ズンドコキヨシ with Scss

scss

@charset "UTF-8";
body {
  &::before {
    $generated: "";
    $zundokoLoop: true;
    $zundokoCount: 0;
    @while $zundokoLoop {
      $choise: "ドコ";
      @if random() < 0.5 {
        $choise: "ズン";
        $zundokoCount: $zundokoCount + 1;
      } @else {
        @if $zundokoCount >= 4 {
          $zundokoLoop: false;
          $choise: $choise + "キ・ヨ・シ！";
        }
        $zundokoCount: 0;
      }
      $generated: $generated + $choise;
    }
    content: $generated;
  }
}

（もう少し短く書けるので後で直す。）