feat: init basic settings

src/styles/theme.ts

@@ -0,0 +1,17 @@
+import '@emotion/react';
+
+interface AffineTheme {
+  colors: {
+    primary: string;
+  };
+}
+
+export const theme: AffineTheme = {
+  colors: {
+    primary: '#0070f3',
+  },
+};
+
+declare module '@emotion/react' {
+  export interface Theme extends AffineTheme {}
+}