Improve map UX: compact modal, visible crosshair, smart marker overlap

- Reduce create post modal height (max 45vh) and add scroll
- Lower modal position (bottom: 8%) to keep map visible
- Move crosshair higher (top: 30%) for better visibility
- Implement smart marker offsetting for nearby posts
- Add visual connection line from offset markers to true position
- Create cascade effect for clustered markers (45° circular pattern)
- Maintain pointer accuracy when zooming

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/components/Map/markerManager.js

@@ -294,6 +294,50 @@ function openCenteredOverlay({ map, post, theme }) {
   };
 }
 
+function calculateSmartOffset(post, markersRef, map) {
+  if (!map || !markersRef.current) return { x: 0, y: 0 };
+
+  const lat = typeof post.lat === "number" ? post.lat : typeof post.latitude === "number" ? post.latitude : null;
+  const lon = typeof post.lon === "number" ? post.lon : typeof post.lng === "number" ? post.lng : null;
+  if (lat == null || lon == null) return { x: 0, y: 0 };
+
+  const currentPoint = map.project([lon, lat]);
+  const PROXIMITY_THRESHOLD = 80; // pixels
+  const MAX_OFFSET = 60; // max offset in pixels
+
+  const nearbyMarkers = [];
+
+  for (const marker of markersRef.current) {
+    if (!marker.post || marker.post.id === post.id) continue;
+
+    const mLat = typeof marker.post.lat === "number" ? marker.post.lat : marker.post.latitude;
+    const mLon = typeof marker.post.lon === "number" ? marker.post.lon : marker.post.lng;
+    if (mLat == null || mLon == null) continue;
+
+    const mPoint = map.project([mLon, mLat]);
+    const dist = Math.sqrt(
+      Math.pow(currentPoint.x - mPoint.x, 2) +
+      Math.pow(currentPoint.y - mPoint.y, 2)
+    );
+
+    if (dist < PROXIMITY_THRESHOLD) {
+      nearbyMarkers.push({ marker, distance: dist, point: mPoint });
+    }
+  }
+
+  if (nearbyMarkers.length === 0) return { x: 0, y: 0 };
+
+  // Create a cascade effect: offset markers in a circular pattern
+  const index = nearbyMarkers.length;
+  const angle = (index * 45) * (Math.PI / 180); // 45 degrees apart
+  const offsetMagnitude = Math.min(20 + (index * 12), MAX_OFFSET);
+
+  return {
+    x: Math.cos(angle) * offsetMagnitude,
+    y: Math.sin(angle) * offsetMagnitude
+  };
+}
+
 export function createMarkerForPost(post, mapRef, markersRef, expandedElRef, theme = "blue") {
   const map = mapRef.current;
   if (!map) return;
@@ -316,6 +360,9 @@ export function createMarkerForPost(post, mapRef, markersRef, expandedElRef, the
 
   const lngLat = [lon, lat];
 
+  // Calculate smart offset for nearby markers
+  const offset = calculateSmartOffset(post, markersRef, map);
+
   const root = document.createElement("div");
   root.classList.add("sw-appear");
   requestAnimationFrame(() => root.classList.add("sw-appear-in"));
@@ -334,9 +381,19 @@ export function createMarkerForPost(post, mapRef, markersRef, expandedElRef, the
     root.className = "post-pin post-pin--compact sw-appear sw-appear-in";
     root.style.zIndex = "1";
 
+    // Add connecting line if offset is significant
+    const hasOffset = Math.abs(offset.x) > 5 || Math.abs(offset.y) > 5;
+    const lineHTML = hasOffset
+      ? `<svg class="sw-offset-line" style="position:absolute;bottom:0;left:50%;transform:translateX(-50%);overflow:visible;pointer-events:none;z-index:-1;">
+           <line x1="0" y1="0" x2="${-offset.x}" y2="${-offset.y}" stroke="rgba(56,189,248,0.4)" stroke-width="2" stroke-dasharray="4,4"/>
+           <circle cx="${-offset.x}" cy="${-offset.y}" r="4" fill="#38bdf8" opacity="0.6"/>
+         </svg>`
+      : '';
+
     root.innerHTML = `
       <div class="sw-template-mini-wrap"></div>
       <div class="post-pin-pointer-small"></div>
+      ${lineHTML}
     `;
 
     const wrap = root.querySelector(".sw-template-mini-wrap");
@@ -352,7 +409,11 @@ export function createMarkerForPost(post, mapRef, markersRef, expandedElRef, the
   renderCompact();
   root.__renderCompact = renderCompact;
 
-  const marker = new maplibregl.Marker({ element: root, anchor: "bottom" })
+  const marker = new maplibregl.Marker({
+    element: root,
+    anchor: "bottom",
+    offset: [offset.x, offset.y]
+  })
     .setLngLat(lngLat)
     .addTo(map);
 

src/styles/map.css

@@ -109,7 +109,7 @@
 /* Crosshair pour création */
 .map-crosshair{
   left:50%;
-  top:40%;
+  top:30%;
   transform:translate(-50%,-50%);
 }
 .crosshair-aim{
@@ -141,10 +141,12 @@
 /* Panneau de création */
 .create-post-panel{
   left:50%;
-  bottom:20%;
+  bottom:8%;
   transform:translateX(-50%);
   width:92%;
   max-width:520px;
+  max-height:45vh;
+  overflow-y:auto;
   background: rgba(15, 23, 42, 0.96);
   border-radius:16px;
   border:1px solid rgba(148, 163, 184, 0.9);