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

:root {
    --primary-blue: #4285F4;
    --primary-green: #34A853;
    --primary-yellow: #FBBC05;
    --primary-red: #EA4335;
    --text-dark: #202124;
    --text-gray: #5f6368;
    --bg-light: #f8f9fa;
    --border-color: #dadce0;
    --white: #ffffff;
}

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

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* Header */
.header {
    background: var(--white);
    box-shadow: 0 2px 4px rgba(0,0,0,0.08);
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 16px 0;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 24px;
    font-weight: 500;
}

.logo svg {
    height: 28px;
}

.nav {
    display: flex;
    gap: 32px;
}

.nav a {
    color: var(--text-dark);
    text-decoration: none;
    font-size: 14px;
    transition: color 0.2s;
}

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

/* Hero Section */
.hero {
    padding: 120px 0 80px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: var(--white);
    min-height: 100vh;
    display: flex;
    align-items: center;
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
}

.hero-title {
    font-size: 56px;
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 24px;
}

.hero-subtitle {
    font-size: 20px;
    margin-bottom: 32px;
    opacity: 0.95;
}

.hero-actions {
    display: flex;
    gap: 16px;
}

.btn {
    padding: 14px 32px;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 500;
    transition: all 0.2s;
    display: inline-block;
}

.btn-primary {
    background: var(--primary-blue);
    color: var(--white);
    box-shadow: 0 4px 12px rgba(66, 133, 244, 0.3);
}

.btn-primary:hover {
    background: #3367d6;
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(66, 133, 244, 0.4);
}

.btn-secondary {
    background: rgba(255,255,255,0.15);
    color: var(--white);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255,255,255,0.3);
}

.btn-secondary:hover {
    background: rgba(255,255,255,0.25);
    transform: translateY(-2px);
}

.hero-illustration {
    display: flex;
    justify-content: center;
}

.browser-illustration {
    width: 100%;
    max-width: 500px;
    filter: drop-shadow(0 20px 40px rgba(0,0,0,0.2));
    animation: float 6s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translateY(0px); }
    50% { transform: translateY(-20px); }
}

/* Features Section */
.features {
    padding: 100px 0;
    background: var(--white);
}

.section-title {
    text-align: center;
    font-size: 40px;
    font-weight: 700;
    margin-bottom: 60px;
}

.section-subtitle {
    text-align: center;
    font-size: 18px;
    color: var(--text-gray);
    margin-bottom: 48px;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 32px;
}

.feature-card {
    padding: 40px 32px;
    background: var(--bg-light);
    border-radius: 16px;
    transition: transform 0.2s, box-shadow 0.2s;
}

.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 24px rgba(0,0,0,0.1);
}

.feature-icon {
    width: 64px;
    height: 64px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 24px;
}

.feature-icon-blue { background: var(--primary-blue); }
.feature-icon-green { background: var(--primary-green); }
.feature-icon-yellow { background: var(--primary-yellow); }
.feature-icon-red { background: var(--primary-red); }

.feature-card h3 {
    font-size: 20px;
    margin-bottom: 12px;
}

.feature-card p {
    color: var(--text-gray);
    font-size: 15px;
}

/* AI Features Section */
.ai-features {
    padding: 100px 0;
    background: var(--bg-light);
}

.ai-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 24px;
}

.ai-card {
    background: var(--white);
    padding: 32px;
    border-radius: 12px;
    transition: transform 0.2s, box-shadow 0.2s;
}

.ai-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 16px rgba(0,0,0,0.08);
}

.ai-icon {
    width: 56px;
    height: 56px;
    border-radius: 12px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 20px;
}

.ai-card h3 {
    font-size: 18px;
    margin-bottom: 12px;
}

.ai-card p {
    color: var(--text-gray);
    font-size: 14px;
    line-height: 1.7;
}

/* Download Section */
.download-section {
    padding: 100px 0;
    background: var(--white);
}

.download-buttons {
    display: flex;
    gap: 24px;
    justify-content: center;
    flex-wrap: wrap;
}

.download-btn {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 32px 40px;
    background: var(--bg-light);
    border: 2px solid var(--border-color);
    border-radius: 16px;
    text-decoration: none;
    transition: all 0.2s;
    min-width: 220px;
}

.download-btn:hover {
    border-color: var(--primary-blue);
    background: var(--white);
    transform: translateY(-4px);
    box-shadow: 0 8px 16px rgba(66, 133, 244, 0.15);
}

.os-name {
    display: block;
    font-size: 20px;
    font-weight: 600;
    color: var(--text-dark);
}

.os-version {
    display: block;
    font-size: 14px;
    color: var(--text-gray);
}

/* FAQ Section */
.faq-section {
    padding: 100px 0;
    background: var(--bg-light);
}

.faq-list {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    background: var(--white);
    margin-bottom: 16px;
    border-radius: 8px;
    overflow: hidden;
}

.faq-question {
    padding: 24px;
    font-weight: 600;
    font-size: 16px;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.faq-question::after {
    content: '+';
    font-size: 24px;
    color: var(--primary-blue);
}

.faq-item.active .faq-question::after {
    content: '−';
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease, padding 0.3s ease;
    padding: 0 24px;
    color: var(--text-gray);
}

.faq-item.active .faq-answer {
    max-height: 200px;
    padding: 0 24px 24px;
}

/* Footer */
.footer {
    background: #f1f3f4;
    padding: 40px 0;
    border-top: 1px solid var(--border-color);
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 16px;
}

.footer-links {
    display: flex;
    gap: 24px;
}

.footer-links a {
    color: var(--text-gray);
    text-decoration: none;
    font-size: 14px;
    transition: color 0.2s;
}

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

.footer-copyright {
    color: var(--text-gray);
    font-size: 14px;
}

/* Responsive */
@media (max-width: 768px) {
    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .hero-title {
        font-size: 36px;
    }

    .hero-subtitle {
        font-size: 16px;
    }

    .hero-actions {
        justify-content: center;
    }

    .nav {
        display: none;
    }

    .section-title {
        font-size: 32px;
    }

    .features-grid,
    .ai-grid {
        grid-template-columns: 1fr;
    }

    .download-buttons {
        flex-direction: column;
        align-items: center;
    }

    .footer-content {
        flex-direction: column;
        text-align: center;
    }

    .footer-links {
        flex-wrap: wrap;
        justify-content: center;
    }
}