在材料设计中从.mdl-layout__drawer-button中删除外边框线？

Question

我想从 .mdl-layout__drawer-button 中删除外边框。 当我点击它时，它显示我外部方框。 我指的是this site。
以下是代码和截图：

<!-- Uses a transparent header that draws on top of the layout's background -->
<style>
.demo-layout-transparent {
  background: url('../assets/demos/transparent.jpg') center / cover;
}
.demo-layout-transparent .mdl-layout__header,
.demo-layout-transparent .mdl-layout__drawer-button {
  /* This background is dark, so we set text to white. Use 87% black instead if
     your background is light. */
  color: white;
}
</style>

<div class="demo-layout-transparent mdl-layout mdl-js-layout">
  <header class="mdl-layout__header mdl-layout__header--transparent">
    <div class="mdl-layout__header-row">
      <!-- Title -->
      <span class="mdl-layout-title">Title</span>
      <!-- Add spacer, to align navigation to the right -->
      <div class="mdl-layout-spacer"></div>
      <!-- Navigation -->
      <nav class="mdl-navigation">
        <a class="mdl-navigation__link" href="">Link</a>
        <a class="mdl-navigation__link" href="">Link</a>
        <a class="mdl-navigation__link" href="">Link</a>
        <a class="mdl-navigation__link" href="">Link</a>
      </nav>
    </div>
  </header>
  <div class="mdl-layout__drawer">
    <span class="mdl-layout-title">Title</span>
    <nav class="mdl-navigation">
      <a class="mdl-navigation__link" href="">Link</a>
      <a class="mdl-navigation__link" href="">Link</a>
      <a class="mdl-navigation__link" href="">Link</a>
      <a class="mdl-navigation__link" href="">Link</a>
    </nav>
  </div>
  <main class="mdl-layout__content">
  </main>
</div>

Answer 1

添加到你的mdl-layout__drawer-button类：

outline: none;

Answer 2

特殊菜单标记添加样式

  

轮廓：0;

OR

  

式：＆＃34;轮廓：0;＆＃34;内联标签

Answer 3

将这些样式添加到按钮类 - 概述：无; 重点：无;