html - div 周围的样式边框

Question

我有点卡在 div 框周围的样式边框上。

问题是我不能让边框不像:

这是我的真实例子:

.num.num_1 {
  border-left-color: #0D2431;
}
.num {
  width: 60px;
  height: 60px;
  line-height: 50px;
  border-width: 5px;
  font-size: 40px;
}
.num {
  float: left;
  width: 40px;
  height: 40px;
  line-height: 36px;
  text-align: center;
  border: 2px solid #eee;
  font-size: 20px;
  color: #0D2431;
  background-color: #fff;
}
div {
  margin: 0;
  padding: 0;
  border: 0;
  font: inherit;
  font-size: 100%;
  vertical-align: baseline;
}
}

<div class="num num_1">1</div>

Answer 1

.num.cheat:before {
    content:"";
    position: absolute;
    left: -5px;
    right: -5px;
    top: -5px;
    bottom: -5px;
    
}
.num_1:before {
    border-left: 5px solid black;
}
.num_2:before {
    border-left: 5px solid black;
    border-top: 5px solid black;
}
.num_3:before {
    border-left: 5px solid black;
    border-top: 5px solid black;
    border-right: 5px solid black;
}
.num_4:before {
    border-left: 5px solid black;
    border-top: 5px solid black;
    border-right: 5px solid black;
    border-bottom: 5px solid black;
}
.num {
  width: 60px;
  height: 60px;
  line-height: 50px;
  border-width: 5px;
  font-size: 40px;
  position: relative;
  margin-right: 10px;
}
.num {
  float: left;
  width: 40px;
  height: 40px;
  line-height: 36px;
  text-align: center;
  border: 5px solid #eee;
  font-size: 20px;
  color: #0D2431;
  background-color: #fff;
}
div {
  margin: 0;
  padding: 0;
  border: 0;
  font: inherit;
  font-size: 100%;
  vertical-align: baseline;
}
}

<div class="num num_1 cheat">1</div>
<div class="num num_2 cheat">2</div>
<div class="num num_3 cheat">3</div>
<div class="num num_4 cheat">4</div>

我稍微修改了你的 CSS。我使用 :before 伪元素解决了这个问题。