.nice-number {
    display: inline-flex;
    justify-content: stretch;
}

    .nice-number input {
        vertical-align: middle;
        -moz-appearance: textfield;
        box-sizing: content-box;
        margin: 0;
        text-align: center;
    }

        .nice-number input::-webkit-inner-spin-button, .nice-number input::-webkit-outer-spin-button {
            -webkit-appearance: none;
            margin: 0;
        }