fix several small problems

backend/package-lock.json

@@ -6427,6 +6427,8 @@
       "license": "ISC",
       "engines": {
         "node": ">= 10.x"
+      }
+    },
     "node_modules/path-to-regexp": {
       "version": "8.3.0",
       "resolved": "https://registry.npmjs.org/path-to-regexp/-/path-to-regexp-8.3.0.tgz",
@@ -12619,6 +12621,7 @@
           "integrity": "sha512-UcjcJOWknrNkF6PLX83qcHM6KHgVKNkV62Y8a5uYDVv9ydGQVwAHMKqHdJje1VTWpljG0WYpCDhrCdAOYH4TWg=="
         }
       }
+    },
     "path-to-regexp": {
       "version": "8.3.0",
       "resolved": "https://registry.npmjs.org/path-to-regexp/-/path-to-regexp-8.3.0.tgz",

backend/src/common/color.js

@@ -83,7 +83,7 @@ const getCardColors = ({
   theme,
 }) => {
   const defaultTheme = themes["default"];
-  const isThemeProvided = theme !== null && theme !== undefined;
+  const isThemeProvided = theme !== null && theme !== undefined && theme in themes;
 
   // @ts-ignore
   const selectedTheme = isThemeProvided ? themes[theme] : defaultTheme;