body {
    font-family: 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.8;
    background-color: #e0e0e0;
    margin: 0;
    padding: 0;
}

.container {
    max-width: 900px;
    margin: 50px auto;
    background: #fff;
    padding: 40px;
    border-radius: 10px;
    box-shadow: 0 0 20px rgba(0, 0, 0, 0.1);
}

h1, h2, h3 {
    color: #333;
    font-weight: bold;
    margin-left: 0;
    margin-bottom: 10px;
}

h1 {
    font-size: 2.5em;
    text-align: left;
    margin-bottom: 20px;
}

h2 {
    font-size: 2em;
    margin-top: 40px;
    margin-bottom: 20px;
    padding-bottom: 5px;
    border-bottom: 2px solid #ddd;
}

h3 {
    color: #555;
    font-size: 1.5em;
    margin-top: 30px;
    margin-bottom: 20px;
    padding-bottom: 5px;
    border-bottom: 2px solid #ddd; /* 下線を追加 */
}

h4 {
    color: #666;
    font-size: 1.3em;
    margin-top: 20px;
}

ol {
    background: #f9f9f9;
    padding: 20px;
    margin-left: 20px;
    border-radius: 5px;
    list-style-position: inside;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.05);
    counter-reset: item;
}

ol li {
    margin: 10px 0;
    padding-left: 0;
    position: relative;
    list-style-type: decimal;
    color: #333;
    font-weight: normal;
    font-size: 1em;
}

a {
    color: #3498db;
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

code {
    background-color: #f4f4f4;
    border-radius: 3px;
    padding: 4px 6px;
    font-size: 90%;
    color: #c7254e;
    font-family: Menlo, Monaco, Consolas, "Courier New", monospace;
}

strong {
    font-weight: bold;
    color: #333;
}