #000;
    padding: 2rem;
    border-radius: 1rem;
    width: 70%;
    height: 70%;
}

.close {
    position: absolute;
    top: 0;
    right: 1%;
    color: white;
    font-size: 2rem;
    font-weight: bold;
    cursor: pointer;
}

.close:hover {
    color: #ccc;
}

#modalVideo {
    width: 100%;
    height: 100%;
    outline: none;
}

/* Image Modal */
#imageModal .modal-content {
    position: relative;
    background-color: #000;
    padding: 2rem;
    border-radius: 1rem;
    width: 70%;
    height: 70%;
    display: flex;
    align-items: center;
    justify-content: center;
}

#imageModal #modalImage {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
    border-radius: 0.5rem;
}

/* Image Card */
.img-card {
    background: #f3f4f6;
    border-radius: 1.5rem;
    padding: 1rem;
    margin: 2rem auto;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    text-align: center;
    max-width: 1000px;
    transition: all 0.3s ease;
}

.img-card img {
    width: 100%;
    height: auto;
    border-radius: 0.75rem;
    object-fit: contain;
    margin-bottom: 0.5rem;
    cursor: pointer;
}

/* prompt-text 样式（沿用 video 的） */
.img-card .prompt-text {
    font-size: 0.875rem;
    color: #4b5563;
    margin-top: 0.5rem;
    text-align: center;
}

.img-card .prompt-text strong {
    color: #1f2937;
}

/* Hover 效果 */
.img-card:hover {
    box-shadow: 0 10px 15px rgba(0, 0, 0, 0.1);
    transform: translateY(-2px);
    background: #ffffff;
}

/* Image Grid */
.img-grid {
    background: #f3f4f6;
    border-radius: 1.5rem;
    padding: 2rem;
    margin: 3rem auto;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    text-align: center;
}

.img-grid img {
    width: 100%;
    height: auto;
    border-radius: 0.75rem;
    object-fit: contain;
    transition: all 0.3s ease;
    cursor: pointer;
}

.img-grid img:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.1);
}

/* 下一页部分 */
.next-page {
    display: flex;
    justify-content: center;
    margin: 2rem 0;
    cursor: pointer;
}

.next-page .down-arrow {
    width: 50px;
    height: 50px;
}

/* 返回顶部按钮 */
.back-to-top {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 50px;
    height: 50px;
    border: none;
    border-radius: 50%;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0;
}

.back-to-top.show {
    opacity: 1;
    visibility: visible;
}

.back-to-top img {
    width: 90%;
    height: 90%;
    border-radius: 50%;
    background-color: rgba(29, 53, 56, 0.8);
    object-fit: cover;
}