:root {
    --primary: #2c6bb4;
    --secondary: #34a853;
    --accent: #fbbc04;
    --dark: #1a365d;
    --light: #f8fafc;
    --gray: #718096;
    --shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
    --radius: 8px;
    --transition: all 0.3s ease;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
}

body {
    line-height: 1.6;
    color: #333;
    background-color: #f9f9f9;
}

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

/* 头部样式 */
header {
    background: linear-gradient(135deg, var(--dark) 0%, var(--primary) 100%);
    color: white;
    padding: 1.5rem 0;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 15px rgba(0, 0, 0, 0.1);
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 1.8rem;
    font-weight: 700;
}

.logo-icon {
    color: var(--accent);
    font-size: 2rem;
}

.nav-links {
    display: flex;
    gap: 2rem;
}

.nav-links a {
    color: white;
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    padding: 5px 0;
    position: relative;
}

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

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--accent);
    transition: width 0.3s ease;
}

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

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    color: white;
    font-size: 1.5rem;
    cursor: pointer;
}

/* 英雄区域样式 */
.hero {
    background: linear-gradient(rgba(26, 54, 93, 0.85), rgba(44, 107, 180, 0.9)), url('https://images.unsplash.com/photo-1556742049-0cfed4f6a45d?ixlib=rb-4.0.3&auto=format&fit=crop&w=1200&q=80');
    background-size: cover;
    background-position: center;
    color: white;
    padding: 5rem 0;
    text-align: center;
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: 1.5rem;
    line-height: 1.2;
}

.hero p {
    font-size: 1.2rem;
    max-width: 800px;
    margin: 0 auto 2rem;
    opacity: 0.9;
}

.cta-button {
    display: inline-block;
    background-color: var(--accent);
    color: var(--dark);
    padding: 14px 32px;
    border-radius: 50px;
    text-decoration: none;
    font-weight: 700;
    font-size: 1.1rem;
    transition: var(--transition);
    border: 2px solid var(--accent);
}

.cta-button:hover {
    background-color: transparent;
    color: var(--accent);
    transform: translateY(-3px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.2);
}

/* 通用区域样式 */
section {
    padding: 5rem 0;
}

.section-title {
    text-align: center;
    margin-bottom: 3.5rem;
    color: var(--dark);
    position: relative;
}

.section-title h2 {
    font-size: 2.5rem;
    display: inline-block;
    padding-bottom: 15px;
}

.section-title h2::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 80px;
    height: 4px;
    background-color: var(--secondary);
    border-radius: 2px;
}

/* 必要性部分样式 */
.necessity-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.necessity-card {
    background-color: white;
    border-radius: var(--radius);
    padding: 2.5rem 2rem;
    box-shadow: var(--shadow);
    transition: var(--transition);
    border-top: 5px solid var(--primary);
}

.necessity-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.1);
}

.necessity-card:nth-child(2) {
    border-top-color: var(--secondary);
}

.necessity-card:nth-child(3) {
    border-top-color: var(--accent);
}

.card-icon {
    font-size: 2.5rem;
    color: var(--primary);
    margin-bottom: 1.5rem;
}

.necessity-card:nth-child(2) .card-icon {
    color: var(--secondary);
}

.necessity-card:nth-child(3) .card-icon {
    color: var(--accent);
}

.necessity-card h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: var(--dark);
}

/* 案例部分样式 */
.cases {
    background-color: var(--light);
}

.case-tabs {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 3rem;
}

.tab-btn {
    padding: 12px 24px;
    background-color: white;
    border: 2px solid #e2e8f0;
    border-radius: 50px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
}

.tab-btn.active, .tab-btn:hover {
    background-color: var(--primary);
    color: white;
    border-color: var(--primary);
}

.case-content {
    display: none;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    align-items: center;
}

.case-content.active {
    display: grid;
    animation: fadeIn 0.8s ease;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

.case-info h3 {
    font-size: 1.8rem;
    margin-bottom: 1rem;
    color: var(--dark);
}

.case-info .industry {
    display: inline-block;
    background-color: #e6f4ea;
    color: var(--secondary);
    padding: 5px 15px;
    border-radius: 20px;
    font-weight: 600;
    margin-bottom: 1.5rem;
    font-size: 0.9rem;
}

.case-features {
    list-style: none;
    margin-top: 1.5rem;
}

.case-features li {
    padding: 8px 0;
    padding-left: 30px;
    position: relative;
}

.case-features li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--secondary);
    font-weight: bold;
}

.case-image {
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow);
    height: 100%;
    min-height: 300px;
    background-size: cover;
    background-position: center;
}

/* 联系方式部分样式 */
.contact-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.contact-card {
    background-color: white;
    border-radius: var(--radius);
    padding: 2rem;
    box-shadow: var(--shadow);
    display: flex;
    align-items: flex-start;
    gap: 1.5rem;
    transition: var(--transition);
}

.contact-card:hover {
    transform: translateX(10px);
}

.contact-icon {
    background-color: #e8f0fe;
    color: var(--primary);
    width: 60px;
    height: 60px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    flex-shrink: 0;
}

.contact-form {
    background-color: white;
    border-radius: var(--radius);
    padding: 2.5rem;
    box-shadow: var(--shadow);
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: var(--dark);
}

.form-control {
    width: 100%;
    padding: 14px;
    border: 2px solid #e2e8f0;
    border-radius: var(--radius);
    font-size: 1rem;
    transition: var(--transition);
}

.form-control:focus {
    outline: none;
    border-color: var(--primary);
}

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

.submit-btn {
    background-color: var(--primary);
    color: white;
    border: none;
    padding: 15px 30px;
    border-radius: var(--radius);
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: var(--transition);
    width: 100%;
}

.submit-btn:hover {
    background-color: var(--dark);
}

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

.footer-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 2rem;
}

.footer-links {
    display: flex;
    gap: 2rem;
    flex-wrap: wrap;
    justify-content: center;
}

.footer-links a {
    color: #cbd5e0;
    text-decoration: none;
    transition: var(--transition);
}

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

.copyright {
    color: #a0aec0;
    font-size: 0.9rem;
    margin-top: 1rem;
}

/* 响应式设计 */
@media (max-width: 992px) {
    .hero h1 {
        font-size: 2.5rem;
    }

    .contact-container,
    .case-content {
        grid-template-columns: 1fr;
    }

    .case-content {
        gap: 2rem;
    }
}

@media (max-width: 768px) {
    .nav-links {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background-color: var(--dark);
        flex-direction: column;
        padding: 1.5rem;
        gap: 1rem;
        box-shadow: 0 10px 15px rgba(0, 0, 0, 0.1);
    }

    .nav-links.active {
        display: flex;
    }

    .mobile-menu-btn {
        display: block;
    }

    .hero {
        padding: 4rem 0;
    }

    .hero h1 {
        font-size: 2rem;
    }

    section {
        padding: 3rem 0;
    }

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

    .necessity-cards {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .hero h1 {
        font-size: 1.8rem;
    }

    .case-tabs {
        flex-direction: column;
        align-items: center;
    }

    .tab-btn {
        width: 100%;
        max-width: 250px;
    }

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