body-class-test-app.less

body {
  font-family: futura, sans-serif;
}

// generate the selectors for .counter-1
.countTo(counter-, 10);

// looping in less. Never do this.
.countTo(@prefix, @n, @i: 1) when (@i =< @n) {
  .@{prefix}@{i} {
    background: rgba(0,0,0, (@i / @n));
  }

  .countTo(@prefix, @n, (@i + 1));
}