A way down the tree from every page

An arrow fixed at the left edge, half-way up the screen, and the same
link in words at the foot of the page. It goes one level down: the
nearest page below the current path that the visitor may open, found by
taking the path apart a segment at a time, and the front door when none
of those is a page (/status/oppslag -> /, /review/abc -> /review). The
front door itself has none. Labelled with where it goes: 'Tilbake til
starten', or the target page's question in quotation marks.

Content stops needing a 'back' alternative on every page, and a visitor
who went up a branch whose context did not apply is never stranded.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01GT37Z1Xtfd9pUuQtMTg6Yt

style/main.css

@@ -297,6 +297,67 @@ main.not-found {
   }
 }
 
+/* The way down the tree: one level toward the front door, from any
+   page. Fixed at the left edge, half-way up, over the margin rather
+   than the text; small, and half-faded until touched, so it never
+   covers what a visitor is reading. */
+.down-the-tree {
+  position: fixed;
+  left: 0.6rem;
+  top: 50%;
+  transform: translateY(-50%);
+  z-index: 20;
+  width: 2.6rem;
+  height: 2.6rem;
+  display: grid;
+  place-items: center;
+  border-radius: 50%;
+  background: var(--card-bg-opaque);
+  color: var(--ink);
+  box-shadow: 0 0.2rem 0.8rem var(--card-shadow);
+  opacity: 0.7;
+  transition: opacity 120ms, transform 120ms;
+}
+
+.down-the-tree:hover,
+.down-the-tree:focus-visible {
+  opacity: 1;
+  transform: translateY(-50%) translateX(-0.12rem);
+}
+
+.down-the-tree svg {
+  width: 1.3rem;
+  height: 1.3rem;
+}
+
+@media (max-width: 43.75rem) {
+  .down-the-tree {
+    left: 0.25rem;
+    width: 2.2rem;
+    height: 2.2rem;
+    opacity: 0.55;
+  }
+}
+
+.down-the-tree-foot {
+  position: relative;
+  z-index: 1;
+  text-align: center;
+  margin: 2.6rem auto 0;
+  font-size: 0.95rem;
+}
+
+.down-the-tree-foot a {
+  color: var(--ink);
+  text-decoration: none;
+  border-bottom: 0.06rem solid var(--line);
+}
+
+.down-the-tree-foot a:hover {
+  color: var(--accent);
+  border-bottom-color: var(--accent);
+}
+
 .question-nav {
   display: flex;
   flex-wrap: wrap;