test gistpad codeswing

codeswing.json

{
  "scripts": [],
  "styles": []
}

index.html

<div class="playground">
    <button>click me</button>
</div>

script.js

const btn = document.querySelector('button');

btn.addEventListener('click', e => {
   btn.textContent += '!';
});

style.css

html, body {
    height: 100%;
    overflow: hidden;
    margin: 0;
}

body {
    display: grid;
    place-content: center;
}

.playground {
    width: 90vmin;
    height: 90vmin;
    background: red;
    display: grid;
    place-content: center;
}