html {
    width: 100%;
}

h1 {
    padding-top: 5vw;
    font-size: 5vw;
}
a {
    text-decoration: none;
    color:black;
}

.photo-collection {
    z-index: 1;
    position: absolute;
    top: 0;
    bottom: 50%;
    right: 0;
    height: 50%;
    width: 100%;
    background: url("../images/collection.jpg");
    background-size: cover;
}

.photo-stock {
    z-index: 1;
    position: absolute;
    top: 50%;
    bottom: 0;
    height: 50%;
    width: 100%;
    left: 0;
    background: url("../images/stock.jpg");
    background-size: cover;
}

#collection {
    opacity: 0;
    z-index: 2;
    position: absolute;
    text-align: center;
    top: 0;
    bottom: 50%;
    right: 0;
    height: 50%;
    width: 100%;
    background: linear-gradient(to bottom, rgba(255,255,255,0.6), rgba(255,200,0,0.6));
}

#stock {
    opacity: 0;
    z-index: 2;
    position: absolute;
    text-align: center;
    top: 50%;
    bottom: 0;
    height: 50%;
    width: 100%;
    left: 0;
    background: linear-gradient(to bottom, rgba(255,255,255,0.6), rgba(255,200,0,0.6));
}

#collection:hover {
    opacity: 1;
}

#stock:hover {
    opacity: 1;
}