Not able to float div correctly

Question

I have a list with 3 blocks each taking 33% normally. When I resize the window to smaller size I would like the first two blocks to be stacked one above the other and take 50% of the width while the third element to span and take the other 50% on the whole but I am only able to span first two blocks in first row and third block in 2nd row.

And on minimizing it further, I would like all of them to be stacked one below the other.

I have added the layouts:

Here is my code:

li.listChild .time-home {
  float: left;
  height: auto;
  width: 100%;
  line-height: 21px;
  font-size: 12px;
  font-weight: 700;
  text-align: right; 
}
@media only screen and (min-width: 800px) and (max-width: 1023px) {
  li.listChild .time-home {
    width: 100%; } 
}
li.listChild .time-home .listItem {
  float: left; }
li.listChild .time-home .listItem.datum-home {
  width: 33%;
  font-weight: 700; }
@media only screen and (min-width: 1024px) and (max-width: 1443px) {
  li.listChild .time-home .listItem.datum-home {
    width: 50%;
    border-bottom: 1px #e8e8e8 solid; }
}
@media only screen and (min-width: 800px) and (max-width: 1023px) {
  li.listChild .time-home .listItem.datum-home {
    width: 100%;
    border-bottom: 1px #e8e8e8 solid; } 
}
li.listChild .time-home .listItem.zeit-home {
  font-weight: 400;
  width: 33%; 
}
@media only screen and (min-width: 1024px) and (max-width: 1443px) {
  li.listChild .time-home .listItem.zeit-home {
    width: 50%;
    border-bottom: 1px #e8e8e8 solid; }
}
@media only screen and (min-width: 800px) and (max-width: 1023px) {
  li.listChild .time-home .listItem.zeit-home {
    width: 100%;
    border-bottom: 1px #e8e8e8 solid; }
}
li.listChild .time-home .listItem.type-home {
  width: 33%;
  color: #0293ed;
  border: none;
  font-weight: 700;
}
@media only screen and (min-width: 1024px) and (max-width: 1443px) {
  li.listChild .time-home .listItem.type-home {
    width: 100%;
    border-bottom: 1px #e8e8e8 solid;
    border-right: 1px #e8e8e8 solid; }
}
@media only screen and (min-width: 800px) and (max-width: 1023px) {
  li.listChild .time-home .listItem.type-home {
    width: 100%;
    border-bottom: 1px #e8e8e8 solid;
    border-right: 1px #e8e8e8 solid; } 
}

<li class="listChild">
    <div class="time">
        <div class="listItem datum">
            3.6.93
        </div>
        <div class="listItem zeit">
            4.6.93
        </div>
        <div  class="listItem type">
        Thomas
    </div>
    </div>
    
</li>

Answer 1

You don't necessarily need to use flexbox, you could use absolute positioning.

Example: https://jsfiddle.net/yyuwmv1r/

* {
  box-sizing: border-box;
}

.container {
  height: 300px;
  width: 100%;
  position: relative;
}

.one,
.two,
.three {
  border: 2px solid black;
  height: 33.33%;
  width: 100%;
  float: left;
  background: red;
}
.two {
  background: blue;
}
.three {
  background: green;
}

@media only screen and (min-width: 800px) and (max-width: 1200px) {
  .one,
  .two,
  .three {
    position: absolute;
  }
  .one {
    top: 0;
    left: 0;
    height: 50%;
    width: 50%;
  }
  .two {
    top: 50%;
    left: 0;
    height: 50%;
    width: 50%;
  }
  .three {
    top: 0;
    left: 50%;
    height: 100%;
    width: 50%;
  }
}

@media only screen and (min-width: 1200px) {
  .one,
  .two,
  .three {
    border: 2px solid black;
    height: 100%;
    width: 33.33%;
    float: left;
    background: red;
  }
  .two {
    background: blue;
  }
  .three {
    background: green;
  }
}

<div class="container">
  <div class="one">
    One
  </div>
  <div class="two">
    Two
  </div>
  <div class="three">
    Three
  </div>
</div>

Answer 2

Drag the output left and right to simulate media queries. Keep in mind I didn't abide by your media queries, was using my own only to simulate the example.

Fiddle here

<li class="listChild">
  <div class="time">
    <div class="some-container">
      <div class="listItem datum">
        list one
      </div>
      <div class="listItem zeit">
        list two
      </div>
    </div>
    <div class="listItem type">
      list three
    </div>
  </div>
</li>

* {
  box-sizing: border-box;
}

.listItem {
  border: 1px solid #000;
  padding: 10px;
  float: left;
  width: 250px;
  height: 30px;
}

.some-container {
  float: left;
}

.some-container + .listItem {
  float: left;
}

@media (max-width: 800px) and (min-width: 300px) {
  .some-container .listItem {
    height: 30px;
    float: none;
  }
  .some-container + .listItem {
    height: 60px;
  }
}

@media (max-width: 299px) {
  .listItem {
    float: none;
    width: 100%;
  }
}

Answer 3

You can do this with Flexbox and media queries

DEMO

.div-1, .div-2, .div-3 {
  border: 1px solid black;
}

.content {
  display: flex;
  flex-direction: row;
  min-height: 100vh;
}

.group {
  flex: 2;
  display: flex;
}

.div-3, .div-1, .div-2 {
  flex: 1;
}

@media(max-width: 992px) {
  .group {
    flex-direction: column;
  }
}

@media(max-width: 480px) {
  .content {
    flex-direction: column;
  }
}

<div class="content">
  <div class="group">
    <div class="div-1">Div 1</div>
    <div class="div-2">Div 2</div>
  </div>

  <div class="div-3">Div 3</div>
</div>