Color selector based on column count

grid-color.js

const colors = ['yellow', 'pink', 'blue', 'orange', 'teal']

function colorRows (colCount) {
  for (let i = 0; i < items.length; i++) {
    const item = items[i]
    const row = Math.floor(i / colCount)
    const col = i % colCount;
    const index = (row + col) % colors.length
    item.style.background = colors[index]
  }
}