I cannot SASS

but I need

tr.foo {
  background-color: #fa5100;
}

tr.bar {
  background-color: #0c58a2;
}

resolves to

tr.foo {
  background-color: $foo;
}

tr.bar {
  background-color: $bar;
}

styles.scss

$foo: #fa5100;
$bar: #0c58a2;

$things: ('foo', 'bar');

@each $thing in $things {
  tr.#{$thing} {
    background-color: unquote("$#{$thing}");
  }
}

Try something like:

$things: (foo: #fa5100, bar: #0c58a2);

@each $thing, $colour in $things {
  tr.#{$thing} {
    background-color: #{$colour};
  }
}