Printed document - how to get it centred on A4

On my quiz results slide I have a Print screen button which is controlled by the following Javascript:

var styles = `@media print {
body, * { visibility: hidden; }
html, body { overflow: hidden; transform: translateZ(0); }
#slide {
transform: scale(1.3) !important;
}
#wrapper {
transform: scale(1) !important;
}
#slide,
#wrapper {
width: 100% !important;
height: 100% !important;
overflow: visible !important;
}
#frame {
overflow: visible !important;
}
.slide-transition-container {
overflow: visible !important;
}
@page {size: A4 landscape;max-height:99%; max-width:99%}
.slide-container, .slide-container * {
visibility: visible !important;
margin-top: 0px !important;
margin-left: 0px !important;
}
#outline-panel {
display: none !important;
}
}
}`
var stylesheet = document.createElement('style');
stylesheet.type = 'text/css';
stylesheet.innerText = styles;
document.head.appendChild(stylesheet);
window.print();

Problem: the content of printed document is too far to the left of the A4 page. 

Question: how can I tweak the Javascript so it's centred please?