Javascript stylesheet changer changes size of elements on website

Question

So I've added a dark mode theme that I can turn on with a click of a button. A have a javascript that changes the stylesheet with a press of a button:

function nightmode(sheet,sheet2) {
  document.getElementById('light1').setAttribute('href', sheet);
  document.getElementById('light2').setAttribute('href', sheet2);
}

And buttons which can change the stylesheet

<li> <a onclick="nightmode('/cdn/about/css/main_dark.css','/cdn/about/css/bootstrap_dark.css')"  alt="nightmode"> <i class="far fa-moon "></i> </a></li>
<li> <a onclick="nightmode('/cdn/about/css/main.css','/cdn/about/css/bootstrap.css')"  alt="nightmode"> <i class="fas fa-moon "></i> </a></li>

But the problem is when I click one of the button the stylesheet changes size of different elements, for example my icon on the website changes. This can be tested on https://swedcraft.net/Game_Hub/ by pressing on the moons. The difference between the two stylesheets are only colors, no sizes. Thank you!

Answer 1

css file has changed the size.For example, this navbar
.
First, you do nothing,see the css properties,
.
Next,click the moon button and see,padding size has changed,
.
So,the stylesheet changes size of different elements.