body {
            font-family: "Helvetica Neue", Arial, "Hiragino Kaku Gothic ProN", "Hiragino Sans", Meiryo, sans-serif;
            line-height: 1.6;
            color: #333;
            max-width: 800px;
            margin: 0 auto;
            padding: 20px;
            background-color: #f9f9f7;
        }
        header {
            border-bottom: 2px solid #8c7663;
            padding-bottom: 10px;
            margin-bottom: 20px;
        }
        h1 {
            color: #5c4a3c;
            font-size: 22px;
        }
        h2 {
            color: #5c4a3c;
            font-size: 18px;
            margin-top: 40px;
            border-bottom: 1px solid #eeeae4;
            padding-bottom: 5px;
        }
        .nav-back {
            margin-bottom: 20px;
        }
        .nav-back a {
            color: #8c7663;
            text-decoration: none;
            font-size: 14px;
        }
        .nav-back a:hover {
            text-decoration: underline;
        }
        .stone-photo {
            max-width: 100%;
            height: auto;
            border-radius: 4px;
            margin-bottom: 20px;
            display: block;
        }
        table {
            width: 100%;
            border-collapse: collapse;
            margin-bottom: 30px;
            background-color: #fff;
        }
        th, td {
            border: 1px solid #e0dcd5;
            padding: 12px;
            text-align: left;
        }
        th {
            background-color: #eeeae4;
            color: #5c4a3c;
            width: 25%;
        }
        footer {
            margin-top: 50px;
            border-top: 1px solid #e0dcd5;
            padding-top: 15px;
            font-size: 12px;
            text-align: center;
            color: #777;
        }

/* 画面幅が600px以下（スマホなど）の場合の調整 */
@media (max-width: 600px) {
    table, tbody, tr, th, td {
        display: block; /* テーブルをブロック要素にして縦に並べる */
        width: 100% !important;
    }
    th {
        border-bottom: none; /* 項目名と内容の間の線をすっきりさせる */
        padding-bottom: 5px;
    }
    td {
        padding-top: 5px;
        margin-bottom: 10px; /* テーブル内での区切りをわかりやすく */
    }
}