JSFiddle - React, Tailwind, and code Playground

HTML

<div class="wrap">
    <div class="block-left">фикс</div>
    <div class="block-left">фикс</div>
    <div class="block-left">фикс</div>
    <div class="block-right">фикс, но не заданной ширины</div>
    <div class="content">резина</div>
</div>

CSS

.wrap div {
    margin: 0 5px;
    padding: 5px;
    text-align: center;
    line-height: 60px;
    font-family: Tahoma, Arial, sans-serif;
}
.block-left, .block-right {
    background-color: #444;
    color: #fff;
}
.block-left {
    float: left;
    width: 60px;
}
.block-right {
    float: right;
}
.content {
    background-color: #E0D05C;
    overflow: hidden;
}