@import url('https://fonts.googleapis.com/css2?family=Instrument+Sans:ital,wght@0,400;0,500;0,600;0,700;1,400;1,500;1,600;1,700&display=swap');

#rec1748018841 .t706 .t706__cartwin.t706__cartwin_showed .t706__cartwin-content .t706__cartwin-heading,
#rec1748018841 .t706 .t706__cartwin.t706__cartwin_showed .t706__cartwin-content .t706__product-title,
#rec1748018841 .t706 .t706__cartwin.t706__cartwin_showed .t706__cartwin-content .t706__cartwin-prodamount-price,
#rec1748018841 .t706 .t706__cartwin.t706__cartwin_showed .t706__cartwin-content .t706__cartwin-prodamount-label,
#rec1748018841 .t706 .t706__cartwin.t706__cartwin_showed .t706__cartwin-content .t706__cartwin-totalamount-label {
    font-family: 'Instrument Sans', sans-serif !important;
}

/* All cart and form elements */
#rec1748018841 .t706 .t706__cartwin-heading,
#rec1748018841 .t706 .t706__product-title,
#rec1748018841 .t706 .t706__cartwin-prodamount-price,
#rec1748018841 .t706 .t706__cartwin-prodamount-label,
#rec1748018841 .t706 .t706__cartwin-totalamount-label,
.t706__cartwin-prodamount-currency,
.t-input-phonemask__options-code,
.t-input-phonemask__select-code,
.t706 .t-form .t-input.t-input-phonemask,
.t706 .t-form input.t-input,
.t706 .t-form .t-input,
.t706_product-deleted_timer__title,
.t706 .t-form .t-select {
    font-family: 'Instrument Sans', sans-serif !important;
}

/* Preserve original styles */
.t706__cartwin-prodamount-currency, .t706__cartwin-prodamount-price { display: inline-block; }
.t-input-phonemask__options-code, .t-input-phonemask__select-code { margin-left: 10px; }
.t706 .t-form .t-input.t-input-phonemask { height: 100%; }
.t706 .t-form input.t-input { -webkit-transform: translateZ(0); }
.t706 .t-form .t-input, .t706 .t-form .t-select { height: 56px; }


.t706__product-deleted__timer__counter, .t706__product-deleted__timer__title {
    font-family: 'Instrument Sans', sans-serif !important;
}

.t706__product-deleted__timer__return {
    font-family: 'Instrument Sans', sans-serif !important;
}


/* Apply Instrument Sans to range interval text */
#rec1748244331 .t702 .t-popup .t-popup__container.t-width.t-width_8 .t702__wrapper .t-form.t-form_inputs-total_3.t-form_bbonly .t-form__inputsbox.t-form__inputsbox_vertical-form.t-form__inputsbox_inrow.t-form__inputsbox_flex .t-input-group.t-input-group_rg.t-input-group_width100.t-input-group_inrow.t-input-group_inrow-last .t-input-block.t-input-block_width.t-input-block_width100 .t-range__wrapper .t-range__interval-txt-wrapper .t-range__interval-txt.t-range__interval-txt_max.t-descr.t-descr_xxs {
    font-family: 'Instrument Sans', sans-serif !important;
}

#rec1748244331 .t702 .t-popup .t-popup__container.t-width.t-width_8 .t702__wrapper .t-form.t-form_inputs-total_3.t-form_bbonly .t-form__inputsbox.t-form__inputsbox_vertical-form.t-form__inputsbox_inrow.t-form__inputsbox_flex .t-input-group.t-input-group_rg.t-input-group_width100.t-input-group_inrow.t-input-group_inrow-last .t-input-block.t-input-block_width.t-input-block_width100 .t-range__wrapper .t-range__interval-txt-wrapper .t-range__interval-txt.t-range__interval-txt_min.t-descr.t-descr_xxs {
    font-family: 'Instrument Sans', sans-serif !important;
}

#rec1748244331 .t702 .t-popup .t-popup__container.t-width.t-width_8 .t702__wrapper .t-form.t-form_inputs-total_3.t-form_bbonly .t-form__inputsbox.t-form__inputsbox_vertical-form.t-form__inputsbox_inrow.t-form__inputsbox_flex .t-input-group.t-input-group_rg.t-input-group_width100.t-input-group_inrow.t-input-group_inrow-last .t-input-block.t-input-block_width.t-input-block_width100 .t-range__wrapper .t-range__value-txt.t-descr.t-descr_xxs {
    font-family: 'Instrument Sans', sans-serif !important;
}

Here's the updated CSS with those elements included:
css/* Import Instrument Sans font */
@import url('https://fonts.googleapis.com/css2?family=Instrument+Sans:ital,wght@0,400;0,500;0,600;0,700&display=swap');

/* Range value text */
#rec1748244331 .t-range__value-txt {
    font-family: 'Instrument Sans', sans-serif !important;
}

/* Hide submit button */
#rec1748244331 .t702 .t-form__submit .t-submit {
    display: none !important;
}



.t702 .t-popup__block-close {
        background: transparent !important;
    }
    
    
.t-range__value-txt {
    font-family: 'Instrument Sans', sans-serif !important;
}

t-range__interval-txt {
    
        font-family: 'Instrument Sans', sans-serif !important;
}

.t-range__interval-txt-wrapper {
    
            font-family: 'Instrument Sans', sans-serif !important;
}


.t-range__interval-txt_max {
                font-family: 'Instrument Sans', sans-serif !important;
}

.t-range__interval-txt_min {
                font-family: 'Instrument Sans', sans-serif !important;
} 

.t898__icon_link .t898__btn-text {
                font-family: 'Instrument Sans', sans-serif !important;
}