diff --git a/app/scripts/check-responsive.mjs b/app/scripts/check-responsive.mjs
new file mode 100644
index 0000000..0c53c71
--- /dev/null
+++ b/app/scripts/check-responsive.mjs
@@ -0,0 +1,192 @@
+#!/usr/bin/env node
+// scripts/check-responsive.mjs — Responsive layout validation for built dist/
+
+import { readFileSync, readdirSync, statSync } from 'fs';
+import { join, extname } from 'path';
+
+const DIST_DIR = 'dist';
+const MOBILE_WIDTHS = [360, 390, 414, 640];
+const MAX_ALLOWED_OVERFLOW = 1; // Allow 1px tolerance for rounding
+
+console.log('🔍 Checking responsive layout rules...\n');
+
+let errors = 0;
+let warnings = 0;
+
+// Check 1: Verify CSS contains mobile breakpoints
+function checkCSSFiles(dir) {
+  const files = readdirSync(dir);
+  
+  for (const file of files) {
+    const fullPath = join(dir, file);
+    const stat = statSync(fullPath);
+    
+    if (stat.isDirectory()) {
+      checkCSSFiles(fullPath);
+    } else if (extname(file) === '.css') {
+      const content = readFileSync(fullPath, 'utf-8');
+      
+      // Check for mobile media queries
+      if (!content.includes('@media') || !content.includes('max-width')) {
+        console.warn(`⚠️  ${fullPath}: No mobile media queries found`);
+        warnings++;
+      }
+      
+      // Check for overflow prevention
+      if (!content.includes('overflow-x') && !content.includes('overflowX')) {
+        console.warn(`⚠️  ${fullPath}: No overflow-x rules found`);
+        warnings++;
+      }
+      
+      // Check for word-wrap/overflow-wrap
+      if (!content.includes('word-wrap') && !content.includes('overflow-wrap')) {
+        console.warn(`⚠️  ${fullPath}: No word-wrap/overflow-wrap rules found`);
+        warnings++;
+      }
+      
+      console.log(`✓ ${fullPath}: Basic responsive rules present`);
+    }
+  }
+}
+
+// Check 2: Verify HTML contains viewport meta tag
+function checkHTMLFiles(dir) {
+  const files = readdirSync(dir);
+  
+  for (const file of files) {
+    const fullPath = join(dir, file);
+    const stat = statSync(fullPath);
+    
+    if (stat.isDirectory()) {
+      checkHTMLFiles(fullPath);
+    } else if (extname(file) === '.html') {
+      const content = readFileSync(fullPath, 'utf-8');
+      
+      // Skip placeholder files (Google/Bing verification)
+      if (file.includes('placeholder') || file.includes('verification') || content.length < 100) {
+        console.log(`⊘ ${fullPath}: Skipping placeholder/verification file`);
+        continue;
+      }
+      
+      // Check for viewport meta tag
+      if (!content.includes('viewport') || !content.includes('width=device-width')) {
+        console.error(`❌ ${fullPath}: Missing or incorrect viewport meta tag`);
+        errors++;
+      } else {
+        console.log(`✓ ${fullPath}: Viewport meta tag present`);
+      }
+      
+      // Check for max-width constraints on root elements
+      if (!content.includes('max-width') && !content.includes('maxWidth')) {
+        console.warn(`⚠️  ${fullPath}: No max-width constraints found in inline styles`);
+        warnings++;
+      }
+    }
+  }
+}
+
+// Check 3: Verify no hardcoded wide widths in JS bundles
+function checkJSFiles(dir) {
+  const files = readdirSync(dir);
+  
+  for (const file of files) {
+    const fullPath = join(dir, file);
+    const stat = statSync(fullPath);
+    
+    if (stat.isDirectory()) {
+      checkJSFiles(fullPath);
+    } else if (extname(file) === '.js') {
+      const content = readFileSync(fullPath, 'utf-8');
+      
+      // Check for suspicious fixed widths (e.g., width: 1920px, minWidth: 1200px)
+      const suspiciousWidths = content.match(/(?:width|minWidth):\s*["']?\d{4,}px/g);
+      if (suspiciousWidths && suspiciousWidths.length > 0) {
+        console.warn(`⚠️  ${fullPath}: Found potentially problematic fixed widths: ${suspiciousWidths.slice(0, 3).join(', ')}`);
+        warnings++;
+      }
+    }
+  }
+}
+
+// Check 4: Validate article-specific responsive patterns
+function checkArticlePatterns() {
+  console.log('\n📱 Checking article-specific responsive patterns...\n');
+  
+  const patterns = [
+    { name: 'Article detail page wrapper', selector: '.article-detail-page', required: ['overflow-x', 'max-width'] },
+    { name: 'Article layout grid', selector: '.article-layout', required: ['overflow-x', 'min-width'] },
+    { name: 'Article main content', selector: '.article-main', required: ['overflow-x', 'min-width'] },
+    { name: 'Article header title', selector: '.article-header h1', required: ['word-wrap', 'overflow-wrap', 'clamp'] },
+    { name: 'Article breadcrumb', selector: '.article-breadcrumb', required: ['overflow-x'] },
+    { name: 'CVE summary card', selector: '.cve-summary-card', required: ['@media', 'grid-template-columns: 1fr'] },
+    { name: 'Article content', selector: '.article-content', required: ['overflow-x', 'word-wrap'] },
+  ];
+  
+  // Read all CSS files and check for patterns
+  const cssFiles = [];
+  function collectCSS(dir) {
+    const files = readdirSync(dir);
+    for (const file of files) {
+      const fullPath = join(dir, file);
+      const stat = statSync(fullPath);
+      if (stat.isDirectory()) {
+        collectCSS(fullPath);
+      } else if (extname(file) === '.css') {
+        cssFiles.push(fullPath);
+      }
+    }
+  }
+  collectCSS(DIST_DIR);
+  
+  const allCSS = cssFiles.map(f => readFileSync(f, 'utf-8')).join('\n');
+  
+  for (const pattern of patterns) {
+    let found = false;
+    for (const req of pattern.required) {
+      if (allCSS.includes(req)) {
+        found = true;
+        break;
+      }
+    }
+    
+    if (found) {
+      console.log(`✓ ${pattern.name}: Responsive rules present`);
+    } else {
+      console.warn(`⚠️  ${pattern.name}: Missing expected responsive rules (${pattern.required.join(', ')})`);
+      warnings++;
+    }
+  }
+}
+
+// Run all checks
+try {
+  console.log('Checking CSS files...\n');
+  checkCSSFiles(DIST_DIR);
+  
+  console.log('\nChecking HTML files...\n');
+  checkHTMLFiles(DIST_DIR);
+  
+  console.log('\nChecking JS bundles...\n');
+  checkJSFiles(DIST_DIR);
+  
+  checkArticlePatterns();
+  
+  console.log('\n' + '='.repeat(60));
+  console.log(`\n📊 Responsive Check Summary:`);
+  console.log(`   ✓ Errors: ${errors}`);
+  console.log(`   ⚠️  Warnings: ${warnings}`);
+  
+  if (errors > 0) {
+    console.log('\n❌ Responsive check FAILED. Fix errors before deploying.\n');
+    process.exit(1);
+  } else if (warnings > 5) {
+    console.log('\n⚠️  Many warnings detected. Review before deploying.\n');
+    process.exit(0);
+  } else {
+    console.log('\n✅ Responsive check PASSED. Layout should work on mobile.\n');
+    process.exit(0);
+  }
+} catch (err) {
+  console.error('❌ Responsive check failed with error:', err.message);
+  process.exit(1);
+}