diff --git a/src/ax.h b/src/ax.h
index fc04ccd..642c769 100644
--- a/src/ax.h
+++ b/src/ax.h
@@ -24,16 +24,15 @@ void ax_log(struct ax_ctxt* ax, const char* string);
  * -------------------------------------------------------------------------- */
 
 void ax_begin_theme(struct ax_ctxt* ax);
-void ax_set_theme_color(struct ax_ctxt* ax, const char* name,
-                        uint64_t rgb);
-void ax_set_theme_font(struct ax_ctxt* ax,
-                       const char* fnt_cat,
-                       const char* fnt_path,
-                       size_t fnt_size);
-void ax_set_theme_iconset(struct ax_ctxt* ax,
-                          const char* iconset_dir);
 int ax_end_theme(struct ax_ctxt* ax, struct ax_theme** out_thm);
 
+void ax_set_theme_color(
+    struct ax_ctxt* ax, const char* cat, int64_t rgb);
+void ax_set_theme_font(
+    struct ax_ctxt* ax, const char* cat, const char* fnt_path);
+void ax_set_theme_iconset(
+    struct ax_ctxt* ax, const char* iconset_dir);
+
 void ax_select_theme(struct ax_ctxt* ax, struct ax_theme* thm);
 
 /* -----------------------------------------------------------------------------
diff --git a/src/ctxt.h b/src/ctxt.h
index d25ddb5..3b586b9 100644
--- a/src/ctxt.h
+++ b/src/ctxt.h
@@ -2,10 +2,20 @@
 
 #include "util/region.h"
 
+struct ax_theme;
+struct ax_theme_builder;
+
 struct ax_ctxt {
     struct rgn* init_rgn;
+
+    // errors
     struct rgn err_rgn;
     char* err;
+
+    // theme
+    struct ax_theme* sel_theme;
+    struct ax_theme_builder* thmb0;
+    struct ax_theme_builder* thmb;
 };
 
 void ax__ctxt_init(struct ax_ctxt* ax, struct rgn* self_rgn);
diff --git a/src/ctxt/ctxt.c b/src/ctxt/ctxt.c
index ec104a6..e1c8bdc 100644
--- a/src/ctxt/ctxt.c
+++ b/src/ctxt/ctxt.c
@@ -1,5 +1,7 @@
 #include "../ctxt.h"
+#include "../util.h"
 #include "../ax.h"
+#include "theme.h"
 
 /* -----------------------------------------------------------------------------
  * API functions :: init / cleanup
@@ -38,9 +40,68 @@ void ax__ctxt_init(struct ax_ctxt* ax, struct rgn* init_rgn)
 
     rgn_init(&ax->err_rgn, SMALL);
     ax->err = "";
+
+    ax->sel_theme = NULL;
+    ax->thmb0 = ralloc_typed(init_rgn, struct ax_theme_builder, 1);
+    ax->thmb = NULL;
 }
 
 void ax__ctxt_cleanup(struct ax_ctxt* ax)
 {
+    if (ax->thmb != NULL) {
+        ax__theme_builder_cleanup(ax->thmb);
+    }
+
     rgn_cleanup(&ax->err_rgn);
 }
+
+/* -----------------------------------------------------------------------------
+ * API functions :: themes
+ * -------------------------------------------------------------------------- */
+
+void ax_begin_theme(struct ax_ctxt* ax)
+{
+    if (ax->thmb != NULL) {
+        ax__theme_builder_cleanup(ax->thmb);
+    }
+
+    ax->thmb = ax->thmb0;
+    ax__theme_builder_init(ax->thmb);
+}
+
+int ax_end_theme(struct ax_ctxt* ax, struct ax_theme** out_thm)
+{
+    if (ax->thmb == NULL) {
+        ax->err = "not building a theme";
+        return 1;
+    }
+
+    ax__theme_builder_finish(ax->thmb, out_thm);
+    ax__theme_builder_cleanup(ax->thmb);
+    ax->thmb = NULL;
+    return 0;
+}
+
+void ax_set_theme_color(
+    struct ax_ctxt* ax, const char* cat, int64_t rgb)
+{
+    UNIMPLEMENTED();
+}
+
+void ax_set_theme_font(
+    struct ax_ctxt* ax, const char* cat, const char* fnt_path)
+{
+    UNIMPLEMENTED();
+}
+
+void ax_set_theme_iconset(
+    struct ax_ctxt* ax, const char* iconset_dir)
+{
+    UNIMPLEMENTED();
+}
+
+void ax_select_theme(struct ax_ctxt* ax, struct ax_theme* thm)
+{
+    ASSERT_NON_NULL(thm, "theme");
+    ax->sel_theme = thm;
+}
diff --git a/src/ctxt/theme.c b/src/ctxt/theme.c
new file mode 100644
index 0000000..ef4010d
--- /dev/null
+++ b/src/ctxt/theme.c
@@ -0,0 +1,17 @@
+#include "theme.h"
+#include "../util.h"
+
+void ax__theme_builder_init(struct ax_theme_builder* thmb)
+{
+}
+
+void ax__theme_builder_cleanup(struct ax_theme_builder* thmb)
+{
+}
+
+void ax__theme_builder_finish(
+    struct ax_theme_builder* thmb,
+    struct ax_theme** out_thm)
+{
+    UNIMPLEMENTED();
+}
diff --git a/src/ctxt/theme.h b/src/ctxt/theme.h
new file mode 100644
index 0000000..ab46420
--- /dev/null
+++ b/src/ctxt/theme.h
@@ -0,0 +1,18 @@
+#pragma once
+
+#include "../util/region.h"
+
+struct ax_theme {
+    struct rgn rgn;
+};
+
+struct ax_theme_builder {
+    struct rgn rgn;
+};
+
+void ax__theme_builder_init(struct ax_theme_builder* thmb);
+void ax__theme_builder_cleanup(struct ax_theme_builder* thmb);
+
+void ax__theme_builder_finish(
+    struct ax_theme_builder* thmb,
+    struct ax_theme** out_thm);
diff --git a/test/main.c b/test/main.c
index 53daea7..52a4cf3 100644
--- a/test/main.c
+++ b/test/main.c
@@ -1,13 +1,18 @@
 #include <stdio.h>
 #include "../src/ax.h"
-#include "../src/ctxt.h"
+// #include "../src/ctxt.h"
 
 
 int main(void)
 {
     struct ax_ctxt* ax = ax_new();
-    ax__set_error(ax, "hello world");
-    printf("--> %s\n", ax_get_error(ax));
+
+    ax_begin_theme(ax);
+    ax_set_theme_color(ax, "default", 0x112233);
+    struct ax_theme* thm;
+    ax_end_theme(ax, &thm);
+    ax_select_theme(ax, thm);
+
     ax_free(ax);
     return 0;
 }