btcpayserver/BTCPayServer/wwwroot/pos/keypad.css

#PosKeypad {
    --wrap-max-width: 575px;
}

/* modes */
#ModeTabs {
    min-height: 2.75rem;
}

/* keypad */
.keypad {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
}
.keypad .btn {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0;
    position: relative;
    border-radius: 0;
    font-weight: var(--btcpay-font-weight-semibold);
    font-size: 24px;
    min-height: 3.5rem;
    height: 8vh;
    max-height: 6rem;
    color: var(--btcpay-body-text);
}
.keypad .btn[data-key="+"] {
    font-size: 2.25em;
}
.btcpay-pills label,
.btn-secondary.rounded-pill {
    padding-left: 1rem;
    padding-right: 1rem;
}

/* make borders collapse by shifting rows and columns by 1px */
/* second column */
.keypad .btn:nth-child(3n-1) {
    margin-left: -1px;
}
/* third column */
.keypad .btn:nth-child(3n) {
    margin-left: -1px;
}
/* from second row downwards */
.keypad .btn:nth-child(n+4) {
    margin-top: -1px;
}
/* ensure highlighted button is topmost */
.keypad .btn:hover,
.keypad .btn:focus,
.keypad .btn:active {
    z-index: 1;
}

#Calculation {
    min-height: 1.5rem;
}

@media (max-height: 700px) {
    .store-header {
        display: none !important;
    }
}
@media (max-width: 575px) {
    #PosKeypad {
        --wrap-padding-horizontal: 0;
        overflow: hidden;
    }
    .keypad {
        margin-left: -1px;
        margin-right: -1px;
    }
    .store-footer {
        display: none !important;
    }
}
/* fix sticky hover effect on mobile browsers */
@media (hover: none) {
    .keypad .btn-secondary:hover,
    .actions .btn-secondary:hover {
        border-color: var(--btcpay-secondary-border-active) !important;
    }
}