/* 整体页面样式 */
.video-tutorial-page {
    background: #f8f9fa;
    color: #333;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

/* 顶部横幅区域优化 */
.tutorial-hero {
    /* 使用与首页模板相同的背景色 */
    background: #4481eb;  /* 首页的蓝色 */
    padding: 60px 0;
    position: relative;
    overflow: hidden;
    color: white;
    text-align: center;
}

.tutorial-hero-content {
    position: relative;
    z-index: 2;
}

.tutorial-hero h1 {
    font-size: 2.8rem;
    font-weight: 700;
    margin-bottom: 15px;
    color: white;
}

.tutorial-hero .subtitle {
    font-size: 1.2rem;
    color: rgba(255, 255, 255, 0.9);
}

/* 动态背景效果 */
.animated-shapes {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 1;
    pointer-events: none;
}

/* 雪花效果 */
.snowflake {
    position: absolute;
    width: 6px;
    height: 6px;
    background: rgba(255, 255, 255, 0.6);
    border-radius: 50%;
    animation: snowfall linear infinite;
}

/* 创建多个雪花 */
.snowflake:nth-child(1) { left: 10%; animation-duration: 10s; animation-delay: -2s; }
.snowflake:nth-child(2) { left: 30%; animation-duration: 12s; animation-delay: -1s; }
.snowflake:nth-child(3) { left: 50%; animation-duration: 8s; animation-delay: -3s; }
.snowflake:nth-child(4) { left: 70%; animation-duration: 15s; animation-delay: -4s; }
.snowflake:nth-child(5) { left: 90%; animation-duration: 11s; animation-delay: -5s; }

/* 浮动形状 */
.floating-shape {
    position: absolute;
    opacity: 0.2;
    animation: float 20s ease-in-out infinite;
}

.floating-shape.circle {
    width: 100px;
    height: 100px;
    border: 3px solid rgba(255, 255, 255, 0.8);
    border-radius: 50%;
}

.floating-shape.square {
    width: 80px;
    height: 80px;
    border: 3px solid rgba(255, 255, 255, 0.8);
    transform: rotate(45deg);
}

/* 定位浮动形状 */
.floating-shape:nth-child(1) { top: 20%; left: 10%; animation-delay: -5s; }
.floating-shape:nth-child(2) { top: 60%; left: 80%; animation-delay: -10s; }
.floating-shape:nth-child(3) { top: 30%; left: 60%; animation-delay: -15s; }

/* 动画定义 */
@keyframes snowfall {
    0% {
        transform: translateY(-100px) rotate(0deg);
        opacity: 0;
    }
    20% {
        opacity: 1;
    }
    100% {
        transform: translateY(500px) rotate(360deg);
        opacity: 0;
    }
}

@keyframes float {
    0%, 100% {
        transform: translate(0, 0) rotate(0deg);
    }
    25% {
        transform: translate(20px, -20px) rotate(5deg);
    }
    50% {
        transform: translate(-10px, 20px) rotate(-5deg);
    }
    75% {
        transform: translate(-20px, -10px) rotate(3deg);
    }
}

/* 主要内容区域 */
.tutorial-content {
    padding: 30px 0;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 视频播放区域 */
.video-player-section {
    background: white;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
    overflow: hidden;
    margin-bottom: 40px;
    width: 100%; /* 确保容器宽度为100% */
}

.main-video-container {
    position: relative;
    width: 100%;
    height: 0;
    padding-bottom: 56.25%; /* 16:9 比例 */
    background: #000;
}

/* 视频标签样式优化 */
.video-tabs {
    display: flex;
    width: 100%;
    margin-bottom: 0;
    padding: 0;
    background: #f5f5f5;
    border-radius: 8px 8px 0 0;
    height: 80px;
}

.tab-btn {
    flex: 1;
    height: 100%;
    padding: 0;
    border: none;
    margin: 0;
    background: transparent;
    color: #666;
    font-size: 16px;
    cursor: pointer;
    transition: all 0.3s ease;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
}

.tab-btn:first-child {
    border-radius: 8px 0 0 0;
}

.tab-btn:last-child {
    border-radius: 0 8px 0 0;
}

.tab-btn:not(:last-child)::after {
    content: '';
    position: absolute;
    right: 0;
    top: 25%;
    height: 50%;
    width: 1px;
    background: rgba(0, 0, 0, 0.1);
}

.tab-btn:hover {
    background: rgba(26, 115, 232, 0.05);
}

.tab-btn.active {
    background: #1a73e8;
    color: white;
    font-weight: 500;
}

.tab-btn.active::after,
.tab-btn.active + .tab-btn::after {
    display: none;
}

/* 视频占位图样式优化 */
.video-placeholder {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: none;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #1a73e8 0%, #0d47a1 100%);
    color: white;
    cursor: pointer;
    z-index: 2;
}

/* 移除单人配音的占位图 */
.video-placeholder[data-video="single"] {
    display: none !important;
}

.video-placeholder.active {
    display: flex;
}

.video-placeholder:hover {
    background: linear-gradient(135deg, #1557b0 0%, #083272 100%);
}

.play-icon {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    border: 4px solid white;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 20px;
}

.play-icon::before {
    content: '';
    width: 0;
    height: 0;
    border-style: solid;
    border-width: 20px 0 20px 30px;
    border-color: transparent transparent transparent white;
    margin-left: 8px;
}

.main-video {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: block;
    object-fit: fill;
    z-index: 1; /* 确保视频在底层 */
}

.video-info {
    padding: 25px;
}

.video-title {
    font-size: 1.8rem;
    margin-bottom: 15px;
}

.video-meta {
    color: #666;
    font-size: 1rem;
}

.video-meta span {
    margin-right: 25px;
}

/* 视频列表区域 */
.video-list-section {
    margin-top: 40px;
}

.video-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 30px;
    margin-top: 20px;
}

.video-card {
    background: white;
    border-radius: 15px;
    overflow: hidden;
    box-shadow: 0 5px 15px rgba(0,0,0,0.05);
    transition: transform 0.3s ease;
}

.video-card:hover {
    transform: translateY(-5px);
}

.thumbnail {
    position: relative;
    padding-top: 56.25%;
    background: #f0f0f0;
}

.thumbnail img {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.thumbnail .duration {
    position: absolute;
    bottom: 10px;
    right: 10px;
    background: rgba(0,0,0,0.7);
    color: white;
    padding: 3px 8px;
    border-radius: 4px;
    font-size: 0.8rem;
}

.video-card .video-info {
    padding: 15px;
}

.video-card h4 {
    font-size: 1.1rem;
    margin-bottom: 5px;
}

.video-card p {
    color: #666;
    font-size: 0.9rem;
}

/* 课程特点区域 */
.features-section {
    background: white;
    padding: 80px 0;
}

.features-section h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 50px;
    color: #1a73e8;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
}

.feature-card {
    text-align: center;
    padding: 40px 20px;
    background: #f8f9fa;
    border-radius: 15px;
    transition: transform 0.3s ease;
}

.feature-card:hover {
    transform: translateY(-5px);
}

.feature-card .icon {
    font-size: 3rem;
    margin-bottom: 20px;
}

.feature-card h3 {
    font-size: 1.5rem;
    margin-bottom: 15px;
    color: #1a73e8;
}

.feature-card p {
    color: #666;
}

/* 动画效果 */
@keyframes circleFloat {
    0%, 100% {
        transform: translate(0, 0);
    }
    50% {
        transform: translate(30px, 20px);
    }
}

/* 响应式设计 */
@media (max-width: 768px) {
    .tutorial-hero h1 {
        font-size: 2.5rem;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .video-grid {
        grid-template-columns: 1fr;
    }
}