/* Three columns: 100px each */
.grid-container {
    display: grid;
    grid-template-columns: 600px 0.5fr 0.5fr;
    grid-template-rows: 600px;
    grid-gap: 1rem;
}

/* Three columns: 100px each */
.grid-container {
    display: grid;
    grid-template-columns: 0.5fr 0.5fr;
    grid-template-rows: 600px;
    grid-gap: 1rem;
}

Change layout from px to 0.5fr 0.5fr
Change layout from px to 0.5fr 0.5fr
