JSFiddle - React, Tailwind, and code Playground

HTML

<div id="upbuttoncontainer">
    <div id="uptopdiv" class="up">
        <div id="uptoparrow-border-left"></div>
        <div id="uptoparrow-border-right"></div>
        <div id="uptoparrow-up-internal"></div>
        <div id="uptoparrow-up"></div>
    </div>
    <div id="upbottomdiv">
        <div id="uparrow-border-left"></div>
        <div id="uparrow-border-right"></div>
        <div id="uparrow-up-internal"></div>
        <div id="uparrow-up"></div>
    </div>
</div>
<div id="container">
    <ul>
        <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum. Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur, sunt in culpa qui officia deserunt mollit anim id est laborum.</p>
        <br>
        <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.</p>
        <li>3</li>
        <li>4</li>
    </ul>
</div>
<div id="downbuttoncontainer">
    <div id="downtopdiv" class="down">
        <div...

CSS

#container {
    height: 250px;
    width: 450px;
    background-color: #fff;
    overflow: hidden;
    margin-left: auto;
    margin-right: auto;
}
#container ul li {
    height: 50px;
}
#uparrow-border-left {
    width:0px;
    height:0px;
    border-left:22px solid transparent;
    /* left arrow slant */
    border-right:22px solid transparent;
    /* right arrow slant */
    border-bottom:22px solid #E27AC2;
    /* bottom, add background color here */
    font-size:0px;
    line-height:0px;
    margin-left: auto;
    margin-right: auto;
    top: 10px;
    left: 180px;
    position: absolute;
    z-index: 100;
}
#uparrow-border-right {
    width:0px;
    height:0px;
    border-left:22px solid transparent;
    /* left arrow slant */
    border-right:22px solid transparent;
    /* right arrow slant */
    border-bottom:22px solid #E27AC2;
    /* bottom, add background color here */
    font-size:0px;
    line-height:0px;
    margin-left: auto;
    margin-right: auto;
    top: 10px;
    left: 250px;
    position: absolute;
    z-index: 100;
}
#uparrow-up {
    width:0px;
    height:0px;
    border-left:22px solid transparent;
    /* left arrow slant */
    border-right:22px solid transparent;
    /* right arrow slant */
    border-bottom:22px solid #fff;
    /* bottom, add background color here */
    font-size:0px;
    line-height:0px;
    margin-left: auto;
    margin-right: auto;
    top: 10px;
    left: 214px;
    position: absolute;
    z-index: 98;
}
#uparrow-up-internal {
    width:0px;
    height:0px;
    border-left:13px solid transparent;
    /* left arrow slant */
    border-right:13px solid transparent;
    /* right arrow slant */
    border-bottom:13px solid #E27AC2;
    /* bottom, add background color here */
    font-size:0px;
    line-height:0px;
    margin-left: auto;
    margin-right: auto;
    position: absolute;
    top: 19px;
    left: 223px;
    z-index: 99;
}
#upbottomdiv {
    width: 450px;
    height: 40px;
    background-color: #E27AC2;
...

JavaScript

$(function () {
    var y = 0;
    $(".down").click(function (e) {
        e.preventDefault();
        $("#container").animate({
            scrollTop: y += 250
        }, 500);
    })
    $(".up").click(function (e) {
        e.preventDefault();
        $("#container").animate({
            scrollTop: y -= 250
        }, 500);
    })
})

$(document).ready(function () {
    $("#downtopdiv").hover(function () {
        $(this).stop().animate({
            "opacity": "0"
        }, 'fast');
    }, function () {
        $(this).stop().animate({
            "opacity": "1"
        }, 'fast');
    });
    $("#uptopdiv").hover(function () {
        $("#uptopdiv").stop().animate({
            "opacity": "0"
        }, 'fast');
    }, function () {
        $("#uptopdiv").stop().animate({
            "opacity": "1"
        }, 'fast');
    });
});