direction: rtl

The direction property set the direction of text, table columns and horizontal overflow. direction: rtl will change to writing mode from right to left.

Flexbox over floating layout

Use flex layout instead of floating layout, because flex items always start from the start edge of the flex container. With direction: rtl

Symmetric margin and padding

If just setting margin-left or padding-left, then you have to overwrite them for Arabic web. The best solution is to set symmetric margin and padding to avoid two set of styles.

Avoid text-align

Avoid setting text-align

Issues

Layout-related Javascript logic

If appling positioning styles like position: relative and left: 10px in Javascript, then you will find it hard to reverse for Arabic countries.