JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://bgrins.github.io/spectrum/spectrum.js"></script>
<link rel="stylesheet" href="https://bgrins.github.io/spectrum/spectrum.css">
<h2>Design your own calendar's colors!</h2>
<p>Choose an outside and inside color</p>

<div id="control-container">
    <label for="outside" class="color-label">Outside Color
        <input type="text" name="outside" class="colorpicker">
    </label>
    <label for="inside" class="color-label" id="inside-color-label">Inside Color
        <input type="text" name="inside" class="colorpicker">
    </label>
</div>
<div id="result">&nbsp;</div>

<div id="calendar-position">
    <div class="container" id="outside-preview">
        <div class="container" id="inside-preview">
            <div id="image-square"></div>
        </div>
    </div>
</div>

CSS

#control-container {
    margin: 50px auto;
}

.color-label {
    display: inline-block;
    font-size: 1.3em;
}

#inside-color-label {
    margin-right: 150px;
}

#calendar-position {
    margin: 0 auto;
    width: 500px;
}

#outside-preview,
#inside-preview {
    border: 1px solid black;
    border-radius: 8px;
}

#outside-preview {
    width: 500px;
    height: 600px;
    position: relative;
    border-bottom-left-radius: 0px;
    border-bottom-right-radius: 0px;
}

#inside-preview {
    width: 440px;
    height: 568px;
    position: absolute;
    z-index: 1;
    left: 5.5%;
    bottom: 0;
    background: #FFF;
}

#image-square {
    top: 17px;
    width: 400px;
    height: 176px;
    background: #FFF;
    position: relative;
    display: block;
    z-index: 2;
    margin: 0 auto;
}

JavaScript

$(document).ready(function() {

    $(".colorpicker").spectrum({
        color: "#FFF",
        showInput: true,
        className: "full-spectrum",
        showInitial: true,
        showPalette: true,
        showSelectionPalette: true,
        maxSelectionSize: 10,
        preferredFormat: "hex",
        localStorageKey: "spectrum.demo",
        change: function(color) {
            var eq = $(this).index('.colorpicker');
            $('.container').eq(eq).css('background-color', color.toHexString())
            var color = $("#outside-preview").css("background-color");
            $("#result").html("That div is " + color + "");
        },
        palette: [
            ["rgb(0, 0, 0)", "rgb(67, 67, 67)", "rgb(102, 102, 102)",
                "rgb(204, 204, 204)", "rgb(217, 217, 217)", "rgb(255, 255, 255)"
            ],
            ["rgb(152, 0, 0)", "rgb(255, 0, 0)", "rgb(255, 153, 0)", "rgb(255, 255, 0)", "rgb(0, 255, 0)",
                "rgb(0, 255, 255)", "rgb(74, 134, 232)", "rgb(0, 0, 255)", "rgb(153, 0, 255)", "rgb(255, 0, 255)"
            ],
            ["rgb(230, 184, 175)", "rgb(244, 204, 204)", "rgb(252, 229, 205)", "rgb(255, 242, 204)", "rgb(217, 234, 211)",
                "rgb(208, 224, 227)", "rgb(201, 218, 248)", "rgb(207, 226, 243)", "rgb(217, 210, 233)", "rgb(234, 209, 220)",
                "rgb(221, 126, 107)", "rgb(234, 153, 153)", "rgb(249, 203, 156)", "rgb(255, 229, 153)", "rgb(182, 215, 168)",
                "rgb(162, 196, 201)", "rgb(164, 194, 244)", "rgb(159, 197, 232)", "rgb(180, 167, 214)", "rgb(213, 166, 189)",
                "rgb(204, 65, 37)", "rgb(224, 102, 102)", "rgb(246, 178, 107)", "rgb(255, 217, 102)", "rgb(147, 196, 125)",
                "rgb(118, 165, 175)", "rgb(109, 158, 235)", "rgb(111, 168, 220)", "rgb(142, 124, 195)", "rgb(194, 123, 160)",
                "rgb(166, 28, 0)", "rgb(204, 0, 0)", "rgb(230, 145, 56)", "rgb(241, 194, 50)", "rgb(106, 168, 79)",
                "rgb(69, 129, 142)", "rgb(60, 120, 216)",...