separate thems into separate files

src/seqta/ui/themes/Themes.ts

@@ -0,0 +1,27 @@
+import { base64toblobURL } from '../../utils/imageConversions';
+
+export const imageData: Record<string, { url: string; variableName: string }> = {};
+
+export const UpdateImageData = (image: { id: string; base64: string }) => {
+  const { id, base64 } = image;
+
+  if (imageData[id]) {
+    imageData[id].url = base64toblobURL(base64);
+    const { variableName } = imageData[id];
+    document.documentElement.style.setProperty('--' + variableName, `url(${imageData[id].url})`);
+  }
+};
+
+export function applyCustomCSS(customCSS: string) {
+  let styleElement = document.getElementById('custom-theme');
+  if (!styleElement) {
+    styleElement = document.createElement('style');
+    styleElement.id = 'custom-theme';
+    document.head.appendChild(styleElement);
+  }
+  styleElement.textContent = customCSS;
+}
+
+export function removeImageFromDocument(variableName: string) {
+  document.documentElement.style.removeProperty('--' + variableName);
+}