JSFiddle - React, Tailwind, and code Playground

by Alexey Lisovy

HTML

<button>кнопка</button>

CSS

button {
  box-shadow:
    -1px -1px 0 blue,
    -2px -2px 0 blue,
    -3px -3px 0 blue,
    -4px -4px 0 blue;
 
  color: #fff;
  border: lightblue 1px solid;
  background-color: blue;
  display: block;
  position: relative;
}
button::after {
            content: '';
            color: black;
            display: block;
            position: absolute;
            top: -5px;
            left: -5px;
            width: 4px;
            height: 4px;
            background: linear-gradient(45deg, transparent 49%, white 49%, white 51%, transparent 51%);
}