style.css

body  {
    background: rgb(243, 241, 239);
    color: #323232;
    font-weight: 300;    
    display: flexbox;
    justify-content: center;
    align-items:center;
    text-align: center;
    font-family: Helvetica, sans-serif;
    background-image: url('background.jpg');
    background-repeat: no-repeat;
    background-attachment: fixed;
    background-size: cover;
}

h1{
    font-size: 50px;    
}


h3{
    color: rgb(75, 70, 70);
    font-size: 25px;
}

.container {
    display: flex;
    justify-content: center;   
    height: 50vh;        
}

.grid{
    width: 200px;
    height: 400px;
    display: flex;
    flex-wrap: wrap;
    border: rgb(211, 223, 161);
    border-style: solid;
    background-color:rgb(242, 250, 228);          
}

.grid div{
    height: 20px;
    width: 20px; 
   
}

.mini-grid {
    margin-left: 50px;
    width: 80px;
    height: 80px;
    display: flex;
    flex-wrap: wrap;
    border: rgb(211, 223, 161);
    border-style: solid;
    background-color: rgb(236, 225, 225);    
}

.mini-grid div {
    height: 20px;
    width: 20px;
}

#start-button{
    background: rgb(43, 41, 41);
    color: white;
    display: inline-block;
    padding: .5em 2.5em;
    text-decoration: none;
    cursor: pointer;
    font-size: .8rem;
    text-transform: uppercase;
    letter-spacing: 2px;
    transition: transform 200ms ease-in-out;
}

#start-button:hover {
    transform: scale(1.2);
}