/* 重置样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* 基础样式 */
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    line-height: 1.6;
    color: #000;
    background-color: #fff;
    overflow-x: hidden;
}

/* 导航栏 */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    padding: 20px 5%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    background-color: rgba(0, 0, 0, 0.9);
    backdrop-filter: blur(10px);
    transition: all 0.3s ease;
}

.navbar.white {
    background-color: rgba(255, 255, 255, 0.9);
}

.logo img {
    height: 40px;
    width: auto;
    transition: opacity 0.3s ease;
}

.nav-links {
    display: flex;
    gap: 30px;
    align-items: center;
}

.nav-links a {
    color: #fff;
    text-decoration: none;
    font-weight: 300;
    font-size: 14px;
    letter-spacing: 1px;
    transition: all 0.3s ease;
    padding: 10px 15px;
    border-radius: 2px;
}

.navbar.white .nav-links a {
    color: #000;
}

.nav-links a:hover {
    background-color: rgba(255, 255, 255, 0.1);
}

.navbar.white .nav-links a:hover {
    background-color: rgba(0, 0, 0, 0.1);
}

/* 主页背景 */
.hero-section {
    height: 100vh;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    z-index: -1;
}

/* 信息卡片容器 */
.info-cards {
    position: absolute;
    bottom: 80px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    gap: 15px;
    width: 90%;
    max-width: 400px;
    z-index: 10;
}

/* 信息卡片 */
.info-card {
    background: rgba(255, 255, 255, 0.15);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
    padding: 20px 25px;
    border-radius: 3px;
    text-align: center;
    transition: all 0.3s ease;
    cursor: pointer;
    color: #fff;
    font-size: 14px;
    font-weight: 300;
    letter-spacing: 0.5px;
    word-wrap: break-word;
    word-break: break-all;
}

.info-card:hover {
    background: rgba(255, 255, 255, 0.25);
    transform: translateY(-2px);
}

/* PDF预览页面 */
.pdf-container {
    width: 100%;
    height: 100vh;
    background: #000;
}

.pdf-viewer {
    width: 100%;
    height: 100%;
    border: none;
}

/* 联系页面 */
.contact-section {
    height: 100vh;
    position: relative;
    overflow: hidden;
}

.contact-video {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    z-index: -1;
}

.contact-info {
    position: absolute;
    bottom: 50px;
    left: 50%;
    transform: translateX(-50%);
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(5px);
    padding: 30px 40px;
    border-radius: 5px;
    text-align: center;
    color: #000;
}

.contact-info p {
    font-size: 16px;
    font-weight: 300;
    margin-bottom: 10px;
}

.contact-info p:last-child {
    margin-bottom: 0;
}

/* 加载动画 */
.loading {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: #000;
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 9999;
    transition: opacity 0.5s ease;
}

.loading-spinner {
    width: 40px;
    height: 40px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-top: 2px solid #fff;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* 响应式设计 */
@media (max-width: 768px) {
    .navbar {
        padding: 15px 4%;
    }
    
    .nav-links {
        gap: 15px;
    }
    
    .nav-links a {
        font-size: 12px;
        padding: 8px 10px;
    }
    
    .info-cards {
        width: 95%;
        max-width: 350px;
        bottom: 60px;
    }
    
    .info-card {
        padding: 15px 20px;
        font-size: 13px;
    }
    
    .contact-info {
        padding: 25px 30px;
        bottom: 30px;
    }
    
    .contact-info p {
        font-size: 14px;
    }
}

@media (max-width: 480px) {
    .navbar {
        padding: 12px 3%;
    }
    
    .nav-links {
        gap: 10px;
    }
    
    .nav-links a {
        font-size: 11px;
        padding: 6px 8px;
    }
    
    .info-cards {
        width: 98%;
        bottom: 40px;
        gap: 12px;
    }
    
    .info-card {
        padding: 12px 15px;
        font-size: 12px;
    }
    
    .contact-info {
        padding: 20px 25px;
        bottom: 20px;
    }
    
    .contact-info p {
        font-size: 13px;
    }
}

/* 预加载优化 */
.preload {
    position: absolute;
    left: -9999px;
    top: -9999px;
    opacity: 0;
}

/* 平滑滚动 */
html {
    scroll-behavior: smooth;
}

/* 防止图片拖拽 */
img, video {
    -webkit-user-drag: none;
    -khtml-user-drag: none;
    -moz-user-drag: none;
    -o-user-drag: none;
    user-drag: none;
    user-select: none;
}

/* 慢网络优化 */
.slow-network img:not(.critical) {
    opacity: 0;
    transition: opacity 0.3s ease;
}

.slow-network img:not(.critical).loaded {
    opacity: 1;
}

.slow-network video {
    display: none;
}

.slow-network .hero-bg {
    background-color: #000;
}

/* 加载状态优化 */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.9);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 10000;
    opacity: 1;
    transition: opacity 0.5s ease;
}

.loading-overlay.hidden {
    opacity: 0;
    pointer-events: none;
}

.loading-progress {
    width: 200px;
    height: 2px;
    background: rgba(255, 255, 255, 0.2);
    margin-top: 20px;
    overflow: hidden;
}

.loading-progress-bar {
    height: 100%;
    background: #fff;
    width: 0%;
    transition: width 0.3s ease;
}

.loading-text {
    color: #fff;
    font-size: 14px;
    font-weight: 300;
    margin-top: 15px;
    text-align: center;
}

/* 连接状态指示 */
.network-status {
    position: fixed;
    bottom: 20px;
    left: 20px;
    background: rgba(255, 0, 0, 0.9);
    color: #fff;
    padding: 10px 15px;
    border-radius: 3px;
    font-size: 12px;
    z-index: 1000;
    opacity: 0;
    transform: translateY(20px);
    transition: all 0.3s ease;
}

.network-status.show {
    opacity: 1;
    transform: translateY(0);
}

.network-status.online {
    background: rgba(0, 255, 0, 0.9);
}

/* 性能优化类 */
.optimize-fonts {
    font-display: swap;
}

.will-change-transform {
    will-change: transform;
}

.will-change-opacity {
    will-change: opacity;
}