diff --git a/scripts/e2e-settings-visual-theme.test.mjs b/scripts/e2e-settings-visual-theme.test.mjs
index 0871c1f..557146b 100644
--- a/scripts/e2e-settings-visual-theme.test.mjs
+++ b/scripts/e2e-settings-visual-theme.test.mjs
@@ -31,6 +31,9 @@ test('theme registry exposes the requested Monaco themes and safe fallback', ()
     assert.deepEqual(theme.terminalTheme.selectionBackground, theme.selection.background);
     assert.deepEqual(theme.terminalTheme.selectionInactiveBackground, theme.selection.inactiveBackground);
     assert.ok(contrastRatio(theme.selection.foreground, theme.selection.background) >= 4.5);
+    if (theme.id.startsWith('monochrome-')) {
+      assert.ok(contrastRatio(theme.selection.foreground, theme.selection.inactiveBackground) >= 4.5);
+    }
     assert.notEqual(theme.selection.background, theme.terminalTheme.background);
   }
   assert.deepEqual(VISUAL_THEMES.map(({ id }) => id), [
@@ -91,6 +94,24 @@ test('monochrome themes separate panels and outline buttons', async () => {
   assert.match(css, /monochrome-dark[^}]*border-color: var\(--blue\);/);
 });
 
+test('monochrome Monaco selection backgrounds contrast with normal code text', async () => {
+  const css = await readFile(new URL('../src/ui/styles.css', import.meta.url), 'utf8');
+  for (const theme of VISUAL_THEMES.filter(({ id }) => id.startsWith('monochrome-'))) {
+    assert.equal(theme.selection.foreground, theme.cssTokens.text);
+    assert.ok(contrastRatio(theme.cssTokens.text, theme.selection.background) >= 4.5);
+    assert.ok(contrastRatio(theme.cssTokens.text, theme.selection.inactiveBackground) >= 4.5);
+  }
+  assert.doesNotMatch(css, /\.monaco-editor\s+\.selected-text\s*\{[^}]*color:/s);
+});
+
+test('Monaco selection smoke hook reads a real editor selection', async () => {
+  const editor = await readFile(new URL('../src/ui/editor.js', import.meta.url), 'utf8');
+  assert.match(editor, /_editor\.setSelection\(new monaco\.Range\(/);
+  assert.match(editor, /editorNode\.querySelector\('\.view-overlays \.selected-text'\)/);
+  assert.match(editor, /editorNode\.querySelector\('\.view-lines \.view-line span'\)/);
+  assert.doesNotMatch(editor, /document\.createElement\('div'\)/);
+});
+
 function contrastRatio(foreground, background) {
   const luminance = (color) => {
     const channels = color.match(/[0-9a-f]{2}/gi).map((channel) => parseInt(channel, 16) / 255);
diff --git a/scripts/smoke-browser.mjs b/scripts/smoke-browser.mjs
index 3d3c547..b9b35d0 100644
--- a/scripts/smoke-browser.mjs
+++ b/scripts/smoke-browser.mjs
@@ -448,6 +448,18 @@ function parseRgbColor(color) {
   return rgb ? rgb.slice(1, 4).map(Number) : null;
 }
 
+function wcagContrastRatio(foreground, background) {
+  const colors = [parseRgbColor(foreground), parseRgbColor(background)];
+  if (colors.some((color) => !color)) return 0;
+  const luminances = colors.map((color) => {
+    const channels = color.map((channel) => channel / 255).map((channel) => (
+      channel <= 0.03928 ? channel / 12.92 : ((channel + 0.055) / 1.055) ** 2.4
+    ));
+    return channels[0] * 0.2126 + channels[1] * 0.7152 + channels[2] * 0.0722;
+  }).sort((a, b) => b - a);
+  return (luminances[0] + 0.05) / (luminances[1] + 0.05);
+}
+
 async function openExtensionPage(cdp, extensionId) {
   const { targetId } = await cdp.send('Target.createTarget', {
     url: 'about:blank',
@@ -1052,6 +1064,10 @@ int main() {
       assert(monacoColors?.background && monacoColors.foreground && monacoColors.inactiveBackground,
         `${themeId} Monaco selection styles were not computed`);
       if (themeId.startsWith('monochrome-')) {
+        assert(wcagContrastRatio(monacoColors.foreground, monacoColors.background) >= 4.5,
+          `${themeId} active Monaco selection fails WCAG AA contrast`);
+        assert(wcagContrastRatio(monacoColors.foreground, monacoColors.inactiveBackground) >= 4.5,
+          `${themeId} inactive Monaco selection fails WCAG AA contrast`);
         const editorTextColors = await evaluate(cdp, sessionId, `(() => {
           const spans = [...document.querySelectorAll('.monaco-editor .view-lines .view-line span')];
           return spans.map((element) => getComputedStyle(element).color).filter(Boolean);
@@ -1225,8 +1241,8 @@ int main() {
     const expectedSelectionBackground = {
       vs: '#0969da',
       'hc-light': '#0037da',
-      'monochrome-light': '#666666',
-      'monochrome-dark': '#999999',
+      'monochrome-light': '#999999',
+      'monochrome-dark': '#555555',
     }[themeId];
     assert(selection.theme.selectionBackground, `${themeId} terminal selection background is missing`);
     assert(selection.theme.selectionForeground, `${themeId} terminal selection foreground is missing`);
@@ -1239,6 +1255,10 @@ int main() {
         selection.theme.selectionBackground, selection.theme.selectionForeground];
       assert(colors.every((color) => /^#([\da-f]{2})\1\1$/i.test(color)),
         `${themeId} terminal colors are not grayscale: ${colors.join(', ')}`);
+      assert(wcagContrastRatio(selection.theme.selectionForeground, selection.theme.selectionBackground) >= 4.5,
+        `${themeId} active terminal selection fails WCAG AA contrast`);
+      assert(wcagContrastRatio(selection.theme.selectionForeground, selection.theme.selectionInactiveBackground) >= 4.5,
+        `${themeId} inactive terminal selection fails WCAG AA contrast`);
     }
     const currentTerminal = await evaluate(
       cdp,
diff --git a/src/ui/editor.js b/src/ui/editor.js
index eee011c..9ebf073 100644
--- a/src/ui/editor.js
+++ b/src/ui/editor.js
@@ -156,23 +156,30 @@ export function createEditor(container, { theme = 'browser-cpp-dark' } = {}) {
     container.__browserCppReadSelectionColors = () => {
       const editorNode = _editor.getDomNode();
       if (!editorNode) return null;
-      const viewLine = document.createElement('div');
-      viewLine.className = 'view-line focused';
-      const selected = document.createElement('span');
-      selected.className = 'selected-text inline-selected-text';
-      selected.textContent = 'theme color probe';
-      viewLine.append(selected);
-      editorNode.append(viewLine);
       const toHex = (value) => {
         const channels = value.match(/[\d.]+/g)?.map(Number);
         if (!channels || channels.length < 3) return value;
         return `#${channels.slice(0, 3).map((channel) => Math.round(channel).toString(16).padStart(2, '0')).join('')}`;
       };
+      const originalValue = _editor.getValue();
+      const originalSelections = _editor.getSelections();
+      _editor.setValue('theme color probe');
+      _editor.setSelection(new monaco.Range(1, 1, 1, 6));
+      _editor.focus();
+      _editor.render(true);
+      const selected = editorNode.querySelector('.view-overlays .selected-text');
+      const selectedText = editorNode.querySelector('.view-lines .view-line span');
+      if (!selected || !selectedText) return null;
       const background = toHex(getComputedStyle(selected).backgroundColor);
-      const foreground = toHex(getComputedStyle(selected).color);
-      viewLine.classList.remove('focused');
-      const inactiveBackground = toHex(getComputedStyle(selected).backgroundColor);
-      viewLine.remove();
+      const foreground = toHex(getComputedStyle(selectedText).color);
+      editorNode.querySelector('textarea.inputarea')?.blur();
+      _editor.render(true);
+      const inactiveSelected = editorNode.querySelector('.view-overlays .selected-text');
+      if (!inactiveSelected) return null;
+      const inactiveBackground = toHex(getComputedStyle(inactiveSelected).backgroundColor);
+      _editor.setValue(originalValue);
+      if (originalSelections?.length) _editor.setSelections(originalSelections);
+      _editor.render(true);
       return { background, foreground, inactiveBackground };
     };
   }
diff --git a/src/ui/themes.mjs b/src/ui/themes.mjs
index a20295c..dee6d5e 100644
--- a/src/ui/themes.mjs
+++ b/src/ui/themes.mjs
@@ -77,13 +77,13 @@ export const VISUAL_THEMES = Object.freeze([
   }),
   visualTheme({
     id: 'monochrome-light', label: 'Monochrome Light', monacoTheme: 'browser-cpp-monochrome-light',
-    selection: { foreground: '#ffffff', background: '#666666', inactiveBackground: '#999999' },
+    selection: { foreground: '#000000', background: '#999999', inactiveBackground: '#bbbbbb' },
     cssTokens: { crust: '#ffffff', mantle: '#ffffff', base: '#ffffff', surface0: '#ffffff', surface1: '#666666', overlay0: '#666666', text: '#000000', subtext0: '#666666', green: '#000000', red: '#666666', yellow: '#666666', blue: '#000000', mauve: '#000000', peach: '#666666' },
     terminalColors: { background: '#dddddd', foreground: '#000000', accent: '#666666', ansi: monochromeAnsi('#000000', '#666666') }, preview: { background: '#ffffff', foreground: '#000000', accent: '#666666' },
   }),
   visualTheme({
     id: 'monochrome-dark', label: 'Monochrome Dark', monacoTheme: 'browser-cpp-monochrome-dark',
-    selection: { foreground: '#000000', background: '#999999', inactiveBackground: '#666666' },
+    selection: { foreground: '#ffffff', background: '#555555', inactiveBackground: '#707070' },
     cssTokens: { crust: '#000000', mantle: '#000000', base: '#000000', surface0: '#000000', surface1: '#999999', overlay0: '#999999', text: '#ffffff', subtext0: '#999999', green: '#ffffff', red: '#999999', yellow: '#999999', blue: '#ffffff', mauve: '#ffffff', peach: '#999999' },
     terminalColors: { background: '#222222', foreground: '#ffffff', accent: '#999999', ansi: monochromeAnsi('#ffffff', '#999999') }, preview: { background: '#000000', foreground: '#ffffff', accent: '#999999' },
   }),