@charset "utf-8";

.box { width: 680px;
    margin: 40px auto;
    display: flex; 
    flex-wrap: wrap; }

.season-box { width: 330px;
    height: 214px; 
    border-radius: 5px; 
    display: block; 
    margin: 5px;
    background-size: 100%;
    background-repeat: no-repeat; 
    opacity: .5; 
    transition: opacity 3s; }

.season-box:hover { opacity: 1.0; }
.winter { background-image: url("images/winter.jpg"); }
.spring { background-image: url("images/spring.jpg"); }
.summer { background-image: url("images/summer.jpg"); }
.fall { background-image: url("images/fall.jpg"); }