html {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
  font-size: 16px;
  font-weight: 300;
}

$h1: 3rem;
$h2: 2.5rem;
$h3: 2rem;
$h4: 1.5rem;
$h5: 1.25rem;
$h6: 1rem;

$headings: ( h1: $h1, h2: $h2, h3: $h3, h4: $h4, h5: $h5, h6: $h6 );

@each $heading, $size in $headings {
    #{$heading} {        
        font-weight: 300;
        font-size: $size;
    }
}