用CSS绘制一条方形线,插入一个div

Question

我想知道是否有可能追踪1px方形轮廓,插入div内的特定距离.目前,css和HTML看起来像这样

.object {
    width: 100px;
    height: 100px;
    background-color: red;
    color: white;
    padding: 5px;
}

<div class="object">
    Hello World!
</div>

结果如下:

http://i.imgur.com/qdB0yb6.png

而预期的结果将是这样的:

http://i.imgur.com/vnfFhmY.png

Answer 1

方法#01:

您可以绘制outline和使用outline-offset属性.

注意: outline-offset IE不支持.

.object {
  outline: solid #fff 1px;
  outline-offset: -5px;
  width: 100px;
  height: 100px;
  background-color: red;
  color: white;
  margin: 5px;
  padding: 10px;
}

<div class="object">
    Hello World!
</div>

方法#02:

您可以使用:before或:after伪元素绘制轮廓或background从四面延伸.

.object {
  position: relative;
  width: 100px;
  height: 100px;
  border: 1px solid #fff;
  color: white;
  padding: 5px;
  margin: 10px;
}

.object:before {
  background-color: red;
  position: absolute;
  content: '';
  left: -5px;
  right: -5px;
  top: -5px;
  bottom: -5px;
  z-index: -1;
}

<div class="object">
    Hello World!
</div>

方法#03:

您可以使用css3绘制多个背景图像linear-gradient().以下是必要的css:

div {
  background-image: linear-gradient(to right, white, white),
                    linear-gradient(to bottom, white, white),
                    linear-gradient(to right, white, white),
                    linear-gradient(to bottom, white, white),
                    linear-gradient(to right, red, red);

  background-repeat: no-repeat;
  background-size: calc(100% - 10px) 1px, 1px calc(100% - 10px), calc(100% - 10px) 1px, 1px calc(100% - 10px), 100% 100%;
  background-position:  5px 5px, top 5px right 5px, bottom 5px right 5px, 5px 5px, 0 0;
}

.object {
    width: 100px;
    height: 100px;
    background-image: linear-gradient(to right, white, white),
                      linear-gradient(to bottom, white, white),
                      linear-gradient(to right, white, white),
                      linear-gradient(to bottom, white, white),
                      linear-gradient(to right, red, red);
    
    background-repeat: no-repeat;
    background-size: calc(100% - 10px) 1px, 1px calc(100% - 10px), calc(100% - 10px) 1px, 1px calc(100% - 10px), 100% 100%;
    background-position:  5px 5px, top 5px right 5px, bottom 5px right 5px, 5px 5px, 0 0;
    
    color: white;
    padding: 10px;
}

<div class="object">
    Hello World!
</div>