* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* 视频播放器样式 */
.video-section {
    padding: 60px 0;
    position: relative;
}

.video-container {
    max-width: 800px;
    margin: 80px auto;
    position: relative;
    z-index: 1;
}

.video-wrapper {
    position: relative;
    width: 100%;
    border-radius: 20px;
    overflow: hidden;
    box-shadow: 0 15px 40px rgba(0, 0, 0, 0.6),
                0 0 20px rgba(0, 255, 255, 0.2),
                inset 0 0 0 2px rgba(0, 255, 255, 0.3);
}

.video-poster {
    position: relative;
    width: 100%;
    height: 0;
    padding-bottom: 56.25%; /* 16:9 比例 */
    background-color: #000;
    cursor: pointer;
    overflow: hidden;
}

.video-poster img {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: contain;
    transition: transform 0.3s ease;
}

.video-poster:hover img {
    transform: scale(1.05);
}

.play-button {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 80px;
    height: 80px;
    background-color: rgba(0, 188, 212, 0.7);
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    transition: background-color 0.3s ease, transform 0.3s ease;
}

.play-button svg {
    width: 40px;
    height: 40px;
}

.video-poster:hover .play-button {
    background-color: rgba(0, 188, 212, 0.9);
    transform: translate(-50%, -50%) scale(1.1);
}

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

.video-iframe-container iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: none;
}

body {
    font-family: 'Arial', 'Microsoft YaHei', sans-serif;
    line-height: 1.6;
    color: #e8f4f8;
    background: #0a1628;
}

/* 1. 标题部分 */
.header {
    /* background: linear-gradient(135deg, #0a1628 0%, #1e3a5f 50%, #2d5aa0 100%); */
    color: #ffffff;
    text-align: center;
    padding: 20px 0;
    position: relative;
    overflow: hidden;
}

.header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle at center, rgba(0, 255, 255, 0.1) 0%, transparent 70%);
    pointer-events: none;
}

.brand-title {
    font-size: 5rem;
    font-weight: 900;
    letter-spacing: 12px;
    text-shadow: 
        0 0 10px rgba(0, 255, 255, 0.8),
        0 0 20px rgba(0, 255, 255, 0.6),
        0 0 30px rgba(0, 255, 255, 0.4);
    position: relative;
    z-index: 1;
}

/* 2. 三维图片轮播 */
.carousel-section {
    /* background: linear-gradient(180deg, #0a1628 0%, #1a2332 50%, #0a1628 100%); */
    /* padding: 100px 0; */
    overflow: hidden;
    position: relative;
    padding:80px 0;
}

.carousel-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    pointer-events: none;
}

.carousel-container {
    max-width: 1200px;
    margin: 0 auto;
    perspective: 1200px;
    height: 450px;
    position: relative;
    z-index: 1;
}

.carousel-wrapper {
    position: relative;
    width: 100%;
    height: 100%;
    transform-style: preserve-3d;
    transition: transform 1s ease-in-out;
}

.carousel-item {
    position: absolute;
    width: 320px;
    height: 320px;
    left: 50%;
    top: 50%;
    margin-left: -160px;
    margin-top: -160px;
    border-radius: 20px;
    overflow: hidden;
    box-shadow: 
        0 15px 40px rgba(0, 0, 0, 0.6),
        0 0 20px rgba(0, 255, 255, 0.2),
        inset 0 0 0 2px rgba(0, 255, 255, 0.3);
    cursor: pointer;
    transition: all 0.5s ease;
    border: 1px solid rgba(0, 255, 255, 0.4);
}

.carousel-item img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.carousel-item:hover {
    transform: scale(1.08);
    box-shadow: 
        0 20px 50px rgba(0, 0, 0, 0.8),
        0 0 30px rgba(0, 255, 255, 0.5),
        inset 0 0 0 3px rgba(0, 255, 255, 0.6);
}

/* 轮播位置计算 */
.carousel-item:nth-child(1) { transform: rotateY(0deg) translateZ(400px); }
.carousel-item:nth-child(2) { transform: rotateY(72deg) translateZ(400px); }
.carousel-item:nth-child(3) { transform: rotateY(144deg) translateZ(400px); }
.carousel-item:nth-child(4) { transform: rotateY(216deg) translateZ(400px); }
.carousel-item:nth-child(5) { transform: rotateY(288deg) translateZ(400px); }

/* 3. 三列内容区域 */
.content-section {
    padding: 100px 0;
    /* background: linear-gradient(180deg, #0a1628 0%, #152238 100%); */
    position: relative;
}

.content-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    /* background: 
        linear-gradient(45deg, transparent 49%, rgba(0, 255, 255, 0.02) 50%, transparent 51%),
        linear-gradient(-45deg, transparent 49%, rgba(45, 90, 160, 0.03) 50%, transparent 51%); */
    background-size: 60px 60px;
    pointer-events: none;
}

.content-container {
    max-width: 1400px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 50px;
    padding: 0 20px;
    position: relative;
    z-index: 1;
}

.content-column {
    text-align: center;
    background: linear-gradient(145deg, #1a2332 0%, #243447 100%);
    border-radius: 20px;
    padding: 40px 30px;
    box-shadow: 
        0 10px 30px rgba(0, 0, 0, 0.4),
        0 0 0 1px rgba(0, 255, 255, 0.2),
        inset 0 1px 0 rgba(255, 255, 255, 0.1);
    transition: all 0.4s ease;
    border: 1px solid rgba(0, 255, 255, 0.15);
}

.content-column:hover {
    transform: translateY(-15px);
    box-shadow: 
        0 20px 40px rgba(0, 0, 0, 0.6),
        0 0 0 2px rgba(0, 255, 255, 0.4),
        0 0 20px rgba(0, 255, 255, 0.2),
        inset 0 1px 0 rgba(255, 255, 255, 0.2);
}

/* Tab 切换样式 */
.tab-buttons {
    display: flex;
    justify-content: center;
    margin-bottom: 30px;
    gap: 20px;
}

.tab-button {
    padding: 12px 30px;
    background: linear-gradient(145deg, #1a2332 0%, #243447 100%);
    border: 1px solid rgba(0, 255, 255, 0.3);
    border-radius: 10px;
    color: #e8f4f8;
    font-size: 1.2rem;
    font-weight: bold;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 
        0 5px 15px rgba(0, 0, 0, 0.3),
        0 0 0 1px rgba(0, 255, 255, 0.2);
}

.tab-button:hover {
    transform: translateY(-3px);
    box-shadow: 
        0 8px 20px rgba(0, 0, 0, 0.4),
        0 0 0 2px rgba(0, 255, 255, 0.4),
        0 0 15px rgba(0, 255, 255, 0.3);
}

.tab-button.active {
    background: linear-gradient(145deg, #2d5aa0 0%, #1e3a5f 100%);
    border-color: rgba(0, 255, 255, 0.6);
    box-shadow: 
        0 0 20px rgba(0, 255, 255, 0.4),
        inset 0 0 10px rgba(255, 255, 255, 0.1);
}

/* 语言切换样式 */
.language-switcher {
    display: flex;
    justify-content: center;
    margin-bottom: 20px;
    gap: 15px;
}

.language-button {
    padding: 8px 20px;
    background: linear-gradient(145deg, #1a2332 0%, #243447 100%);
    border: 1px solid rgba(0, 255, 255, 0.3);
    border-radius: 8px;
    color: #e8f4f8;
    font-size: 1rem;
    font-weight: bold;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 
        0 4px 12px rgba(0, 0, 0, 0.3),
        0 0 0 1px rgba(0, 255, 255, 0.2);
}

.language-button:hover {
    transform: translateY(-2px);
    box-shadow: 
        0 6px 16px rgba(0, 0, 0, 0.4),
        0 0 0 2px rgba(0, 255, 255, 0.4),
        0 0 12px rgba(0, 255, 255, 0.3);
}

.language-button.active {
    background: linear-gradient(145deg, #2d5aa0 0%, #1e3a5f 100%);
    border-color: rgba(0, 255, 255, 0.6);
    box-shadow: 
        0 0 15px rgba(0, 255, 255, 0.4),
        inset 0 0 8px rgba(255, 255, 255, 0.1);
}

.tab-content {
    display: none;
    animation: fadeIn 0.5s ease-in-out;
}

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

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

/* 案例研究样式 */
.case-study {
    background: rgba(0, 255, 255, 0.1);
    border-left: 4px solid rgba(0, 255, 255, 0.6);
    padding: 15px 20px;
    margin: 15px 0;
    border-radius: 0 8px 8px 0;
    font-style: italic;
}

.section-omitted {
    color: #8ca0b3;
    font-style: italic;
    text-align: center;
    margin: 20px 0;
    padding: 15px;
    background: rgba(255, 255, 255, 0.05);
    border-radius: 8px;
}

.course-designer {
    text-align: center;
    margin-top: 40px;
    padding: 20px;
    background: rgba(45, 90, 160, 0.1);
    border-radius: 10px;
    border: 1px solid rgba(45, 90, 160, 0.3);
}

.content-image {
    width: 100%;
    /* height: 220px; */
    border-radius: 15px;
    margin-bottom: 30px;
    position: relative;
    overflow: hidden;
}

.content-image::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(45deg, rgba(0, 255, 255, 0.1) 0%, rgba(45, 90, 160, 0.1) 100%);
    border-radius: 15px;
}

.content-text {
    margin-bottom: 30px;
}

.content-text p {
    font-size: 1.2rem;
    font-weight: 400;
    color: #b8d4e3;
    line-height: 1.8;
    letter-spacing: 0.5px;
}

.more-btn {
    background: linear-gradient(135deg, #00bcd4 0%, #2d5aa0 100%);
    color: #ffffff;
    border: none;
    padding: 15px 35px;
    border-radius: 30px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    text-transform: uppercase;
    letter-spacing: 1px;
    box-shadow: 
        0 5px 15px rgba(0, 188, 212, 0.3),
        inset 0 1px 0 rgba(255, 255, 255, 0.2);
}

.more-btn:hover {
    transform: translateY(-3px);
    box-shadow: 
        0 8px 25px rgba(0, 188, 212, 0.5),
        0 0 20px rgba(0, 255, 255, 0.3),
        inset 0 1px 0 rgba(255, 255, 255, 0.3);
    background: linear-gradient(135deg, #00e5ff 0%, #3f7cac 100%);
}

/* 4. Footer */
.footer {
    background: linear-gradient(45deg, #442a28 0%, #8b7063 100%); 
    color: #7a9bb8;
    text-align: center;
    padding: 10px 0;
    border-top: 1px solid rgba(0, 255, 255, 0.2);
    position: relative;
}

.footer::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent 0%, rgba(0, 255, 255, 0.5) 50%, transparent 100%);
}

.footer-content p {
    margin: 8px 0;
    font-size: 0.95rem;
    font-weight: 300;
    letter-spacing: 0.5px;
}

.footer-content p:first-child {
    font-size: 1rem;
    color: #9bb5c9;
    font-weight: 400;
}

.footer-content .banner-wrapper {
    /* margin-top: 15px; */
    width: 100%;
}
.footer-content .title-wrapper{
    margin: 10px 0;
    display: flex;
    justify-content: center;
}

.footer-content .img-group{
    display: flex;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
    justify-content: center;
    padding: 20px;
}

.footer-content .img-group img{
    width: 120px;
    height: 120px;
    border-radius: 15px;
    box-shadow: 
        0 10px 30px rgba(0, 0, 0, 0.4),
        0 0 0 1px rgba(0, 255, 255, 0.2);
    transition: all 0.4s ease;
}

.footer-content .img-group img:hover {
    transform: translateY(-10px);
    box-shadow: 
        0 20px 40px rgba(0, 0, 0, 0.6),
        0 0 0 2px rgba(0, 255, 255, 0.4),
        0 0 20px rgba(0, 255, 255, 0.2);
}

/* 链接样式 */
.footer-content .img-group a {
    display: block;
    text-decoration: none;
    border-radius: 15px;
    transition: all 0.4s ease;
}

.footer-content .img-group a:hover {
    transform: translateY(-10px);
    box-shadow: 
        0 20px 40px rgba(0, 0, 0, 0.6),
        0 0 0 2px rgba(0, 255, 255, 0.4),
        0 0 20px rgba(0, 255, 255, 0.2);
}

/* 响应式设计 - 图片容器 */
@media (max-width: 768px) {
    .footer-content .img-group{
        grid-template-columns: 1fr;
        gap: 20px;
        padding: 0 15px;
    }
}

/* 课程大纲样式 */
.outline-container {
    padding: 30px;
    line-height: 1.8;
}

.outline-intro {
    font-size: 1.2rem;
    color: #b8d4e3;
    margin-bottom: 30px;
    font-style: italic;
    text-align: center;
}

.outline-title {
    font-size: 2.5rem;
    color: #ffffff;
    text-align: center;
    margin: 30px 0;
    text-shadow: 0 0 10px rgba(0, 255, 255, 0.5);
}

.pedagogical-model {
    font-size: 1.3rem;
    color: #00bcd4;
    text-align: center;
    margin: 30px 0;
    font-weight: 600;
}

.main-section {
    margin: 40px 0;
    padding: 25px;
    background: linear-gradient(145deg, rgba(26, 35, 50, 0.8) 0%, rgba(36, 52, 71, 0.8) 100%);
    border-radius: 15px;
    border-left: 4px solid #00bcd4;
}

.section-title {
    font-size: 1.8rem;
    color: #ffffff;
    margin-bottom: 25px;
    padding-bottom: 10px;
    border-bottom: 2px solid rgba(0, 255, 255, 0.3);
}

.subsection {
    margin: 20px 0;
    padding: 15px;
    background: rgba(255, 255, 255, 0.05);
    border-radius: 10px;
    border-left: 3px solid #2d5aa0;
}

.subsection-title {
    font-size: 1.4rem;
    color: #00e5ff;
    margin-bottom: 15px;
}

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

.topic-list li {
    font-size: 1.1rem;
    color: #b8d4e3;
    margin: 8px 0;
    padding: 8px 15px;
    background: rgba(0, 255, 255, 0.1);
    border-radius: 6px;
    border-left: 2px solid rgba(0, 255, 255, 0.5);
    transition: all 0.3s ease;
}

.topic-list li:hover {
    background: rgba(0, 255, 255, 0.2);
    transform: translateX(5px);
}

/* 响应式设计 */
@media (max-width: 768px) {
    .brand-title {
        font-size: 3rem;
        letter-spacing: 6px;
        text-shadow: 
            0 0 8px rgba(0, 255, 255, 0.6),
            0 0 15px rgba(0, 255, 255, 0.4);
    }
    
    .header {
        padding: 60px 0;
    }
    .video-container {
        margin:20px 0;
    }
    
    .content-container {
        grid-template-columns: 1fr;
        gap: 30px;
    }
    
    .carousel-item {
        width: 280px;
        height: 280px;
        margin-left: -140px;
        margin-top: -140px;
    }
    
    .carousel-section {
        padding: 20px 0;
    }
    
    .content-section {
        padding: 80px 0;
    }
    
    .content-text p {
        font-size: 1.1rem;
    }
    
    .more-btn {
        padding: 12px 28px;
        font-size: 1rem;
    }
    
    /* 课程大纲响应式样式 */
    .outline-container {
        padding: 20px;
    }
    
    .outline-title {
        font-size: 2rem;
        margin: 20px 0;
    }
    
    .pedagogical-model {
        font-size: 1.1rem;
        margin: 20px 0;
    }
    
    .main-section {
        margin: 30px 0;
        padding: 20px;
    }
    
    .section-title {
        font-size: 1.5rem;
        margin-bottom: 20px;
    }
    
    .subsection {
        margin: 15px 0;
        padding: 12px;
    }
    
    .subsection-title {
        font-size: 1.2rem;
        margin-bottom: 12px;
    }
    
    .topic-list li {
        font-size: 1rem;
        padding: 6px 12px;
    }
}

@media (max-width: 480px) {
    .brand-title {
        font-size: 2.2rem;
        letter-spacing: 3px;
    }
    
    .carousel-item {
        width: 240px;
        height: 240px;
        margin-left: -120px;
        margin-top: -120px;
    }
    
    .content-column {
        padding: 30px 20px;
    }
    
    .content-text p {
        font-size: 1rem;
    }
    
    /* 课程大纲小屏幕响应式样式 */
    .outline-container {
        padding: 15px;
    }
    
    .outline-title {
        font-size: 1.8rem;
        margin: 15px 0;
    }
    
    .outline-intro {
        font-size: 1rem;
        margin-bottom: 20px;
    }
    
    .pedagogical-model {
        font-size: 1rem;
        margin: 15px 0;
    }
    
    .main-section {
        margin: 25px 0;
        padding: 15px;
    }
    
    .section-title {
        font-size: 1.3rem;
        margin-bottom: 15px;
    }
    
    .subsection {
        margin: 12px 0;
        padding: 10px;
    }
    
    .subsection-title {
        font-size: 1.1rem;
        margin-bottom: 10px;
    }
    
    .topic-list li {
        font-size: 0.95rem;
        padding: 5px 10px;
        margin: 6px 0;
    }
}

.golden-sand {
    position: relative;
    width: 100%;
    border-radius: 8px;
    background-color: #c8a951;
    overflow: hidden;
}

/* 基础沙砾纹理层 */
.golden-sand::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image: 
        radial-gradient(circle, rgba(255, 210, 100, 0.3) 1px, transparent 1px),
        radial-gradient(circle, rgba(218, 165, 32, 0.4) 1px, transparent 2px),
        radial-gradient(circle, rgba(255, 223, 120, 0.2) 1px, transparent 1px);
    background-size: 30px 30px, 50px 50px, 20px 20px;
    background-position: 0 0, 15px 15px, 10px 10px;
    background-blend-mode: overlay;
    opacity: 0.8;
}

/* 增强噪点和沙砾感 */
.golden-sand::after {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image: 
        /* 较大的沙砾颗粒 */
        radial-gradient(circle, rgba(255, 200, 80, 0.5) 2px, transparent 3px),
        radial-gradient(circle, rgba(210, 170, 50, 0.6) 2px, transparent 4px),
        /* 细小的沙砾颗粒 */
        radial-gradient(circle, rgba(255, 220, 100, 0.3) 1px, transparent 1px);
    background-size: 40px 40px, 60px 60px, 15px 15px;
    background-position: 5px 5px, 20px 20px, 0 0;
    background-blend-mode: soft-light;
    
    /* 叠加一层渐变光效，增强立体感 */
    background: linear-gradient(
        135deg,
        rgba(255, 240, 180, 0.1) 0%,
        rgba(184, 134, 11, 0.2) 50%,
        rgba(139, 101, 8, 0.1) 100%
    ), 
    /* 沙砾噪点图案 */
    repeating-conic-gradient(
        from 0deg,
        rgba(255, 215, 0, 0.1) 0deg 15deg,
        rgba(218, 165, 32, 0.15) 15deg 30deg
    ),
    /* 细小颗粒 */
    radial-gradient(
        circle,
        rgba(255, 223, 120, 0.2) 1px,
        transparent 1px
    );
    background-size: 100% 100%, 40px 40px, 10px 10px;
}