<div class="container">
  <div class="item-container">
    <div class="item-spacer"></div>
    <div class="item-content">item 1</div>
  </div>
  <div class="item-container">
    <div class="item-spacer"></div>
    <div class="item-content">item 2</div>
  </div>
</div>

.container {
  width: 100%;
  min-height: 200px;
  background: silver;
  padding: 5px;
}

.item-container {
  position: relative;
  float: left;
  width: 20%;
  min-width: 80px;
  margin: 5px;
}

.item-spacer {
  width: 100%;
  height: 0;
  padding-bottom: 100%;
  background: orange;
}

.item-content {
  position: absolute;
  top: 0;
  left: 0;
  padding: 5px;
}