diff --git a/includes/colors.c b/includes/colors.c
index 580e95a..519c5e2 100644
--- a/includes/colors.c
+++ b/includes/colors.c
@@ -2,9 +2,8 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <math.h>
+#include <ctype.h>
 #include "colors.h"
-#define ASCII_ZERO 48
-#define ASCII_NINE 57
 #define MIN_CONTRAST 0.5
 
 void hsl2rgb(struct Rgb *dest, const struct Hls const *src) {
@@ -134,24 +133,30 @@ static void hexspan(const char *str) {
 }
 
 static void b(char * const str) {
-#define IS_DIGIT(x) (x >= ASCII_ZERO && x <= ASCII_NINE)
     char *token = strtok(str, "^");
     char c;
     printf("<TD>");
     while (token) {
         c = token[0];
-        if (IS_DIGIT(c)) {
+        if (isdigit(c)) {
             decspan(c - ASCII_ZERO);
-            printf("%s", token + 1);
-        } else if (c == 'x' && strlen(token) > 4) {
-            hexspan(token + 1); //exclude x
-            printf("%s", token + 4);
+            if (strlen(token) > 1) {
+                printf("%s", token + 1);
+            }
+        } else if (c == 'x' && strlen(token) > 3) {
+            if (isxdigit(token[1]) && isxdigit(token[2]) && isxdigit(token[3])) {
+                hexspan(token + 1); //exclude x
+                if (strlen(token) > 4){
+                    printf("%s", token + 4);
+                }
+                printf("</span>");
+            }
         } else {
             printf("%s", token);
         }
         token = strtok(NULL, "^");
     }
-    printf("</span></TD>");
+    printf("</TD>");
 }
 
 void print_plname(const char* str) {