:root {
    --primary-color: #0056b3; 
    --secondary-color: #00a8cc; 
    --text-color: #333;
    --light-bg: #f4f7f6;
    --white: #ffffff;
    --transition: all 0.3s ease;
}

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

html, body {
    overflow-x: hidden; 
    width: 100%;        
    position: relative; 
}

html {
    scroll-behavior: smooth; 
}

body {
    font-family: 'Helvetica Neue', Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    line-height: 1.6;
    color: var(--text-color);
}

a {
    text-decoration: none;
    color: inherit;
}

ul {
    list-style: none;
}

img {
    width: 100%;
    display: block;
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 20px;
}

.section {
    padding: 80px 0;
}

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

.btn {
    display: inline-block;
    padding: 12px 30px;
    border-radius: 5px;
    cursor: pointer;
    font-weight: bold;
    transition: var(--transition);
}

.btn-primary {
    background-color: var(--primary-color);
    color: var(--white);
    border: none;
}

.btn-primary:hover {
    background-color: #004494;
}

header {
    background: var(--white);
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
    height: 70px;
    display: flex;
    align-items: center;
}

.hero-content {
    padding: 15px;
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
}

.logo a {
    font-size: 24px;
    font-weight: 800;
    color: var(--primary-color);
}

.logo span {
    color: var(--text-color);
}

.nav-links {
    display: flex;
}

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

.nav-links a {
    font-weight: 500;
    transition: var(--transition);
}

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

.burger {
    display: none;
    cursor: pointer;
}

.burger div {
    width: 25px;
    height: 3px;
    background-color: var(--text-color);
    margin: 5px;
    transition: var(--transition);
}

.hero {
    height: 600px;
    background: linear-gradient(rgba(0,0,0,0.6), rgba(0,0,0,0.6)), url('https://images.unsplash.com/photo-1497366216548-37526070297c?ixlib=rb-1.2.1&auto=format&fit=crop&w=1350&q=80');
    background-size: cover;
    background-position: center;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    color: var(--white);
}

.hero h1 {
    font-size: 48px;
    margin-bottom: 20px;
}

.hero p {
    font-size: 18px;
    margin-bottom: 30px;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.about-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 50px;
    align-items: center;
}

.about-text h2 {
    font-size: 32px;
    margin-bottom: 10px;
    color: var(--primary-color);
}

.about-text .subtitle {
    font-size: 18px;
    font-weight: bold;
    margin-bottom: 20px;
    color: #666;
}

.features-list {
    margin-top: 20px;
}

.features-list li {
    margin-bottom: 10px;
    display: flex;
    align-items: center;
}

.features-list i {
    color: var(--primary-color);
    margin-right: 10px;
}

.about-img img {
    border-radius: 10px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}

.section-header {
    text-align: center;
    margin-bottom: 50px;
}

.section-header h2 {
    font-size: 32px;
    color: var(--primary-color);
    margin-bottom: 10px;
}

.services-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

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

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

.card .icon {
    font-size: 40px;
    color: var(--primary-color);
    margin-bottom: 20px;
}

.card h3 {
    margin-bottom: 15px;
}

.stats {
    background: var(--primary-color);
    color: var(--white);
    padding: 60px 0;
}

.stats-container {
    display: flex;
    justify-content: space-around;
    text-align: center;
}

.stat-item h3 {
    font-size: 36px;
    margin-bottom: 5px;
}

footer {
    background: #222;
    color: #ddd;
    padding-top: 50px;
}

.footer-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
    padding-bottom: 40px;
}

.footer-col h3 {
    color: var(--white);
    margin-bottom: 20px;
}

.footer-col h4 {
    color: var(--white);
    margin-bottom: 20px;
}

.footer-col ul li {
    margin-bottom: 10px;
}

.footer-col ul li a:hover {
    color: var(--secondary-color);
}

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

.copyright {
    background: #111;
    text-align: center;
    padding: 20px;
    font-size: 14px;
}

@media screen and (max-width: 768px) {
    .nav-links {
        position: absolute;
        right: 0px;
        top: 70px;
        background-color: var(--white);
        flex-direction: column;
        align-items: center;
        width: 50%;
        transform: translateX(100%);
        transition: transform 0.5s ease-in;
        box-shadow: -2px 5px 10px rgba(0,0,0,0.1);
    }

    .nav-links li {
        margin: 20px 0;
    }

    .burger {
        display: block;
    }

    .nav-active {
        transform: translateX(0%);
    }

    .about-container {
        grid-template-columns: 1fr;
    }

    .hero h1 {
        font-size: 32px;
    }
    
    .stats-container {
        flex-direction: column;
        gap: 30px;
    }
}