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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Pretendard', 'Segoe UI', 'Roboto', 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #fff;
}

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

/* Header */
header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 40px 0;
    text-align: center;
}

header h1 {
    font-size: 3em;
    font-weight: 700;
    margin-bottom: 10px;
}

.tagline {
    font-size: 1.2em;
    opacity: 0.9;
}

/* Hero Section */
.hero {
    padding: 80px 0;
    text-align: center;
    background: linear-gradient(180deg, #f8f9fa 0%, #ffffff 100%);
}

.hero h2 {
    font-size: 2.5em;
    font-weight: 700;
    margin-bottom: 20px;
    color: #2d3748;
    line-height: 1.3;
}

.hero .description {
    font-size: 1.2em;
    color: #718096;
    margin-bottom: 40px;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.download-buttons {
    display: flex;
    gap: 20px;
    justify-content: center;
    flex-wrap: wrap;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 15px 30px;
    border-radius: 12px;
    text-decoration: none;
    font-weight: 600;
    font-size: 1.1em;
    transition: all 0.3s ease;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.btn-android {
    background-color: #3DDC84;
    color: white;
}

.btn-android:hover {
    background-color: #2fb66d;
    transform: translateY(-2px);
    box-shadow: 0 6px 8px rgba(0, 0, 0, 0.15);
}

.btn-ios {
    background-color: #000000;
    color: white;
}

.btn-ios:hover {
    background-color: #333333;
    transform: translateY(-2px);
    box-shadow: 0 6px 8px rgba(0, 0, 0, 0.15);
}

/* Features Section */
.features {
    padding: 80px 0;
    background-color: #ffffff;
}

.features h3 {
    font-size: 2.5em;
    text-align: center;
    margin-bottom: 60px;
    color: #2d3748;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
}

.feature-card {
    text-align: center;
    padding: 30px;
    border-radius: 12px;
    background-color: #f8f9fa;
    transition: all 0.3s ease;
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
}

.feature-icon {
    font-size: 3em;
    margin-bottom: 20px;
}

.feature-card h4 {
    font-size: 1.5em;
    margin-bottom: 15px;
    color: #2d3748;
}

.feature-card p {
    color: #718096;
    line-height: 1.8;
}

/* About Section */
.about {
    padding: 80px 0;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    text-align: center;
}

.about h3 {
    font-size: 2.5em;
    margin-bottom: 30px;
}

.about p {
    font-size: 1.2em;
    max-width: 800px;
    margin: 0 auto 20px;
    line-height: 1.8;
    opacity: 0.95;
}

/* Contact Section */
.contact {
    padding: 80px 0;
    text-align: center;
    background-color: #f8f9fa;
}

.contact h3 {
    font-size: 2.5em;
    margin-bottom: 20px;
    color: #2d3748;
}

.contact p {
    font-size: 1.2em;
    color: #718096;
    margin-bottom: 30px;
}

.contact-info {
    margin-top: 40px;
}

.contact-info p {
    font-size: 1.1em;
    margin: 10px 0;
}

.contact-info a {
    color: #667eea;
    text-decoration: none;
    font-weight: 600;
}

.contact-info a:hover {
    text-decoration: underline;
}

/* Footer */
footer {
    background-color: #2d3748;
    color: white;
    padding: 40px 0;
    text-align: center;
}

.footer-links {
    margin-top: 20px;
    display: flex;
    gap: 30px;
    justify-content: center;
}

.footer-links a {
    color: #cbd5e0;
    text-decoration: none;
    transition: color 0.3s ease;
}

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

/* Responsive Design */
@media (max-width: 768px) {
    header h1 {
        font-size: 2em;
    }

    .hero h2 {
        font-size: 1.8em;
    }

    .hero .description {
        font-size: 1em;
    }

    .features h3,
    .about h3,
    .contact h3 {
        font-size: 2em;
    }

    .feature-grid {
        grid-template-columns: 1fr;
    }

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

    .btn {
        width: 100%;
        max-width: 300px;
    }

    .footer-links {
        flex-direction: column;
        gap: 15px;
    }
}