fix(editor): la barre de numerotation de ligne suit le theme (BUG-058)

tests/frontend/editor-inline.test.mjs

@@ -380,6 +380,19 @@ test("style.css: #editor-body scrolls through the CodeMirror scroller only", ()
     "global .cm-scroller min-height override reintroduces the double scrollbar");
 });
 
+// ── BUG-058: the line-number gutter follows the active theme ──
+test("style.css themes the CodeMirror line-number gutter with CSS variables", () => {
+  const gutter = cssSrc.match(/\.cm-editor \.cm-gutters \{([^}]*)\}/);
+  assert.ok(gutter, "themed .cm-gutters rule not found");
+  assert.match(gutter[1], /background:\s*color-mix\([^;]*var\(--text-primary\)/,
+    "gutter background must derive from the theme, not CodeMirror's hardcoded #f5f5f5");
+  assert.match(gutter[1], /color:\s*var\(--text-secondary\)/);
+  assert.match(gutter[1], /border-right:\s*1px solid var\(--border\)/);
+  const active = cssSrc.match(/\.cm-editor \.cm-gutters \.cm-activeLineGutter \{([^}]*)\}/);
+  assert.ok(active, "themed .cm-activeLineGutter rule not found");
+  assert.match(active[1], /color-mix\([^;]*var\(--text-primary\)/);
+});
+
 // ── BUG-054: the shared save button must not stay stuck on the spinner ──
 test("utils.js resetSaveButton restores the checkmark and re-enables the button", () => {
   const fn = utilsSrc.match(/function resetSaveButton\(\) \{([\s\S]*?)\n\}/);