:root {
    --primary-color: #007AFF;
    --secondary-color: #5856D6;
    --success-color: #34C759;
    --warning-color: #FF9500;
    --danger-color: #FF3B30;
    --dark-color: #1C1C1E;
    --light-color: #F2F2F7;
    --text-primary: #1C1C1E;
    --text-secondary: #6C6C70;
    --border-color: #E5E5EA;
    --background-color: #FFFFFF;
    --card-background: #FFFFFF;
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 40px rgba(0, 0, 0, 0.15);
}

@media (prefers-color-scheme: dark) {
    :root {
        --text-primary: #FFFFFF;
        --text-secondary: #8E8E93;
        --background-color: #000000;
        --card-background: #1C1C1E;
        --border-color: #38383A;
        --shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
        --shadow-lg: 0 10px 40px rgba(0, 0, 0, 0.5);
    }
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Hiragino Sans', 'Hiragino Kaku Gothic ProN', Meiryo, sans-serif;
    color: var(--text-primary);
    background-color: var(--background-color);
    line-height: 1.8;
    font-weight: 400;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

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

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: var(--background-color);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    transition: all 0.3s ease;
}

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

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 20px;
    font-weight: 600;
    color: var(--text-primary);
}

.logo svg {
    color: var(--primary-color);
}

.nav-links {
    display: flex;
    gap: 32px;
    align-items: center;
}

.nav-links a {
    color: var(--text-primary);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
}

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

.github-link {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 8px 16px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    transition: all 0.3s ease;
}

.github-link:hover {
    border-color: var(--primary-color);
    background-color: var(--primary-color);
    color: white !important;
}

/* Hero Section */
.hero {
    padding: 120px 0 80px;
    text-align: center;
    background: linear-gradient(135deg, var(--light-color) 0%, var(--background-color) 100%);
}

.hero-content h1 {
    font-size: 56px;
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 24px;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 24px;
    color: var(--text-primary);
    margin-bottom: 48px;
    line-height: 1.6;
    font-weight: 400;
    opacity: 0.85;
}

.cta-buttons {
    display: flex;
    gap: 16px;
    justify-content: center;
    margin-bottom: 80px;
}

.btn {
    display: inline-block;
    padding: 16px 36px;
    border-radius: 12px;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.3s ease;
    font-size: 17px;
    letter-spacing: 0.02em;
}

.btn-primary {
    background: var(--primary-color);
    color: white;
    box-shadow: 0 4px 16px rgba(0, 122, 255, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(0, 122, 255, 0.4);
}

.btn-secondary {
    background: var(--card-background);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

.btn-outline {
    background: transparent;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
}

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

.hero-stats {
    display: flex;
    gap: 64px;
    justify-content: center;
}

.stat {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.stat-value {
    font-size: 32px;
    font-weight: 700;
    color: var(--primary-color);
}

.stat-label {
    font-size: 14px;
    color: var(--text-secondary);
}

/* Features Section */
.features {
    padding: 80px 0;
}

.features h2 {
    font-size: 40px;
    font-weight: 700;
    text-align: center;
    margin-bottom: 56px;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 32px;
}

.feature-card {
    background: var(--card-background);
    padding: 32px;
    border-radius: 16px;
    box-shadow: var(--shadow);
    transition: all 0.3s ease;
}

.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.feature-icon {
    font-size: 48px;
    margin-bottom: 16px;
}

.feature-card h3 {
    font-size: 24px;
    margin-bottom: 12px;
}

.feature-card p {
    color: var(--text-primary);
    line-height: 1.8;
    font-size: 16px;
    opacity: 0.8;
}

/* Security Section */
.security {
    padding: 80px 0;
    background: var(--light-color);
}

.security h2 {
    font-size: 40px;
    font-weight: 700;
    text-align: center;
    margin-bottom: 56px;
}

.security-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 64px;
    align-items: center;
}

.security-diagram svg {
    width: 100%;
    height: auto;
    color: var(--text-primary);
}

.security-features {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.security-item h4 {
    font-size: 18px;
    margin-bottom: 8px;
}

.security-item p {
    color: var(--text-primary);
    opacity: 0.8;
    font-size: 15px;
}

/* Pricing Section */
.pricing {
    padding: 80px 0;
}

.pricing h2 {
    font-size: 40px;
    font-weight: 700;
    text-align: center;
    margin-bottom: 56px;
}

.pricing-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 32px;
    max-width: 1000px;
    margin: 0 auto;
}

.pricing-card {
    position: relative;
    background: var(--card-background);
    padding: 40px 32px;
    border-radius: 16px;
    box-shadow: var(--shadow);
    transition: all 0.3s ease;
}

.pricing-card.featured {
    transform: scale(1.05);
    box-shadow: var(--shadow-lg);
    border: 2px solid var(--primary-color);
}

.badge {
    position: absolute;
    top: -12px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--primary-color);
    color: white;
    padding: 4px 16px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
}

.pricing-card h3 {
    font-size: 24px;
    margin-bottom: 24px;
    text-align: center;
}

.price {
    text-align: center;
    margin-bottom: 32px;
}

.currency {
    font-size: 24px;
    color: var(--text-secondary);
}

.amount {
    font-size: 48px;
    font-weight: 700;
    color: var(--text-primary);
}

.period {
    font-size: 18px;
    color: var(--text-secondary);
}

.features-list {
    list-style: none;
    margin-bottom: 32px;
}

.features-list li {
    padding: 12px 0;
    border-bottom: 1px solid var(--border-color);
    font-size: 16px;
    font-weight: 400;
}

.features-list li:last-child {
    border-bottom: none;
}

/* Download Section */
.download {
    padding: 80px 0;
    background: var(--light-color);
}

.download h2 {
    font-size: 40px;
    font-weight: 700;
    text-align: center;
    margin-bottom: 56px;
}

.download-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 32px;
    max-width: 600px;
    margin: 0 auto 32px;
}

.download-card {
    background: var(--card-background);
    padding: 40px;
    border-radius: 16px;
    text-align: center;
    box-shadow: var(--shadow);
}

.download-card h3 {
    font-size: 24px;
    margin: 16px 0 8px;
}

.download-card p {
    color: var(--text-secondary);
    margin-bottom: 24px;
}

.source-link {
    text-align: center;
}

.source-link a {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
}

/* Footer */
.footer {
    background: var(--dark-color);
    color: white;
    padding: 64px 0 32px;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 48px;
    margin-bottom: 48px;
}

.footer-section h4 {
    font-size: 18px;
    margin-bottom: 16px;
}

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

.footer-section li {
    margin-bottom: 12px;
}

.footer-section a {
    color: rgba(255, 255, 255, 0.8);
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-section a:hover {
    color: white;
}

.footer-bottom {
    text-align: center;
    padding-top: 32px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: rgba(255, 255, 255, 0.6);
}

/* Responsive */
@media (max-width: 768px) {
    .hero-content h1 {
        font-size: 40px;
    }
    
    .hero-subtitle {
        font-size: 18px;
    }
    
    .cta-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .hero-stats {
        gap: 32px;
    }
    
    .security-content {
        grid-template-columns: 1fr;
    }
    
    .pricing-card.featured {
        transform: none;
    }
    
    .nav-links {
        display: none;
    }
}