JSFiddle - React, Tailwind, and code Playground

by 智翔

HTML

<div class="scrollbar">
	<div class="scrollbar-content">
		<ul class="box">
			<li>11111</li>
      <li>11111</li>
      <li>11111</li>
      <li>11111</li>
			<li>11111</li>
      <li>11111</li>
      <li>11111</li>
      <li>11111</li>
			<li>11111</li>
      <li>11111</li>
      <li>11111</li>
      <li>11111</li>
			<li>11111</li>
      <li>11111</li>
      <li>11111</li>
      <li>11111</li>
		</ul>
	</div>
	<div class='scrollbar-bar'>
		<div ref="thumb" class="scrollbar-thumb"></div>
	</div>
</div>
<button id="add">增加li</button>
<button id="del">删除li</button>

CSS

*{margin:0;padding:0;list-style: none;}
.scrollbar{
  position: relative;
}
.scrollbar-bar{
  position: absolute;
  right: 2px;
  bottom: 2px;
  z-index: 1;
  width: 6px;
  height: 100%;
  border-radius: 4px;
  opacity: 0;
  transition: opacity 120ms ease-out;
}
.scrollbar-thumb {
  position: relative;
  display: block;
  width: 100%;
  height: 0;
  border-radius: inherit;
  background-color: rgba(135,141,153,.3);
  transition: .3s background-color;
  cursor: pointer;
}
.scrollbar:hover .scrollbar-bar{
  opacity: 1;
  transition: opacity 340ms ease-out;
}
.box{ height: 400px;  overflow: auto; }
li{ line-height: 46px;  height: 46px; }