diff --git a/core/frontend/graph.js b/core/frontend/graph.js
index 370fb55..4ae0733 100644
--- a/core/frontend/graph.js
+++ b/core/frontend/graph.js
@@ -85,12 +85,25 @@ hotkeys('space', (e) => {
 const elts = {};
 const imageFileValidExtnames = new Set(['jpg', 'jpeg', 'png']);
 
+// Precompute bidirectional edges
+const edgeSet = new Set(data.edges.map((e) => `${e.source.key}--${e.target.key}`));
+const bidirectionalEdges = new Set(
+  data.edges
+    .filter((e) => edgeSet.has(`${e.target.key}--${e.source.key}`))
+    .map((e) => e.key)
+);
+
 simulation.on('tick', () => {
   elts.links
-    .attr('x1', (d) => d.source.x)
-    .attr('y1', (d) => d.source.y)
-    .attr('x2', (d) => d.target.x)
-    .attr('y2', (d) => d.target.y);
+  .attr('d', (d) => {
+    const dx = d.target.x - d.source.x;
+    const dy = d.target.y - d.source.y;
+    const dr = Math.sqrt(dx * dx + dy * dy);
+    if (bidirectionalEdges.has(d.key)) {
+      return `M ${d.source.x},${d.source.y} A ${dr},${dr} 0 0,1 ${d.target.x},${d.target.y}`;
+    }
+    return `M ${d.source.x},${d.source.y} L ${d.target.x},${d.target.y}`;
+  });
 
   elts.nodes.attr('transform', (d) => 'translate(' + d.x + ',' + d.y + ')');
 
@@ -105,10 +118,11 @@ simulation.on('tick', () => {
 /** @type {d3.Selection<SVGLineElement, Link, SVGElement, any>} */
 elts.links = svgSub
   .append('g')
-  .selectAll('line')
+  .selectAll('path')
   .data(data.edges)
   .enter()
-  .append('line')
+  .append('path')
+  .attr('fill', 'none')
   .attr('stroke', (d) => `var(--l_${d.attributes.type})`)
   .attr('title', (d) => d.attributes.title)
   .attr('data-link', (d) => d.key)
@@ -128,9 +142,14 @@ elts.links = svgSub
   });
 
 if (graphProperties.graph_arrows === true) {
-  elts.links.attr('marker-end', 'url(#arrow)');
+  if (graphProperties.graph_arrows_reversed === true) {
+    elts.links.attr('marker-start', 'url(#arrow-reversed)');
+  } else {
+    elts.links.attr('marker-end', 'url(#arrow)');
+  }
 }
 
+
 const strokeWidth = 2;
 
 /** @type {d3.Selection<SVGGElement, Node, SVGElement, any>} */
@@ -484,9 +503,8 @@ function highlightNodes(nodeIds) {
   nodeIds
     .filter((nodeId) => graph.hasNode(nodeId))
     .forEach((nodeId) => {
-      const { links, node } = getNodeNetwork(nodeId);
+      const { node } = getNodeNetwork(nodeId);
       node.node().classList.add('highlight');
-      links.nodes().forEach((elt) => elt.classList.add('highlight'));
     });
 
   highlightedNodes = highlightedNodes.concat(nodeIds);
@@ -501,14 +519,7 @@ function unlightNodes() {
     return;
   }
 
-  highlightedNodes
-    .filter((nodeId) => graph.hasNode(nodeId))
-    .forEach((nodeId) => {
-      const { links, node } = getNodeNetwork(nodeId);
-      node.node().classList.remove('highlight');
-      links.nodes().forEach((elt) => elt.classList.remove('highlight'));
-    });
-
+  elts.nodes.nodes().forEach((elt) => elt.classList.remove('highlight'));
   highlightedNodes = [];
 }
 
diff --git a/core/frontend/styles.css b/core/frontend/styles.css
index 70d5e07..f0e3f31 100644
--- a/core/frontend/styles.css
+++ b/core/frontend/styles.css
@@ -714,8 +714,8 @@ text {
 /* arrows */
 marker {
   /* set into config.yml file by 'undefined' link type */
-  stroke: var(--l_undefined);
-  fill: var(--l_undefined);
+  stroke: context-stroke;
+  fill: context-stroke;
 }
 
 /* ---
diff --git a/core/i18n.yml b/core/i18n.yml
index 762c93c..f78256f 100644
--- a/core/i18n.yml
+++ b/core/i18n.yml
@@ -397,6 +397,9 @@ config:
     graph_arrows:
       fr: La commande de fléchage des liens est invalide
       en: Invalid link arrow command
+    graph_arrows_reversed:
+      fr: La commande d'inversion des flèches est invalide
+      en: Invalid reverse arrow command
     devtools:
       fr: La commande d'activation des outils de développement est invalide
       en: Invalid devtools activation command
diff --git a/core/models/config.js b/core/models/config.js
index f513387..9c169c1 100644
--- a/core/models/config.js
+++ b/core/models/config.js
@@ -57,6 +57,7 @@ import Joi from 'joi';
  * @property {boolean} graph_highlight_on_hover
  * @property {number} graph_text_size
  * @property {boolean} graph_arrows
+ * @property {boolean} graph_arrows_reversed
  * @property {'unique'|'degree'} node_size_method
  * @property {number} node_size
  * @property {number} [node_size_max]
@@ -183,6 +184,7 @@ const optionsSchema = Joi.object({
   graph_highlight_on_hover: Joi.boolean(),
   graph_text_size: Joi.number(),
   graph_arrows: Joi.boolean(),
+  graph_arrows_reversed: Joi.boolean(),
   node_size_method: Joi.string().valid('unique', 'degree'),
   node_size: Joi.number().integer().min(0),
   node_size_max: Joi.number().integer().min(0).optional(),
@@ -254,6 +256,7 @@ class Config {
     graph_highlight_on_hover: true,
     graph_text_size: 10,
     graph_arrows: true,
+    graph_arrows_reversed: false,
     node_size_method: 'degree',
     node_size: 10,
     node_size_max: 20,
diff --git a/static/template/cosmoscope.njk b/static/template/cosmoscope.njk
index e0e414f..f2be964 100644
--- a/static/template/cosmoscope.njk
+++ b/static/template/cosmoscope.njk
@@ -269,8 +269,11 @@
         <svg id="graph-canvas">
             <defs>
                 <marker id="arrow" viewBox="0 0 10 10" refX="22" refY="5" markerUnits="strokeWidth" markerWidth="5" markerHeight="5" orient="auto">
-                    <path d="M 0 0 L 10 5 L 0 10 z"></path>
-                </marker>
+    <path d="M 0 0 L 10 5 L 0 10 z" fill="context-stroke"></path>
+</marker>
+<marker id="arrow-reversed" viewBox="0 0 10 10" refX="22" refY="5" markerUnits="strokeWidth" markerWidth="5" markerHeight="5" orient="auto-start-reverse">
+    <path d="M 0 0 L 10 5 L 0 10 z" fill="context-stroke"></path>
+</marker>
                 <filter id="double">
                     <feMorphology in="SourceGraphic" result="a" operator="dilate" radius="0.2"></feMorphology>
                     <feComposite in="SourceGraphic" in2="a" result="xx" operator="xor"></feComposite>
@@ -612,4 +615,4 @@
 
 </body>
 
-</html>
\ No newline at end of file
+</html>