source: main/waeup-hugo/public/sass/layout/_bg.scss

///
/// Dimension by HTML5 UP
/// html5up.net | @ajlkn
/// Free for personal and commercial use under the CCA 3.0 license (html5up.net/license)
///

/* BG */

  #bg {
    @include vendor('transform', 'scale(1.0)');
    -webkit-backface-visibility: hidden;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100vh;
    z-index: 1;

    &:before, &:after {
      content: '';
      display: block;
      position: absolute;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
    }

    &:before {
      @include vendor('transition', 'background-color #{_duration(bg)} ease-in-out');
      @include vendor('transition-delay', '#{_duration(intro)}');
      background-image:   linear-gradient(to top, #{_palette(bg-overlay)}, #{_palette(bg-overlay)}),
                  url('/images/overlay.png');
      background-size:    auto,
                  256px 256px;
      background-position:  center,
                  center;
      background-repeat:    no-repeat,
                  repeat;
      z-index: 2;
    }

    &:after {
      @include vendor('transform', 'scale(1.125)');
      @include vendor('transition', (
        'transform #{_duration(article)} ease-in-out',
        'filter #{_duration(article)} ease-in-out'
      ));
      background-image:   url('/images/bg.jpg');
      background-position:  center;
      background-size:    cover;
      background-repeat:    no-repeat;
      z-index: 1;
    }

    body.is-article-visible & {
      &:after {
        @include vendor('transform', 'scale(1.0825)');
        @include vendor('filter', 'blur(0.2rem)');
      }
    }

    body.is-loading & {
      &:before {
        background-color: _palette(bg-alt);
      }
    }
  }