I tried to apply font style to a single cell but the style gets applied to the entire worksheet. eg

worksheet.getCell('A1').font = { color: { argb: '3a80d5' }}

Expected result:
Cell A1 font color should be #3a80d5

Actual result:
All cells in the worksheet have font color #3a80d5

Also I tried to apply this to a column as follows:

worksheet.getColumn('columnId').eachCell((cell, rowNumber) => { 
     cell.font = { color: { argb: '3a80d5' }}
})

I expect that all cells in column columnId should have the new font color and all other cells remain with the default black font color. But instead. all cells in the worksheet are styled to have the color #3a80d5.