/* 基础样式重置与设定 */
:root {
    --primary-blue: #0066cc;
    --dark-blue: #004d99;
    --light-blue: #e6f2ff;
    --dark-gray: #333;
    --medium-gray: #666;
    --light-gray: #f5f5f5;
    --white: #ffffff;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: var(--dark-gray);
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 语言切换器 */
.language-switcher {
    position: fixed;
    top: 15px;
    right: 20px;
    z-index: 1001;
    display: flex;
    background: white;
    border-radius: 4px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    overflow: hidden;
}

.lang-btn {
    padding: 6px 12px;
    background: none;
    border: none;
    cursor: pointer;
    font-size: 14px;
    font-weight: 500;
    color: var(--medium-gray);
    transition: all 0.3s;
}

.lang-btn:hover {
    background-color: var(--light-gray);
}

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

/* 导航栏样式 */
.navbar {
    background-color: var(--white);
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
    transition: background-color 0.3s, backdrop-filter 0.3s;
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 20px;
    max-width: 1200px;
    margin: 0 auto;
}

.logo img {
    height: 40px;
}

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

.nav-menu li {
    margin-left: 30px;
}

.nav-menu a {
    text-decoration: none;
    color: var(--dark-gray);
    font-weight: 500;
    transition: color 0.3s;
}

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

/* 英雄大图区域 */
.hero {
    background: linear-gradient(rgba(0, 51, 102, 0.8), rgba(0, 51, 102, 0.9)), url('assets/images/hero-bg.jpg') center/cover no-repeat;
    color: var(--white);
    text-align: center;
    padding: 180px 20px 100px;
    margin-top: 70px;
}

.hero-content h1 {
    font-size: 3rem;
    margin-bottom: 20px;
    line-height: 1.2;
}

.hero-content p {
    font-size: 1.2rem;
    max-width: 800px;
    margin: 0 auto 30px;
    line-height: 1.5;
}

/* 按钮样式 */
.btn-primary {
    display: inline-block;
    background-color: var(--primary-blue);
    color: white;
    padding: 12px 30px;
    border-radius: 4px;
    text-decoration: none;
    font-weight: 600;
    transition: background-color 0.3s, transform 0.3s;
    border: none;
    cursor: pointer;
}

.btn-primary:hover {
    background-color: var(--dark-blue);
    transform: translateY(-2px);
}

/* 通用内容区块 */
.section {
    padding: 80px 0;
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 50px;
    color: var(--dark-blue);
}

.bg-light {
    background-color: var(--light-gray);
}

.bg-dark {
    background-color: var(--dark-blue);
    color: white;
}

.bg-dark .section-title {
    color: white;
}

/* 技术理念网格布局 */
.philosophy-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
    margin-top: 40px;
}

.card {
    background: white;
    padding: 30px;
    border-radius: 8px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.05);
    text-align: center;
    transition: transform 0.3s, box-shadow 0.3s;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px rgba(0,0,0,0.1);
}

.card i {
    font-size: 2.5rem;
    color: var(--primary-blue);
    margin-bottom: 20px;
}

.card h4 {
    margin-bottom: 15px;
    color: var(--dark-blue);
}

/* 核心优势布局 */
.advantages-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
}

.advantage-item {
    background: white;
    padding: 30px;
    border-radius: 8px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.05);
    transition: transform 0.3s, box-shadow 0.3s;
}

.advantage-item:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 20px rgba(0,0,0,0.08);
}

.advantage-icon {
    display: inline-block;
    background-color: var(--primary-blue);
    color: white;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    text-align: center;
    line-height: 40px;
    font-weight: bold;
    margin-bottom: 15px;
}

.advantage-item h3 {
    margin-bottom: 15px;
    color: var(--dark-blue);
}

/* 项目案例布局 */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.project-card {
    background: white;
    padding: 30px;
    border-radius: 8px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.05);
    border-top: 4px solid var(--primary-blue);
    transition: transform 0.3s, box-shadow 0.3s;
}

.project-card:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 20px rgba(0,0,0,0.08);
}

.project-location {
    color: var(--primary-blue);
    font-weight: 600;
    margin: 10px 0;
}

.project-highlights {
    margin-top: 15px;
    padding-left: 20px;
}

.project-highlights li {
    margin-bottom: 8px;
    position: relative;
}

.project-highlights li::before {
    content: "✓";
    color: var(--primary-blue);
    position: absolute;
    left: -20px;
}

/* 联系表单布局 */
.contact-wrapper {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 50px;
    align-items: start;
}

.contact-form {
    display: flex;
    flex-direction: column;
}

.contact-form input,
.contact-form textarea {
    padding: 12px;
    margin-bottom: 20px;
    border: 1px solid #ddd;
    border-radius: 4px;
    font-family: inherit;
    font-size: 16px;
    transition: border-color 0.3s;
}

.contact-form input:focus,
.contact-form textarea:focus {
    border-color: var(--primary-blue);
    outline: none;
}

.contact-form button {
    align-self: flex-start;
}

.contact-info i {
    margin-right: 10px;
    color: var(--light-blue);
}

.contact-info h3 {
    margin-bottom: 20px;
}

.contact-info p {
    margin-bottom: 10px;
    display: flex;
    align-items: flex-start;
}

/* 页脚样式 */
.footer {
    background-color: #222;
    color: #aaa;
    text-align: center;
    padding: 30px 0;
}

.footer p {
    margin-bottom: 10px;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .nav-menu {
        display: none; /* 移动端可扩展为汉堡菜单 */
    }
    
    .hero-content h1 {
        font-size: 2.2rem;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .language-switcher {
        top: 10px;
        right: 10px;
    }
    
    .lang-btn {
        padding: 5px 10px;
        font-size: 13px;
    }
}

/* 中文字体优化 */
html[lang="zh-CN"] body {
    font-family: 'Microsoft YaHei', 'Segoe UI', sans-serif;
}

html[lang="zh-CN"] h1,
html[lang="zh-CN"] h2,
html[lang="zh-CN"] h3,
html[lang="zh-CN"] h4 {
    font-weight: 600;
}