[S@NL - BlackBik]

You can do this by altering the "vsa_chatbox_input" template.
Just add a style background element that has the color that you want.
For example:

<input type="text" class="primary textbox" name="vsacb_entermessage" id="vsacb_entermessage" style="width:100%;font-size:{vb:raw vsacb_textsize};color:{vb:raw vsacb_color_default};background-color:{vb:stylevar blockrow_background.backgroundColor};" onkeydown="if (event.keyCode == 13) {return VSacb_postMessage(vsacb_post_form);}" onkeyup="VSacb_LimitChars('vsacb_entermessage', 'vsacb_counter','{vb:raw vboptions.vsachatbox_charlimit}');" onfocus="if(!this._haschanged){this.value=''};this ._haschanged=true;vsacb_submitbutton.disabled=fals e;" <vb:if condition="$vsacb_cantpost">disabled="disabled"</vb:if> value="{vb:rawphrase message}..." />

"blockrow_background.backgroundColor" is the styleelement I used, but you can also pick another one.