JSFiddle - React, Tailwind, and code Playground

HTML

<div class="step">
    <input type="number" name="amount" maxlength="3" size="3" />
    <div class="b">
            <span class="up">&uarr;</span>
            <span class="down">&darr;</span>
    </div>
</div>

CSS

.step input {
    font-size:1.25em;
    float:left;
    width:100px;
    height:20px;
    padding:5px 3px;
}
.step .b {
     float:left;
     height:32px;
      overflow:hidden;  
    border:1px solid #ccc;
}
.step span.up, .step span.down {
    font-size:30px;
    height:18px;
   width:20px;
   overflow:hidden; 
    float:right;
    cursor:pointer;
    text-align:center;
    background: rgb(246,248,249); /* Old browsers */
background: -moz-linear-gradient(top, rgba(246,248,249,1) 0%, rgba(229,235,238,1) 50%, rgba(215,222,227,1) 51%, rgba(245,247,249,1) 100%); /* FF3.6+ */
background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,rgba(246,248,249,1)), color-stop(50%,rgba(229,235,238,1)), color-stop(51%,rgba(215,222,227,1)), color-stop(100%,rgba(245,247,249,1))); /* Chrome,Safari4+ */
background: -webkit-linear-gradient(top, rgba(246,248,249,1) 0%,rgba(229,235,238,1) 50%,rgba(215,222,227,1) 51%,rgba(245,247,249,1) 100%); /* Chrome10+,Safari5.1+ */
background: -o-linear-gradient(top, rgba(246,248,249,1) 0%,rgba(229,235,238,1) 50%,rgba(215,222,227,1) 51%,rgba(245,247,249,1) 100%); /* Opera 11.10+ */
background: -ms-linear-gradient(top, rgba(246,248,249,1) 0%,rgba(229,235,238,1) 50%,rgba(215,222,227,1) 51%,rgba(245,247,249,1) 100%); /* IE10+ */
background: linear-gradient(top, rgba(246,248,249,1) 0%,rgba(229,235,238,1) 50%,rgba(215,222,227,1) 51%,rgba(245,247,249,1) 100%); /* W3C */
filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#f6f8f9', endColorstr='#f5f7f9',GradientType=0 ); /* IE6-9 */
}
.step span.up {
 margin-top:-5px;   
}
.step span.up:hover, .step span.down:hover {
background: rgb(255,255,255); /* Old browsers */
background: -moz-linear-gradient(top, rgba(255,255,255,1) 0%, rgba(241,241,241,1) 50%, rgba(225,225,225,1) 51%, rgba(246,246,246,1) 100%); /* FF3.6+ */
background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,rgba(255,255,255,1)), color-stop(50%,rgba(241,241,241,1)),...

JavaScript

$(document).ready(function(){
    $("span.up").click(function(){
       $(this).closest("div.step").find("input").val((Number($(this).closest("div.step").find("input").val())+1));
    });
        $("span.down").click(function(){  
            $(this).closest("div.step")
                .find("input")
                .val((Number($(this).closest("div.step").find("input").val())-1));
    });
});