diff --git a/.editorconfig b/.editorconfig
new file mode 100644
index 0000000..7a9d74e
--- /dev/null
+++ b/.editorconfig
@@ -0,0 +1,18 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+indent_style = space
+indent_size = 2
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[*.go]
+indent_style = tab
+
+[Makefile]
+indent_style = tab
+
+[*.md]
+trim_trailing_whitespace = false
diff --git a/.gitignore b/.gitignore
index 1e602b0..ae66203 100644
--- a/.gitignore
+++ b/.gitignore
@@ -32,7 +32,6 @@ resources/
 
 # Node.js dependencies
 node_modules/
-package-lock.json
 
 # Hugo build artifacts
 public/
diff --git a/.nvmrc b/.nvmrc
new file mode 100644
index 0000000..ee09fac
--- /dev/null
+++ b/.nvmrc
@@ -0,0 +1 @@
+v20.11.1
diff --git a/.prettierignore b/.prettierignore
new file mode 100644
index 0000000..7ef555f
--- /dev/null
+++ b/.prettierignore
@@ -0,0 +1,11 @@
+node_modules
+exampleSite/public
+exampleSite/resources
+public
+resources
+.hugo_build.lock
+flake.lock
+package-lock.json
+*.min.js
+*.min.css
+static/bibtex
diff --git a/.prettierrc.json b/.prettierrc.json
new file mode 100644
index 0000000..15049be
--- /dev/null
+++ b/.prettierrc.json
@@ -0,0 +1,13 @@
+{
+  "semi": true,
+  "singleQuote": true,
+  "trailingComma": "all",
+  "printWidth": 100,
+  "tabWidth": 2,
+  "useTabs": false,
+  "endOfLine": "lf",
+  "overrides": [
+    { "files": "*.md", "options": { "printWidth": 80, "proseWrap": "preserve" } },
+    { "files": "*.html", "options": { "parser": "html" } }
+  ]
+}
diff --git a/.stylelintignore b/.stylelintignore
new file mode 100644
index 0000000..b38ddd1
--- /dev/null
+++ b/.stylelintignore
@@ -0,0 +1,5 @@
+node_modules
+exampleSite/public
+public
+resources
+**/*.min.css
diff --git a/.stylelintrc.json b/.stylelintrc.json
new file mode 100644
index 0000000..48d0d71
--- /dev/null
+++ b/.stylelintrc.json
@@ -0,0 +1,9 @@
+{
+  "extends": "stylelint-config-standard",
+  "rules": {
+    "declaration-no-important": [true, { "severity": "warning" }],
+    "custom-property-pattern": "^[a-z][a-z0-9]*(-[a-z0-9]+)*$",
+    "selector-class-pattern": null,
+    "no-descending-specificity": null
+  }
+}
diff --git a/eslint.config.mjs b/eslint.config.mjs
new file mode 100644
index 0000000..381fc6b
--- /dev/null
+++ b/eslint.config.mjs
@@ -0,0 +1,25 @@
+import js from '@eslint/js';
+import globals from 'globals';
+
+export default [
+  js.configs.recommended,
+  {
+    languageOptions: {
+      ecmaVersion: 2023,
+      sourceType: 'module',
+      globals: { ...globals.browser, ...globals.node },
+    },
+    rules: {
+      'prefer-const': 'warn',
+      'no-var': 'warn',
+      eqeqeq: ['warn', 'smart'],
+      'no-unused-vars': ['warn', { argsIgnorePattern: '^_' }],
+      'no-console': ['warn', { allow: ['warn', 'error'] }],
+    },
+  },
+  {
+    files: ['scripts/**/*.js'],
+    languageOptions: { sourceType: 'commonjs' },
+  },
+  { ignores: ['node_modules', 'exampleSite/public', 'public', 'resources', '**/*.min.js'] },
+];
diff --git a/package.json b/package.json
index f97fe40..604907c 100644
--- a/package.json
+++ b/package.json
@@ -5,23 +5,33 @@
   "private": true,
   "scripts": {
     "build": "hugo --gc --minify",
-    "build:advanced": "npm run build && npm run optimize-images && npm run seo-audit",
     "dev": "hugo server --disableFastRender --navigateToChanged",
     "optimize-images": "node scripts/optimize-images.js",
-    "seo-audit": "node scripts/seo-audit.js",
-    "validate-seo": "node scripts/validate-seo.js"
+    "lint": "eslint assets/js scripts && stylelint 'assets/css/**/*.css'",
+    "lint:fix": "eslint --fix assets/js scripts && stylelint --fix 'assets/css/**/*.css'",
+    "format": "prettier --write 'assets/**/*.{js,css,md}' 'layouts/**/*.html' 'scripts/**/*.js' '**/*.md'",
+    "format:check": "prettier --check 'assets/**/*.{js,css,md}' 'layouts/**/*.html' 'scripts/**/*.js' '**/*.md'"
   },
   "devDependencies": {
-    "sharp": "^0.34.0",
+    "@eslint/js": "^9.0.0",
+    "autoprefixer": "^10.4.0",
+    "cheerio": "^1.0.0",
+    "eslint": "^9.0.0",
+    "globals": "^15.0.0",
     "glob": "^11.0.0",
-    "cheerio": "^1.0.0"
+    "postcss": "^8.4.0",
+    "postcss-preset-env": "^9.5.0",
+    "prettier": "^3.2.0",
+    "sharp": "^0.34.0",
+    "stylelint": "^16.0.0",
+    "stylelint-config-standard": "^36.0.0"
   },
   "engines": {
-    "node": ">=18.17.0"
+    "node": ">=20.0.0"
   },
   "repository": {
     "type": "git",
-    "url": "https://github.com/your-username/pkb-theme"
+    "url": "https://github.com/stradichenko/PKB-theme"
   },
   "keywords": [
     "hugo",
diff --git a/postcss.config.js b/postcss.config.js
new file mode 100644
index 0000000..ec964bc
--- /dev/null
+++ b/postcss.config.js
@@ -0,0 +1,6 @@
+module.exports = {
+  plugins: {
+    autoprefixer: {},
+    'postcss-preset-env': { stage: 2 },
+  },
+};