:root {
    --brand: #3498db;
    --text: #333333;
    --muted: #7f8c8d;
    --heading: #2c3e50;
    --bg: #ffffff;
    --bg-alt: #f8f9fa;
    --card: #ffffff;
    --footer-bg: #2c3e50;
    --footer-border: #34495e;
    --radius-md: 10px;
    --radius-lg: 15px;
    --nav-bg: rgba(255, 255, 255, 0.95);
    --nav-bg-scrolled: rgba(255, 255, 255, 0.98);
    --nav-shadow: 0 2px 20px rgba(0, 0, 0, 0.1);
    --nav-shadow-scrolled: 0 2px 20px rgba(0, 0, 0, 0.15);
}

html { scroll-behavior: smooth; }

/* 屏幕阅读器可见性工具类 */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

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

body {
    font-family: 'Noto Sans SC', sans-serif;
    line-height: 1.6;
    color: #333;
    overflow-x: hidden;
}

body.nav-open {
    overflow: hidden;
}

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

/* 导航栏样式 */
.navbar {
    background: var(--nav-bg);
    backdrop-filter: blur(10px);
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
    transition: all 0.3s ease;
    box-shadow: var(--nav-shadow);
}

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

.nav-logo h2 {
    color: var(--heading);
    font-weight: 700;
    font-size: 1.5rem;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-link {
    text-decoration: none;
    color: var(--text);
    font-weight: 500;
    transition: color 0.3s ease;
    position: relative;
}

.nav-link:hover {
    color: var(--brand);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--brand);
    transition: width 0.3s ease;
}

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

/* 当前导航项高亮（aria-current 支持） */
.nav-link[aria-current="true"] { color: var(--brand); }
.nav-link[aria-current="true"]::after { width: 100%; }

/* 当前导航项高亮（配合 ScrollSpy） */
.nav-link.active {
    color: var(--brand);
}

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

.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
}

.bar {
    width: 25px;
    height: 3px;
    background: var(--text);
    margin: 3px 0;
    transition: 0.3s;
}

/* 首页横幅 */
.hero {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    min-height: 100vh;
    display: flex;
    align-items: center;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grain" width="100" height="100" patternUnits="userSpaceOnUse"><circle cx="50" cy="50" r="1" fill="%23ffffff" opacity="0.1"/></pattern></defs><rect width="100" height="100" fill="url(%23grain)"/></svg>') repeat;
    opacity: 0.4; /* 稍加强覆盖层以保证可读性 */
}

/* 细微装饰叠层：轻网格线条 */
.hero::after {
    content: '';
    position: absolute;
    inset: 0;
    pointer-events: none;
    background-image: linear-gradient(rgba(255,255,255,0.05) 1px, transparent 1px),
                      linear-gradient(90deg, rgba(255,255,255,0.05) 1px, transparent 1px);
    background-size: 40px 40px, 40px 40px;
    mix-blend-mode: overlay;
}

.hero-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    position: relative;
    z-index: 1;
}

.hero .hero-content {
    text-shadow: 0 1px 2px rgba(0, 0, 0, 0.25);
}

.hero h1 {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    animation: fadeInUp 1s ease;
}

.hero-subtitle {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    opacity: 0.9;
    animation: fadeInUp 1s ease 0.2s both;
}

.hero-description {
    font-size: 1.1rem;
    margin-bottom: 2rem;
    opacity: 0.8;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
    animation: fadeInUp 1s ease 0.4s both;
}

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

/* 按钮样式 */
.btn {
    display: inline-block;
    padding: 12px 30px;
    text-decoration: none;
    border-radius: 50px;
    font-weight: 500;
    transition: all 0.3s ease;
    border: 2px solid transparent;
    cursor: pointer;
    font-size: 1rem;
    position: relative;
    overflow: hidden;
}

.btn-primary {
    background: #3498db;
    color: white;
    border-color: #3498db;
}

.btn-primary:hover {
    background: transparent;
    color: #3498db;
    border-color: #3498db;
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(52, 152, 219, 0.3);
}

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

.btn-secondary:hover {
    background: white;
    color: #333;
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(255, 255, 255, 0.3);
}

/* 可访问性：键盘焦点可见样式 */
.nav-link:focus-visible,
.btn:focus-visible {
    outline: 3px solid var(--brand);
    outline-offset: 3px;
    border-radius: 6px;
}

/* 通用区块样式 */
section {
    padding: 80px 0;
    scroll-margin-top: 80px;
}

.section-header {
    text-align: center;
    margin-bottom: 60px;
}

.section-header h2 {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--heading);
    margin-bottom: 1rem;
}

.section-header p {
    font-size: 1.1rem;
    color: var(--muted);
    max-width: 600px;
    margin: 0 auto;
}

/* 关于我们区块 */
.about {
    background: var(--bg-alt);
}

.about-text h3 {
    font-size: 1.8rem;
    color: var(--heading);
    margin-bottom: 1rem;
    margin-top: 2rem;
}

.about-text h3:first-child {
    margin-top: 0;
}

.about-text p {
    font-size: 1.1rem;
    line-height: 1.8;
    color: #555;
    margin-bottom: 1.5rem;
}

.culture-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.culture-item {
    background: white;
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease;
}

.culture-item:hover {
    transform: translateY(-5px);
}

.culture-item h4 {
    font-size: 1.3rem;
    color: var(--brand);
    margin-bottom: 1rem;
}

.culture-item p {
    color: #666;
    line-height: 1.6;
}

/* 服务项目区块 */
.services-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 3rem;
}

.service-card {
    background: white;
    padding: 3rem;
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
    text-align: center;
}

.service-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15);
}

.service-icon {
    font-size: 3rem;
    margin-bottom: 1.5rem;
}

.service-icon .icon,
.advantage-icon .icon {
    width: 2.25rem;
    height: 2.25rem;
    stroke: var(--brand);
    stroke-width: 1.5;
    stroke-linecap: round;
    stroke-linejoin: round;
}

.service-icon .icon rect,
.service-icon .icon circle,
.service-icon .icon path,
.advantage-icon .icon rect,
.advantage-icon .icon circle,
.advantage-icon .icon path {
    fill: none;
}

.service-card h3 {
    font-size: 1.5rem;
    color: var(--heading);
    margin-bottom: 1rem;
}

.service-card p {
    color: #666;
    line-height: 1.6;
    margin-bottom: 1.5rem;
}

.service-card ul {
    list-style: none;
    text-align: left;
}

.service-card li {
    padding: 0.5rem 0;
    color: #555;
    position: relative;
    padding-left: 1.5rem;
}

.service-card li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--brand);
    font-weight: bold;
}

/* 公司优势区块 */
.advantages {
    background: var(--bg-alt);
}

.advantages-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.advantage-item {
    background: white;
    padding: 2rem;
    border-radius: 10px;
    text-align: center;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
}

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

.advantage-icon {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.advantage-item h3 {
    font-size: 1.3rem;
    color: var(--heading);
    margin-bottom: 1rem;
}

.advantage-item p {
    color: #666;
    line-height: 1.6;
}

/* 联系我们区块 */
.contact-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: start;
}

.contact-item {
    display: flex;
    align-items: center;
    margin-bottom: 2rem;
}

.contact-icon {
    font-size: 2rem;
    margin-right: 1rem;
    width: 60px;
    text-align: center;
}

.contact-details h3 {
    font-size: 1.2rem;
    color: var(--heading);
    margin-bottom: 0.5rem;
}

.contact-details p {
    color: #666;
    font-size: 1.1rem;
}

/* 微信公众号二维码样式 */
.contact-wechat {
    display: flex;
    align-items: center;
    justify-content: center;
}

.wechat-item {
    flex-direction: column;
    align-items: center;
    text-align: center;
}

.wechat-item .contact-icon {
    margin-right: 0;
    margin-bottom: 0.5rem;
}

.wechat-qrcode {
    margin-top: 1rem;
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    max-width: 240px;
    height: auto;
}

.contact-form {
    background: #f8f9fa;
    padding: 2rem;
    border-radius: 10px;
}

.contact-form h3 {
    font-size: 1.5rem;
    color: #2c3e50;
    margin-bottom: 1.5rem;
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 12px 15px;
    border: 1px solid #ddd;
    border-radius: 5px;
    font-size: 1rem;
    transition: border-color 0.3s ease;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--brand);
}

/* 页脚 */
.footer {
    background: var(--footer-bg);
    color: white;
    padding: 3rem 0 1rem;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-section h3,
.footer-section h4 {
    margin-bottom: 1rem;
    color: var(--brand);
}

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

.footer-section li {
    margin-bottom: 0.5rem;
}

.footer-section p {
    color: #bdc3c7;
    line-height: 1.6;
}

.footer-section .email-link {
    color: #bdc3c7;
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-section .email-link:hover {
    color: #fff;
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid var(--footer-border);
    color: #bdc3c7;
}

.footer-bottom .icp-info {
    margin-top: 0.5rem;
    font-size: 0.9rem;
}

.footer-bottom .icp-info a {
    color: #bdc3c7;
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-bottom .icp-info a:hover {
    color: var(--brand);
}

.icp-divider {
    margin: 0 10px;
    color: #5a6a7a;
}

.beian-icon {
    width: 14px;
    height: 14px;
    vertical-align: middle;
    margin-right: 4px;
}

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

/* 按钮点击波纹效果 */
.btn .ripple {
    position: absolute;
    border-radius: 50%;
    transform: scale(0);
    pointer-events: none;
    background: rgba(255, 255, 255, 0.35);
    animation: ripple 0.6s linear;
}

@keyframes ripple {
    to {
        transform: scale(4);
        opacity: 0;
    }
}

/* 响应式设计 */
@media (max-width: 768px) {
    .hamburger {
        display: flex;
    }
    
    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background-color: white;
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: 0 10px 27px rgba(0, 0, 0, 0.05);
        padding: 2rem 0;
    }
    
    .nav-menu.active {
        left: 0;
    }
    
    .hero h1 {
        font-size: 2.5rem;
    }
    
    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .services-grid {
        grid-template-columns: 1fr;
    }
    
    .contact-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
    
    .contact-wechat {
        justify-content: center;
    }
    
    .culture-grid,
    .advantages-grid {
        grid-template-columns: 1fr;
    }
    
    .section-header h2 {
        font-size: 2rem;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }
    
    .hero h1 {
        font-size: 2rem;
    }
    
    .service-card,
    .contact-form {
        padding: 1.5rem;
    }
    
    section {
        padding: 60px 0;
    }
}

/* 跳过链接（无障碍） */
.skip-link {
    position: absolute;
    left: -999px;
    top: 0;
    background: #3498db;
    color: #fff;
    padding: 8px 12px;
    border-radius: 6px;
    z-index: 2000;
}

.skip-link:focus {
    left: 12px;
    top: 12px;
}

.tel-link {
    color: #3498db;
    text-decoration: none;
}
.tel-link:hover {
    text-decoration: underline;
}

.back-to-top {
    position: fixed;
    right: 20px;
    bottom: 20px;
    width: 42px;
    height: 42px;
    border-radius: 50%;
    border: 2px solid var(--brand);
    background: rgba(255,255,255,0.9);
    color: var(--brand);
    display: grid;
    place-items: center;
    cursor: pointer;
    z-index: 1200;
    box-shadow: 0 10px 20px rgba(0,0,0,.08);
    transition: transform .2s ease, opacity .2s ease;
    opacity: 0;
    transform: translateY(20px);
}
.back-to-top:hover { transform: translateY(-2px); }
.back-to-top.show { opacity: 1; transform: translateY(0); }

.form-status {
    min-height: 1.25rem;
    margin-bottom: 0.5rem;
    color: var(--muted);
    font-size: 0.95rem;
}

/* 尊重系统减少动效设置 */
@media (prefers-reduced-motion: reduce) {
    * {
        animation: none !important;
        transition: none !important;
        scroll-behavior: auto !important;
    }
    html { scroll-behavior: auto; }
}

@media (prefers-color-scheme: dark) {
    :root {
        --text: #e5e7eb;
        --muted: #9ca3af;
        --heading: #f3f4f6;
        --bg: #0b1220;
        --bg-alt: #111827;
        --card: #111827;
        --footer-bg: #0b1220;
        --footer-border: #1f2937;
        --nav-bg: rgba(17, 24, 39, 0.85);
        --nav-bg-scrolled: rgba(17, 24, 39, 0.95);
        --nav-shadow: 0 2px 20px rgba(0, 0, 0, 0.4);
        --nav-shadow-scrolled: 0 2px 20px rgba(0, 0, 0, 0.5);
    }

    body { background: var(--bg); color: var(--text); }

    .service-card,
    .advantage-item,
    .culture-item,
    .contact-form {
        background: var(--card);
        box-shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
    }

    .footer-section p,
    .footer-bottom { color: #9ca3af; }

    .btn-secondary { color: var(--text); border-color: var(--text); }
    .btn-secondary:hover { color: #111827; }
}

.brand { display: inline-flex; align-items: center; gap: 10px; text-decoration: none; }
.brand-text { color: var(--heading); font-weight: 700; font-size: 1.1rem; }
.brand:hover .brand-text { color: var(--brand); }

/* Language switch link */
.lang-switch {
    background: var(--brand);
    color: #fff !important;
    padding: 6px 14px;
    border-radius: 20px;
    font-size: 0.9rem;
    transition: background 0.3s ease, transform 0.2s ease;
}
.lang-switch:hover {
    background: #2980b9;
    transform: translateY(-1px);
}
.lang-switch::after { display: none !important; }

.brand-hero { display: block; margin: 0 auto 16px; max-width: min(90%, 560px); height: auto; }
@media (max-width: 480px) { .brand-hero { max-width: 92%; margin-bottom: 10px; } }