protected void setContentCellStyle(Cell cell, Head head, Integer relativeRowIndex) {
        throw new UnsupportedOperationException("Custom styles must override the setContentCellStyle method.");
    }
Sets the cell style of content

@param cell
@param head
@param relativeRowIndex
fastexcel-core/src/main/java/cn/idev/excel/write/style/AbstractCellStyleStrategy.java