<div class="wrapper">
  <div>
    <div class="box box16x9">16x9</div>
    <div class="box box4x3">4x3</div>
  </div>
  
  <div>
    <div class="box box16x9">16x9</div>
    <div class="box box4x3">4x3</div>
  </div>
</div>

:root {
  --light-gray: hsla(300, 4%, 81%, 1);
  --ghost-white: hsla(225, 100%, 99%, 1);
  --davys-grey: hsla(12, 5%, 36%, 1);
  --blue-sapphire: hsla(196, 67%, 33%, 1);
 --charcoal: hsla(207, 38%, 25%, 1);
}
/* from https://coolors.co/d0ccd0-fbfcff-605856-1c6e8c-274156*/

* {
  box-sizing: border-box;
}

body {
  background-color: var(--charcoal);
  font: 1.2em/1.3 Roboto, sans-serif;
}

.wrapper {
  box-sizing: border-box;
  width: 960px;
  height: 540px;
  margin: 100px auto;
  background-color: var(--ghost-white);
  display: grid;
  grid-template-columns: 200px 350px;
  gap: 20px;
  justify-content: center;
  padding: 20px;
}

.box {
  background-color: hsla(196, 67%, 33%, .2);
  border: 1px solid hsla(196, 67%, 33%, 1);
  margin: 20px;
}

.box {
  padding: 10px;
}

.box16x9 {
  aspect-ratio: 16/9;
}

.box4x3 {
  aspect-ratio: 4/3;
}

.wrapper > * {
  border: 2px dotted var(--charcoal);
  padding: 10px;
}