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

body {
    font-family: 'Helvetica Neue', Arial, 'Hiragino Kaku Gothic ProN', 'Hiragino Sans', Meiryo, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f8f9fa;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
}

header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    text-align: center;
    padding: 2rem 0;
    margin-bottom: 2rem;
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
}

header p {
    font-size: 1.1rem;
    opacity: 0.9;
}

nav {
    background: white;
    padding: 1rem 0;
    margin-bottom: 2rem;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    border-radius: 8px;
}

nav ul {
    list-style: none;
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 2rem;
}

nav a {
    color: #333;
    text-decoration: none;
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: 4px;
    transition: background-color 0.3s ease;
}

nav a:hover {
    background-color: #667eea;
    color: white;
}

nav a.current {
    background-color: #667eea;
    color: white;
    font-weight: 600;
}

main {
    background: white;
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    margin-bottom: 2rem;
}

h1, h2, h3 {
    color: #333;
    margin-bottom: 1rem;
}

h1 {
    font-size: 2.2rem;
    border-bottom: 3px solid #667eea;
    padding-bottom: 0.5rem;
}

h2 {
    font-size: 1.8rem;
    color: #667eea;
    margin-top: 2rem;
}

h3 {
    font-size: 1.4rem;
    color: #555;
    margin-top: 1.5rem;
}

p, li {
    margin-bottom: 1rem;
}

ul, ol {
    margin-left: 2rem;
    margin-bottom: 1rem;
}

.app-features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin: 2rem 0;
}

.feature-card {
    background: #f8f9fa;
    padding: 1.5rem;
    border-radius: 8px;
    border-left: 4px solid #667eea;
}

.feature-card h3 {
    color: #667eea;
    margin-top: 0;
}

.contact-info {
    background: #f8f9fa;
    padding: 1.5rem;
    border-radius: 8px;
    margin: 2rem 0;
}

.contact-info h3 {
    color: #667eea;
    margin-top: 0;
}

.contact-methods {
    margin: 2rem 0;
}

.form-container {
    background: white;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    margin: 1.5rem 0;
    padding: 1rem;
}

.form-container iframe {
    border-radius: 4px;
}

footer {
    text-align: center;
    padding: 2rem 0;
    color: #666;
    border-top: 1px solid #eee;
    margin-top: 3rem;
}

.back-link {
    display: inline-block;
    margin-bottom: 1rem;
    color: #667eea;
    text-decoration: none;
    font-weight: 500;
}

.back-link:hover {
    text-decoration: underline;
}

@media (max-width: 768px) {
    .container {
        padding: 10px;
    }
    
    header h1 {
        font-size: 2rem;
    }
    
    nav ul {
        flex-direction: column;
        gap: 0.5rem;
    }
    
    main {
        padding: 1rem;
    }
}