moved the modal logic to it's own file to

declutter index.js

public/js/modal.js

@@ -0,0 +1,42 @@
+// INFO-MODAL LOGIC
+const aboutButton = document.getElementById("about-button");
+const modalOverlay = document.getElementById("modal-overlay");
+const modalContent = document.getElementById("modal-content");
+const modalClose = document.getElementById("modal-close");
+
+function show_modal_with(content) {
+    modalOverlay.classList.remove("hidden");
+    modalContent.innerHTML = "";
+    modalContent.appendChild(content);
+    modalOverlay.focus();
+}
+
+// open modal
+aboutButton.addEventListener("click", () => {
+    show_modal_with(about.content.cloneNode(true));
+});
+
+// close modal via “×” button
+modalClose.addEventListener("click", () => {
+    modalOverlay.classList.add("hidden");
+});
+
+// also close if you click outside the white box
+modalOverlay.addEventListener("click", (e) => {
+    if (e.target === modalOverlay) {
+        modalOverlay.classList.add("hidden");
+    }
+});
+
+modalOverlay.addEventListener("keydown", (e) => {
+    if (e.key === "Escape") {
+        modalOverlay.classList.add("hidden");
+        console.log("hiding");
+    }
+});
+
+["download", "upload", "results"].forEach((section) => {
+    window[`info-${section}-btn`].addEventListener("click", () => {
+        show_modal_with(window[`info-${section}`].content.cloneNode(true));
+    });
+});