How can I adjust the placement and size of my cart quantity selector?

Hi @Ryan1998 ,

Go to Online Store → Theme → Edit code.
please add this css to the very end of your base.css file and check

.product-form .product-form__submit {
    width: calc(100% - 116px) !important;
    margin-left: 120px !important;
    margin-top: -70px !important;
        font-size: 16px !important;
}

#shopify-section-template--21220955717961__main button.quantity__button.no-js-hidden {
    margin-left: -11px;
    margin-top: 2px;
    display: flex !important;
}

#shopify-section-template--21220955717961__main quantity-input.quantity {
    width: 97px !important;
}

label.quantity__label.form__label{
      font-size: 2rem !important;
}

Thanks!