article {
    display: grid;
    grid-template-columns: 100%;
    grid-column: 3 / -1;

}

.arc {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    grid-template-areas: "a b b";
    padding-bottom: 1em;
}



article h1 {
    grid-area: a;
}

section.description {
    grid-area: b;
}



li {
    list-style-type: none;
}

main {
    padding-top: 2em;
}


@media only screen and (995px < width <=1500px) {

    article {
        grid-column: 1 / -1;
    }
}



@media only screen and (width <=995px) {
    article {
        grid-column: 1 / -1;
    }

    .arc {
        display: grid;
        grid-template-columns: repeat(3, 1fr);
        grid-template-areas:
            "a a a"
            "b b b";
        padding-bottom: 1em;
    }
}