如何链接一个插件CSS和一个普通CSS而不覆盖另一个CSS？

Question

由于尝试了许多选项，我如何使我的html能够使插件CSS不覆盖普通CSS。这是我的代码：

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta/css/bootstrap.min.css">
<link href="path/to/css/bootstrap-tabs-x-bs4.css" media="all" rel="stylesheet" type="text/css" />
<script src="https://code.jquery.com/jquery-3.2.1.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.11.0/umd/popper.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta/js/bootstrap.min.js" type="text/javascript"></script>
<script src="path/to/js/bootstrap-tabs-x.js" type="text/javascript"></script>


<fieldset>
  <legend>Tabs Above Centered (Bordered)</legend>
</fieldset>

<div class="tabs-x align-center tabs-above tab-bordered">
  <!-- Nav tabs -->
  <ul class="nav nav-tabs" id="myTab" role="tablist">
    <li role="presentation" class="active"><a href="#home" aria-controls="home" role="tab" data-toggle="tab">Home</a></li>
    <li role="presentation"><a href="#profile" aria-controls="profile" role="tab" data-toggle="tab">Profile</a></li>
    <li role="presentation" class="dropdown">
      <a href="#" class="dropdown-toggle" id="myTabDrop1" data-toggle="dropdown" aria-controls="myTabDrop1-contents">
          Dropdown <span class="caret"></span></a>
      <ul class="dropdown-menu" aria-labelledby="myTabDrop1" id="myTabDrop1-contents">
        <li><a href="#dropdown1" role="tab" id="dropdown1-tab" data-toggle="tab" aria-controls="dropdown1">Dropdown 1</a></li>
        <li><a href="#dropdown2" role="tab" id="dropdown2-tab" data-toggle="tab" aria-controls="dropdown2">Dropdown 1</a></li>
      </ul>
    </li>
  </ul>

  <!-- Tab panes -->
  <div class="tab-content">
    <div role="tabpanel" class="tab-pane fade in active active" id="home">...</div>
    <div role="tabpanel" class="tab-pane" id="profile">...</div>
    <div role="tabpanel" class="tab-pane" id="settings">...</div>
    <div class="tab-pane fade" id="dropdown1" role="tabpanel" aria-labelledby="dropdown1-tab">...</div>
    <div class="tab-pane fade" id="dropdown2" role="tabpanel" aria-labelledby="dropdown2-tab">...</div>
  </div>
</div>

<h1>Gaming</h1>

<h2>Have you ever felt a rush of adrenaline just by sitting? That's easily achievable with most video games. They take you to another world, one where you have nothing to worry about, and everything to love. </h2>

<h3>Now, many people are under the illusion that games are unhealthy and are the cause of many sicknesses. That is a wrong belief. Scientific reasearch has proved that playing games has nothing to do with your physical health and the only reason most people
  who play games are unhealthy is because of their lifestyle. In fact, they have been proved to help mental ability in some areas, and many people who play games are better at reacting quick and thinking fast. </h3>

<h4>THE WORLD IS GETTING INCREASINGLY INVOLVED IN GAMING. YOU SHOULD TOO</h4>

但是我也尝试在CSS中导入，但插件无法正常工作。与将插件代码复制粘贴到我的CSS中相同