habitica/website/client/assets/scss/task.scss

 .task {
  // for editing rewards or when a task is created
  &-purple {
    background: $purple-300;
  }

  &-worst {
    background: $maroon-100;
    &-control-habit {
      background: darken($maroon-100, 12%);
    }

    &-control-daily-todo {
      background: $maroon-500;
    }
  }

  &-worse {
    background: $red-100;
    &-control-habit {
      background: darken($red-100, 12%);
    }

    &-control-daily-todo {
      background: $red-500;
    }
  }

  &-bad {
    background: $orange-100;
    &-control-habit {
      background: darken($orange-100, 12%);
    }

    &-control-daily-todo {
      background: $orange-500;
    }
  }

  &-neutral {
    background: $yellow-50;
    &-control-habit {
      background: darken($yellow-50, 12%);
    }

    &-control-daily-todo {
      background: $yellow-500;
    }
  }

  &-good {
    background: $green-10;
    &-control-habit {
      background: darken($green-10, 12%);
    }

    &-control-daily-todo {
      background: $green-500;
    }
  }

  &-better {
    background: $blue-50;
    &-control-habit {
      background: darken($blue-50, 12%);
    }

    &-control-daily-todo {
      background: $blue-500;
    }
  }

  &-best {
    background: $teal-50;
    &-control-habit {
      background: darken($teal-50, 12%);
    }

    &-control-daily-todo {
      background: $teal-500;
    }
  }

  &-reward {
    background: rgba($yellow-500, 0.26);
  }

  &-daily-todo-disabled {
    background: $gray-500;

    &-control-daily-todo {
      background: $gray-400;
      color: $gray-200;
    }
  }

  &-daily-todo-content-disabled {
    background: $gray-600;

    * {
      color: $gray-300 !important;
    }
  }

  &-habit-disabled {
    background: $gray-700;
    color: rgba(0, 0, 0, 0.12);

    &-control-habit {
      color: rgba(0, 0, 0, 0.12) !important;
      border: 1px solid rgba(0, 0, 0, 0.12);
    }
  }
}