* {
    margin: 0;
    padding: 0
}

.main {
    margin: 0 auto;
    max-width: 750px;
    position: relative;
    padding-bottom: 100px;
}

.pic {
    width: 100%;
    display: block;
}

.footer {
    max-width: 750px;
    position: fixed;
    bottom: 0;
}

.kf {
    position: fixed;
    right: 0;
    top: 30%;
    width: 80px;
}

.jump {
    animation: jump 2s ease infinite;
}

@keyframes jump {
    0% {
        transform: scale(1.08);
    }

    50% {
        transform: scale(0.92);
    }

    100% {
        transform: scale(1.08);
    }
}