模拟列表中的边界折叠（无表）

<ul>
    <li>one</li>
    <li>two</li>
</ul>

ul{
    border: 0 solid silver;
    border-width: 0 0 1px 1px;
}
li{
    border: 0 solid silver;
    border-width: 1px 1px 0 0;
    padding:.5em;
}

li {
    border: 1px solid #000;
    border-right: none;
}

li:last-child {
    border-right: 1px solid #000;
}

li

li:last-child {border-bottom:2px solid silver;}

li:hover {border-color:#0cf;}

li:hover + li {border-top-color:#0cf;}

li{
  border: 2px solid gray;
}

li + li{
  border-top: none;
}

/* Makeup */ li{width: 12rem;list-style: none;padding: .5rem 1rem;}

<li>First</li>
<li>Second</li>
<li>Third</li>
<li>Fourth</li>
<li>Fifth</li>

ul {
  list-style-type: none;
  width: 100px;
  margin: 0;
  /* also set the parent\'s padding to half of the intended border\'s width to prevent the outlines from overlapping anything they shouldn\'t overlap */
  padding: 0.5px;
}
li {
  display: inline-block;
  float: left;
  box-sizing: border-box;
  text-align: center;
  width: 20px;
  height: 20px;
  padding: 0;
  margin: 0;

  /* simulates a 1px-wide border */
  border: 0.5px solid black;
  outline: 0.5px solid black;
}

<ul>
  <li>1</li>
  <li>2</li>
  <li>3</li>
  <li>4</li>
  <li>5</li>
  <li>6</li>
  <li>7</li>
  <li>8</li>
</ul>

<ul>
    <li>Stuff</li>
    <li>Other Stuff</li>
<ul>

li { border: 1px solid #000; margin: 5px 0; }