metamask-extension/ui/app/pages/first-time-flow/welcome/index.scss

.welcome-page {
  display: flex;
  flex-direction: column;
  justify-content: flex-start;
  align-items: center;
  max-width: 442px;
  padding: 0 18px;
  color: black;

  &__wrapper {
    display: flex;
    flex-direction: row;
    justify-content: center;
    align-items: flex-start;
    height: 100%;
    margin-top: 110px;
  }

  &__header {
    font-size: 28px;
    margin-bottom: 22px;
    margin-top: 50px;
    text-align: center;
  }

  &__description {
    text-align: center;

    div {
      font-size: 16px;
    }

    @media screen and (max-width: 575px) {
      font-size: 0.9rem;
    }
  }

  .first-time-flow__button {
    width: 184px;
    font-weight: 500;
    margin-top: 44px;
  }
}