diff --git a/bin/__build_sgr_code b/bin/__build_sgr_code
index 04b26f9..eba9f6f 100755
--- a/bin/__build_sgr_code
+++ b/bin/__build_sgr_code
@@ -120,10 +120,14 @@ function ext_color()
 
 function rgb_color()
 {
+    color=$1
+    case $1 in
+        [0-9a-fA-F][0-9a-fA-F][0-9a-fA-F]) color=${1:0:1}${1:0:1}${1:1:1}${1:1:1}${1:2:1}${1:2:1} ;;
+    esac
     # First split off the red, green, and blue components...
-    red_hex=${1:0:2}
-    green_hex=${1:2:2}
-    blue_hex=${1:4:2}
+    red_hex=${color:0:2}
+    green_hex=${color:2:2}
+    blue_hex=${color:4:2}
 
     # Convert to decimal...
     red_dec=$((16#${red_hex}))
@@ -297,14 +301,20 @@ do
 
         ansi:*) make_color 0 ansi_color ${1:5} ;;
         ext:*) make_color 0 ext_color ${1:4} ;;
+        # 12-bit color also supported
+        [0-9a-fA-F][0-9a-fA-F][0-9a-fA-F]) make_color 0 rgb_color $1 ;;
         [0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F]) make_color 0 rgb_color $1 ;;
 
         fg:ansi:*) make_color 0 ansi_color ${1:8} ;;
         fg:ext:*) make_color 0 ext_color ${1:7} ;;
+        # 12-bit color also supported
+        fg:[0-9a-fA-F][0-9a-fA-F][0-9a-fA-F]) make_color 0 rgb_color ${1:3} ;;
         fg:[0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F]) make_color 0 rgb_color ${1:3} ;;
 
         bg:ansi:*) make_color 1 ansi_color ${1:8} ;;
         bg:ext:*) make_color 1 ext_color ${1:7} ;;
+        # 12-bit color also supported
+        bg:[0-9a-fA-F][0-9a-fA-F][0-9a-fA-F]) make_color 1 rgb_color ${1:3} ;;
         bg:[0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F]) make_color 1 rgb_color ${1:3} ;;
 
         fg:*) make_color 0 named_color ${1:3} ;;