@mixin button {
    display: inline-block;
    background: var(--game-container-background); // TODO: darken 20%
    border-radius: 3px;
    padding: 0 20px;
    border: none;
    text-decoration: none;
    color: var(--bright-text-color) !important;
    height: 40px;
    line-height: 42px;
    flex: content;
  }