:root {
  
  --light: #FFFFFF;
  --dark: #000000;
}

body
{
  color-scheme: light dark;
  color: light-dark(var(--dark),var(--light));
  background-color: light-dark(var(--light), var(--dark));
  /* background-color: red; */
}

.div
{
  width: 100px;
  height: 100px;
  border: 1px solid;
  margin-top: 10px;
  text-align: center;
}
#div1 {
  color: light-dark(var(--dark),var(--light));
  background-color: light-dark(var(--light), var(--dark));
}
#div2
{
  background-color: red;
}