////
/// @group Main
////

/// Return the amount of padding required to offset a rounded corner so
/// content sits flush against the visible curve rather than the bounding
/// box. Refer to this diagram for the geometric derivation:
/// https://drive.google.com/file/d/1rvrC-3H2ecSWgajRA-U7DM4NK344Fx-7/view
///
/// @param {Number} $radius - Corner radius (any unit accepted by Sass math)
/// @return {Number} - Padding value in the same unit as `$radius`
@function rounded-corner-padding($radius) {
  $sqrt2: 1.4142;// square root of 2, rounded down from 1.4142135624
  $corner-diagonal: ($sqrt2 * $radius) - $radius;
  $corner-padding: $sqrt2 * ($corner-diagonal * 0.5);
  @return $corner-padding;
}