# Defining a textbox with colors in Markdown

I'm trying to build a document in R Markdown using R studio, and I originally posted this question to stackoverflow, where a kind user referred me to this site.

I'm in no way a LaTeX expert, but I initially tried to, with the help of another user, build a dark blue box with white writing using the following code:

---
output:
pdf_document:
keep_tex: yes
---

\begin{Form}
\TextField[width = 10cm,%
height = 3cm,%
multiline=true,%
bordercolor = 0 0 0.5,%
backgroundcolor = 0 0 0.5,%
color = 1 1 1,%
value = {%
This is the textbox.\string\n
I would like a dark blue textbox with white writing
}%
]{}
\end{Form}


Now this actually helped me build a box, but the box was only white with a black outline and black text. Furthermore, the line shift \string\n did not help shift the lines.

Can someone here maybe help me out or take a look at this?

---