Row Max Width

The largest width the row is allowed to grow to.

Where to find it: Labelled Max Width in the "Entire Row" section of the Modify drawer.
Per device: Yes — you can set one value for every screen, or separate values for phone, tablet, and desktop.
Underlying CSS: maxWidth

In plain English

Caps the row so wide screens do not stretch the band endlessly.

When you would use it

A centred content band should never exceed a readable measure.

How to change it

Open "Entire Row", then "Max Width".

One value, or one per device? Every input in this setting sits under a “Same value for all resolutions” checkbox. Leave it checked for a single value everywhere, or uncheck it to give phones, tablets, and desktops their own. How per-device values work.

Related settings

Row Width
Max Width
Horizontal Alignment
Using a CSS variable instead of a typed value

Where to go next

Back to the full attribute reference
The Composer — the editing surface these settings live in.
Publishing — how a change like this reaches your live site.