JSFiddle - React, Tailwind, and code Playground
HTML
<table>
<thead>
<th>A</th>
<th>B</th>
<th>C</th>
<th>D</th>
<th>E</th>
</thead>
<tbody>
<tr>
<th class="subheader" scope="rowgroup" colspan="5">Data group 1</th>
</tr>
<tr>
<td>1</td>
<td>6</td>
<td>3</td>
<td>6</td>
<td>2</td>
</tr>
<tr>
<td>1</td>
<td>5</td>
<td>7</td>
<td>2</td>
<td>5</td>
</tr>
<tr>
<td>S</td>
<td>2</td>
<td>3</td>
<td>4</td>
<td>6</td>
</tr>
<tr>
<td>8</td>
<td>5</td>
<td>3</td>
<td>7</td>
<td>9</td>
</tr>
<tr>
<th class="subheader" scope="rowgroup" colspan="5">Data group 2</th>
</tr>
<tr>
<td>A</td>
<td>5</td>
<td>3</td>
<td>H</td>
<td>D</td>
</tr>
<tr>
<td>Q</td>
<td>R</td>
<td>T</td>
<td>2</td>
<td>3</td>
</tr>
<tr>
<td>6</td>
<td>4</td>
<td>W</td>
<td>2</td>
<td>6</td>
</tr>
<tr>
<td>5</td>
<td>3</td>
<td>W</td>
<td>5</td>
<td>6</td>
</tr>
<tr>
<th class="subheader" scope="rowgroup" colspan="5">Data group 3</th>
</tr>
<tr>
<td>1</td>
<td>9</td>
<td>E</td>
<td>3</td>
<td>S</td>
</tr>
<tr>
<td>T</td>
<td>4</td>
<td>D</td>
<td>H</td>
<td>S</td>
</tr>
<tr>
<td>4</td>
<td>S</td>
<td>5</td>
...
CSS
table {
font-family:arial;
width:400px;
text-align:center;
border:1px solid black;
margin:15px;
}
th
{
width:20%;
color:white;
background-color:black;
height:20px;
line-height:20px;
}
tr
{
}
td
{
font-size:11px;
height:18px;
line-height:18px;
}
.subheader {
background-color:#dedede;
text-align:left;
font-size:12px;
height:20px;
line-height:20px;
padding-left:10px;
}