@media (max-width: 720px) {
    #main-wrapper {
        width: 90%;
    }
    
    #main-menu ul {
        flex-direction: column;
        align-items: center;
    }
    
    #splash {
        padding: 16px;
        background-image: none;
    }
    
    .column-holder {
        flex-direction: column;
    }
    
    .large-column, .small-column {
        flex-grow: 0;
    }
}