JSFiddle - React, Tailwind, and code Playground

HTML

<div class="block">
    <div class="num">1</div>
    <div class="num">2</div>
    <p>дней</p>
</div>

CSS

.block {
    display: inline-block;
    text-align: center;  
    font-family: arial;
}
.num {
    text-align: center;    
    display: inline-block;
    border-radius: 5px;
    width: 40px;
    height: 60px;
    line-height: 60px;
    font-size: 40px;
    background: #eee;
}

/* -------------------------- */

.num {
    position: relative;
}

.num:before {
    content: '';
    
    position: absolute;
    top: 0;        left: 0;
    bottom: 0;     right: 0;
    
    z-index: -1;
    
    border-radius: 5px;
    box-shadow: 0 0 40px black;
}