Hover over another div when it comes to

Question

when I hover over "Div2", I want the hover of "Div1" to work

 .Div1:hover{ background:red; }

 <div class="Div1">Hello!</div> <div class="Div2">Open hello!</div>

Answer 1

You can choose one class for both to make hoover works for both.

 .DivHoover:hover{ background:red; }

 <div class="Div1 DivHoover">Hello!</div> <div class="Div1 DivHoover">Open hello!</div>

Answer 2

You can use display: flex on the container, then change the rendering order. Then you can hover on div2 and highlight div1.

.container {
  display: flex;
  flex-wrap: wrap;
}

.div1, .div2 {
  flex: 0 0 100%;
}

.div1 { order: 1; }
.div2 { order: 2; }

.div2:hover ~ .div1 {
  background-color: red;
}

<div class="container">
  <div class="div2">hello!</div>
  <div class="div1">open hello!</div>
</div>