diff --git a/.github/CODEOWNERS b/.github/CODEOWNERS
new file mode 100644
index 0000000..b6fdf93
--- /dev/null
+++ b/.github/CODEOWNERS
@@ -0,0 +1,2 @@
+# Default owner for all files
+* @roman-rouba
diff --git a/.github/pull_request_template.md b/.github/pull_request_template.md
new file mode 100644
index 0000000..86fe542
--- /dev/null
+++ b/.github/pull_request_template.md
@@ -0,0 +1,21 @@
+# Description
+<!-- What this pr is for -->
+
+## Ticket
+<!-- Jira ticket number -->
+
+## Screenshot/Video (optional)
+<!-- Demonstration of changes -->
+
+# Checklist
+<!-- Checklist to be followed by the author -->
+- [ ] Linters passed
+- [ ] Tests passed
+- [ ] Documentation updated (if needed)
+
+# Review level
+<!-- Who is needed for this review -->
+- [ ] Standard review (peer review by 1-2 developers)
+- [ ] Techlead/Architect review required
+- [ ] QA review required
+
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..fa00a27
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,110 @@
+name: CI
+
+on:
+  push:
+    branches: [ main, 'CALC-*' ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+  validate:
+    name: Validate HTML and Code Quality
+    runs-on: ubuntu-latest
+    
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+      
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+      
+      - name: Validate HTML file exists
+        run: |
+          if [ ! -f index.html ]; then
+            echo "❌ Error: index.html not found"
+            exit 1
+          fi
+          echo "✅ index.html exists"
+      
+      - name: Check HTML structure
+        run: |
+          # Check for required HTML elements
+          if ! grep -q "<!DOCTYPE html>" index.html; then
+            echo "❌ Missing DOCTYPE declaration"
+            exit 1
+          fi
+          if ! grep -q "<html" index.html; then
+            echo "❌ Missing <html> tag"
+            exit 1
+          fi
+          if ! grep -q "<head" index.html; then
+            echo "❌ Missing <head> tag"
+            exit 1
+          fi
+          if ! grep -q "<body" index.html; then
+            echo "❌ Missing <body> tag"
+            exit 1
+          fi
+          echo "✅ Basic HTML structure is valid"
+      
+      - name: Validate JavaScript syntax
+        run: |
+          # Extract JavaScript content
+          awk '/<script>/,/<\/script>/' index.html | sed '1d;$d' > /tmp/extracted.js
+          
+          # Check if JavaScript exists
+          if [ -s /tmp/extracted.js ]; then
+            echo "Validating JavaScript syntax..."
+            node --check /tmp/extracted.js && echo "✅ JavaScript syntax is valid" || {
+              echo "⚠️  JavaScript validation skipped (inline script may have issues)"
+            }
+          else
+            echo "⚠️  No JavaScript found to validate"
+          fi
+      
+      - name: Check for common issues
+        run: |
+          # Check for console.log (should be removed in production)
+          if grep -q "console\.log" index.html; then
+            echo "⚠️  Warning: console.log found in code"
+          fi
+          
+          # Check for TODO/FIXME comments
+          if grep -qi "TODO\|FIXME" index.html; then
+            echo "ℹ️  Info: TODO/FIXME comments found"
+          fi
+          
+          # Check file size (should be reasonable)
+          SIZE=$(wc -c < index.html)
+          if [ $SIZE -gt 100000 ]; then
+            echo "⚠️  Warning: index.html is larger than 100KB"
+          fi
+          echo "✅ Code quality checks passed"
+      
+      - name: Display repository structure
+        run: |
+          echo "📁 Repository structure:"
+          find . -type f -not -path './.git/*' -not -path './node_modules/*' | sort
+
+  html-validate:
+    name: HTML Validation
+    runs-on: ubuntu-latest
+    continue-on-error: true
+    
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+      
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+      
+      - name: Install html-validate
+        run: npm install -g html-validate
+      
+      - name: Validate HTML
+        run: |
+          html-validate index.html || echo "HTML validation completed with warnings"
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..066c77e
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,42 @@
+# OS-specific files
+.DS_Store
+.DS_Store?
+._*
+.Spotlight-V100
+.Trashes
+ehthumbs.db
+Thumbs.db
+desktop.ini
+
+# Editor directories and files
+.vscode/
+.idea/
+*.swp
+*.swo
+*~
+.project
+.classpath
+.settings/
+
+# Temporary files
+*.tmp
+*.temp
+*.log
+PR_DESCRIPTION.md
+
+# Node modules (if you add npm packages later)
+node_modules/
+package-lock.json
+yarn.lock
+
+# Build outputs
+dist/
+build/
+*.min.js
+*.min.css
+
+# Environment files
+.env
+.env.local
+.env.*.local
+
diff --git a/.htmlvalidate.json b/.htmlvalidate.json
new file mode 100644
index 0000000..c7fbc3b
--- /dev/null
+++ b/.htmlvalidate.json
@@ -0,0 +1,9 @@
+{
+  "extends": ["html-validate:recommended"],
+  "rules": {
+    "valid-id": "off",
+    "no-inline-style": "warn",
+    "no-missing-references": "off"
+  }
+}
+
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..c295b90
--- /dev/null
+++ b/README.md
@@ -0,0 +1,71 @@
+# Calculator Application
+
+A simple, modern calculator web application built with vanilla HTML, CSS, and JavaScript.
+
+## Features
+
+- Basic arithmetic operations (addition, subtraction, multiplication)
+- Clean and intuitive user interface
+- Responsive design
+- Real-time calculation display
+
+## Getting Started
+
+Simply open `index.html` in your web browser. No build process or dependencies required.
+
+## Usage
+
+1. Click number buttons to enter digits
+2. Click an operator button (+, -, *) to select an operation
+3. Enter the second number
+4. Click the equals (=) button to calculate the result
+5. Click Clear (C) to reset the calculator
+
+## Project Structure
+
+```
+tl_tech_task/
+├── index.html          # Main calculator application
+├── README.md           # Project documentation
+├── .htmlvalidate.json  # HTML validation configuration
+└── .github/            # GitHub templates and workflows
+    ├── pull_request_template.md
+    └── workflows/
+        └── ci.yml      # GitHub Actions CI workflow
+```
+
+## Development
+
+This is a single-file application. All HTML, CSS, and JavaScript are contained in `index.html`.
+
+## Contributing
+
+We welcome contributions! Please follow these guidelines:
+
+1. **Branch Naming**: Use the format `feature/<issue>-description`
+   - Example: `feature/CALC-4-add-division`
+   - Fork the repository and create your branch from the fork
+
+2. **Keep PRs Small**: Pull requests should be under 500 lines of code
+   - Break large features into smaller, focused PRs
+   - Each PR should address a single concern
+
+3. **Requirements Before Merging**:
+   - ✅ CI checks must pass
+   - ✅ 1-2 approvals required
+   - ✅ Code owner review (if CODEOWNERS is configured)
+
+## CI/CD
+
+This repository uses GitHub Actions for continuous integration. The CI workflow automatically:
+- Validates HTML structure and syntax
+- Checks JavaScript syntax
+- Performs code quality checks
+- Runs on every push and pull request
+
+See `.github/workflows/ci.yml` for the complete CI configuration.
+
+## License
+
+[Add your license here]
+
diff --git a/index.html b/index.html
index 8bfd362..cf40e23 100644
--- a/index.html
+++ b/index.html
@@ -22,7 +22,7 @@
     <div class="display" id="display">0</div>
     <div class="buttons">
         <button class="clear" id="clear">C</button>
-        <button class="operator disabled" id="divide">/</button> <button class="operator disabled" id="multiply">*</button> <button class="number">7</button>
+        <button class="operator disabled" id="divide">/</button> <button class="operator" id="multiply">*</button> <button class="number">7</button>
         <button class="number">8</button>
         <button class="number">9</button>
         <button class="operator" id="subtract">-</button>
@@ -74,6 +74,7 @@
             switch (operator) {
                 case '+': result = firstOperand + secondOperand; break;
                 case '-': result = firstOperand - secondOperand; break;
+                case '*': result = firstOperand * secondOperand; break;
             }
             currentInput = result.toString();
             operator = null;
