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

body {
    background-color: #f5f7fa;
    color: #333;
    line-height: 1.6;
}

/* 背景图区域 */
.hero {
    position: relative;
    height: 100vh;
    background: linear-gradient(rgba(0, 0, 0, 0.5), rgba(0, 0, 0, 0.7)), url('https://images.unsplash.com/photo-1529390079861-591de354faf5?ixlib=rb-4.0.3&ixid=M3wxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8fA%3D%3D&auto=format&fit=crop&w=1920&q=80') no-repeat center center/cover;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    color: white;
    padding: 0 20px;
}

.hero-content {
    max-width: 800px;
}

.hero h1 {
    font-size: 3.5rem;
    margin-bottom: 20px;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.5);
}

.hero p {
    font-size: 1.5rem;
    margin-bottom: 30px;
}

.cta-button {
    display: inline-block;
    background: #4a6fa5;
    color: white;
    padding: 15px 30px;
    font-size: 1.2rem;
    text-decoration: none;
    border-radius: 50px;
    transition: all 0.3s ease;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.3);
}

.cta-button:hover {
    background: #3a5a80;
    transform: translateY(-3px);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.3);
}

/* 导航栏 */
.navbar {
    background: rgba(255, 255, 255, 0.95);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 20px;
}

.logo {
    font-size: 1.8rem;
    font-weight: bold;
    color: #4a6fa5;
    display: flex;
    align-items: center;
}

.logo i {
    margin-right: 10px;
}

.nav-links {
    display: flex;
    list-style: none;
}

.nav-links li {
    margin: 0 15px;
}

.nav-links a {
    text-decoration: none;
    color: #333;
    font-weight: 500;
    padding: 8px 12px;
    border-radius: 4px;
    transition: all 0.3s ease;
}

.nav-links a.active {
    background: #eef2f7;
    color: #4a6fa5;
}

.nav-links a:hover {
    background: #eef2f7;
    color: #4a6fa5;
}

/* 板块区域 */
.section {
    padding: 80px 20px;
    max-width: 1200px;
    margin: 0 auto;
}

.section-title {
    text-align: center;
    margin-bottom: 50px;
    color: #2c3e50;
    position: relative;
}

.section-title h2 {
    font-size: 2.5rem;
    display: inline-block;
    padding-bottom: 15px;
}

.section-title h2::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 100px;
    height: 4px;
    background: #4a6fa5;
    border-radius: 2px;
}

/* 资源中心 */
.resource-center {
    background: white;
    border-radius: 10px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
    padding: 30px;
}

.resource-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
}

.resource-card {
    background: #f8f9fa;
    border-radius: 8px;
    overflow: hidden;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border: 1px solid #e9ecef;
}

.resource-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
}

.resource-icon {
    background: #4a6fa5;
    color: white;
    font-size: 2.5rem;
    padding: 25px;
    text-align: center;
}

.resource-content {
    padding: 25px;
}

.resource-content h3 {
    margin-bottom: 15px;
    color: #2c3e50;
}

.resource-content p {
    color: #6c757d;
    margin-bottom: 20px;
}

.btn {
    display: inline-block;
    background: #4a6fa5;
    color: white;
    padding: 10px 20px;
    border-radius: 5px;
    text-decoration: none;
    font-weight: 500;
    transition: background 0.3s ease;
}

.btn:hover {
    background: #3a5a80;
}

/* 教材资源库选择器 */
.selector-container {
    background: white;
    border-radius: 10px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
    padding: 30px;
    margin-top: 50px;
}

.selector-title {
    text-align: center;
    margin-bottom: 30px;
    color: #2c3e50;
}

.selector-steps {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 20px;
    margin-bottom: 30px;
}

.selector-step {
    flex: 1;
    min-width: 250px;
    max-width: 350px;
}

.selector-step h3 {
    margin-bottom: 15px;
    color: #4a6fa5;
    display: flex;
    align-items: center;
}

.selector-step h3 i {
    margin-right: 10px;
}

.selector-step select {
    width: 100%;
    padding: 12px;
    border: 1px solid #ced4da;
    border-radius: 5px;
    font-size: 1rem;
    background: white;
}

.video-container {
    background: #2c3e50;
    border-radius: 8px;
    overflow: hidden;
    margin-top: 30px;
    position: relative;
    padding-top: 56.25%;
    /* 16:9 Aspect Ratio */
}

.video-placeholder {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    color: white;
    background: rgba(44, 62, 80, 0.9);
}

.video-placeholder i {
    font-size: 4rem;
    margin-bottom: 20px;
    color: #4a6fa5;
}

/* 其他板块样式 */
.support-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.support-card {
    background: white;
    border-radius: 8px;
    padding: 30px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
    transition: transform 0.3s ease;
}

.support-card:hover {
    transform: translateY(-10px);
}

.support-card i {
    font-size: 2.5rem;
    color: #4a6fa5;
    margin-bottom: 20px;
}

.support-card h3 {
    margin-bottom: 15px;
    color: #2c3e50;
}

.support-card p {
    color: #6c757d;
    margin-bottom: 20px;
}

/* 页脚 */
footer {
    background: #2c3e50;
    color: white;
    padding: 50px 20px;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
}

.footer-section h3 {
    margin-bottom: 20px;
    font-size: 1.5rem;
    position: relative;
    padding-bottom: 10px;
}

.footer-section h3::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 50px;
    height: 3px;
    background: #4a6fa5;
}

.footer-links {
    list-style: none;
}

.footer-links li {
    margin-bottom: 10px;
}

.footer-links a {
    color: #bbbbbb;
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-links a:hover {
    color: white;
}

.copyright {
    text-align: center;
    padding-top: 30px;
    margin-top: 30px;
    border-top: 1px solid #3a506b;
    color: #bbbbbb;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .hero h1 {
        font-size: 2.5rem;
    }

    .hero p {
        font-size: 1.2rem;
    }

    .nav-container {
        flex-direction: column;
    }

    .nav-links {
        margin-top: 15px;
        flex-wrap: wrap;
        justify-content: center;
    }

    .nav-links li {
        margin: 5px 10px;
    }

    .section-title h2 {
        font-size: 2rem;
    }
}