:root {
    --primary: #4C4C7E;
    --primary-dark: #3A3A5C;
    --secondary: #6F5B9F;
    --gray-light: #f5f5f5;
    --gray-dark: #333;
    --text-color: #333;
    --border-radius: 8px;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Helvetica Neue', sans-serif;
    line-height: 1.6;
    color: var(--text-color);
}

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

header.header {
    background: white;
    border-bottom: 1px solid #eee;
    position: sticky;
    top: 0;
    z-index: 100;
}

.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 0;
}

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

.logo {
    font-size: 20px;
    font-weight: bold;
    color: var(--primary);
    text-decoration: none;
}

.nav-menu {
    list-style: none;
    display: flex;
    gap: 30px;
}

.nav-menu a {
    color: var(--text-color);
    text-decoration: none;
    transition: color 0.3s;
}

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

.lang-switcher {
    list-style: none;
    display: flex;
    gap: 15px;
}

.lang-switcher a {
    color: var(--text-color);
    text-decoration: none;
    font-size: 14px;
    transition: color 0.3s;
}

.lang-switcher a.active {
    color: var(--primary);
    font-weight: bold;
}

.lang-switcher a:hover {
    color: var(--primary);
}

.hero {
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    color: white;
    padding: 100px 0;
    text-align: center;
}

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

.hero-subtitle {
    font-size: 18px;
    margin-bottom: 30px;
    opacity: 0.95;
}

.btn {
    display: inline-block;
    padding: 12px 30px;
    border-radius: var(--border-radius);
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s;
    cursor: pointer;
    border: none;
    font-size: 16px;
}

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

.btn-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

.btn-large {
    padding: 15px 40px;
    font-size: 18px;
}

.features {
    padding: 80px 0;
    background: white;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
}

.feature-card {
    padding: 30px;
    border: 1px solid #eee;
    border-radius: var(--border-radius);
    text-align: center;
    transition: all 0.3s;
}

.feature-card:hover {
    border-color: var(--primary);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    transform: translateY(-5px);
}

.feature-card h3 {
    color: var(--primary);
    margin-bottom: 15px;
    font-size: 20px;
}

.stats {
    background: var(--gray-light);
    padding: 80px 0;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 40px;
}

.stat-box {
    text-align: center;
}

.stat-box h3 {
    font-size: 28px;
    color: var(--primary);
    margin-bottom: 10px;
}

.stat-box p {
    color: #666;
}

.cta {
    background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    color: white;
    padding: 80px 0;
    text-align: center;
}

.cta h2 {
    font-size: 36px;
    margin-bottom: 15px;
}

.cta p {
    font-size: 18px;
    margin-bottom: 30px;
    opacity: 0.95;
}

.download-options {
    padding: 80px 0;
}

.download-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
}

.download-card {
    padding: 30px;
    border: 2px solid #eee;
    border-radius: var(--border-radius);
    text-align: center;
    transition: all 0.3s;
}

.download-card:hover {
    border-color: var(--primary);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.1);
}

.download-card h3 {
    color: var(--primary);
    font-size: 24px;
    margin-bottom: 15px;
}

.download-card .version {
    color: #666;
    font-size: 14px;
    margin: 10px 0;
}

.download-card .size {
    color: #999;
    font-size: 13px;
    margin: 10px 0;
}

.download-card .system-req {
    color: #999;
    font-size: 13px;
    margin-top: 15px;
}

.install-guide {
    background: var(--gray-light);
    padding: 80px 0;
}

.guide-steps {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 30px;
}

.step {
    background: white;
    padding: 30px;
    border-radius: var(--border-radius);
    text-align: center;
}

.step h3 {
    color: var(--primary);
    margin-bottom: 15px;
}

.feature-details {
    padding: 80px 0;
}

.feature-article {
    margin-bottom: 60px;
}

.feature-article h2 {
    color: var(--primary);
    font-size: 28px;
    margin-bottom: 20px;
}

.feature-article p {
    color: #666;
    margin-bottom: 15px;
    line-height: 1.8;
}

.about-content {
    padding: 80px 0;
}

.about-content article {
    margin-bottom: 60px;
}

.about-content h2 {
    color: var(--primary);
    font-size: 28px;
    margin-bottom: 20px;
}

.about-content p {
    color: #666;
    margin-bottom: 15px;
    line-height: 1.8;
}

.about-content ul,
.about-content ol {
    margin: 15px 0 15px 30px;
    color: #666;
}

.about-content li {
    margin-bottom: 10px;
}

.faq {
    margin-top: 30px;
}

.faq h3 {
    color: var(--primary);
    margin-top: 20px;
    margin-bottom: 10px;
}

.faq p {
    color: #666;
    margin-bottom: 20px;
}

.footer {
    background: var(--gray-dark);
    color: white;
    padding: 60px 0 20px;
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 40px;
    margin-bottom: 40px;
}

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

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

.footer-col a {
    color: #ccc;
    text-decoration: none;
    transition: color 0.3s;
    display: block;
    margin-bottom: 8px;
}

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

.footer-bottom {
    border-top: 1px solid #555;
    padding-top: 20px;
    text-align: center;
    color: #999;
    font-size: 14px;
}

@media (max-width: 768px) {
    .navbar {
        flex-wrap: wrap;
    }

    .navbar .container {
        flex-direction: column;
        gap: 15px;
    }

    .nav-menu {
        flex-direction: column;
        gap: 10px;
        width: 100%;
    }

    .hero h1 {
        font-size: 32px;
    }

    .lang-switcher {
        width: 100%;
        justify-content: center;
    }

    .features-grid,
    .stats-grid,
    .download-grid,
    .guide-steps {
        grid-template-columns: 1fr;
    }
}