:root {
    background-color:burlywood;
    font-size: 62.5%;
}

* {
    box-sizing: border-box;
    font-family: Arial, Helvetica, sans-serif;
    margin: 0;
    padding: 0;
    color: #333;
}

 h1,
 h2,
 h3,
 h4 {
     margin-bottom: 1rem;
 }

 h1 {
     font-size: 5.4rem;
     color: #56a5eb;
     margin-bottom: 5rem;
 }

 h1 > span {
     font-size: 2.4rem;
     font-weight: 500;
 }

 h2 {
     font-size: 4.2rem;
     margin-bottom: 4rem;
     font-weight: 700;
 }

 h3 {
     font-size: 2.8rem;
     font-weight: 500;
 }

 h4 {
     font-size: 2.2rem;
     color: #56a5eb;
     margin-top: 1rem;
     margin-bottom: 2rem;
     font-weight: 500;
 }

 img {
     float: left;
 }

 /* UTILITIES */

 /* CENTERS HORIZONTALLY AND VERTICALLY */
 .container {
     width: 100vw;
     height: 100vh;
     display: flex;
     justify-content: center;
     align-items: center;
     max-width: 80rem;
     margin: 0 auto;
     padding: 2rem;
 }

/* ENSURES ANY CHILD OF MY CONTAINER HAS WIDTH OF 100% SO IT WILL STAY CENTERED HORIZONTALLY */ 
 .container > * {
     width: 100%;
 }

 .flex-column {
     display: flex;
     flex-direction: column; /* Vertical instead of horizontal, Play and High Scores stacked */
 }

 .flex-center {
     justify-content: center;
     align-items: center;
 }

 .justify-center {
     justify-content: center;
 }

 .text-center {
     text-align: center;
 }

/* HIDES THINGS IF YOU NEED TO */
 .hidden {
     display: none;
 }


 /* BUTTONS */
 .btn {
     font-size: 1.8rem;
     padding: 1rem 0;
     width: 20rem;
     text-align: center;
     border: 0.1rem solid #56a5eb;
     margin-bottom: 1rem;
     text-decoration: none; /* REMOVES LINK UNDERLINING */
     color: #56a5eb;
     background-color: white;
 }

 .btn:hover {
     cursor: pointer;
     box-shadow: 0 0.4rem 1.4rem 0 rgba(86, 185, 235, 0.5);
     transform: translateY(-0.1rem);
     transition: transform 150ms;
 }

 .btn[disabled]:hover {
     cursor: not-allowed;
     box-shadow: none;
     transform: none;
 }

 /* FORMS */
 form {
     width: 100%;
     display: flex;
     flex-direction: column;
     align-items: center;
 }

 input {
     margin-bottom: 1rem;
     width: 20rem;
     padding: 1.5rem;
     font-size: 1.8rem;
     border: none;
     box-shadow: 0 0.1rem 1.4rem 0 rgba(86, 185, 235, 0.5);
 }

 input::placeholder {
     color: #aaa;
 }