message: Button: simplify styles
diff: .Button__in {
  display: flex;
  align-items: center;
  + justify-content: center;
  width: 100%;
  min-height: 100%;
  + text-align: center;
  }
  .Button--aln-left .Button__in {
  text-align: left;
  }
  -.Button--aln-center .Button__in {
  - justify-content: center;
  - text-align: center;
  -}
  -
  .Button--aln-right .Button__in {
  justify-content: flex-end;
  text-align: right;
  }
  -.Button--str .Button__in {
  - justify-content: center;
  -}
  -
  .Button[disabled] {
  opacity: .4;
  }
  