JSFiddle - React, Tailwind, and code Playground

HTML

<body class="body-common-styles">
            <div class="css-grid-container-common-styles">
                <nav class="navbar navbar-expand-lg navbar-light bg-light css-grid-item-nav-div-common-styles">
                    <button class="navbar-toggler navbar-toggler-right" type="button" data-toggle="collapse" data-target="#navbar1" aria-controls="navbar1" aria-expanded="false" aria-label="Toggle navigation">
                    <span class="navbar-toggler-icon"></span>
                    </button>
                    <a class="navbar-brand" href="index.html">CodingJedi</a>
                    <div class="collapse navbar-collapse justify-content-between" id="navbar1">
                        <ul class="navbar-nav">
                            <li class="nav-item active">
                                <a class="nav-link" href="index.html">Home</a>
                            </li>
                            <li class="nav-item">
                                <a class="nav-link" href="widgets.html">About</a>
                            </li>
                        </ul>                   
                    </div>
                </nav>
                <div class="css-grid-item-info-div-common-styles"> <!-- this container item is also a container -->
                    <div class="css-grid-container-practice-create-div-common-styles"> <!-- this is a container -->
                        <p class="css-grid-item-practice-para1-div-common-styles"> P1. </p>
                        <p class="css-grid-item-practice-para2-div-common-styles"> P2. </p>
                        <p class="css-grid-item-practice-para3-div-common-styles"> P3. </p>
                        <button type="button" class="button-common-styles-normal css-grid-item-practice-button-div-common-styles"> P! </button>                     


                        <p class="css-grid-item-create-para1-div-common-styles"> P4</p>
                        <p...

CSS

button {
   align-self: center;
   justify-self: center;
}





.body-common-styles {
    background: linear-gradient(45deg,#33b1f8 37%,#6e90f6 100%); /*syntax linear-gradient(direction, color1 limit, color2 limit)*/
    color:white;
    font-family: Helvetica;
    line-height: 1;
}

.div-common-styles{
    background-color:#0F2148;
}

.button-common-styles-normal{
    /*background: radial-gradient(ellipse,#268ff4 5%,#4da3f8 95%);  */
    background-color: #4da3f8;
    border:none;
    color:white;
    border-radius: 8px;
    width:100px; /* sets the width of the content area to 200 px */
    height: 40px;
    box-sizing: border-box;
    text-align: center;
    padding-top: 10px;
    padding-bottom: 10px;
}   

.button-common-styles-normal:hover {
    background-color:  #268ff4;
}

.center-horizontally-common-styles {
    display: block;
    margin: auto auto;
}

.centre-vertical-common-styles {
   position: fixed; /*Fixed positioning acts similarly to absolute positioning with a couple of differences.*/
   left: 50%; /*creates a space equal to 50% from left creating effect of moving the element towards the center horizontally*/
   top: 50%; /* creates a space equal to 50% from top creating effect of moving the element towards the center vertically*/
   transform: translate(-50%, -50%);
}

.centre-button-vertical-common-styles {
   position: absolute; /*An absolutely positioned element is positioned relative to the first parent element that has a position other than static applied to it. */
   left: 50%; /*creates a space equal to 50% from left creating effect of moving the element towards the center horizontally*/
   top: 50%; /* creates a space equal to 50% from top creating effect of moving the element towards the center vertically*/
   transform: translate(-50%, -50%);
}

.debug-border-common-styles {
    border: 3px solid black;
    height:200px;
    width:400px;
}

.css-grid-container-common-styles{
    height:100vh; /*???*/
    display: grid;
   ...