diff --git a/src/main.cpp b/src/main.cpp
index 5ffbf9e..0c1b17d 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -8,7 +8,7 @@
 #include <cmath>
 
 // Configuration defaults - edit to change default run mode
-#define DEFAULT_CONFIG_FILE "configs/test_simple.txt"
+#define DEFAULT_CONFIG_FILE "configs/test_simple.toml"
 #define DEFAULT_HEADLESS 0      // 0 = GUI mode, 1 = headless mode
 #define DEFAULT_READABLE 1      // 0 = scientific notation, 1 = human-readable (AU, km/s)
 #define DEFAULT_SIM_DAYS 365    // Default simulation duration for headless mode