change default debug theme to 1 and make black "30" readable in the preview

_debug_replacements.php

@@ -90,5 +90,5 @@ return [
 	'uart_stopbits' => 1,
 	'uart_parity' => 2,
 
-	'theme' => 7,
+	'theme' => 1,
 ];

pages/cfg_term.php

@@ -27,7 +27,7 @@
 
 	<div class="Row color-preview">
 		<div class="colorprev">
-			<span data-fg=0 data-bg="0">30</span><!--
+			<span data-fg=0 data-bg="0" style="text-shadow: 0 0 4px white;">30</span><!--
 			--><span data-fg=1 data-bg="0">31</span><!--
 			--><span data-fg=2 data-bg="0">32</span><!--
 			--><span data-fg=3 data-bg="0">33</span><!--