Add css/js to make a collapsible sidebar nav in Python API docs Fixes #7867

api-docs/source/_static/css/sidebar_toggle.css

@@ -0,0 +1,52 @@
+/* Toggle button */
+#bn-sidebar-toggle {
+  position: fixed;
+  top: 12px;
+  left: 12px;
+  z-index: 10000;
+
+  width: 36px;
+  height: 36px;
+
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+
+  border: 1px solid rgba(0, 0, 0, 0.25);
+  border-radius: 6px;
+  background: #ffffff;
+  color: #111111;
+
+  font-size: 18px;
+  line-height: 1;
+  cursor: pointer;
+
+  /* Avoid stealing too much attention */
+  opacity: 0.85;
+}
+
+#bn-sidebar-toggle:hover {
+  opacity: 1.0;
+}
+
+/* When sidebar is collapsed, reclaim space */
+html.bn-sidebar-collapsed .wy-nav-side {
+  width: 0 !important;
+  min-width: 0 !important;
+  overflow: hidden !important;
+}
+
+html.bn-sidebar-collapsed .wy-side-scroll {
+  width: 0 !important;
+  overflow: hidden !important;
+}
+
+/* RTD uses margin-left to make room for the sidebar */
+html.bn-sidebar-collapsed .wy-nav-content-wrap {
+  margin-left: 0 !important;
+}
+
+/* Optional: ensure content doesn't look overly narrow after reclaiming space */
+html.bn-sidebar-collapsed .wy-nav-content {
+  max-width: 2000px !important;
+}

api-docs/source/_static/js/sidebar_toggle.js

@@ -0,0 +1,63 @@
+(() => {
+  const STORAGE_KEY = "bn_api_sidebar";
+  const CLASS_NAME = "bn-sidebar-collapsed";
+  const BUTTON_ID = "bn-sidebar-toggle";
+
+  function isCollapsed() {
+    return document.documentElement.classList.contains(CLASS_NAME);
+  }
+
+  function setCollapsed(collapsed) {
+    document.documentElement.classList.toggle(CLASS_NAME, collapsed);
+    try {
+      localStorage.setItem(STORAGE_KEY, collapsed ? "collapsed" : "expanded");
+    } catch (_) {
+      // ignore storage failures (private mode, policy, etc.)
+    }
+    const btn = document.getElementById(BUTTON_ID);
+    if (btn) {
+      btn.setAttribute("aria-pressed", collapsed ? "true" : "false");
+      btn.title = collapsed ? "Show navigation" : "Hide navigation";
+    }
+  }
+
+  function initialCollapsed() {
+    try {
+      const saved = localStorage.getItem(STORAGE_KEY);
+      if (saved === "collapsed") return true;
+      if (saved === "expanded") return false;
+    } catch (_) {
+      // ignore
+    }
+
+    // Default: collapse in narrower / split-screen-ish layouts.
+    return window.matchMedia("(max-width: 1400px)").matches;
+  }
+
+  function ensureButton() {
+    if (document.getElementById(BUTTON_ID)) return;
+
+    const btn = document.createElement("button");
+    btn.id = BUTTON_ID;
+    btn.type = "button";
+    btn.setAttribute("aria-label", "Toggle navigation");
+    btn.setAttribute("aria-pressed", "false");
+    btn.textContent = "☰";
+
+    btn.addEventListener("click", () => setCollapsed(!isCollapsed()));
+
+    // Append to body so it always exists even when the sidebar is collapsed.
+    document.body.appendChild(btn);
+  }
+
+  function init() {
+    ensureButton();
+    setCollapsed(initialCollapsed());
+  }
+
+  if (document.readyState === "loading") {
+    document.addEventListener("DOMContentLoaded", init);
+  } else {
+    init();
+  }
+})();

api-docs/source/conf.py

@@ -90,6 +90,8 @@ def fnlist(module):
 
 def setup(app):
 	app.add_css_file('css/other.css')
+	app.add_css_file('css/sidebar_toggle.css')
+	app.add_js_file('js/sidebar_toggle.js')
 	app.is_parallel_allowed('write')
 
 def generaterst():