* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
}

body {
    background: linear-gradient(135deg, #f8f9fa 0%, #eef2f6 100%);
    color: #333;
    line-height: 1.6;
    padding: 20px;
    min-height: 100vh;
}

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

header {
    text-align: center;
    margin-bottom: 30px;
    padding: 20px 0;
    position: relative;
}

.logo {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 10px;
    color: #2c3e50;
    position: relative;
    display: inline-block;
    text-shadow: 1px 1px 3px rgba(0,0,0,0.1);
}

.logo::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 50%;
    transform: translateX(-50%);
    width: 120px;
    height: 4px;
    background: linear-gradient(90deg, #3498db, #2ecc71);
    border-radius: 2px;
}

.subtitle {
    color: #7f8c8d;
    font-size: 1.1rem;
    margin-top: 5px;
}

/* 手臂型号选择器 */
.arm-selector {
    margin: 15px auto;
    max-width: 800px;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 10px;
}

.arm-option {
    background: white;
    border: 2px solid #3498db;
    border-radius: 30px;
    padding: 10px 20px;
    font-size: 1rem;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 8px;
    box-shadow: 0 4px 10px rgba(52, 152, 219, 0.2);
}

.arm-option:hover {
    background: #e3f2fd;
    transform: translateY(-3px);
    box-shadow: 0 6px 15px rgba(52, 152, 219, 0.3);
}

.arm-option.active {
    background: linear-gradient(135deg, #3498db, #2ecc71);
    color: white;
    border-color: #2ecc71;
}

.arm-option i {
    font-size: 1.2rem;
}

.content {
    display: flex;
    gap: 25px;
    margin-bottom: 30px;
    position: relative;
}

.categories {
    flex: 1;
    background: #fff;
    border-radius: 12px;
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.08);
    padding: 25px;
    position: sticky;
    top: 20px;
    align-self: flex-start;
    height: fit-content;
    max-height: 90vh;
    overflow-y: auto;
    transition: transform 0.3s ease;
}

.category-group {
    margin-bottom: 25px;
    border-bottom: 1px solid #eee;
    padding-bottom: 20px;
}

.category-group:last-child {
    border-bottom: none;
    margin-bottom: 0;
    padding-bottom: 0;
}

.category-title {
    font-size: 1.3rem;
    color: #2c3e50;
    margin-bottom: 15px;
    padding-left: 10px;
    border-left: 4px solid #3498db;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 10px;
}

.category-title i {
    color: #3498db;
    font-size: 1.2rem;
}

.sub-categories {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
    gap: 15px;
}

.sub-category {
    background: #f8f9fa;
    border-radius: 10px;
    padding: 18px 15px;
    transition: all 0.3s ease;
    cursor: pointer;
    position: relative;
    overflow: hidden;
    border: 1px solid #eaeaea;
    box-shadow: 0 3px 8px rgba(0, 0, 0, 0.05);
}

.sub-category:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.1);
    background: linear-gradient(to bottom right, #eef7ff, #e3f2fd);
    border-color: #c2e0ff;
}

.sub-category.active {
    background: linear-gradient(to bottom right, #e3f2fd, #d1e8ff);
    border-left: 4px solid #3498db;
    box-shadow: 0 5px 15px rgba(52, 152, 219, 0.2);
}

.sub-category h3 {
    font-size: 1.05rem;
    margin-bottom: 8px;
    color: #2c3e50;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 8px;
}

.sub-category h3 i {
    color: #3498db;
    font-size: 0.9rem;
}

.sub-category p {
    font-size: 0.85rem;
    color: #7f8c8d;
    line-height: 1.5;
}

.player-section {
    flex: 2;
    background: #fff;
    border-radius: 12px;
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.08);
    padding: 25px;
    transition: all 0.3s ease;
    position: sticky;
    top: 20px;
    align-self: flex-start;
}

.player-section.sticky {
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.15);
    border: 1px solid #e0e0e0;
}

.breadcrumb {
    display: flex;
    gap: 8px;
    color: #7f8c8d;
    font-size: 0.95rem;
    margin-bottom: 15px;
    padding: 8px 0;
    flex-wrap: wrap;
}

.breadcrumb span:last-child {
    color: #3498db;
    font-weight: 600;
}

.breadcrumb span:not(:last-child):after {
    content: '/';
    margin-left: 8px;
    color: #bdc3c7;
}

.video-container {
    width: 100%;
    aspect-ratio: 16/9;
    background: linear-gradient(45deg, #1a2a3a, #2c3e50);
    border-radius: 10px;
    overflow: hidden;
    margin-bottom: 20px;
    box-shadow: 0 12px 25px rgba(0, 0, 0, 0.2);
    position: relative;
}

.video-container::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(to bottom, rgba(0,0,0,0.1) 0%, rgba(0,0,0,0.3) 100%);
    z-index: -1;
}

.video-container video {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
}

.video-info {
    padding: 20px 0;
}

.video-info h2 {
    font-size: 1.6rem;
    margin-bottom: 15px;
    color: #2c3e50;
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: 10px;
}

.video-info h2 i {
    color: #3498db;
}

.video-info p {
    color: #555;
    line-height: 1.7;
    margin-bottom: 20px;
    padding: 10px 0;
    border-top: 1px solid #eee;
    border-bottom: 1px solid #eee;
}

.compatible-arms {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 15px;
}

.arm-tag {
    background: #e3f2fd;
    color: #3498db;
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 5px;
}

.stats {
    display: flex;
    gap: 15px;
    color: #7f8c8d;
    font-size: 0.95rem;
    flex-wrap: wrap;
    margin-top: 12px;
}

.stat-item {
    display: flex;
    align-items: center;
    gap: 8px;
    background: #f1f8ff;
    padding: 8px 18px;
    border-radius: 30px;
    font-size: 0.9rem;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.05);
}

.stat-item i {
    color: #3498db;
}

footer {
    text-align: center;
    padding: 25px;
    color: #7f8c8d;
    font-size: 0.95rem;
    border-radius: 12px;
    margin-top: 30px;
}

.logo-container {
    display: flex;
    justify-content: center;
    margin-top: 15px;
}

.logo-small {
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, #3498db, #2ecc71);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: bold;
    font-size: 18px;
    margin: 0 10px;
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}

/* 响应式设计 */
@media (max-width: 992px) {
    .content {
        flex-direction: column;
    }

    .sub-categories {
        grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
    }

    .categories, .player-section {
        position: static;
    }
}

@media (max-width: 768px) {
    .logo {
        font-size: 2rem;
    }

    .subtitle {
        font-size: 0.95rem;
    }

    .sub-categories {
        grid-template-columns: 1fr;
    }

    .video-info h2 {
        font-size: 1.4rem;
    }

    body {
        padding: 15px;
    }

    .arm-selector {
        flex-direction: column;
        align-items: center;
    }

    .arm-option {
        width: 90%;
        justify-content: center;
    }

    /* 移动端分类菜单按钮 */
    .mobile-toggle {
        display: block;
        position: fixed;
        bottom: 20px;
        right: 20px;
        width: 60px;
        height: 60px;
        background: linear-gradient(135deg, #3498db, #2ecc71);
        border-radius: 50%;
        z-index: 1000;
        box-shadow: 0 5px 15px rgba(0,0,0,0.3);
        display: flex;
        align-items: center;
        justify-content: center;
        color: white;
        font-size: 1.5rem;
        cursor: pointer;
    }

    .categories {
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100%;
        z-index: 999;
        transform: translateX(-100%);
        transition: transform 0.3s ease;
        padding-top: 70px;
        max-height: 100vh;
        overflow-y: auto;
        border-radius: 0;
    }

    .categories.active {
        transform: translateX(0);
    }

    .close-menu {
        position: absolute;
        top: 20px;
        right: 20px;
        font-size: 1.5rem;
        color: #e74c3c;
        cursor: pointer;
        z-index: 1001;
    }

    .player-section {
        margin-bottom: 80px;
    }
}

/* 动画效果 */
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.fade-in {
    animation: fadeIn 0.4s ease-out;
}

/* 滚动提示 */
.scroll-hint {
    position: fixed;
    bottom: 30px;
    right: 30px;
    background: #3498db;
    color: white;
    width: 45px;
    height: 45px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    box-shadow: 0 4px 12px rgba(52, 152, 219, 0.4);
    z-index: 100;
    transition: all 0.3s ease;
    opacity: 0;
    transform: translateY(20px);
}

.scroll-hint.visible {
    opacity: 1;
    transform: translateY(0);
}

.scroll-hint:hover {
    transform: translateY(-3px) scale(1.05);
    box-shadow: 0 6px 15px rgba(52, 152, 219, 0.5);
}

/* 进度条 */
.progress-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: transparent;
    z-index: 1000;
}

.progress-bar {
    height: 4px;
    background: linear-gradient(90deg, #3498db, #2ecc71);
    width: 0%;
    transition: width 0.2s ease;
}