html, body {
    font-family: "Lucida Sans Unicode", "Lucida Grande", sans-serif;
    background-color: #4F5A64;
    color: #C0C0C0;
}

a {
    color: lightblue;
}

button, p, h3 {
    color: #C0C0C0;
}

img {
    border-radius: 5px;
}

.btn {
    margin: 10px;
}

.signin-signout {
    margin: 20px auto;
    width: 120px;
}

.small-img {
    width: 100%;
}

@media (min-width: 640px) {
    .small-card {
        display: inline-block;
        width: 300px;
        height: 300px;
        margin: 10px;
    }
    
    .card-group {
        margin: auto;
        width: 640px;
    }
}

@media (max-width: 639px) {
    .small-card {
        width: 300px;
        height: 300px;
        margin: 10px;
    }
    
    .card-group {
        margin: auto;
        width: 320px;
    }
}