Update _settings.scss

changed $reveal-position-top: rem-calc(100);
added // We use this to set the default radius used throughout the core.

changed 
// We use these to style the reveal close button
$reveal-close-font-size: rem-calc(40);
$reveal-close-top: rem-calc(8);
$reveal-close-side: rem-calc(11);
$reveal-close-color: #aaa;
$reveal-close-weight: bold;