SOURCE

<div class="gradient-wrapper">
	<div class="inside">
        <div>hsdfhsdfjsdfjsdfjas</div>
        <div>dsfsdl;jfsdjflsd;jfsdjflsdsd;fjsd;fjsd</div>
        <div>lsdjfsjf;sd</div>
        <div>fds;fjsd;fjs;ldjfdsfsdfsdfgdfgsdgsdgfsdfas</div>
        <div>sdfasdfsdfsadfasdf</div>
        <div>fsdfasdfasfsf</div>
        <div>gsdfgdsfgdf</div>
	</div>
</div>

@keyframes wrapper-gradient {
    0% {
        transform: translateY(-100%);
    }
    100% {
        transform: translateY(0);
    }
}

@keyframes img-gradient {
    0% {
        transform: translateY(100%);
        opacity: 0;
    }
    100% {
        transform: translateY(0);
        opacity: 1;
    }
}

.gradient-wrapper {
    overflow: hidden;
    animation: wrapper-gradient 2s linear;
}

.gradient-wrapper>.inside {
    width: 400px;
    height: 250px;
    animation: img-gradient 2s linear;
}