diff --git a/src/ui/cyberTheme.test.mjs b/src/ui/cyberTheme.test.mjs
index 3ac1a6172..9b02b3de7 100644
--- a/src/ui/cyberTheme.test.mjs
+++ b/src/ui/cyberTheme.test.mjs
@@ -780,7 +780,16 @@ test('the Display selector, voice schema and final stylesheet expose Cyber', ()
   assert.match(cyberStyles, /flex: 1 1 auto;/);
   assert.match(cyberStyles, /#left-panel-stack:has/);
   assert.match(cyberStyles, /left: calc\(54px \+ var\(--panel-rail-clearance\)\);/);
-  assert.match(cyberStyles, /right: calc\(62px \+ var\(--panel-rail-clearance\)\);/);
+  assert.match(cyberStyles, /right: calc\(51px \+ var\(--panel-rail-clearance\)\);/);
+  // Each side's edge line shows only beside an open panel.
+  assert.match(
+    cyberStyles,
+    /#left-panel-stack:has\(> \[data-panel-id\]:not\(\.collapsed, \[hidden\]\)\) \{\s*border-left-color:/,
+  );
+  assert.match(
+    cyberStyles,
+    /#right-context-rail:has\(> \[data-panel-id\]:not\(\.collapsed, \[hidden\]\)\) \{\s*border-right-color:/,
+  );
   assert.match(cyberStyles, /bottom: calc\(2vh \+ 13rem\);/);
   assert.doesNotMatch(cyberStyles, /NAV 01  \/\/  COMMAND BUS  \/\/  VIS 03/);
   assert.match(cyberStyles, /data-layer-id='satellites'/);
diff --git a/src/ui/styles/cyber.css b/src/ui/styles/cyber.css
index 4f5b4f9f9..33e0993d1 100644
--- a/src/ui/styles/cyber.css
+++ b/src/ui/styles/cyber.css
@@ -1661,7 +1661,20 @@
     left: calc(54px + var(--panel-rail-clearance));
     width: 300px;
     padding-left: 10px;
-    border-left: 1px solid rgba(196, 84, 84, 0.72);
+    border-left: 1px solid transparent;
+  }
+
+  /* An edge line marks each side's open panel, mirrored left and right. */
+  :root[data-ui-theme='cyber']
+    body:not(.cockpit-mode)
+    #left-panel-stack:has(> [data-panel-id]:not(.collapsed, [hidden])) {
+    border-left-color: rgba(196, 84, 84, 0.72);
+  }
+
+  :root[data-ui-theme='cyber']
+    body:not(.cockpit-mode)
+    #right-context-rail:has(> [data-panel-id]:not(.collapsed, [hidden])) {
+    border-right-color: rgba(196, 84, 84, 0.72);
   }
 
   :root[data-ui-theme='cyber']
@@ -1740,8 +1753,11 @@
   :root[data-ui-theme='cyber'] #right-context-rail {
     --right-display-collapsed-width: var(--cyber-panel-collapsed-width);
     --right-context-collapsed-width: var(--cyber-panel-collapsed-width);
-    right: calc(62px + var(--panel-rail-clearance));
-    width: 312px;
+    /* The edge line and its gap keep the panels where they were. */
+    right: calc(51px + var(--panel-rail-clearance));
+    width: 323px;
+    padding-right: 10px;
+    border-right: 1px solid transparent;
   }
 
   /* The map rails now use one visible expanded width. Keeping the rail itself