JSFiddle - React, Tailwind, and code Playground

HTML

<table>
<thead>
<tr>
<td><div class="rhead">need 300px</div></td>
<td colspan="7">Week #0</td>
<td colspan="7">Week #1</td>
<td colspan="7">Week #2</td>
<td colspan="7">Week #3</td>
<td colspan="7">Week #4</td>
<td colspan="7">Week #5</td>
<td colspan="7">Week #6</td>
<td colspan="7">Week #7</td>
<td colspan="7">Week #8</td>
<td colspan="7">Week #9</td>
<td colspan="7">Week #10</td>
<td colspan="7">Week #11</td>
<td colspan="7">Week #12</td>
<td colspan="7">Week #13</td>
<td colspan="7">Week #14</td>
<td colspan="7">Week #15</td>
<td colspan="7">Week #16</td>
<td colspan="7">Week #17</td>
<td colspan="7">Week #18</td>
<td colspan="7">Week #19</td>
<td colspan="7">Week #20</td>
<td colspan="7">Week #21</td>
<td colspan="7">Week #22</td>
<td colspan="7">Week #23</td>
<td colspan="7">Week #24</td>
<td colspan="7">Week #25</td>
<td colspan="7">Week #26</td>
<td colspan="7">Week #27</td>
<td colspan="7">Week #28</td>
<td colspan="7">Week #29</td>
<td colspan="7">Week #30</td>
<td colspan="7">Week #31</td>
<td colspan="7">Week #32</td>
<td colspan="7">Week #33</td>
<td colspan="7">Week #34</td>
<td colspan="7">Week #35</td>
<td colspan="7">Week #36</td>
<td colspan="7">Week #37</td>
<td colspan="7">Week #38</td>
<td colspan="7">Week #39</td>
<td colspan="7">Week #40</td>
<td colspan="7">Week #41</td>
<td colspan="7">Week #42</td>
<td colspan="7">Week #43</td>
<td colspan="7">Week #44</td>
<td colspan="7">Week #45</td>
<td colspan="7">Week #46</td>
<td colspan="7">Week #47</td>
<td colspan="7">Week #48</td>
<td colspan="7">Week #49</td>
<td colspan="7">Week #50</td>
<td colspan="7">Week #51</td>
</tr>
<tr>
<td class="rhead"...

CSS

.rhead {
  width: 300px;
}