* {
    margin: 0;
    padding: 0;
}

html, body {
    width: 100%;
    height: 100%;
    display: flex;
    flex-direction: column;
    align-items: center;
}

h1 {
    margin: 20px;
}

.main {
    width: 750px;
    height: 1334px;
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    align-items: flex-start;
}

.box {
    width: 750px;
}

#box1 {
    background:url("../images/1-1.jpg") no-repeat;
    background-size: 100%;
}

#box2 {
    background: url("../images/2-1.jpg") no-repeat;
    background-size: 100%;
}

#box3 {
    background:url("../images/3-1.jpg") no-repeat;
    background-size: 100%;
}

#box4 {
    background:url("../images/4-1.jpg") no-repeat;
    background-size: 100%;
}


.pic {
    width: 750px;
    opacity: 0;
    transition: all 3s linear;
	cursor:pointer;
}

.show {
    opacity: 1;
}