<div class="cont">
  <div class="element__box element__box-1">
    <div class="element__cont">
      <div class="element-cont__box">
        <h5 class="element-cont__title">AREA - 1</h5>
      </div>
      <div class="element-cont__box">
        <h5 class="element-cont__title">AREA - 2</h5>
      </div>
    </div>
  </div>
  <div class="element__box element__box-2">
    <h5 class="element-cont__title">AREA - 3</h5>
  </div>
</div>
body {
  padding: 40px;
  background: #fff;
}

.cont {
  width: 100%;
  max-width: 1200px;
  display: flex;
  justify-content: center;
  align-items: center;
  flex-wrap: wrap;
}

.element__box {
  width: calc(50% - 20px);
  background: #252525;
  height: 500px;
}

.element__box:not(:last-child) {
  margin: 0 10px 0 0;
}

.element__cont {
  display: flex;
  justify-content: center;
  flex-direction: column;
  align-items: center;
  height: 100%;
  padding: 10px;
}

.element-cont__box {
  width: 100%;
  flex: 1 1 calc(50% - 10px);
  background: #ed64c5;
}

.element-cont__box,
.element__box-2 {
  /* СТИЛИ ДЛЯ ДЕМО */
  display: flex;
  justify-content: center;
  flex-direction: column;
  align-items: center;
}

.element__box-2 {
  background: crimson;
}

.element-cont__title {
  font-size: 40px;
  letter-spacing: 2px;
  text-transform: upeprcase;
  color: white;
  font-family: "Oswald", sans-serif;
}

.element-cont__box:not(:last-child) {
  margin: 0 0 10px 0;
}

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

  .element__box:not(:last-child) {
    margin: 0 0 10px 0;
  }

  .element__cont {
    flex-wrap: wrap;
    flex-direction: row;
  }

  .element-cont__box {
    height: 100%;
  }

  .element__box-1 {
    height: 300px;
  }

  .element-cont__box:not(:last-child) {
    margin: 0 10px 0 0;
  }

  .element__box {
    width: 100%;
  }
}

External CSS

  1. https://moonpresence.site/moonpresence/foundation/css/base.css

External JavaScript

This Pen doesn't use any external JavaScript resources.