* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 62.5%;
}

body {
    font: 'Raleway', sans-serif;
}

.container .img-container {
    padding: 0.5rem;
}

h1 {
   font-size: 3rem;
   padding: 2rem;
   text-align: center; 
}

.image {
    display: block;
    width: 100%;
}
.row {
    margin: 5rem;
}

.overlay {
    position: absolute;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
    height: 100%;
    width: 100%;
    opacity: 0;
    transition: .5s ease;
    background-color: rgba(255,255,255,0.9);
} 

.caption {
    font-size: 2rem;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%,-50%);
    text-align: center;
}

.thumbnail:hover {
   transform: translateY(-4px); 
}

.img-container:hover .overlay {
    opacity: 0.5;
}