grid-template-columns: 1fr 2fr 3fr;
grid-column-gap: 12px;

grid-template-columns: 20% 30% 50%;
grid-column-gap: 12px;

grid-template-columns: calc(20% - 8px)
calc(30% - 8px) calc(50% - 8px);
grid-column-gap: 12px;