如何在css中为菜单添加弯角

Question

我想在.second-level-menu中对css中的角进行曲线化。

我尝试添加.second-level-menu和.second-level-menu > li：

border-radius: 0px 0px 8px 8px; 
-moz-border-radius: 0px 0px 8px 8px; 
-webkit-border-radius: 0px 0px 8px 8px; 

/* Menu Styles */

.third-level-menu {
  position: absolute;
  top: 0;
  right: -150px;
  width: 150px;
  list-style: none;
  padding: 0;
  margin: 0;
  display: none;
}
.third-level-menu > li {
  height: 30px;
  background: #999999;
}
.third-level-menu > li:hover {
  background: #CCCCCC;
}
.second-level-menu {
  position: absolute;
  top: 30px;
  left: 0;
  width: 150px;
  list-style: none;
  padding: 0;
  margin: 0;
  display: none;
}
.second-level-menu > li {
  position: relative;
  height: 30px;
  background: #999999;
}
.second-level-menu > li:hover {
  background: #CCCCCC;
}
.top-level-menu {
  list-style: none;
  padding: 0;
  margin: 0;
}
.top-level-menu > li {
  position: relative;
  float: left;
  height: 30px;
  width: 150px;
  background: #999999;
}
.top-level-menu > li:hover {
  background: #CCCCCC;
}
.top-level-menu li:hover > ul {
  /* On hover, display the next level's menu */
  display: inline;
}
/* Menu Link Styles */

.top-level-menu a
/* Apply to all links inside the multi-level menu */

{
  font: bold 14px Arial, Helvetica, sans-serif;
  color: #FFFFFF;
  text-decoration: none;
  padding: 0 0 0 10px;
  /* Make the link cover the entire list item-container */
  display: block;
  line-height: 30px;
}
.top-level-menu a:hover {
  color: #000000;
}

<ul class="top-level-menu">
  <li><a href="#">About</a>
  </li>
  <li><a href="#">Services</a>
  </li>
  <li>
    <a href="#">Offices</a>
    <ul class="second-level-menu">
      <li><a href="#">Chicago</a>
      </li>
      <li><a href="#">Los Angeles</a>
      </li>
      <li>
        <a href="#">New York</a>
        <ul class="third-level-menu">
          <li><a href="#">Information</a>
          </li>
          <li><a href="#">Book a Meeting</a>
          </li>
          <li><a href="#">Testimonials</a>
          </li>
          <li><a href="#">Jobs</a>
          </li>
        </ul>
      </li>
      <li><a href="#">Seattle</a>
      </li>
    </ul>
  </li>
  <li><a href="#">Contact</a>
  </li>
</ul>

Answer 1

它适用于border-radius，你只是因为重叠的li元素而无法看到它。将overflow:hidden设置为.second-level-menu将导致显示半径。

/* Menu Styles */

.third-level-menu {
  position: absolute;
  top: 0;
  right: -150px;
  width: 150px;
  list-style: none;
  padding: 0;
  margin: 0;
  display: none;
}
.third-level-menu > li {
  height: 30px;
  background: #999999;
}
.third-level-menu > li:hover {
  background: #CCCCCC;
}
.second-level-menu {
  position: absolute;
  top: 30px;
  left: 0;
  width: 150px;
  list-style: none;
  padding: 0;
  margin: 0;
  display: none;
  border-radius:0px 0px 8px 8px;
  overflow:hidden;
}
.second-level-menu > li {
  position: relative;
  height: 30px;
  background: #999999;
}
.second-level-menu > li:hover {
  background: #CCCCCC;
}
.top-level-menu {
  list-style: none;
  padding: 0;
  margin: 0;
}
.top-level-menu > li {
  position: relative;
  float: left;
  height: 30px;
  width: 150px;
  background: #999999;
}
.top-level-menu > li:hover {
  background: #CCCCCC;
}
.top-level-menu li:hover > ul {
  /* On hover, display the next level's menu */
  display: inline;
}
/* Menu Link Styles */

.top-level-menu a
/* Apply to all links inside the multi-level menu */

{
  font: bold 14px Arial, Helvetica, sans-serif;
  color: #FFFFFF;
  text-decoration: none;
  padding: 0 0 0 10px;
  /* Make the link cover the entire list item-container */
  display: block;
  line-height: 30px;
}
.top-level-menu a:hover {
  color: #000000;
}

<ul class="top-level-menu">
  <li><a href="#">About</a>
  </li>
  <li><a href="#">Services</a>
  </li>
  <li>
    <a href="#">Offices</a>
    <ul class="second-level-menu">
      <li><a href="#">Chicago</a>
      </li>
      <li><a href="#">Los Angeles</a>
      </li>
      <li>
        <a href="#">New York</a>
        <ul class="third-level-menu">
          <li><a href="#">Information</a>
          </li>
          <li><a href="#">Book a Meeting</a>
          </li>
          <li><a href="#">Testimonials</a>
          </li>
          <li><a href="#">Jobs</a>
          </li>
        </ul>
      </li>
      <li><a href="#">Seattle</a>
      </li>
    </ul>
  </li>
  <li><a href="#">Contact</a>
  </li>
</ul>

Answer 2

如果你添加overflow: hidden，它会部分解决问题，但是你的第三级菜单是不可见的。我只想补充一下：

.second-level-menu > li:last-child {
  border-radius: 0px 0px 8px 8px;
}

演示：https://jsfiddle.net/cw8w6rwr/

（如果需要，第三级菜单相同）