/* ========================================
   全局样式
   ======================================== */

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

:root {
    --primary-color: #1E88E5;
    --secondary-color: #43A047;
    --text-color: #333333;
    --light-gray: #F5F5F5;
    --border-color: #EEEEEE;
    --white: #FFFFFF;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 4px 16px rgba(0, 0, 0, 0.15);
}

html {
    scroll-behavior: smooth;
}

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

/* ========================================
   容器和基础布局
   ======================================== */

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 40px;
}

@media (max-width: 768px) {
    .container {
        padding: 0 20px;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 16px;
    }
}

/* ========================================
   导航栏
   ======================================== */

.navbar {
    background-color: var(--white);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: var(--shadow);
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 40px;
}

.navbar-brand h1 {
    font-size: 24px;
    font-weight: 700;
    color: var(--primary-color);
    margin: 0;
}

.navbar-menu {
    display: flex;
    list-style: none;
    gap: 32px;
    align-items: center;
}

.navbar-menu a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    font-size: 14px;
    transition: color 0.3s ease;
}

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

.navbar-menu .cta-button {
    background-color: var(--primary-color);
    color: var(--white);
    padding: 8px 16px;
    border-radius: 4px;
    transition: background-color 0.3s ease;
}

.navbar-menu .cta-button:hover {
    background-color: #1565C0;
}

@media (max-width: 768px) {
    .navbar-menu {
        gap: 16px;
        font-size: 12px;
    }
    
    .navbar-brand h1 {
        font-size: 18px;
    }
}

@media (max-width: 480px) {
    .navbar .container {
        flex-direction: column;
        gap: 16px;
    }
    
    .navbar-menu {
        flex-wrap: wrap;
        justify-content: center;
        gap: 12px;
    }
}

/* ========================================
   Hero Section
   ======================================== */

.hero {
    background: linear-gradient(135deg, #1E88E5 0%, #43A047 100%);
    color: var(--white);
    padding: 96px 0;
    text-align: center;
}

.hero-content h2 {
    font-size: 56px;
    font-weight: 800;
    margin: 0 0 24px;
    line-height: 1.15;
    color: #FFFFFF;
    letter-spacing: 4px;
    font-family: "PingFang SC", "HarmonyOS Sans SC", "Microsoft YaHei UI",
        "Microsoft YaHei", "Hiragino Sans GB", "Helvetica Neue", Arial, sans-serif;
    text-shadow:
        0 2px 4px rgba(0, 0, 0, 0.15),
        0 8px 24px rgba(15, 35, 70, 0.25);
    position: relative;
    display: inline-block;
    padding-bottom: 18px;
}

.hero-content h2::after {
    content: "";
    position: absolute;
    left: 50%;
    bottom: 0;
    transform: translateX(-50%);
    width: 72px;
    height: 4px;
    border-radius: 2px;
    background: linear-gradient(90deg, rgba(255, 255, 255, 0.95), rgba(255, 255, 255, 0.35));
    box-shadow: 0 2px 8px rgba(255, 255, 255, 0.35);
}

.hero-content > p:first-of-type {
    font-size: 20px;
    margin-bottom: 8px;
    font-weight: 500;
}

.hero-subtitle {
    font-size: 16px;
    margin-bottom: 32px;
    opacity: 0.95;
}

.hero .button {
    margin: 0 12px;
}

@media (max-width: 768px) {
    .hero {
        padding: 64px 0;
    }
    
    .hero-content h2 {
        font-size: 40px;
        letter-spacing: 3px;
        padding-bottom: 14px;
    }

    .hero-content h2::after {
        width: 56px;
        height: 3px;
    }

    .hero-content > p:first-of-type {
        font-size: 16px;
    }
}

@media (max-width: 480px) {
    .hero {
        padding: 48px 0;
    }

    .hero-content h2 {
        font-size: 30px;
        letter-spacing: 2px;
        padding-bottom: 12px;
    }

    .hero-content h2::after {
        width: 44px;
        height: 3px;
    }
    
    .hero .button {
        display: block;
        margin: 12px 0;
    }
}

/* ========================================
   按钮
   ======================================== */

.button {
    display: inline-block;
    padding: 12px 32px;
    border-radius: 4px;
    text-decoration: none;
    font-weight: 600;
    font-size: 16px;
    transition: all 0.3s ease;
    border: none;
    cursor: pointer;
}

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

.button-primary:hover {
    background-color: #1565C0;
    box-shadow: var(--shadow-lg);
}

.button-secondary {
    background-color: var(--white);
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
}

.button-secondary:hover {
    background-color: #F5F5F5;
}

.button-large {
    padding: 16px 48px;
    font-size: 18px;
}

/* ========================================
   通用区域样式
   ======================================== */

section {
    padding: 80px 0;
}

section h2 {
    font-size: 40px;
    font-weight: 700;
    margin-bottom: 16px;
    text-align: center;
    color: var(--text-color);
}

.section-subtitle {
    font-size: 18px;
    color: #666666;
    text-align: center;
    margin-bottom: 48px;
}

@media (max-width: 768px) {
    section {
        padding: 48px 0;
    }
    
    section h2 {
        font-size: 32px;
    }
    
    .section-subtitle {
        font-size: 16px;
    }
}

/* ========================================
   服务区域
   ======================================== */

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

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

.service-card {
    background-color: var(--white);
    padding: 32px;
    border-radius: 8px;
    box-shadow: var(--shadow);
    transition: all 0.3s ease;
}

.service-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.service-card h3 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 16px;
    color: var(--primary-color);
}

.service-card p {
    font-size: 14px;
    line-height: 1.8;
    margin-bottom: 16px;
    color: #666666;
}

.service-card a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
    font-size: 14px;
    transition: color 0.3s ease;
}

.service-card a:hover {
    color: #1565C0;
}

/* ========================================
   为什么选择我们
   ======================================== */

.why-us {
    background-color: var(--white);
}

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

.feature {
    text-align: center;
}

.feature h3 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--primary-color);
}

.feature p {
    font-size: 14px;
    line-height: 1.8;
    color: #666666;
}

/* ========================================
   客户案例
   ======================================== */

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

.cases-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 32px;
}

.case-card {
    background-color: var(--white);
    padding: 32px;
    border-radius: 8px;
    box-shadow: var(--shadow);
    border-left: 4px solid var(--secondary-color);
}

.case-card h3 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 16px;
    color: var(--text-color);
}

.case-card p {
    font-size: 14px;
    line-height: 1.8;
    margin-bottom: 12px;
    color: #666666;
}

.case-card strong {
    color: var(--primary-color);
}

.case-card a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
    font-size: 14px;
    margin-top: 12px;
    display: inline-block;
}

/* ========================================
   隔音知识
   ======================================== */

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

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

.knowledge-card {
    background-color: var(--light-gray);
    padding: 32px;
    border-radius: 8px;
    transition: all 0.3s ease;
}

.knowledge-card:hover {
    background-color: var(--white);
    box-shadow: var(--shadow);
}

.knowledge-card h3 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 12px;
    color: var(--primary-color);
}

.knowledge-card p {
    font-size: 14px;
    line-height: 1.8;
    margin-bottom: 16px;
    color: #666666;
}

.knowledge-card a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
    font-size: 14px;
}

/* ========================================
   行动号召
   ======================================== */

.cta {
    background: linear-gradient(135deg, #1E88E5 0%, #43A047 100%);
    color: var(--white);
    text-align: center;
    padding: 80px 0;
}

.cta h2 {
    color: var(--white);
    margin-bottom: 16px;
}

.cta p {
    font-size: 18px;
    margin-bottom: 32px;
}

/* ========================================
   页脚
   ======================================== */

.footer {
    background-color: #2C3E50;
    color: #ECEFF1;
    padding: 48px 0 0;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
    margin-bottom: 40px;
}

.footer-section h4 {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: 16px;
    color: var(--white);
}

.footer-section p {
    font-size: 14px;
    line-height: 1.8;
    margin-bottom: 8px;
}

.footer-section a {
    color: #ECEFF1;
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-section a:hover {
    color: var(--primary-color);
}

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

.footer-section li {
    margin-bottom: 8px;
}

.social-links {
    display: flex;
    gap: 16px;
}

.footer-bottom {
    background-color: #1A252F;
    padding: 24px 0;
    text-align: center;
    font-size: 12px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-bottom a {
    color: #ECEFF1;
    text-decoration: none;
    margin: 0 8px;
}

/* ========================================
   响应式设计
   ======================================== */

@media (max-width: 768px) {
    .footer-content {
        grid-template-columns: repeat(2, 1fr);
        gap: 24px;
    }
}

@media (max-width: 480px) {
    .footer-content {
        grid-template-columns: 1fr;
    }
    
    .social-links {
        flex-wrap: wrap;
    }
}

/* ========================================
   无障碍和SEO优化
   ======================================== */

h1, h2, h3, h4, h5, h6 {
    margin: 0;
    padding: 0;
}

a {
    color: inherit;
}

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

/* 跳过链接 */
.skip-link {
    position: absolute;
    top: -40px;
    left: 0;
    background: var(--primary-color);
    color: var(--white);
    padding: 8px;
    text-decoration: none;
    z-index: 100;
}

.skip-link:focus {
    top: 0;
}