metamask-extension/ui/components/app/signature-request/signature-request-footer/index.scss

.signature-request-footer {
  display: flex;
  border-top: 1px solid #d2d8dd;

  button {
    text-transform: uppercase;
    flex: 1;
    margin: 1rem 0.5rem;
  }

  button:first-child {
    flex: 1 1 100%;
    padding: 0;
  }

  button:last-child {
    flex: 1 1 100%;
    margin-right: 1rem;
  }

  &__tooltip {
    display: flex;
  }
}