Answers for "navbar items centered"

navbar items center

# css
.navbar-expand-lg .navbar-collapse {
display: flex!important;
justify-content: space-around;
flex-basis: auto;
}

css menu center of screen

/* 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>