css alight everything in the center of the site code example

Example 1: center with css

.parent {
  position: relative;
}
.child {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}

Example 2: css centraliz page

Use a container element and set a specific max-width.
A common width many websites use is 960px.
To actually center the page, add margin: auto.
The following example will center the website on screens that are wider than
500px.On screens that are less than 500px wide,
it will span the whole of the page:

<style>
.content {
  max-width: 500px;
  margin: auto;
}
</style>
<body>

<div class="content">
  <!-- Page content -->
</div>

</body>