Small improvement

app/src/main/java/eu/faircode/email/HtmlHelper.java

@@ -383,10 +383,10 @@ public class HtmlHelper {
 
                 String[] params = style.split(";");
                 for (String param : params) {
-                    String[] kv = param.split(":");
+                    int semi = param.indexOf(':');
-                    if (kv.length == 2) {
+                    if (semi > 0) {
-                        String key = kv[0].trim().toLowerCase(Locale.ROOT);
+                        String key = param.substring(0, semi).trim().toLowerCase(Locale.ROOT);
-                        String value = kv[1].toLowerCase(Locale.ROOT)
+                        String value = param.substring(semi + 1).toLowerCase(Locale.ROOT)
                                 .replace("!important", "")
                                 .trim()
                                 .replaceAll("\\s+", " ");