:root {
    --primary-color: #0052d9;
    --secondary-color: #0052d9;
    --secondary-light: #05a8ff;
    --text-color: #333333;
    --text-light: #666666;
    --text-lighter: #888888;
    --border-color: #e0e0e0;
    --background-light: #f5f5f5;
    --white: #ffffff;
    --black: #000000;
    --transition: all 0.3s ease;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    background-color: var(--white);
    color: var(--text-color);
    line-height: 1.6;
}

/* 头部样式 */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100000;
    transition: background 0.3s ease;
}

.header.transparent {
    background: transparent;
}

.header.white {
    background: var(--white);
}

.header.hidden {
    transform: translateY(-100%);
}

.header.has-dropdown {
    background: var(--white);
    padding-bottom: 0;
}

.header.has-dropdown::after {
    content: '';
    position: absolute;
    top: 100%;
    left: -10px;
    right: -10px;
    height: 300px;
    background: var(--white);
    z-index: 1;
}

.header.has-dropdown .logo {
    color: var(--text-color);
}

.header.has-dropdown .logo img {
    filter: none;
}

.header.has-dropdown .nav-links a {
    color: var(--text-color);
}

.nav {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 40px 0 20px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 70px;
}

.nav-left {
    display: flex;
    align-items: center;
}

.hamburger {
    display: none;
    margin-right: 20px;
}

.close-btn {
    display: none;
    position: absolute;
    top: 15px;
    right: 15px;
    font-size: 24px;
    cursor: pointer;
    color: var(--text-color);
    z-index: 1000;
}

.logo {
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 10px;
}

.logo img {
    height: 36px;
    width: auto;
    transition: filter 0.3s;
}

.header.white .logo img {
    filter: none;
}

.header.transparent .logo img {
    filter: brightness(0) invert(1);
}

.nav-links {
    display: flex;
    gap: 40px;
}

.nav-item {
    position: relative;
}

.nav-links a {
    color: var(--white);
    text-decoration: none;
    font-size: 15px;
    font-weight: 600;
    transition: var(--transition);
    position: relative;
    display: block;
    padding: 8px 0;
}

.header.white .nav-links a {
    color: var(--text-color);
}

.nav-links a:hover {
    color: var(--primary-color);
}

.header.white .nav-links a:hover {
    color: var(--primary-color);
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary-color);
    transition: width 0.3s;
}

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

.dropdown {
    position: absolute;
    top: 100%;
    left: 50%;
    transform: translateX(-50%) translateY(10px);
    padding: 15px 0;
    min-width: 180px;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    z-index: 999;
}

.nav-item:hover .dropdown {
    opacity: 1;
    visibility: visible;
    transform: translateX(-50%) translateY(0);
}

.dropdown a {
    color: var(--text-color) !important;
    padding: 8px 20px;
    font-size: 14px;
    font-weight: 500;
    display: block;
    text-align: center;
    transition: var(--transition);
}

.dropdown a:hover {
    background: var(--background-light);
    color: var(--primary-color) !important;
}

.dropdown a::after {
    display: none;
}

/* 通用部分样式 */
.section {
    max-width: 1200px;
    margin: 0 auto;
    padding: 80px 40px;
}

.section-title {
    font-size: 36px;
    font-weight: 700;
    color: var(--text-color);
    margin-bottom: 50px;
    text-align: center;
    position: relative;
}

.section-title::after {
    content: '';
    display: block;
    width: 60px;
    height: 4px;
    background: linear-gradient(135deg, var(--secondary-color) 0%, var(--secondary-light) 100%);
    margin: 15px auto 0;
    border-radius: 2px;
}

/* 页脚样式 */
.footer {
    background: var(--white);
    color: var(--text-color);
    padding: 20px 0 15px;
}

.footer-top {
    max-width: 1200px;
    margin: 0 auto;
    padding: 10px 40px 20px;
}

.footer-top-content {
    display: flex;
    align-items: center;
    gap: 20px;
}

.footer-top-title {
    font-size: 20px;
    font-weight: 500;
    color: var(--text-lighter);
}

.social-links {
    display: flex;
    gap: 10px;
}

.social-link {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    background: var(--background-light);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-lighter);
    text-decoration: none;
    transition: var(--transition);
    font-size: 18px;
}

.social-link:hover {
    background: var(--primary-color);
    color: var(--white);
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px 40px;
    display: flex;
    justify-content: space-between;
}

.footer-sections-container {
    display: flex;
    width: 50%;
}

.footer-section {
    flex: 1;
    margin-right: 10px;
}

.footer-section h3 {
    font-size: 20px;
    font-weight: normal;
    margin-bottom: 10px;
    color: var(--text-lighter);
}

.footer-section ul {
    list-style: none;
}

.footer-section ul li {
    margin-bottom: 8px;
}

.footer-section ul li a {
    color: var(--text-lighter);
    text-decoration: none;
    font-size: 16px;
    transition: color 0.3s;
}

.footer-section ul li a:hover {
    color: var(--primary-color);
}

.footer-logo {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 50%;
}

.footer-logo img {
    height: 40px;
    width: auto;
}

.footer-bottom {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px 40px 0;
    text-align: left;
    font-size: 16px;
    color: var(--text-lighter);
}

.footer-bottom p {
    margin-bottom: 5px;
}

/* 返回顶部按钮 */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 40px;
    height: 40px;
    background: transparent;
    border: 2px solid #0052d9;
    border-radius: 50%;
    color: #0052d9;
    text-decoration: none;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 32px;
    transition: all 0.3s ease;
    z-index: 10;
    opacity: 0;
    visibility: hidden;
}

.back-to-top:hover {
    background: #0052d9;
    color: white;
    transform: translateY(-2px);
}

.back-to-top.show {
    opacity: 1;
    visibility: visible;
}

/* 装饰元素 */
.decorative-circle {
    position: fixed;
    border-radius: 50%;
    pointer-events: none;
    z-index: -1;
}

.circle-1 {
    width: 500px;
    height: 500px;
    background: radial-gradient(circle, rgba(7, 196, 135, 0.08) 0%, transparent 70%);
    top: 10%;
    right: -200px;
}

.circle-2 {
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(0, 217, 160, 0.06) 0%, transparent 70%);
    bottom: 20%;
    left: -250px;
}

/* 手机端样式 */
@media (max-width: 768px) {
    /* 导航栏 */
    .nav {
        padding: 0 20px;
        height: 60px;
    }
    
    .nav-left {
        position: relative;
        width: 100%;
        display: flex;
        align-items: center;
        justify-content: center;
    }
    
    .hamburger {
        position: absolute;
        left: 10px;
        margin-right: 0;
        display: block;
        cursor: pointer;
        z-index: 100000;
        top: 50%;
        transform: translateY(-50%);
    }
    
    .hamburger span {
        display: block;
        width: 20px;
        height: 2px;
        background: var(--text-color);
        margin: 4px 0;
        transition: var(--transition);
    }
    
    .header.transparent .hamburger span {
        background: var(--white);
    }
    
    .logo img {
        height: 30px;
    }
    
    .nav-links {
        display: none;
        position: fixed;
        top: 0;
        left: -100%;
        width: 66.67%;
        height: 100vh;
        background: #fff;
        flex-direction: column;
        gap: 0;
        padding: 110px 20px 20px;
        box-shadow: 2px 0 10px rgba(0,0,0,0.1);
        z-index: 100000;
        transition: left 0.3s ease;
    }
    
    .nav-links.active {
        display: flex;
        left: 0;
    }
    
    .close-btn {
        display: block;
        position: absolute;
        top: 15px;
        left: 30px;
        height: 30px;
        font-size: 24px;
        line-height: 30px;
        color: var(--text-color);
        z-index: 100000;
    }
    
    .nav-item {
        width: 100%;
        text-align: left;
    }
    
    .nav-links a {
        font-size: 16px;
        padding: 16px 0 16px 20%;
        color: #000 !important;
        text-decoration: none;
        display: block;
        font-weight: normal;
    }
    
    .nav-links a:hover {
        color: #333 !important;
    }
    
    .dropdown {
        display: none;
    }
    
    /* 禁用鼠标移动到菜单栏的特效 */
    .header.has-dropdown {
        background: transparent;
        padding-bottom: 20px;
    }
    
    .header.has-dropdown::after {
        display: none;
    }
    
    .header.has-dropdown .logo img {
        filter: brightness(0) invert(1);
    }
    
    .header.has-dropdown .nav-links a {
        color: var(--white) !important;
    }
    
    /* 返回顶部按钮 */
    .back-to-top {
        background: #0052d9;
        color: white;
        border-color: #0052d9;
    }
    
    .back-to-top:hover {
        background: #0040b8;
        border-color: #0040b8;
    }
    
    /* 通用 */
    .section {
        padding: 20px 20px;
    }
    
    .section-title {
        font-size: 28px;
        margin-bottom: 30px;
    }
    
    /* 页脚 */
    .footer {
        padding: 20px 0 30px;
    }
    
    .footer-top {
        padding: 0 20px 15px;
    }
    
    .footer-top-content {
        flex-direction: column;
        align-items: flex-start;
        gap: 10px;
    }
    
    .footer-top-title {
        font-size: 16px;
        font-weight: 500;
        color: #333;
    }
    
    .social-links {
        display: flex;
        gap: 15px;
    }
    
    .social-link {
        width: 36px;
        height: 36px;
        border-radius: 50%;
        background: #f5f5f5;
        display: flex;
        align-items: center;
        justify-content: center;
        color: #666;
        text-decoration: none;
        font-size: 18px;
        transition: var(--transition);
    }
    
    .social-link:hover {
        background: #0052d9;
        color: white;
    }
    
    .footer-content {
        flex-direction: column;
        padding: 15px 20px;
    }
    
    .footer-sections-container {
        width: 100%;
        margin-bottom: 0;
        display: flex;
        flex-direction: column;
        gap: 15px;
    }
    
    .footer-section {
        flex: 1;
        margin-right: 0;
    }
    
    .footer-section h3 {
        font-size: 16px;
        font-weight: 500;
        color: #333;
        margin-bottom: 0;
        display: flex;
        align-items: center;
        justify-content: space-between;
        cursor: pointer;
        padding: 10px 0;
        border-bottom: 1px solid #f0f0f0;
    }
    
    .footer-section h3::after {
        content: '▼';
        font-size: 12px;
        color: #999;
        transition: transform 0.3s;
    }
    
    .footer-section h3.active::after {
        transform: rotate(180deg);
    }
    
    .footer-section ul {
        list-style: none;
        max-height: 0;
        overflow: hidden;
        transition: max-height 0.3s ease;
    }
    
    .footer-section ul.show {
        max-height: 200px;
    }
    
    .footer-section ul li {
        margin-bottom: 8px;
        padding: 5px 0;
    }
    
    .footer-section ul li a {
        color: #666;
        text-decoration: none;
        font-size: 14px;
        transition: color 0.3s;
    }
    
    .footer-section ul li a:hover {
        color: #0052d9;
    }
    
    .footer-logo {
        display: none;
    }
    
    .footer-bottom {
        padding: 15px 20px 0;
        font-size: 12px;
        color: #999;
        line-height: 1.5;
    }
    
    .footer-bottom p {
        margin-bottom: 5px;
    }
    
    /* 返回顶部按钮 */
    .back-to-top {
        background: #0052d9;
        color: white;
        border-color: #0052d9;
        width: 44px;
        height: 44px;
        font-size: 24px;
        bottom: 20px;
        right: 20px;
    }
    
    .back-to-top:hover {
        background: #0040b8;
        border-color: #0040b8;
    }
}