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

/* 根变量定义 */
:root {
    --primary-color: #2563eb;
    --secondary-color: #1e40af;
    --accent-color: #3b82f6;
    --text-dark: #1f2937;
    --text-light: #6b7280;
    --text-white: #ffffff;
    --bg-light: #f9fafb;
    --bg-white: #ffffff;
    --border-color: #e5e7eb;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

/* 基础样式 */
html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--text-dark);
    background-color: var(--bg-white);
}

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

/* 导航栏样式 */
.header {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    z-index: 1000;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.navbar {
    padding: 1rem 0;
}

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

.logo h2 {
    color: var(--primary-color);
    font-size: 1.8rem;
    font-weight: 700;
    margin: 0;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
    margin: 0;
    padding: 0;
}

.nav-link {
    text-decoration: none;
    color: var(--text-dark);
    font-weight: 500;
    font-size: 1rem;
    transition: var(--transition);
    position: relative;
}

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

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

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

/* 汉堡菜单 */
.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
}

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

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

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1440 320"><path fill="%23ffffff" fill-opacity="0.1" d="M0,96L48,112C96,128,192,160,288,186.7C384,213,480,235,576,213.3C672,192,768,128,864,128C960,128,1056,192,1152,208C1248,224,1344,192,1392,176L1440,160L1440,320L1392,320C1344,320,1248,320,1152,320C1056,320,960,320,864,320C768,320,672,320,576,320C480,320,384,320,288,320C192,320,96,320,48,320L0,320Z"></path></svg>') no-repeat bottom;
    background-size: cover;
}

.hero-container {
    position: relative;
    z-index: 1;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.3);
    animation: fadeInUp 1s ease-out;
}

.hero-subtitle {
    font-size: 1.3rem;
    margin-bottom: 2rem;
    opacity: 0.9;
    animation: fadeInUp 1s ease-out 0.2s backwards;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    animation: fadeInUp 1s ease-out 0.4s backwards;
}

.btn {
    padding: 12px 30px;
    border: none;
    border-radius: 50px;
    font-size: 1rem;
    font-weight: 500;
    text-decoration: none;
    cursor: pointer;
    transition: var(--transition);
    display: inline-block;
    text-align: center;
}

.btn-primary {
    background-color: var(--primary-color);
    color: var(--text-white);
    box-shadow: var(--shadow-md);
}

.btn-primary:hover {
    background-color: var(--secondary-color);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

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

.btn-secondary:hover {
    background-color: var(--text-white);
    color: var(--primary-color);
    transform: translateY(-2px);
}

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

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

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

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

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

.about-text h3 {
    font-size: 1.8rem;
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: 1.5rem;
}

.about-text p {
    font-size: 1.1rem;
    line-height: 1.8;
    color: var(--text-dark);
    margin-bottom: 1.5rem;
}

.company-values {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.value-item {
    text-align: center;
    padding: 2rem;
    background-color: var(--bg-white);
    border-radius: 10px;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.value-item:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.value-item h4 {
    font-size: 1.3rem;
    font-weight: 600;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.value-item p {
    color: var(--text-light);
    font-size: 1rem;
}

/* 业务范围区块 */
.business-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
}

.business-item {
    background-color: var(--bg-white);
    padding: 2.5rem 2rem;
    border-radius: 15px;
    text-align: center;
    box-shadow: var(--shadow-md);
    transition: var(--transition);
    border: 1px solid var(--border-color);
}

.business-item:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow-xl);
    border-color: var(--accent-color);
}

.business-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    border-radius: 50%;
    margin-bottom: 1.5rem;
    color: var(--text-white);
}

.business-item h3 {
    font-size: 1.4rem;
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: 1rem;
}

.business-item p {
    color: var(--text-light);
    line-height: 1.7;
    font-size: 1rem;
}

/* 联系我们区块 */
.contact {
    background-color: var(--bg-light);
}

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

.contact-info {
    display: grid;
    gap: 2rem;
}

.contact-item {
    display: flex;
    align-items: center;
    gap: 1.5rem;
    padding: 2rem;
    background-color: var(--bg-white);
    border-radius: 10px;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.contact-item:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
}

.contact-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    border-radius: 50%;
    color: var(--text-white);
    flex-shrink: 0;
}

.contact-details h3 {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: 0.5rem;
}

.contact-details p {
    color: var(--text-light);
    font-size: 1rem;
}

/* 页脚样式 */
.footer {
    background-color: var(--text-dark);
    color: var(--text-white);
    padding: 3rem 0 1.5rem;
}

.footer-content {
    text-align: center;
}

.footer-info h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-white);
}

.footer-info p {
    color: #d1d5db;
    margin-bottom: 2rem;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.footer-bottom {
    border-top: 1px solid #374151;
    padding-top: 1.5rem;
    margin-top: 2rem;
}

.footer-bottom p {
    color: #9ca3af;
    font-size: 0.9rem;
    margin-bottom: 0.5rem;
}

.footer-bottom a {
    color: var(--accent-color);
    text-decoration: none;
    transition: var(--transition);
}

.footer-bottom a:hover {
    text-decoration: underline;
}

/* 返回顶部按钮 */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    color: var(--text-white);
    border: none;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
    z-index: 1000;
    box-shadow: var(--shadow-lg);
}

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

.back-to-top:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-xl);
}

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

/* 响应式设计 */
@media screen and (max-width: 768px) {
    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background-color: var(--bg-white);
        width: 100%;
        text-align: center;
        transition: var(--transition);
        box-shadow: var(--shadow-lg);
        padding: 2rem 0;
    }

    .nav-menu.active {
        left: 0;
    }

    .nav-item {
        margin: 1rem 0;
    }

    .hamburger {
        display: flex;
    }

    .hamburger.active .bar:nth-child(2) {
        opacity: 0;
    }

    .hamburger.active .bar:nth-child(1) {
        transform: translateY(8px) rotate(45deg);
    }

    .hamburger.active .bar:nth-child(3) {
        transform: translateY(-8px) rotate(-45deg);
    }

    .hero-title {
        font-size: 2.5rem;
    }

    .hero-subtitle {
        font-size: 1.1rem;
    }

    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }

    .btn {
        width: 200px;
    }

    section {
        padding: 60px 0;
    }

    .section-header h2 {
        font-size: 2rem;
    }

    .company-values {
        grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
        gap: 1.5rem;
    }

    .business-grid {
        grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
        gap: 1.5rem;
    }

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

@media screen and (max-width: 480px) {
    .container {
        padding: 0 15px;
    }

    .hero-title {
        font-size: 2rem;
    }

    .section-header h2 {
        font-size: 1.8rem;
    }

    .business-item {
        padding: 2rem 1.5rem;
    }

    .value-item {
        padding: 1.5rem;
    }

    .contact-item {
        padding: 1.5rem;
    }
}

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

::-webkit-scrollbar-track {
    background: #f1f1f1;
}

::-webkit-scrollbar-thumb {
    background: var(--primary-color);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--secondary-color);
}

/* 选择文本样式 */
::selection {
    background-color: var(--accent-color);
    color: var(--text-white);
}