外溢出设置为隐藏的轮廓边框样式

The CSS style:

CSS样式:

.outer {
  position: relative;
  width: 100%;
  height: 200px;
  background-color: #000;
  overflow: hidden;
}

.outer:focus {
  outline: 10px solid #00FF00;
}

.inner {
  position: absolute;
  width: 50%;
  height: 200px;
  background-color: #F0F;
  left: 50%;
}

.inner:focus {
  outline: 10px solid #FFFF00;
}
.outer {
  position: