.mainDiv {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 10px;
}

.mainDivEvent {
    padding: 20px;
    box-sizing: border-box;
    border: 1px solid black;

}

@media (max-width: 600px) {
    .mainDiv{
        grid-template-columns: 1fr;
    }
}

.mainDiv a {
    text-decoration: none;
    color: black;
}