fixed问题

html：

<div class="wrap">
    <label for="sliderbartroggle" class="troggle">☰</label>
    <div class="content"></div>
    <div class="slidebar"></div>  
</div>

sass:

.content
  position: absolute
  width: 100vw
  height: 100vh
  top: 0
  background-color: wheat
  z-index: 0

.slidebar
  position: fixed
  left: 0
  top: 0
  width: 120px
  height: 1000px
  padding: 30px
  font-size: 16px
  color: black
  z-index: 0

为什么能实现

米色div为什么不是从left为0开始的？

---

.content
  position: absolute
  width: 100vw
  height: 100vh
  top: 0
  left: 0 // <----
  background-color: wheat
  z-index: 0