diff --git a/arena.h b/arena.h
index ec9ae52..a9f45ef 100644
--- a/arena.h
+++ b/arena.h
@@ -1,4 +1,4 @@
-// arena.h - v1.1.2 - MIT License
+// arena.h - v1.1.3 - MIT License
 // single header library for region-based memory management.
 //
 // [License and changelog]
@@ -158,7 +158,7 @@ struct Arena_Region {
     Arena_Region *next;
     size_t count;
     size_t capacity;
-    uint8_t data[];
+    alignas(ARENA_ALIGNMENT) uint8_t data[];
 };
 
 typedef struct Arena {
@@ -335,6 +335,7 @@ char *arena_strdup(Arena *a, const char *s)
 /*
  * Revision history:
  *
+ *     1.1.3 (2026-01-14) Align Arena_Region data flexible array member
  *     1.1.2 (2026-01-10) Minor changes; check result of alloc in arena_copy()
  *     1.1.1 (2025-11-18) Implement memory alignment; improve docs
  *     1.1.0 (2025-11-18) New helper functions: arena_copy(), arena_strdup()
diff --git a/test.c b/test.c
index 9bef270..15bc8ab 100644
--- a/test.c
+++ b/test.c
@@ -25,7 +25,15 @@ void arena_print(Arena arena)
 
 int main(void)
 {
+    printf("struct Arena_Region {\n");
+    printf("    Arena_Region *next; (%zu)\n", offsetof(struct Arena_Region, next));
+    printf("    size_t count;       (%zu)\n", offsetof(struct Arena_Region, count));
+    printf("    size_t capacity;    (%zu)\n", offsetof(struct Arena_Region, capacity));
+    printf("    uint8_t data[];     (%zu)\n", offsetof(struct Arena_Region, data));
+    printf("};\n");
+
     printf("Alignment: %zu\n", ARENA_ALIGNMENT);
+    printf("================================================================\n");
 
     Arena a = {0};