JSFiddle - React, Tailwind, and code Playground

HTML

<div class="indicator"></div>
<div class="mainPanel">
    <div>Speichern</div>
    <div>Style</div>
    <div>Speichern</div>
</div>
<br>
<br>
 <div class="indicator"></div>
<div class="mainPanel">
    <div>Speichern</div>
    <div>Style long long long long</div>
    <div>Speichern</div>
</div>   
    
<br>
<br>    
<div class="indicator"></div>
<div class="mainPanel">
    <div>L</div>
    <div>Style</div>
    <div>Speichern</div>
</div>
<br>
<br>
<div class="indicator"></div>
<div class="mainPanel">
    <div>L</div>
    <div>Style Style Style Style Style Style Style Style Style</div>
    <div>Speichern</div>
</div>

CSS

.mainPanel {
    width: 300px;
    height: 50px;
    -webkit-box-sizing: border-box;
    -moz-box-sizing: border-box;
    box-sizing: border-box;
    display: -webkit-box;
    display: -ms-flexbox;
    display: -webkit-flex;
    display: flex;
    -webkit-box-pack: justify;
    -ms-flex-pack: justify;
    -webkit-justify-content: space-between;
    justify-content: space-between;
    -webkit-box-align: center;
    -ms-flex-align: center;
    -webkit-align-items: center;
    align-items: center;
}
.mainPanel > div {
    padding: 0 10px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    flex: 1 1 25%;
    border: solid 1px #999;
}
.mainPanel > div:nth-child(2) {
    flex: 2 0 auto;
    max-width: 50%;
}