diff --git a/packages/superdoc/src/assets/styles/helpers/compat.test.ts b/packages/superdoc/src/assets/styles/helpers/compat.test.ts
index 46238e5163..ff8efe1144 100644
--- a/packages/superdoc/src/assets/styles/helpers/compat.test.ts
+++ b/packages/superdoc/src/assets/styles/helpers/compat.test.ts
@@ -6,6 +6,7 @@ import { fileURLToPath } from 'node:url';
 const __dirname = dirname(fileURLToPath(import.meta.url));
 const variablesCss = readFileSync(resolve(__dirname, 'variables.css'), 'utf-8');
 const compatCss = readFileSync(resolve(__dirname, 'compat.css'), 'utf-8');
+const themesCss = readFileSync(resolve(__dirname, 'themes.css'), 'utf-8');
 
 /** Extract all --sd-* variable declarations from a CSS string. */
 const extractDeclaredVars = (css: string): Set<string> => {
@@ -130,4 +131,39 @@ describe('backward compatibility', () => {
       }
     });
   });
+
+  describe('preset themes', () => {
+    /** Extract variables declared inside each .sd-theme-* block. */
+    const extractThemeBlocks = (css: string): Map<string, Set<string>> => {
+      const themes = new Map<string, Set<string>>();
+      const blockRegex = /\.(sd-theme-[\w-]+)\s*\{([^}]+)\}/g;
+      for (const match of css.matchAll(blockRegex)) {
+        const vars = new Set<string>();
+        for (const decl of match[2].matchAll(/(--sd-[\w-]+)\s*:/g)) {
+          vars.add(decl[1]);
+        }
+        themes.set(match[1], vars);
+      }
+      return themes;
+    };
+
+    const themeBlocks = extractThemeBlocks(themesCss);
+
+    it('contains all expected preset themes', () => {
+      expect([...themeBlocks.keys()].sort()).toEqual(['sd-theme-blueprint', 'sd-theme-docs', 'sd-theme-word']);
+    });
+
+    it('every theme variable is declared in variables.css', () => {
+      const declaredInVariables = extractDeclaredVars(variablesCss);
+      const broken: string[] = [];
+      for (const [theme, vars] of themeBlocks) {
+        for (const v of vars) {
+          if (!declaredInVariables.has(v)) {
+            broken.push(`${theme}: ${v}`);
+          }
+        }
+      }
+      expect(broken, `Theme variables not in variables.css: ${broken.join(', ')}`).toEqual([]);
+    });
+  });
 });
diff --git a/packages/superdoc/tests/consumer-types/test.ts b/packages/superdoc/tests/consumer-types/test.ts
index bbf568afda..75f4706be0 100644
--- a/packages/superdoc/tests/consumer-types/test.ts
+++ b/packages/superdoc/tests/consumer-types/test.ts
@@ -10,6 +10,7 @@
 
 // Main entry point
 import type { SuperDoc } from 'superdoc';
+import { createTheme, buildTheme } from 'superdoc';
 
 // Super-editor entry point
 import type { EditorView, EditorState, Transaction, Schema } from 'superdoc/super-editor';
@@ -17,7 +18,13 @@ import type { EditorView, EditorState, Transaction, Schema } from 'superdoc/supe
 // Types entry point
 import type { ProseMirrorJSON, NodeConfig, MarkConfig } from 'superdoc/types';
 
-// Verify the types are usable (not just importable)
-type _AssertSuperDoc = SuperDoc extends object ? true : never;
-type _AssertEditorView = EditorView extends object ? true : never;
-type _AssertJSON = ProseMirrorJSON extends object ? true : never;
+// Verify the types are usable (not just importable).
+// AssertExtends<false> is a compile error, so signature mismatches fail the build.
+type AssertExtends<T extends true> = T;
+type _AssertSuperDoc = AssertExtends<SuperDoc extends object ? true : false>;
+type _AssertEditorView = AssertExtends<EditorView extends object ? true : false>;
+type _AssertJSON = AssertExtends<ProseMirrorJSON extends object ? true : false>;
+type _AssertCreateTheme = AssertExtends<typeof createTheme extends (...args: any[]) => string ? true : false>;
+type _AssertBuildTheme = AssertExtends<
+  typeof buildTheme extends (...args: any[]) => { className: string; css: string } ? true : false
+>;