<style>
        body {
            font-family: 'Helvetica Neue', Arial, 'Hiragino Kaku Gothic ProN', 'Hiragino Sans', Meiryo, sans-serif;
            line-height: 1.7;
            color: rgba(0,0,0,0.87);
            margin: 0;
            padding: 0;
            background-color: #f5f5f5;
        }
        .container {
            max-width: 800px;
            margin: 40px auto;
            padding: 40px;
            background: white;
            border-radius: 8px;
            box-shadow: 0 2px 4px rgba(0,0,0,0.1);
        }
        h1 {
            font-size: 24px;
            font-weight: 700;
            margin-bottom: 30px;
            padding-bottom: 15px;
            border-bottom: 2px solid #f0f0f0;
        }
        h2 {
            font-size: 18px;
            margin-top: 30px;
            margin-bottom: 15px;
            color: #333;
        }
        h3 {
            font-size: 16px;
            margin-top: 20px;
            color: #444;
        }
        p {
            margin-bottom: 15px;
        }
        .section {
            margin-bottom: 30px;
        }
        ul {
            padding-left: 20px;
            margin-bottom: 15px;
        }
        li {
            margin-bottom: 8px;
        }
        .update-history {
            margin-top: 40px;
            padding-top: 20px;
            border-top: 1px solid #eee;
        }
        .contact {
            margin-top: 30px;
            padding: 15px;
            background: #f8f9fa;
            border-radius: 4px;
        }
        @media (max-width: 600px) {
            .container {
                margin: 20px;
                padding: 20px;
            }
        }
    </style>