JSFiddle - React, Tailwind, and code Playground

HTML

<div class='fixed_block'>
    <div class='children_block'>
    
    </div>
  </div>
 
<button>
    Увеличить размер блока ".children_block
  </button>
  <br />
  <a href=''>
    Исходное положение
  </a>

CSS

.fixed_block {
  width: 150px;
  min-height: 150px;
  background-color: blue;
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
    
}

.children_block {
  width: 130px;
  height: 130px;
  background-color: #fff;
  margin: 10px auto;
}

JavaScript

$('button').on('click', function(){
  $('.children_block').height('170px');
});

$('a').on('click', function(e){
  e.preventDefault();
  $('.children_block').height('130px');
});