body {
    margin: 0;
    background-color: #212121;
    font-family: Helvetica, sans-serif;
}

.container {
    max-width: 600px;
    margin: 0 auto;
}


h2 {
    margin: 0;
    padding: 20px 0;
    text-transform: uppercase;
    text-align: center;
    font-weight: 100;
    color: #FFF;
    background-color: #303F9F;
    transition: background-color 0.3s;
}

#guessDisplay {
    font-size: 2rem;
    font-weight: 800;
}

#nav {
    overflow: hidden;
    background-color: #FFF;
}

button {
    border: none;
    font-weight: 800;
    font-size: 1rem;
    padding: 10px;
    color: #303F9F;
    transition: all 0.3s;
}

button:focus {
    outline:none;
}

.selected {
    background-color: #303F9F;
    color: #FFF;
}

#reset {
    float: left;
}

#easy, #hard {
    float: right;
}

.square {
    background-color: black;
    border-radius: 25%;
    width: 30%;
    padding-bottom: 30%;
    margin: 1.66%;
    float: left;
    transition: all 0.5s;
}