CSS 使用 :before 和 :after 创建的元素不显示

Question

我尝试像这样显示 html 元素： here

这是一个底部有箭头的正方形，我使用这种样式创建它：

.square {
  min-width: 60px;
  height: 60px;
  margin-left: 5px;
  display: flex;
  justify-content: center;
  align-items: center;
  background-color: #1db911;
  border-radius: 15px;
  font-size: 14px;
  color: #ffffff;
}

.square:after,
.square:before {
  bottom: 30%;
  left: 31%;
  border: solid transparent;
  content: ' ';
  height: 0;
  width: 0;
  position: absolute;
  pointer-events: none;
  display: block;
}

.square:after {
  border-color: rgba(238, 238, 238, 0);
  border-top-color: #1db911;
  border-width: 10px;
  margin-left: -10px;
  display: block;
}
.square:before {
  border-color: rgba(204, 204, 204, 0);
  border-top-color: #1db911;
  border-width: 10px;
  margin-left: -10px;
  display: block;
}

但是有一个问题。当我水平滚动时，三角形停留在： here 这是我的父元素： here 可以水平滚动。我也尝试将 position: relative 用于 square class，但它有问题。它没有在正方形上显示三角形。像这样： here（为了显示更好，我把三角形涂成了黑色）这是我这个州的风格

.square {
  min-width: 60px;
  height: 60px;
  margin-left: 5px;
  display: flex;
  justify-content: center;
  align-items: center;
  background-color: #1db911;
  border-radius: 15px;
  font-size: 14px;
  color: #ffffff;
  position: relative;
}

.square:after,
.square:before {
  bottom: -22%;
  left: 50%;
  border: solid transparent;
  content: ' ';
  height: 0;
  width: 0;
  position: absolute;
  pointer-events: none;
  display: block;
}

.square:after {
  border-color: rgba(238, 238, 238, 0);
  border-top-color: black;
  border-width: 10px;
  margin-left: -10px;
  display: block;
}

.square:before {
  border-color: rgba(204, 204, 204, 0);
  border-top-color: #1db911;
  border-width: 10px;
  margin-left: -10px;
  display: block;
}

<div class="square">
  <span>sample</span>
</div>

谢谢！

Answer 1

您可以使用 top:100% 而不是底部，如果您希望正方形仅与内容一样宽，您可以使用 inline-flex:

.square {
  min-width: 60px;
  height: 60px;
  margin-left: 5px;
  display: inline-flex;
  justify-content: center;
  align-items: center;
  background-color: #1db911;
  border-radius: 15px;
  font-size: 14px;
  color: #ffffff;
  position: relative;
}

.square:after,
.square:before {
  top: 100%;
  left: 50%;
  border: solid transparent;
  content: ' ';
  height: 0;
  width: 0;
  position: absolute;
  pointer-events: none;
  display: block;
}

.square:after {
  border-color: rgba(238, 238, 238, 0);
  border-top-color: #1DB911;
  border-width: 10px;
  margin-left: -10px;
  display: block;
}

.square-container:before {
  border-color: rgba(204, 204, 204, 0);
  border-top-color: #1db911;
  border-width: 10px;
  margin-left: -10px;
  display: block;
}

<div class="square">
  <span>sample</span>
</div>

CSS 使用 :before 和 :after 创建的元素不显示

CSS element created with :before and :after doesn't show

html

css

css-selectors

pseudo-element