Support for SermonSpeaker 5.x is in bugfix mode only, the same as it is for Joomla 3.10.
I will not add any new features to this releases.
Please upgrade to SermonSpeaker 6.x and Joomla 4.x, which is better anyway.
Currently, your template sets the width for inputs with the class "input-mini" to 60px. So this rule would make it 10px wider, but only for the limit field.