May I know what is the difference between
Out of the whole page of the Styles and Themes. You may be looking for this line.
When you apply a style to a single View in the layout, the properties defined by the style are applied only to that View. If a style is applied to a ViewGroup, the child View elements will not inherit the style properties—only the element to which you directly apply the style will apply its properties. However, you can apply a style so that it applies to all View elements—by applying the style as a theme.
When you apply as theme, it changes everything in scope, depending if you applied it on Activity or Application. Style is more 'local'.