.notice {
    font-weight:bold;
    background-color:black;
    color:white;
    line-height:28px;
    overflow:hidden;
}
.notice span {
    display:inline-block;
    animation:notice-mess-in 25s linear infinite;
}

@keyframes notice-mess {
    from {
        height:0;
    }
    to {
        height:28px;
    }
}

@keyframes notice-mess-in {
    0% {
        transform:translateX(100vw);
    }
    100% {
        transform:translateX(-100%);
    }
}