html - div 未与顶部对齐

Question

为什么会发生这种情况？我需要有人可以解释为什么 div 不能正确对齐？

HTML 和 CSS:

.horizontal-ruler {
  width: 100%;
  height: 25px;
  line-height: 25px;
  display: block;
  font-size: 14px;
  color: #373737;
}
.horizontal-ruler .ruler-unit {
  width: 30px;
  text-align: center;
  display: inline-block;
  line-height: 25px;
  height: 25px;
  vertical-align: middle;
}
.h-ruler-first-line,
.h-ruler-second-line {
  width: calc(50% - 15px);
  margin: 12px 0;
  height: 1px;
  background-color: #373737;
  display: inline-block;
}

<div class="horizontal-ruler">
  <div class="h-ruler-first-line"></div><!--
--><div class="ruler-unit">24"</div><!--
--><div class="h-ruler-second-line"></div>
</div>

https://jsfiddle.net/6xuvr6vw/1/

如您所见，.ruler-unit 未包含在 .horizo​​ntal-ruler 中。

Answer 1

您还需要在行中添加vertical-align: middle

.horizontal-ruler {
  width: 100%;
  height: 25px;
  line-height: 25px;
  display: block;
  font-size: 14px;
  color: #373737;
}

.horizontal-ruler .ruler-unit {
  width: 30px;
  text-align: center;
  display: inline-block;
  line-height: 25px;
  height: 25px;
  vertical-align: middle;
}

.h-ruler-first-line,
.h-ruler-second-line {
  width: calc(50% - 15px);
  vertical-align: middle;
  margin: 12px 0;
  height: 1px;
  background-color: #373737;
  display: inline-block;
}

<div class="horizontal-ruler">
  <div class="h-ruler-first-line"></div><!--
--><div class="ruler-unit">24"</div><!--
--><div class="h-ruler-second-line"></div>
</div>