QS:Time limit warning style
From LimeSurvey Manual
Time limit warning CSS style (time_limit_warning_style)
Description
It allows (and overrides the default) css styling used to display the time limit warning message. The default style value for this attribute will be used if it does not exist, which is: 'top: 10px; left: 35%; width: 30%; height: 60px; padding: 16px; border: 8px solid #555; background-color: white; z-index: 1001; text-align: center; overflow: auto'.
Any text entered into this attribute will overwrite the entire default css style for the warning message, so you should ensure that care is taken when entering a value for this attribute. It is strongly recommended that you re-use the z-index value, or that, at least, the z-index value be lower than that used for the time_limit_message_style attribute (which defaults to 1002).
This settings is only applicable if the general time limit setting is activated. This setting also exists for a second warning message.
Example
top: 10px; left: 35%; width: 30%; height: 60px; padding: 16px; border: 8px solid #555; background-color: gray; color: white; z-index: 1001; text-align: center; overflow: auto