调整存储的Scheme内容。

src/material-2-scheme.ts

@@ -22,13 +22,13 @@ export type MaterialDesign2Scheme = {
 };
 
 export type MaterialDesign2SchemeSource = {
-  primary: string;
-  secondary: string;
-  error: string;
-  custom_colors: Record<string, string>;
+  primary: string | null;
+  secondary: string | null;
+  error: string | null;
+  custom_colors?: Record<string, string>;
 };
 
 export type MaterialDesign2SchemeStorage = {
-  source: MaterialDesign2SchemeSource;
-  scheme: MaterialDesign2Scheme;
+  source?: MaterialDesign2SchemeSource;
+  scheme?: MaterialDesign2Scheme;
 };