btcpayserver/BTCPayServer/wwwroot/pos/keypad.css

#PosKeypad {
    --wrap-max-width: 500px;
    overflow: hidden;
    position: relative;
}
#PosKeypad .alert {
    margin-top: var(--btcpay-space-xl);
}

button[data-bs-toggle] {
    position: absolute;
    top: 1.75rem;
    z-index: 1;
    color: var(--btcpay-header-link);
}
button[data-bs-toggle]:hover {
    color: var(--btcpay-header-link-accent);
}
button[data-bs-toggle] .icon {
    --icon-size: 1.75em;
}
#ItemsListToggle {
    right: var(--btcpay-space-m);
}
#RecentTransactionsToggle {
    left: var(--btcpay-space-m);
}

@media (max-width: 359px) {
    #RecentTransactions .list-group .badge-container {
        flex-grow: 1;
    }
}

#PosItems {
    --image-size: 3rem;
}

#PosItems .img img {
    width: var(--image-size);
    height: var(--image-size);
}

#PosItems .img img {
    max-width: var(--image-size);
    max-height: var(--image-size);
    object-fit: scale-down;
    border-radius: var(--btcpay-border-radius);
}

/* 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;
    border-color: transparent !important;
    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) {
    .actions .btn-secondary:hover {
        border-color: var(--btcpay-secondary-border-active) !important;
    }
}