/* ========================================
   北京智动益企网络科技有限公司 - 企业网站样式
   版本：1.0
   最后更新：2024
======================================== */

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

:root {
    --primary-color: #0066cc;
    --primary-dark: #004d99;
    --primary-light: #3399ff;
    --secondary-color: #00c4cc;
    --text-color: #333333;
    --text-light: #666666;
    --bg-light: #f8f9fa;
    --bg-white: #ffffff;
    --border-color: #e0e0e0;
    --shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    --shadow-hover: 0 4px 20px rgba(0, 0, 0, 0.15);
    --transition: all 0.3s ease;
}

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

a {
    text-decoration: none;
    color: inherit;
    transition: var(--transition);
}

ul {
    list-style: none;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

/* ========== 容器布局 ========== */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* ========== 导航栏 ========== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: var(--bg-white);
    box-shadow: var(--shadow);
    z-index: 1000;
    transition: var(--transition);
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.logo {
    font-size: 20px;
    font-weight: bold;
    color: var(--primary-color);
}

.logo-text {
    display: flex;
    align-items: center;
    gap: 8px;
}

.logo-icon {
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: bold;
    font-size: 18px;
}

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

.nav-link {
    font-size: 16px;
    font-weight: 500;
    color: var(--text-color);
    padding: 8px 0;
    position: relative;
}

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

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

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

/* 移动端菜单按钮 */
.menu-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
    padding: 10px;
}

.menu-toggle span {
    width: 25px;
    height: 3px;
    background: var(--text-color);
    border-radius: 3px;
    transition: var(--transition);
}

/* ========== 英雄区域 ========== */
.hero {
    padding-top: 70px;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    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"><circle cx="50" cy="50" r="40" fill="none" stroke="rgba(255,255,255,0.1)" stroke-width="2"/></svg>');
    background-size: 300px 300px;
    animation: float 20s linear infinite;
}

@keyframes float {
    0% { transform: translateX(0) translateY(0); }
    100% { transform: translateX(-300px) translateY(-300px); }
}

.hero .container {
    position: relative;
    z-index: 1;
    padding: 100px 20px;
    text-align: center;
}

.hero-title {
    font-size: 48px;
    font-weight: bold;
    margin-bottom: 20px;
    animation: fadeInUp 0.8s ease;
}

.hero-subtitle {
    font-size: 20px;
    opacity: 0.95;
    margin-bottom: 40px;
    animation: fadeInUp 0.8s ease 0.2s both;
}

.hero-cta {
    display: inline-flex;
    gap: 20px;
    animation: fadeInUp 0.8s ease 0.4s both;
}

.btn {
    display: inline-block;
    padding: 14px 32px;
    border-radius: 50px;
    font-size: 16px;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    border: none;
}

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

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
}

.btn-outline {
    background: transparent;
    color: white;
    border: 2px solid white;
}

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

/* ========== 章节通用样式 ========== */
.section {
    padding: 80px 0;
}

.section-title {
    font-size: 36px;
    font-weight: bold;
    text-align: center;
    margin-bottom: 15px;
    color: var(--text-color);
}

.section-subtitle {
    text-align: center;
    color: var(--text-light);
    margin-bottom: 60px;
    font-size: 18px;
}

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

.about-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
}

.about-content h3 {
    font-size: 28px;
    margin-bottom: 20px;
    color: var(--text-color);
}

.about-content p {
    color: var(--text-light);
    margin-bottom: 20px;
    line-height: 1.8;
}

.about-features {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    margin-top: 30px;
}

.feature-item {
    display: flex;
    align-items: center;
    gap: 10px;
}

.feature-icon {
    width: 40px;
    height: 40px;
    background: var(--primary-color);
    color: white;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
}

.about-image {
    background: linear-gradient(135deg, var(--primary-light), var(--secondary-color));
    border-radius: 20px;
    padding: 60px;
    color: white;
    text-align: center;
}

.about-image h4 {
    font-size: 48px;
    margin-bottom: 10px;
}

.about-image p {
    font-size: 18px;
}

/* ========== 服务展示 ========== */
.services-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
}

.service-card {
    background: var(--bg-white);
    border-radius: 16px;
    padding: 40px 30px;
    box-shadow: var(--shadow);
    transition: var(--transition);
    text-align: center;
    border: 1px solid var(--border-color);
}

.service-card:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow-hover);
}

.service-icon {
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: 50%;
    margin: 0 auto 25px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 36px;
}

.service-card h3 {
    font-size: 22px;
    margin-bottom: 15px;
    color: var(--text-color);
}

.service-card p {
    color: var(--text-light);
    line-height: 1.8;
}

/* ========== 优势展示 ========== */
.advantages-section {
    background: var(--bg-light);
}

.advantages-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 30px;
}

.advantage-item {
    text-align: center;
    padding: 30px;
}

.advantage-number {
    font-size: 48px;
    font-weight: bold;
    color: var(--primary-color);
    margin-bottom: 10px;
}

.advantage-label {
    font-size: 16px;
    color: var(--text-light);
}

/* ========== 联系区域 ========== */
.contact-section {
    background: var(--bg-white);
}

.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
}

.contact-info h3 {
    font-size: 28px;
    margin-bottom: 30px;
    color: var(--text-color);
}

.contact-item {
    display: flex;
    gap: 20px;
    margin-bottom: 25px;
}

.contact-icon {
    width: 50px;
    height: 50px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 22px;
    flex-shrink: 0;
}

.contact-text h4 {
    font-size: 18px;
    margin-bottom: 5px;
    color: var(--text-color);
}

.contact-text p {
    color: var(--text-light);
}

.contact-form h3 {
    font-size: 28px;
    margin-bottom: 30px;
    color: var(--text-color);
}

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

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 15px 20px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    font-size: 16px;
    font-family: inherit;
    transition: var(--transition);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(0, 102, 204, 0.1);
}

.form-group textarea {
    resize: vertical;
    min-height: 150px;
}

.btn-submit {
    width: 100%;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    font-size: 18px;
    padding: 16px;
}

.btn-submit:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 25px rgba(0, 102, 204, 0.3);
}

/* ========== 页脚 ========== */
.footer {
    background: #1a1a2e;
    color: white;
    padding: 60px 0 30px;
}

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

.footer-section h4 {
    font-size: 18px;
    margin-bottom: 20px;
}

.footer-section p {
    color: rgba(255, 255, 255, 0.7);
    line-height: 1.8;
}

.footer-links li {
    margin-bottom: 12px;
}

.footer-links a {
    color: rgba(255, 255, 255, 0.7);
}

.footer-links a:hover {
    color: var(--secondary-color);
}

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: 30px;
    text-align: center;
    color: rgba(255, 255, 255, 0.5);
}

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

.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ========== 响应式设计 ========== */
@media (max-width: 1024px) {
    .about-grid {
        grid-template-columns: 1fr;
        gap: 40px;
    }
    
    .advantages-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .footer-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .menu-toggle {
        display: flex;
    }
    
    .nav-menu {
        position: absolute;
        top: 70px;
        left: 0;
        right: 0;
        background: var(--bg-white);
        flex-direction: column;
        gap: 0;
        padding: 0;
        max-height: 0;
        overflow: hidden;
        transition: var(--transition);
        box-shadow: var(--shadow);
    }
    
    .nav-menu.active {
        max-height: 300px;
    }
    
    .nav-link {
        padding: 15px 20px;
        border-bottom: 1px solid var(--border-color);
    }
    
    .hero-title {
        font-size: 32px;
    }
    
    .hero-subtitle {
        font-size: 16px;
    }
    
    .hero .container {
        padding: 60px 20px;
    }
    
    .section {
        padding: 60px 0;
    }
    
    .section-title {
        font-size: 28px;
    }
    
    .section-subtitle {
        font-size: 16px;
    }
    
    .contact-grid {
        grid-template-columns: 1fr;
    }
    
    .about-features {
        grid-template-columns: 1fr;
    }
    
    .footer-grid {
        grid-template-columns: 1fr;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 26px;
    }
    
    .hero-cta {
        flex-direction: column;
    }
    
    .btn {
        width: 100%;
        text-align: center;
    }
    
    .advantages-grid {
        grid-template-columns: 1fr;
    }
    
    .advantage-number {
        font-size: 36px;
    }
}

/* ========== 页面内部链接滚动 ========== */
html {
    scroll-behavior: smooth;
}

/* ========== 回到顶部按钮 ========== */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background: var(--primary-color);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
    box-shadow: var(--shadow);
    z-index: 999;
}

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

.back-to-top:hover {
    background: var(--primary-dark);
    transform: translateY(-3px);
}