Header.php

<div class="row">
            <nav class="navbar navbar-expand-lg navbar-light col-12 fixed-top " style="background-color: rgb(55, 194, 232) ; box-shadow: rgba(247, 250, 253, 0.04) 0px px 0px, rgba(255, 255, 255, 0.25) 0px 3px 0px inset;">
                <a class="navbar-brand" href="#">
                    <img src="./images/LogoMakr-9eSAAC.png" alt="logo" width="40px" >
                    <span style="color: white;">Filter&nbsp;</span><span>Finder</span><sup><strong>pk</strong></sup>
                </a>
                <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarNav" aria-controls="navbarNav" aria-expanded="false" aria-label="Toggle navigation">
                  <span class="navbar-toggler-icon"></span>
                </button>
                <div class="collapse navbar-collapse justify-content-end  "  id="navbarNav">
                    
                  <ul class="navbar-nav">
                    <li class="nav-item active mx-3">
                      <a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
                    </li>
                    <li class="nav-item mx-3">
                      <a class="nav-link" href="#contact">Contact</a>
                    </li>
                    <li class="nav-item mx-3">
                      <a class="nav-link" href="#About">About</a>
                    </li>
                    <li class="nav-item mx-3">
                      <a href="./RegForm.html" target="_blank">
                        <button type="button" class="btn btn-outline-light" >Register Filter</button>
                      </a>
                    </li>
                  </ul>
                </div>
              </nav>
              
        </div>