Good readability on all browsers
Line length is very important for good readability, but there is no simple way of checking it. Irrespective of whether the browser is running on a Smartphone or a 27" screen, various surfaces and formats are available. Modern, elaborate designs react on this problem with a layout, which is dependent on the browser width and change from a single column to a double or triple column format. It is less elaborate, but also less flexible to work with a fixed page width, which is no longer dependent on the browser window. Be sure to check how your web layout reacts to a change in size of the browser, in order to avoid long lines, which are impossible to read.
Text size on the Web
Controlling text size on the Web is even more difficult. In the final analysis you can specify only in what proportions the texts will stand with respect to each other, since the user is able to modify the perceived size of fonts in his or her browser. There is no one way of deactivating this function, to suit all browsers. Therefore, you must take care that your layout will tolerate modifications in the size of the text within certain limits.
The choice of the right fonts
One of the most important areas of typography, the choice of the right font was for a long time on the Web limited to just a few fonts. With the advent of Web fonts, which in the meantime can be licensed directly from Linotype, the situation has fundamentally improved. However, the low resolution of the majority of screens puts high demands on the fonts. Very thin lines, little embellishments and playful details can often be lost. Therefore, take care to set fonts rich in detail in adequate sizes. Only in this way can a typographical treasure reveal its full effect and not become an ordeal for the viewer trying to read it.