/* 基础样式 */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    --color-primary: #1d1d1f;
    --color-secondary: #86868b;
    --color-accent: #0071e3;
    --color-accent-hover: #0077ed;
    --color-bg: #ffffff;
    --color-bg-alt: #f5f5f7;
    --color-border: #d2d2d7;
    --font-family: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --transition: all 0.3s cubic-bezier(0.25, 0.1, 0.25, 1);
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    font-size: 16px;
    line-height: 1.6;
    color: var(--color-primary);
    background: var(--color-bg);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* 导航栏 */
.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: saturate(180%) blur(20px);
    border-bottom: 1px solid rgba(0, 0, 0, 0.1);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
    height: 52px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

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

.logo-img {
    height: 50px;
    width: auto;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 32px;
}

.nav-links a {
    color: var(--color-primary);
    text-decoration: none;
    font-size: 14px;
    font-weight: 400;
    transition: var(--transition);
}

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

.nav-cta {
    background: var(--color-accent) !important;
    color: white !important;
    padding: 8px 16px !important;
    border-radius: 20px;
    font-weight: 500 !important;
}

.nav-cta:hover {
    background: var(--color-accent-hover) !important;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
}

.nav-toggle span {
    width: 24px;
    height: 2px;
    background: var(--color-primary);
    transition: var(--transition);
}

/* Hero 区域 */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 120px 24px 80px;
    background: linear-gradient(180deg, #f5f5f7 0%, #ffffff 100%);
    position: relative;
    overflow: hidden;
}

.hero-content {
    max-width: 800px;
    text-align: center;
    position: relative;
    z-index: 2;
}

.hero-title {
    font-size: clamp(40px, 8vw, 72px);
    font-weight: 700;
    line-height: 1.1;
    letter-spacing: -0.02em;
    margin-bottom: 24px;
}

.hero-title-line {
    display: block;
}

.hero-title-highlight {
    background: linear-gradient(135deg, var(--color-accent) 0%, #00c7be 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: clamp(18px, 3vw, 24px);
    color: var(--color-secondary);
    max-width: 600px;
    margin: 0 auto 40px;
    line-height: 1.5;
}

.hero-cta {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
}

/* 按钮 */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 14px 28px;
    font-size: 17px;
    font-weight: 500;
    text-decoration: none;
    border-radius: 28px;
    transition: var(--transition);
    cursor: pointer;
    border: none;
}

.btn-primary {
    background: var(--color-accent);
    color: white;
}

.btn-primary:hover {
    background: var(--color-accent-hover);
    transform: scale(1.02);
}

.btn-secondary {
    background: transparent;
    color: var(--color-accent);
    border: 2px solid var(--color-accent);
}

.btn-secondary:hover {
    background: var(--color-accent);
    color: white;
}

.btn-full {
    width: 100%;
}

/* DNA 动画背景 */
.hero-visual {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    pointer-events: none;
    opacity: 0.1;
}

.dna-helix {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 600px;
    height: 600px;
}

.dna-strand {
    position: absolute;
    width: 100%;
    height: 100%;
    border: 2px solid var(--color-accent);
    border-radius: 50%;
    animation: rotate 20s linear infinite;
}

.dna-strand:nth-child(2) {
    animation-delay: -10s;
    animation-direction: reverse;
}

@keyframes rotate {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

/* Section 通用样式 */
.section {
    padding: 100px 0;
}

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

.section-label {
    display: inline-block;
    font-size: 14px;
    font-weight: 600;
    color: var(--color-accent);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    margin-bottom: 16px;
}

.section-title {
    font-size: clamp(32px, 5vw, 48px);
    font-weight: 700;
    line-height: 1.2;
    letter-spacing: -0.02em;
}

.section-desc {
    font-size: 18px;
    color: var(--color-secondary);
    max-width: 600px;
    margin: 16px auto 0;
}

/* 关于我们 */
.section-about {
    background: var(--color-bg);
}

.about-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 32px;
}

.about-card {
    background: var(--color-bg-alt);
    padding: 40px 32px;
    border-radius: 24px;
    text-align: center;
    transition: var(--transition);
}

.about-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.08);
}

.about-icon {
    font-size: 48px;
    margin-bottom: 24px;
}

.about-card h3 {
    font-size: 22px;
    font-weight: 600;
    margin-bottom: 16px;
}

.about-card p {
    color: var(--color-secondary);
    font-size: 15px;
    line-height: 1.6;
}

/* 业务领域 */
.section-business {
    background: var(--color-bg-alt);
}

.business-list {
    display: flex;
    flex-direction: column;
    gap: 40px;
}

.business-item {
    display: flex;
    gap: 32px;
    align-items: flex-start;
    background: var(--color-bg);
    padding: 40px;
    border-radius: 24px;
    transition: var(--transition);
}

.business-item:hover {
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.05);
}

.business-number {
    font-size: 48px;
    font-weight: 700;
    color: var(--color-accent);
    opacity: 0.3;
    line-height: 1;
    min-width: 80px;
}

.business-content h3 {
    font-size: 24px;
    font-weight: 600;
    margin-bottom: 12px;
}

.business-content p {
    color: var(--color-secondary);
    font-size: 16px;
    line-height: 1.7;
}

/* 国际标准 */
.section-standards {
    background: linear-gradient(180deg, var(--color-bg) 0%, var(--color-bg-alt) 100%);
}

.standards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-bottom: 48px;
}

.standard-card {
    background: var(--color-bg);
    padding: 32px 24px;
    border-radius: 20px;
    text-align: center;
    border: 1px solid var(--color-border);
    transition: var(--transition);
}

.standard-card:hover {
    border-color: var(--color-accent);
    transform: translateY(-4px);
}

.standard-code {
    font-size: 14px;
    font-weight: 600;
    color: var(--color-accent);
    margin-bottom: 12px;
}

.standard-name {
    font-size: 15px;
    font-weight: 500;
    margin-bottom: 16px;
    line-height: 1.4;
}

.standard-badge {
    display: inline-block;
    font-size: 12px;
    font-weight: 600;
    background: linear-gradient(135deg, var(--color-accent) 0%, #00c7be 100%);
    color: white;
    padding: 6px 14px;
    border-radius: 20px;
}

.standard-card-more {
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--color-accent) 0%, #00c7be 100%);
    border: none;
}

.standard-more-content {
    text-align: center;
    color: white;
}

.standard-more-number {
    display: block;
    font-size: 36px;
    font-weight: 700;
}

.standard-more-text {
    font-size: 14px;
    opacity: 0.9;
}

.standards-award {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 16px;
    background: var(--color-bg);
    padding: 24px 40px;
    border-radius: 100px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
}

.award-badge {
    font-size: 32px;
}

.award-text {
    font-size: 18px;
}

/* 合作伙伴 */
.section-cooperation {
    background: var(--color-bg);
}

.partners-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 40px;
}

.partner-category {
    background: var(--color-bg-alt);
    padding: 32px;
    border-radius: 20px;
}

.partner-category-title {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 20px;
    color: var(--color-accent);
}

.partner-list {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
}

.partner-list span {
    display: inline-block;
    background: var(--color-bg);
    padding: 8px 16px;
    border-radius: 8px;
    font-size: 14px;
    color: var(--color-secondary);
    border: 1px solid var(--color-border);
    transition: var(--transition);
}

.partner-list span:hover {
    border-color: var(--color-accent);
    color: var(--color-primary);
}

/* 联系我们 */
.section-contact {
    background: var(--color-bg-alt);
}

.contact-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 80px;
    align-items: center;
}

.contact-info .section-label,
.contact-info .section-title {
    text-align: left;
}

.contact-desc {
    font-size: 18px;
    color: var(--color-secondary);
    margin-bottom: 32px;
}

.contact-details {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.contact-item {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 16px;
}

.contact-icon {
    font-size: 20px;
}

.contact-form {
    background: var(--color-bg);
    padding: 40px;
    border-radius: 24px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.05);
}

.form-group {
    margin-bottom: 20px;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 16px 20px;
    font-size: 16px;
    font-family: inherit;
    border: 2px solid var(--color-border);
    border-radius: 12px;
    transition: var(--transition);
    background: var(--color-bg);
}

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

.form-group textarea {
    resize: vertical;
    min-height: 120px;
}

/* 页脚 */
.footer {
    background: var(--color-primary);
    color: white;
    padding: 60px 0 30px;
}

.footer-content {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: 60px;
    margin-bottom: 40px;
}

.footer-logo {
    height: 50px;
    filter: brightness(0) invert(1);
    margin-bottom: 16px;
}

.footer-tagline {
    color: rgba(255, 255, 255, 0.6);
    font-size: 14px;
}

.footer-links {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 40px;
}

.footer-column h4 {
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 20px;
    color: rgba(255, 255, 255, 0.6);
}

.footer-column a {
    display: block;
    color: white;
    text-decoration: none;
    font-size: 14px;
    margin-bottom: 12px;
    opacity: 0.8;
    transition: var(--transition);
}

.footer-column a:hover {
    opacity: 1;
}

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: 30px;
    text-align: center;
}

.footer-bottom p {
    font-size: 13px;
    color: rgba(255, 255, 255, 0.5);
}

/* 响应式 */
@media (max-width: 768px) {
    .nav-links {
        display: none;
        position: absolute;
        top: 52px;
        left: 0;
        right: 0;
        background: var(--color-bg);
        flex-direction: column;
        padding: 24px;
        gap: 20px;
        border-bottom: 1px solid var(--color-border);
    }
    
    .nav-links.active {
        display: flex;
    }
    
    .nav-toggle {
        display: flex;
    }
    
    .hero {
        padding: 100px 24px 60px;
    }
    
    .hero-cta {
        flex-direction: column;
        align-items: center;
    }
    
    .business-item {
        flex-direction: column;
        padding: 32px 24px;
    }
    
    .business-number {
        font-size: 36px;
    }
    
    .contact-content {
        grid-template-columns: 1fr;
        gap: 40px;
    }
    
    .contact-info .section-label,
    .contact-info .section-title {
        text-align: center;
    }
    
    .contact-desc {
        text-align: center;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        gap: 40px;
        text-align: center;
    }
    
    .footer-links {
        grid-template-columns: 1fr;
        gap: 30px;
    }
}