:root {
    --primary-color: #2563eb;
    --secondary-color: #1e40af;
    --accent-color: #3b82f6;
    --text-color: #1f2937;
    --light-text: #6b7280;
    --background: #ffffff;
    --light-bg: #f3f4f6;
    --border-color: #e5e7eb;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

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

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

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

h2 {
    font-size: 2.25rem;
    text-align: center;
    margin-bottom: 1.5rem;
    color: var(--text-color);
}

.section-desc {
    text-align: center;
    max-width: 800px;
    margin: 0 auto 3rem;
    color: var(--light-text);
}

/* Navigation */
.main-nav {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background: var(--background);
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    z-index: 1000;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.brand a {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    text-decoration: none;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 2rem;
}

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

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

.mobile-toggle {
    display: none;
}

/* Hero Section */
.hero {
    position: relative;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 4rem 0 2rem 0;
    margin-top: 60px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    text-align: center;
}

.hero-content {
    text-align: center;
    margin-bottom: 2rem;
    max-width: 800px;
    margin: 0 auto;
    padding: 0 1rem;
}

.hero-content h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    line-height: 1.2;
    color: white;
}

.hero-image {
    margin: 2rem 0;
    max-width: 600px;
    width: 100%;
    text-align: center;
}

.platform-image {
    max-width: 100%;
    height: auto;
    border-radius: 10px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.features-image {
    text-align: center;
    margin: 2rem 0;
}

.features-image img {
    max-width: 100%;
    height: auto;
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.hero p {
    font-size: 1.25rem;
    margin-bottom: 2rem;
    color: rgba(255, 255, 255, 0.9);
}

.cta-buttons {
    display: flex;
    justify-content: center;
    gap: 1rem;
}

.cta-btn {
    display: inline-flex;
    align-items: center;
    padding: 1rem 2rem;
    border-radius: 8px;
    font-weight: 600;
    text-decoration: none;
    transition: transform 0.3s;
    white-space: nowrap;
    min-width: 180px;
    justify-content: center;
}

.cta-btn.android {
    background: var(--success-color);
    color: white;
}

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

.cta-btn:hover {
    transform: translateY(-2px);
}

/* Hero Stats */
.hero-stats {
    display: flex;
    justify-content: center;
    gap: 3rem;
    margin-top: 3rem;
}

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

.stat-number {
    display: block;
    font-size: 2rem;
    font-weight: 700;
}

.stat-label {
    font-size: 0.875rem;
    opacity: 0.9;
}

/* Keyword Cloud Section */
.keyword-cloud {
    padding: 40px 0;
    background: var(--light-bg);
}

.cloud-content {
    max-width: 900px;
    margin: 0 auto;
    padding: 2rem;
    background: white;
    border-radius: 12px;
    box-shadow: var(--shadow-md);
    text-align: center;
    font-size: 1.1rem;
    line-height: 1.8;
}

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

.version-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.version-card {
    background: white;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: var(--shadow-md);
}

.card-header {
    padding: 1.5rem;
    color: white;
}

.card-header.android {
    background: var(--success-color);
}

.card-header.ios {
    background: var(--primary-color);
}

.card-content {
    padding: 1.5rem;
}

.card-content p {
    margin-bottom: 1rem;
}

.card-content ul {
    list-style: none;
    margin-bottom: 1.5rem;
}

.card-content li {
    margin-bottom: 0.5rem;
    color: var(--light-text);
}

.download-btn {
    display: block;
    text-align: center;
    padding: 0.75rem;
    background: var(--accent-color);
    color: white;
    text-decoration: none;
    border-radius: 6px;
    font-weight: 500;
    transition: background-color 0.3s;
}

.download-btn:hover {
    background: var(--secondary-color);
}

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

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.feature-item {
    text-align: center;
    padding: 2rem;
    border-radius: 12px;
    background: white;
    box-shadow: var(--shadow-sm);
    transition: transform 0.3s;
}

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

.feature-icon {
    width: 64px;
    height: 64px;
    margin: 0 auto 1rem;
    background: var(--light-bg);
    border-radius: 50%;
}

/* Products Section */
.products-section {
    padding: 80px 0;
    background: var(--light-bg);
}

.product-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.product-card {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--shadow-md);
}

.product-card h3 {
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.product-card ul {
    list-style: none;
    margin-top: 1rem;
}

.product-card li {
    margin-bottom: 0.5rem;
    color: var(--light-text);
}

/* Guide Section */
.guide-section {
    padding: 80px 0;
}

.guide-timeline {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.timeline-item {
    text-align: center;
    position: relative;
}

.timeline-number {
    width: 40px;
    height: 40px;
    background: var(--primary-color);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1rem;
    font-weight: 600;
}

/* About Section */
.about-section {
    padding: 80px 0;
    background: var(--light-bg);
}

.about-content {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
}

.about-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.stat-box {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--shadow-sm);
}

.stat-box .number {
    display: block;
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

.stat-box .label {
    color: var(--light-text);
}

/* Download Reminder Section */
.download-reminder {
    padding: 60px 0;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
}

.reminder-content {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
}

.reminder-content h2 {
    color: white;
    margin-bottom: 1.5rem;
}

.reminder-content p {
    margin-bottom: 2rem;
    opacity: 0.9;
}

.reminder-btn {
    display: inline-block;
    padding: 1rem 2.5rem;
    background: white;
    color: var(--primary-color);
    text-decoration: none;
    border-radius: 8px;
    font-weight: 600;
    transition: transform 0.3s, box-shadow 0.3s;
}

.reminder-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

/* Links Section */
.links-section {
    padding: 40px 0;
    background: white;
}

.links-wrapper {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    justify-content: center;
}

.related-sites {
    list-style: none;
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    justify-content: center;
}

.related-sites a {
    color: var(--light-text);
    text-decoration: none;
    font-size: 0.875rem;
}

/* Ad Section */
.ad-section {
    padding: 20px 0;
    text-align: center;
    background: var(--light-bg);
}

/* Footer */
.site-footer {
    background: var(--text-color);
    color: white;
    padding: 40px 0;
    text-align: center;
}

.footer-content p {
    margin: 0.5rem 0;
    opacity: 0.8;
}

/* Responsive Design */
@media (max-width: 768px) {
    .mobile-toggle {
        display: block;
        cursor: pointer;
    }

    .mobile-toggle span {
        display: block;
        width: 25px;
        height: 2px;
        background: var(--text-color);
        margin: 5px 0;
        transition: 0.3s;
    }

    .mobile-toggle.active span:nth-child(1) {
        transform: rotate(-45deg) translate(-5px, 6px);
    }

    .mobile-toggle.active span:nth-child(2) {
        opacity: 0;
    }

    .mobile-toggle.active span:nth-child(3) {
        transform: rotate(45deg) translate(-5px, -6px);
    }

    .nav-links {
        position: absolute;
        top: 70px;
        left: 0;
        width: 100%;
        background: var(--background);
        flex-direction: column;
        align-items: center;
        padding: 1rem 0;
        gap: 1rem;
        display: none;
        box-shadow: var(--shadow-md);
    }

    .nav-links.active {
        display: flex;
    }

    .hero-image {
        max-width: 90%;
        margin: 1rem 0;
    }
    
    .features-image {
        margin: 1.5rem 0;
    }

    .hero h1 {
        font-size: 2rem;
    }

    .hero-stats {
        flex-direction: column;
        gap: 1.5rem;
    }

    .cta-buttons {
        flex-direction: column;
        width: 100%;
        max-width: 300px;
        margin: 0 auto;
    }
    
    .cta-btn {
        width: 100%;
        margin: 0.5rem 0;
    }

    .about-stats {
        grid-template-columns: 1fr;
    }
    
    .cloud-content {
        padding: 1.5rem;
        font-size: 1rem;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 1rem;
    }

    .hero {
        padding: 100px 0 40px;
    }

    .feature-item,
    .product-card,
    .version-card {
        padding: 1.5rem;
    }
    
    h2 {
        font-size: 1.75rem;
    }
}