JSFiddle - React, Tailwind, and code Playground

HTML

<button type="submit" class="popup-button btn-first">Создать</button>
<button type="submit" class="popup-button btn-second">Создать</button>

CSS

.popup-button {
    max-width: 70px;
    padding: 3px;
    box-shadow: inset 0px -5px 5px rgba(0, 0, 0, 0.1);
    border-radius: 5px
}

.btn-first {
  border-radius: 5px
}

.btn-second {
  border-radius: 0;
}