Changing the default text style
Not sure why the text is coming out in a different color or different style in your composer? Update your default text style to get it back to the color and style you want.
Open your composer, and type
The initial text you type should appear in the different color/style than what you want.
Highlight and change
Highlight the text you've written and use the style bar at the bottom of the composer to update the text style/color to what you want your default text to come out looking like.
Save text as default style
Once you've updated the style of your text, go back to the style bar and find the more option to uncover the 'Save as default style' option. Once you've done that, you need to actually send out your message to save the default style.