Check out example codes for "css menu center of screen". It will help you in understanding the concepts better.

Code Example 1

/* css code */
.container{            
  top: 50%;
  left: 50%;
  transform: translateX(-50%) translateY(-50%);
  position: absolute;
}

/* html code */
<div class="container">
    <li><a href="#" class="link">Home</a></li>
    <li><a href="#" class="link">About Us</a></li>
    <li><a href="#" class="link">Services</a></li>
    <li><a href="#" class="link">Gallery</a></li>
    <li><a href="#" class="link">Contact</a></li>
</div>

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