Themes
From LimeSurvey Manual

Install Limesurvey 3.0+ to get access to the survey theme options feature. This option are not available in the older LimeSurvey versions!

Introduction
The theme options is available on LimeSurvey 3.x, and offers a set of various tools that allows the survey administrators to quickly and easily change the themes-related settings of their surveys.
Options to Change a Theme
There are two ways to use a theme in LimeSurvey 3.x, either through the global setting or through the theme option panel inside a survey.
Changing the Theme from the global setting makes the chosen theme the default theme for all surveys you create. If the theme is changed for a particular survey using the Theme option panel inside the theme, only the theme for that particular survey is changed.
Global setting default Theme
