我想弄清楚为什么我的容器在小屏幕部分与我的标题重叠。我的目标是将容器（及其内部的所有内容）放在页面上的标题下面。它适用于超小屏幕部分，但小屏幕是一切都出错的地方。我刚刚开始我的自助旅程，所以请忽略我的草率代码。
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Title</title>
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<link href="https://fonts.googleapis.com/css?family=Abel" rel="stylesheet">
<link href="https://fonts.googleapis.com/css?family=Anton" rel="stylesheet">
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.1/css/bootstrap.min.css" integrity="sha384-WskhaSGFgHYWDcbwN70/dfYBj47jz9qbsMId/iRN3ewGhXQFZCSftd1LZCfmhktB" crossorigin="anonymous">
<link rel="stylesheet" href="css/grid-system-test.css">
</head>
<body>
<header>
<div class="d-sm-none"> <!-- Navbar is only viewable on extra small screens -->
<div class="white-block">
<img class="comp-logo mx-auto d-block" src="img/logo.png" alt="company logo">
</div>
<nav class="text-center">
<div class="col-12">
<h2 class="thin-font">codeup design</h2>
</div>
<div class="col-12">
<ul class="nav xs-nav">
<li class="nav-item">
<a class="nav-link" href="#"><p>SERVICES</p></a>
</li>
<li class="nav-item">
<a class="nav-link" href="#"><p>WORK</p></a>
</li>
<li class="nav-item">
<a class="nav-link" href="#"><p>BLOG</p></a>
</li>
<li class="nav-item">
<a class="nav-link" href="#"><p>CONTACT</p></a>
</li>
</ul>
</div>
</nav>
</div>
<div class="d-none d-sm-block"> <!------------------------ NAVBAR FOR SMALL SCREEN STARTS HERE -------------------------->
<nav class="white-bg text-center small-nav">
<ul class="nav justify-content-center">
<li class="small-nav-item">
<a class="small-nav-link" href="#">SERVICE</a>
</li>
<li class="small-nav-item">
<a class="small-nav-link" href="#">WORK</a>
</li>
<li class="small-nav-item">
<a class="small-nav-link" href="#"><img class="comp-logo comp-logo-small" src="img/logo.png"></a>
</li>
<li class="small-nav-item">
<a class="small-nav-link" href="#">BLOG</a>
</li>
<li class="small-nav-item">
<a class="small-nav-link" href="#">CONTACT</a>
</li>
</ul>
<div class="col-12">
<h2 class="thin-font">codeup design</h2>
</div>
</nav>
</div>
</header>
<!-------------------------------------------- CONTAINER STARTS HERE -------------------------------------------------->
<div class="container-fluid text-center">
<h2>VISUAL DESIGN & WEB DEVELOPMENT</h2>
<h4 class="park-city-text">FROM PARK CITY, UTAH</h4>
<div class="row">
<div class="col-6">
<div class="circle-big red-bg ml-4">
<h6 class="text-light center-txt">DESIGN</h6>
</div>
</div>
<div class="col-6">
<div class="circle-big orange-bg mr-4">
<h6 class="text-light center-txt">DEVELOP</h6>
</div>
</div>
</div>
<div class="row">
<div class="col-6">
<div class="circle-big green-bg ml-4 circle-margin-top">
<h6 class="text-light center-txt">SUPPORT</h6>
</div>
</div>
<div class="col-6">
<div class="circle-big blue-bg mr-3 circle-margin-top">
<h6 class="text-light center-txt">HOST</h6>
</div>
</div>
</div>
<!-- end of circle images -->
<p class="selectW">SELECTED WORK</p>
<img class="ipad rounded" src="img/apple-ipad.jpg" alt="apple on ipad">
<div class="row">
<div class="col-6">
<p class="float-left ml-3">FEATURED PROJECT</p>
</div>
<div class="col-6">
<div class="circle-sm red-bg small-circle-text float-right mr-2"><p class="font-weight-bold">D</p></div>
<div class="circle-sm orange-bg small-circle-text float-right mr-2"><p class="font-weight-bold">D</p></div>
<div class="circle-sm green-bg small-circle-text float-right mr-2"><p class="font-weight-bold">S</p></div>
<div class="circle-sm blue-bg small-circle-text float-right mr-2"><p class="font-weight-bold">H</p></div>
</div>
</div>
</div>
</body>
</html>