问Navbar Logo固定中心和顶部

EN

<nav class="navbar navbar-expand-lg navbar-dark bg-dark fixed-top">
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarNavDropdown" 
 aria-controls="navbarNavDropdown" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse justify-content-start" id="navbarNavDropdown">
   <ul class="navbar-nav">
      <li class="nav-item dropdown">
       <a class="nav-link dropdown-toggle" href="#" id="navbarDropdownMenuLink" role="button" data- 
        toggle="dropdown" aria-haspopup="true" aria-expanded="false"><i 
        class="fas fa-store mr-3"></i>Product
         </a>

    <div class="dropdown-menu" aria-labelledby="navbarDropdownMenuLink">
      <a class="dropdown-item" href="...">..</a>
    </div>
  </li>

    <li class="nav-item active">
      <a class="nav-link" href="/" style="color: papayawhip"><i class="fas fa-home mr-3"></i>Home 
      <span class="sr-only">(current)</span></a>
    </li>
    </ul>
  </div>

  <a class="navbar-brand mx-auto" href="/"><img src="....." style="max-height: 60px" /></a>


  <div class="collapse navbar-collapse justify-content-end" id="navbarNavDropdown">
    <ul class="navbar-nav"><li class="nav-item">
        <a>...</a>
    </li>
  
    </ul>
   </div>
</nav>