.poster img {
    width: 100%;
    border: 1px lightgrey solid;
}

.poster h3 {
    margin-top: 0.75em;
    font-size: 20px;
}

.poster p {
    margin-bottom: 1.5em;
}

@media (min-width: 768px) {
    .poster {
        margin-left: 2%;
        width: 32%;
        float: left;
        text-align: center;
    }
    
    .poster img {
        height: 13vw;
        object-fit: cover;
    }
    
    .first {
        margin-left: 0px;
    }    
}