/* input.css */
:root {
    --array: foo, bar, baz;
    --from: 1;
    --to: 3;
    --icon-exclude: 2;
    --color-danger: red;
    --nested-variable: color(var(--color-danger) a(90%)) ;
}
@each $val in var(--array) {
    @import "$val.css";
}

/* foo.css */
html {
    background-color: var(--color-danger);
    color: var(--nested-variable);
}

/* bar.css */
.some-class {
    color: #fff;
    @for $val from var(--from) to var(--to) {
        @if $val != var(--icon-exclude) {
            .icon-$val {
                background-position: 0 $(val)px;
            }
        }
    }
}

/* baz.css */
h1 {
    font-size: 24px;
}
@import "biz.css";

/* biz.css */
h2 {
    color: olive;
}

/* Output example */
html {
    background-color: red;
    color: rgba(255, 0, 0, 0.9);
}
.some-class {
    color: #fff;
}
.some-class .icon-1 {
    background-position: 0 1px;
}
.some-class .icon-3 {
    background-position: 0 3px;
}
h1 {
    font-size: 24px;
}
h2 {
    color: olive;
}