* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html, body {
  width: 100vw;
  height: 100vh;
  overflow: hidden;
  position: relative;
}

body {
  display: grid;
  grid-template-areas:
    "quad1 quad2"
    "quad3 quad4";
  grid-template-columns: 1fr 1fr;
  grid-template-rows: 1fr 1fr;
}

.quad {
  overflow: hidden;
  width: 100%;
  height: 100%;
}

iframe {
  display: block;
  width: 100%;
  height: 100%;
  border: none;
}