Using transform to center a div along with animation

Issue

So I'm trying to implement a loader that spins in the middle of the screen I have used transform:translate earlier do this ex:

position: absolute;
left:50%;
top:50%;
transform:  translate(-50%,-50%);

I tried to implement something similar but instead of getting centered the top left appears to be in the center. Here's my code HTML

<section class="waitwrapper" v-else>
<div class="loader"></div>
</section>

CSS

.waitwrapper{
background-color: #455879;
position: relative;
width: 98vw;
height: 97vh;
}
.loader{
border: 16px solid  #f3f3f3;
border-top: 16px solid #455879; /* w3schools loader */
border-radius: 50%;
width: 20%;
aspect-ratio:1;
animation: spin 2s linear infinite;
position: absolute;
left:50%;
top:50%;
transform:  translate(-50%,-50%);

}

@keyframes spin {

0% { transform: rotate(0deg); }
100% { transform: rotate(360deg); }
}

Solution

One trusted way to centralize one item is to use display: flex with justify-content: center and align-items: center in the parent element.

*, *::before, *::after{
  box-sizing:border-box;
}

.waitwrapper{
  background-color: #455879;
  width: 98vw;
  height: 97vh;
  display:flex;
  justify-content:center;
  align-items:center
}

.loader{
  border: 16px solid  #f3f3f3;
  border-top: 16px solid #455879; /* w3schools loader */
  border-radius: 50%;
  width: 20%;
  aspect-ratio:1;
  animation: spin 2s linear infinite;
}

@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

<section class="waitwrapper" v-else>
  <div class="loader"></div>
</section>

But why your code doesn't work very well? I must tell you when you change transform property in your animation actually you overwrite it. And because of it transform: translate(-50%, -50%);, doesn't work enymore. For solve that problem you can use below solution

.waitwrapper{
  background-color: #455879;
  position: relative;
  width: 98vw;
  height: 97vh;
}
.loader{
  border: 16px solid  #f3f3f3;
  border-top: 16px solid #455879; /* w3schools loader */
  border-radius: 50%;
  width: 20%;
  aspect-ratio:1;
  animation: spin 2s linear infinite;
  position: absolute;
  left:50%;
  top:50%;
/* transform:translate(-50%,-50%); */
}

@keyframes spin {
  0%{
    transform: translate(-50%, -50%) rotate(0deg);
  }
  100% {
    transform: translate(-50%, -50%)  rotate(360deg);
  }
}

<section class="waitwrapper" v-else>
  <div class="loader"></div>
</section>

Answered By - Zahra Mirzaei