/// Function for converting a value to rem unit
/// @access public
/// @author Silvestar Bistrović <me@silvestar.codes>
/// @example font-size: rem(20px, 'mobile');
/// @group 3.1.Helpers
/// @name rem
/// @since 1.0.0
/// @param {Unit} $size [20px] A value with unit (e.g. 20px)
/// @param {String} $media ['desktop'] A media, (e.g. 'desktop' or 'mobile')
/// @return {Unit} Returns a value converted in rem; returns 1rem if media is not 'desktop' or 'mobile'
/// @see $color-text

@function rem($size: 20px, $media: 'desktop') {
  @if $media == 'desktop' {
    @return calc(#{strip-unit($size / $font-size--desktop)} * 1rem);
  } @else if $media == 'mobile' {
    @return calc(#{strip-unit($size / $font-size--mobile)} * 1rem);
  } @else {
    @return 1rem;
  }
}

/// Function that calculates tracking
/// @access public
/// @author Silvestar Bistrović <me@silvestar.codes>
/// @example letter-spacing: tracking(200);
/// @group 3.1.Helpers
/// @name tracking
/// @since 1.0.0
/// @param {Integer} $tracking [0] Tracking value without a unit (e.g. 200)
/// @param {String} $media ['desktop'] A media, (e.g. 'desktop' or 'mobile')
/// @return {Unit} Returns a tracking value

@function tracking($tracking: 0) {
  @if $tracking == 0 {
    @return 0;
  } @else {
    @return calc(#{$tracking} / 1000 * 1em);
  }
}

/// Mixin for defining tracking
/// @access public
/// @author Silvestar Bistrović <me@silvestar.codes>
/// @example @include ls(100);
/// @group 3.1.Helpers
/// @name ls
/// @since 1.0.0
/// @param {Integer} $tracking [0] Tracking value without a unit (e.g. 200)
@mixin ls($tracking: 0) {
  letter-spacing: tracking(#{strip-unit($tracking)});
}

/// Mixin for reseting padding and margin to zero
/// @access public
/// @author Silvestar Bistrović <me@silvestar.codes>
/// @example @include zero-box;
/// @group 3.1.Helpers
/// @name zero-box
/// @since 1.0.0
@mixin zero-box() {
  margin: 0;
  padding: 0;
}

/// Mixin for defining transition
/// @access public
/// @author Silvestar Bistrović <me@silvestar.codes>
/// @example @include tra(all, $trd, $tra);
/// @group 3.1.Helpers
/// @name tra
/// @since 1.0.0
/// @param {String} $transition-property [all] A property to transition (e.g. all or color)
/// @param {Unit} $transition-duration [$trd] A duration of the transition (e.g. 1s)
/// @param {String} $transition-animation [$tra] An easing function of the transition (e.g. linear or cubic-bezier(0.04, 0.88, 0.74, 1.04))
@mixin tra($transition-property: all, $transition-duration: $trd, $transition-animation: $tra) {
  transition: $transition-property $transition-duration $transition-animation;
}