fix(timeline): ensure cards always alternate sides across month boundaries

Per-month <ol> containers caused :nth-of-type to reset at each month,
putting the first card of consecutive months on the same side. Flatten
all items into a single container and use :nth-child(odd of .timeline-item)
for continuous left/right alternation across months and infinite scroll.

templates/partials/timeline_month.html

@@ -7,11 +7,9 @@
       </svg>
     </button>
   </h2>
-  <ol class="timeline-list relative">
-    {# Central timeline line #}
-    <div class="timeline-line absolute top-0 bottom-0 w-0.5 bg-amber-200" aria-hidden="true"></div>
-    {% for event in month.events %}
-    <li class="timeline-item relative mb-8 last:mb-0" data-timeline-event>
+</div>
+{% for event in month.events %}
+<div class="timeline-item relative mb-8" data-timeline-event>
   {# Timeline node/bullet #}
   <span
     class="timeline-node absolute h-5 w-5 rounded-full border-4 border-amber-50 bg-amber-600"
@@ -109,7 +107,5 @@
     </ul>
     {% endif %} {% endif %}
   </div>
-    </li>
-    {% endfor %}
-  </ol>
 </div>
+{% endfor %}

templates/styles.css

@@ -118,24 +118,24 @@ a {
     padding-right: 0;
   }
 
-  /* Left side items (odd) - uses nth-of-type to skip the timeline-line div */
-  .timeline-item:nth-of-type(odd) {
+  /* Left side items (odd) - counts only .timeline-item children, skipping month headings */
+  .timeline-item:nth-child(odd of .timeline-item) {
     align-self: flex-start;
     padding-right: 2rem;
   }
 
-  .timeline-item:nth-of-type(odd) .timeline-node {
+  .timeline-item:nth-child(odd of .timeline-item) .timeline-node {
     right: -10px;
     left: auto;
   }
 
   /* Right side items (even) */
-  .timeline-item:nth-of-type(even) {
+  .timeline-item:nth-child(even of .timeline-item) {
     align-self: flex-end;
     padding-left: 2rem;
   }
 
-  .timeline-item:nth-of-type(even) .timeline-node {
+  .timeline-item:nth-child(even of .timeline-item) .timeline-node {
     left: -10px;
   }
 

templates/timeline.html

@@ -8,9 +8,7 @@
 
 <div class="mt-8">
   <section
-    class="space-y-12"
     id="timeline-events"
-    data-role="timeline-months"
     data-empty="{{ months.is_empty() }}"
   >
     {% if months.is_empty() %}
@@ -20,7 +18,12 @@
     >
       No events yet.
     </p>
-    {% else %} {% for month in months %} {% include "partials/timeline_month.html" %} {% endfor %}
+    {% else %}
+    <div class="timeline-list relative" id="timeline-items">
+      {# Single central timeline line for all months #}
+      <div class="timeline-line absolute top-0 bottom-0 w-0.5 bg-amber-200" aria-hidden="true"></div>
+      {% for month in months %} {% include "partials/timeline_month.html" %} {% endfor %}
+    </div>
     {% endif %}
 
     <div
@@ -49,15 +52,16 @@
 
 <script type="module">
   const loader = document.getElementById("timeline-loader")
-  const monthsContainer = document.getElementById("timeline-events")
+  const itemsContainer = document.getElementById("timeline-items")
   const loadMoreButton = document.getElementById("timeline-load-more")
   const statusLine = document.getElementById("timeline-status")
   const endLine = document.getElementById("timeline-end")
   const errorLine = document.getElementById("timeline-error")
   const sentinel = document.getElementById("timeline-sentinel")
   const emptyState = document.querySelector('[data-role="timeline-empty-state"]')
+  const section = document.getElementById("timeline-events")
 
-  if (loader && monthsContainer && sentinel) {
+  if (loader && sentinel) {
     let nextUrl = loader.dataset.nextUrl || ""
     let hasMorePages = loader.dataset.hasMore === "true"
     let loading = false
@@ -84,29 +88,32 @@
       }
     }
 
+    const ensureItemsContainer = () => {
+      if (itemsContainer) return itemsContainer
+      // First load on a previously empty timeline: create the container
+      const container = document.createElement("div")
+      container.className = "timeline-list relative"
+      container.id = "timeline-items"
+      const line = document.createElement("div")
+      line.className = "timeline-line absolute top-0 bottom-0 w-0.5 bg-amber-200"
+      line.setAttribute("aria-hidden", "true")
+      container.appendChild(line)
+      section.insertBefore(container, loader)
+      return container
+    }
+
     const appendMonths = (chunk) => {
       const monthsFragment = chunk.querySelector("[data-chunk-months]")
-      if (!monthsFragment) {
-        return
-      }
-      for (const monthNode of Array.from(monthsFragment.children)) {
-        const anchor = monthNode.id
-        if (!anchor) {
+      if (!monthsFragment) return
+
+      const container = ensureItemsContainer()
+
+      for (const node of Array.from(monthsFragment.children)) {
+        // Skip duplicate month headings (same month spanning a page boundary)
+        if (node.hasAttribute("data-timeline-month") && document.getElementById(node.id)) {
           continue
         }
-        const existing = document.getElementById(anchor)
-        if (existing) {
-          // Merge new events into existing month
-          const existingList = existing.querySelector("ol")
-          const newList = monthNode.querySelector("ol")
-          if (existingList && newList) {
-            // CSS :nth-of-type handles alternating pattern automatically
-            const newItems = Array.from(newList.querySelectorAll(".timeline-item"))
-            existingList.append(...newItems)
-          }
-        } else {
-          monthsContainer.insertBefore(monthNode, loader)
-        }
+        container.appendChild(node)
       }
     }
 
@@ -188,6 +195,8 @@
   )
 
   // Use MutationObserver to watch for new month headings being added
+  const timelineItems = document.getElementById("timeline-items")
+  if (timelineItems) {
     const mutationObserver = new MutationObserver((mutations) => {
       mutations.forEach((mutation) => {
         mutation.addedNodes.forEach((node) => {
@@ -200,10 +209,7 @@
         })
       })
     })
-
-  const timelineContainer = document.getElementById("timeline-events")
-  if (timelineContainer) {
-    mutationObserver.observe(timelineContainer, { childList: true })
+    mutationObserver.observe(timelineItems, { childList: true })
   }
 
   // Observe existing headings