/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', sans-serif;
    line-height: 1.6;
    color: #333;
    overflow-x: hidden;
}

body.zh-cn {
    font-family: 'Microsoft YaHei', 'SimHei', sans-serif;
}

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

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(59, 90, 122, 0.95);
    backdrop-filter: blur(10px);
    z-index: 1000;
    transition: all 0.3s ease;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.nav-logo img {
    height: 40px;
    width: auto;
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: 30px;
}

.nav-link {
    color: white;
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
    position: relative;
}

.nav-link:hover {
    color: #64B5F6;
}

.nav-link::after {
    content: '';
    position: absolute;
    width: 0;
    height: 2px;
    bottom: -5px;
    left: 0;
    background-color: #64B5F6;
    transition: width 0.3s ease;
}

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

/* Language Selector */
.language-selector {
    position: relative;
}

.lang-btn {
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.2);
    color: white;
    padding: 8px 15px;
    border-radius: 25px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 14px;
    transition: all 0.3s ease;
}

.lang-btn:hover {
    background: rgba(255, 255, 255, 0.2);
}

.lang-dropdown {
    position: absolute;
    top: 100%;
    right: 0;
    background: white;
    border-radius: 10px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
    min-width: 150px;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: all 0.3s ease;
    z-index: 1001;
}

.lang-dropdown.active {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.lang-option {
    display: block;
    padding: 12px 20px;
    color: #333;
    text-decoration: none;
    transition: background 0.3s ease;
    border-radius: 10px;
}

.lang-option:hover {
    background: #f5f5f5;
}

/* Hero Section */
.hero {
    height: 100vh;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}

.hero-background {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, #3B5A7A 0%, #2C4A6B 100%);
    background-image: url('../images/background_1.jpg');
    background-size: cover;
    background-position: center;
    background-attachment: fixed;
}

.hero-background::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, rgba(59, 90, 122, 0.8) 0%, rgba(44, 74, 107, 0.9) 100%);
}

.hero-content {
    position: relative;
    z-index: 2;
    text-align: center;
    color: white;
    max-width: 800px;
    padding: 0 20px;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 20px;
    opacity: 0;
    animation: fadeInUp 1s ease 0.5s forwards;
}

.hero-subtitle {
    font-size: 1.5rem;
    font-weight: 400;
    margin-bottom: 30px;
    opacity: 0;
    animation: fadeInUp 1s ease 0.7s forwards;
}

.hero-description {
    font-size: 1.1rem;
    margin-bottom: 40px;
    opacity: 0;
    animation: fadeInUp 1s ease 0.9s forwards;
    line-height: 1.8;
}

/* Sections */
.section-header {
    text-align: center;
    margin-bottom: 60px;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    color: #3B5A7A;
    margin-bottom: 20px;
}

.section-subtitle {
    font-size: 1.2rem;
    color: #666;
    max-width: 600px;
    margin: 0 auto;
    line-height: 1.6;
}

/* Mission Section */
.mission {
    padding: 100px 0;
    background: #f8f9fa;
}

.mission-content {
    max-width: 900px;
    margin: 0 auto;
}

.mission-text p {
    font-size: 1.1rem;
    line-height: 1.8;
    margin-bottom: 30px;
    color: #555;
    text-align: justify;
}

/* About Section */
.about {
    padding: 100px 0;
    background: white;
}

.about-content {
    display: grid;
    gap: 60px;
}

.about-text p {
    font-size: 1.1rem;
    line-height: 1.8;
    color: #555;
    text-align: justify;
    margin-bottom: 30px;
}

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

.feature-card {
    background: #f8f9fa;
    padding: 40px 30px;
    border-radius: 15px;
    text-align: center;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.feature-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
}

.feature-icon {
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, #3B5A7A, #64B5F6);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 20px;
}

.feature-icon i {
    font-size: 2rem;
    color: white;
}

.feature-card h3 {
    font-size: 1.5rem;
    font-weight: 600;
    color: #3B5A7A;
    margin-bottom: 15px;
}

.feature-card p {
    color: #666;
    line-height: 1.6;
}

/* Services Section */
.services {
    padding: 100px 0;
    background: #f8f9fa;
}

.services-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: 40px;
}

.service-card {
    background: white;
    padding: 40px 30px;
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.service-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15);
}

.service-icon {
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, #3B5A7A, #64B5F6);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 20px;
}

.service-icon i {
    font-size: 2rem;
    color: white;
}

.service-card h3 {
    font-size: 1.5rem;
    font-weight: 600;
    color: #3B5A7A;
    margin-bottom: 15px;
}

.service-card p {
    color: #666;
    line-height: 1.6;
}

/* Contact Section */
.contact {
    padding: 100px 0;
    background: white;
}

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

.contact-info {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
}

.contact-item {
    display: flex;
    align-items: center;
    gap: 20px;
    padding: 30px;
    background: #f8f9fa;
    border-radius: 15px;
    transition: transform 0.3s ease;
}

.contact-item:hover {
    transform: translateY(-5px);
}

.contact-icon {
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, #3B5A7A, #64B5F6);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.contact-icon i {
    font-size: 1.5rem;
    color: white;
}

.contact-details h4 {
    font-size: 1.2rem;
    font-weight: 600;
    color: #3B5A7A;
    margin-bottom: 5px;
}

.contact-details p {
    color: #666;
    font-size: 1rem;
}

/* Footer */
.footer {
    background: #3B5A7A;
    color: white;
    padding: 40px 0;
    text-align: center;
}

.footer-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 20px;
}

.footer-logo img {
    height: 40px;
    width: auto;
}

.footer-text p {
    color: rgba(255, 255, 255, 0.8);
}

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

/* Responsive Design */
@media (max-width: 768px) {
    .nav-menu {
        gap: 15px;
    }
    
    .nav-link {
        font-size: 14px;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-subtitle {
        font-size: 1.2rem;
    }
    
    .hero-description {
        font-size: 1rem;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .features-grid,
    .services-grid {
        grid-template-columns: 1fr;
    }
    
    .contact-info {
        grid-template-columns: 1fr;
    }
    
    .contact-item {
        flex-direction: column;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }
    
    .nav-container {
        padding: 0 15px;
    }
    
    .hero-content {
        padding: 0 15px;
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .hero-subtitle {
        font-size: 1rem;
    }
    
    .section-title {
        font-size: 1.8rem;
    }
    
    .feature-card,
    .service-card {
        padding: 30px 20px;
    }
}