JSFiddle - React, Tailwind, and code Playground

HTML

<h4>Mai</h4>
            <table class="monat">
             <tr>
              <td class="tag"></td>
              <td class="tag">6</td>
              <td class="tag">13</td>
              <td class="tag">20</td>
              <td class="tag">27</td>
             </tr>
             <tr>
              <td class="tag"></td>
              <td class="tag">7</td>
              <td class="tag">14</td>
              <td class="tag">21</td>
              <td class="tag">28</td>
             </tr>
             <tr>
              <td class="tag">1</td>
              <td class="tag">8</td>
              <td class="tag">15</td>
              <td class="tag">22</td>
              <td class="tag">29</td>
             </tr>
             <tr>
              <td class="tag">2</td>
              <td class="tag">9</td>
              <td class="tag">16</td>
              <td class="tag">23</td>
              <td class="tag">30</td>
             </tr>
             <tr>
              <td class="tag">3</td>
              <td class="tag">10</td>
              <td class="tag">17</td>
              <td class="tag">24</td>
              <td class="tag">31</td>
             </tr>
             <tr>
              <td class="tag"><a class="samstag" href="<?PHP echo $_SERVER['REQUEST_URI'] ?>?fahrplan=samstag">4</a></td>
              <td class="tag"><a class="samstag" href="<?PHP echo $_SERVER['REQUEST_URI'] ?>?fahrplan=samstag">11</a></td>
              <td class="tag"><a class="samstag" href="<?PHP echo $_SERVER['REQUEST_URI'] ?>?fahrplan=samstag">18</a></td>
              <td class="tag"><a class="samstag" href="<?PHP echo $_SERVER['REQUEST_URI'] ?>?fahrplan=samstag">25</a></td>
              <td class="tag"></td>
             </tr>
             <tr>
              <td class="tag">5</td>
              <td class="tag"><a class="sonntag" href="<?PHP echo $_SERVER['REQUEST_URI'] ?>?fahrplan=sonntag">12</a></td>
              <td class="tag">19</td>
              <td class="tag"><a...

CSS

* {
font-family : 'lucida grande',tahoma,verdana,arial,sans-serif;
font-size : 11px;
padding : 0;
margin : 0;
border-spacing : 0;
line-height : normal;
}
td.monat {
width : 120px;
}
a.samstag, a.sonntag {
<!--padding-top : 2.5px;
margin-bottom : -2.5px;-->
display : block;
color : #000000;
background-color : #00FFFF;
text-decoration: none;
text-underline: none;
}
a.samstag {
background-color : #00FFFF;
}
a.sonntag {
background-color : #FF9900;
}
td.tag, td.ltag, a.samstag, a.sonntag {
text-align : center;
vertical-align : middle;
width : 20px;
height : 20px;
}
td.monat, td.legende {
background-color : #999999;
}
td.tag, td.ltag {
background-color : #CCCCCC;
}