/* 重置和基础样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #ffffff;
}

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

/* 头部样式 */
.header {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid rgba(0, 0, 0, 0.1);
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    transition: all 0.3s ease;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: #1890ff;
    text-decoration: none;
}

.nav {
    display: flex;
    gap: 2rem;
}

.nav-link {
    text-decoration: none;
    color: #64748b;
    font-weight: 500;
    transition: color 0.3s ease;
    position: relative;
}

.nav-link:hover {
    color: #1890ff;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: #1890ff;
    transition: width 0.3s ease;
}

.nav-link:hover::after {
    width: 100%;
}

/* 主要内容区域 */
.main {
    margin-top: 80px;
}

/* 英雄区域 */
.hero-section {
    background: linear-gradient(135deg, #1890ff 0%, #096dd9 50%, #0050b3 100%);
    color: white;
    padding: 6rem 0;
    text-align: center;
}

.hero-title {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 1rem;
    opacity: 0;
    animation: fadeInUp 1s ease forwards;
}

.hero-subtitle {
    font-size: 1.25rem;
    font-weight: 500;
    margin-bottom: 1.5rem;
    opacity: 0;
    animation: fadeInUp 1s ease 0.2s forwards;
}

.hero-description {
    font-size: 1.1rem;
    margin-bottom: 2.5rem;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
    opacity: 0;
    animation: fadeInUp 1s ease 0.4s forwards;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
    opacity: 0;
    animation: fadeInUp 1s ease 0.6s forwards;
}

.btn {
    display: inline-block;
    padding: 0.75rem 2rem;
    border-radius: 50px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    border: 2px solid transparent;
}

.btn-primary {
    background: white;
    color: #1890ff;
}

.btn-primary:hover {
    background: transparent;
    color: white;
    border-color: white;
}

.btn-secondary {
    background: transparent;
    color: white;
    border-color: white;
}

.btn-secondary:hover {
    background: white;
    color: #1890ff;
}

/* 知识主页区域 */
.knowledge-section {
    padding: 6rem 0;
    background: linear-gradient(180deg, #f0f9ff 0%, #e6f7ff 100%);
}

.section-header {
    text-align: center;
    margin-bottom: 4rem;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    color: #0050b3;
    margin-bottom: 1rem;
}

.section-subtitle {
    font-size: 1.1rem;
    color: #64748b;
    max-width: 600px;
    margin: 0 auto;
}

.iframe-container {
    background: white;
    border-radius: 20px;
    box-shadow: 0 20px 25px -5px rgba(24, 144, 255, 0.1), 0 10px 10px -5px rgba(24, 144, 255, 0.04);
    overflow: hidden;
    position: relative;
    height: 800px;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border: 1px solid rgba(24, 144, 255, 0.1);
}

.iframe-container:hover {
    transform: translateY(-5px);
    box-shadow: 0 25px 50px -12px rgba(24, 144, 255, 0.25);
}

.knowledge-iframe {
    width: 100%;
    height: 100%;
    border: none;
    display: block;
}

/* 联系区域 */
.contact-section {
    padding: 6rem 0;
    background: white;
}

.contact-content {
    max-width: 800px;
    margin: 0 auto;
}

.contact-info {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 3rem;
}

.contact-item {
    text-align: center;
    padding: 2rem;
    background: linear-gradient(135deg, #f0f9ff 0%, #e6f7ff 100%);
    border-radius: 15px;
    transition: transform 0.3s ease;
    border: 1px solid rgba(24, 144, 255, 0.1);
}

.contact-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px -5px rgba(24, 144, 255, 0.15);
}

.contact-item h3 {
    font-size: 1.25rem;
    font-weight: 600;
    color: #1890ff;
    margin-bottom: 1rem;
}

.contact-item p {
    color: #64748b;
    font-size: 1rem;
}

/* 页脚 */
.footer {
    background: linear-gradient(135deg, #0050b3 0%, #003a8c 100%);
    color: white;
    padding: 3rem 0;
    text-align: center;
}

.footer-content p {
    margin-bottom: 0.5rem;
}

.footer-link {
    color: #69c0ff;
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-link:hover {
    color: #91d5ff;
}

/* 动画 */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* 响应式设计 */
@media (max-width: 768px) {
    .header-content {
        flex-direction: column;
        gap: 1rem;
    }
    
    .nav {
        gap: 1rem;
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .hero-subtitle {
        font-size: 1.1rem;
    }
    
    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .btn {
        width: 200px;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .iframe-container {
        height: 600px;
        margin: 0 -20px;
        border-radius: 0;
    }
    
    .contact-info {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
    
    .main {
        margin-top: 120px;
    }
}

@media (max-width: 480px) {
    .hero-section {
        padding: 4rem 0;
    }
    
    .hero-title {
        font-size: 1.75rem;
    }
    
    .section-title {
        font-size: 1.75rem;
    }
    
    .iframe-container {
        height: 500px;
    }
    
    .knowledge-section,
    .contact-section {
        padding: 4rem 0;
    }
}

/* 加载动画 */
.iframe-container::before {
    content: '正在加载知识主页...';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    color: #64748b;
    font-size: 1.1rem;
    z-index: 1;
}

.knowledge-iframe:not([src=""]) + .iframe-container::before {
    display: none;
}

/* 滚动条样式 */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: #f1f5f9;
}

::-webkit-scrollbar-thumb {
    background: #cbd5e1;
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: #94a3b8;
}