docs/img/box-a1-b1.svg

<?xml version="1.0" standalone="yes"?>
<svg xmlns="http://www.w3.org/2000/svg" width="300" height="120">
    <foreignObject x="0" y="0" width="300" height="120">
        <body xmlns="http://www.w3.org/1999/xhtml">
            <table>
                <thead>
                    <tr>
                        <th></th>
                        <th>A</th>
                        <th>B</th>
                        <th>C</th>
                    </tr>
                </thead>
                <tbody>
                    <tr>
                        <td>1</td>
                        <td>Box A1</td>
                        <td>Box B1</td>
                        <td></td>
                    </tr>
                    <tr>
                        <td>2</td>
                        <td></td>
                        <td></td>
                        <td></td>
                    </tr>
                </tbody>
            </table>
            <div class="tabs">
                <div class="tab active">Sheet1</div>
            </div>
            <style>
                body {
                    font-family:
                        -apple-system, BlinkMacSystemFont,
                        "Segoe UI",
                        "Roboto",
                        "Helvetica Neue", "Ubuntu", Arial, sans-serif,
                        "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
                    font-size: 16px;
                    margin: 0;
                }

                table {
                    border-collapse: collapse;
                    border-spacing: 0;
                }

                th:first-child {
                    min-width: 32px;
                }

                th:not(:first-child) {
                    min-width: 80px;
                }

                th,
                td:first-child {
                    background-color: #e6e6e6;
                    text-align: center;
                    font-weight: normal;
                    border: 1px solid #a2a2a2;
                }

                td:not(:first-child) {
                    border: 1px solid #dfe2e5;
                    padding: 1px 3px;
                }

                .tabs {
                    display: flex;
                    margin-top: 5px;
                    padding-left: 48px;
                    border-top: 1px solid #a2a2a2;
                }

                .tab {
                    color: #777;
                    padding: 4px 8px;
                    border-right: 1px solid #a2a2a2;

                }

                .tab:first-child {
                    border-left: 1px solid #a2a2a2;
                }

                .tab.active {
                    color: black;
                    background-color: white;
                    margin-top: -1px;
                    border-bottom: 2px solid #a2a2a2;
                }

                td.box {
                    font-weight: bold;
                    text-align: center;
                    border-right: 1px solid black;
                    border-bottom: 1px solid black;
                }
            </style>
        </body>
    </foreignObject>
</svg>