diff --git a/.eslintignore b/.eslintignore
index 6d540c41387223..d4930e1f528002 100644
--- a/.eslintignore
+++ b/.eslintignore
@@ -1,30 +1,13 @@
-# See https://help.github.com/articles/ignoring-files for more about ignoring files.
-#
-# If you find yourself ignoring temporary files generated by your text editor
-# or operating system, you probably want to add a global ignore instead:
-#   git config --global core.excludesfile '~/.gitignore_global'
-
-# Ignore bundler config.
-/.bundle
-
-# Ignore the default SQLite database.
-/db/*.sqlite3
-/db/*.sqlite3-journal
-
-# Ignore all logfiles and tempfiles.
-/log/*
-!/log/.keep
-/tmp
-coverage
-public/system
-public/assets
-.env
-.env.production
-node_modules/
-neo4j/
-
-# Ignore Vagrant files
-.vagrant/
-
-# Ignore Capistrano customizations
-config/deploy/*
+/build/**
+/coverage/**
+/db/**
+/lib/**
+/log/**
+/node_modules/**
+/nonobox/**
+/public/**
+!/public/embed.js
+/spec/**
+/tmp/**
+/vendor/**
+!.eslintrc.js
diff --git a/.eslintrc.js b/.eslintrc.js
new file mode 100644
index 00000000000000..56e3d0530f5918
--- /dev/null
+++ b/.eslintrc.js
@@ -0,0 +1,199 @@
+module.exports = {
+  root: true,
+
+  env: {
+    browser: true,
+    node: true,
+    es6: true,
+    jest: true,
+  },
+
+  globals: {
+    ATTACHMENT_HOST: false,
+  },
+
+  parser: 'babel-eslint',
+
+  plugins: [
+    'react',
+    'jsx-a11y',
+    'import',
+    'promise',
+  ],
+
+  parserOptions: {
+    sourceType: 'module',
+    ecmaFeatures: {
+      experimentalObjectRestSpread: true,
+      jsx: true,
+    },
+    ecmaVersion: 2018,
+  },
+
+  settings: {
+    react: {
+      version: 'detect',
+    },
+    'import/extensions': [
+      '.js',
+    ],
+    'import/ignore': [
+      'node_modules',
+      '\\.(css|scss|json)$',
+    ],
+  },
+
+  rules: {
+    'brace-style': 'warn',
+    'comma-dangle': ['error', 'always-multiline'],
+    'comma-spacing': [
+      'warn',
+      {
+        before: false,
+        after: true,
+      },
+    ],
+    'comma-style': ['warn', 'last'],
+    'consistent-return': 'error',
+    'dot-notation': 'error',
+    eqeqeq: 'error',
+    indent: ['warn', 2],
+    'jsx-quotes': ['error', 'prefer-single'],
+    'no-catch-shadow': 'error',
+    'no-cond-assign': 'error',
+    'no-console': [
+      'warn',
+      {
+        allow: [
+          'error',
+          'warn',
+        ],
+      },
+    ],
+    'no-fallthrough': 'error',
+    'no-irregular-whitespace': 'error',
+    'no-mixed-spaces-and-tabs': 'warn',
+    'no-nested-ternary': 'warn',
+    'no-trailing-spaces': 'warn',
+    'no-undef': 'error',
+    'no-unreachable': 'error',
+    'no-unused-expressions': 'error',
+    'no-unused-vars': [
+      'error',
+      {
+        vars: 'all',
+        args: 'after-used',
+        ignoreRestSiblings: true,
+      },
+    ],
+    'object-curly-spacing': ['error', 'always'],
+    'padded-blocks': [
+      'error',
+      {
+        classes: 'always',
+      },
+    ],
+    quotes: ['error', 'single'],
+    semi: 'error',
+    strict: 'off',
+    'valid-typeof': 'error',
+
+    'react/jsx-boolean-value': 'error',
+    'react/jsx-closing-bracket-location': ['error', 'line-aligned'],
+    'react/jsx-curly-spacing': 'error',
+    'react/jsx-equals-spacing': 'error',
+    'react/jsx-first-prop-new-line': ['error', 'multiline-multiprop'],
+    'react/jsx-indent': ['error', 2],
+    'react/jsx-no-bind': 'error',
+    'react/jsx-no-duplicate-props': 'error',
+    'react/jsx-no-undef': 'error',
+    'react/jsx-tag-spacing': 'error',
+    'react/jsx-uses-react': 'error',
+    'react/jsx-uses-vars': 'error',
+    'react/jsx-wrap-multilines': 'error',
+    'react/no-multi-comp': 'off',
+    'react/no-string-refs': 'error',
+    'react/prop-types': 'error',
+    'react/self-closing-comp': 'error',
+
+    'jsx-a11y/accessible-emoji': 'warn',
+    'jsx-a11y/alt-text': 'warn',
+    'jsx-a11y/anchor-has-content': 'warn',
+    'jsx-a11y/anchor-is-valid': [
+      'warn',
+      {
+        components: [
+          'Link',
+          'NavLink',
+        ],
+        specialLink: [
+          'to',
+        ],
+        aspect: [
+          'noHref',
+          'invalidHref',
+          'preferButton',
+        ],
+      },
+    ],
+    'jsx-a11y/aria-activedescendant-has-tabindex': 'warn',
+    'jsx-a11y/aria-props': 'warn',
+    'jsx-a11y/aria-proptypes': 'warn',
+    'jsx-a11y/aria-role': 'warn',
+    'jsx-a11y/aria-unsupported-elements': 'warn',
+    'jsx-a11y/heading-has-content': 'warn',
+    'jsx-a11y/html-has-lang': 'warn',
+    'jsx-a11y/iframe-has-title': 'warn',
+    'jsx-a11y/img-redundant-alt': 'warn',
+    'jsx-a11y/interactive-supports-focus': 'warn',
+    'jsx-a11y/label-has-for': 'off',
+    'jsx-a11y/mouse-events-have-key-events': 'warn',
+    'jsx-a11y/no-access-key': 'warn',
+    'jsx-a11y/no-distracting-elements': 'warn',
+    'jsx-a11y/no-noninteractive-element-interactions': [
+      'warn',
+      {
+        handlers: [
+          'onClick',
+        ],
+      },
+    ],
+    'jsx-a11y/no-onchange': 'warn',
+    'jsx-a11y/no-redundant-roles': 'warn',
+    'jsx-a11y/no-static-element-interactions': [
+      'warn',
+      {
+        handlers: [
+          'onClick',
+        ],
+      },
+    ],
+    'jsx-a11y/role-has-required-aria-props': 'warn',
+    'jsx-a11y/role-supports-aria-props': 'off',
+    'jsx-a11y/scope': 'warn',
+    'jsx-a11y/tabindex-no-positive': 'warn',
+
+    'import/extensions': [
+      'error',
+      'always',
+      {
+        js: 'never',
+      },
+    ],
+    'import/newline-after-import': 'error',
+    'import/no-extraneous-dependencies': [
+      'error',
+      {
+        devDependencies: [
+          'config/webpack/**',
+          'app/javascript/mastodon/test_setup.js',
+          'app/javascript/**/__tests__/**',
+        ],
+      },
+    ],
+    'import/no-unresolved': 'error',
+    'import/no-webpack-loader-syntax': 'error',
+
+    'promise/catch-or-return': 'error',
+  },
+};
diff --git a/.eslintrc.yml b/.eslintrc.yml
deleted file mode 100644
index dddf29eb8200ea..00000000000000
--- a/.eslintrc.yml
+++ /dev/null
@@ -1,172 +0,0 @@
----
-root: true
-
-env:
-  browser: true
-  node: true
-  es6: true
-  jest: true
-
-globals:
-  ATTACHMENT_HOST: false
-
-parser: babel-eslint
-
-plugins:
-- react
-- jsx-a11y
-- import
-- promise
-
-parserOptions:
-  sourceType: module
-  ecmaFeatures:
-    experimentalObjectRestSpread: true
-    jsx: true
-  ecmaVersion: 2018
-
-settings:
-  react:
-    version: detect
-  import/extensions:
-  - .js
-  import/ignore:
-  - node_modules
-  - \\.(css|scss|json)$
-
-rules:
-  brace-style: warn
-  comma-dangle:
-  - error
-  - always-multiline
-  comma-spacing:
-  - warn
-  - before: false
-    after: true
-  comma-style:
-  - warn
-  - last
-  consistent-return: error
-  dot-notation: error
-  eqeqeq: error
-  indent:
-  - warn
-  - 2
-  jsx-quotes:
-  - error
-  - prefer-single
-  no-catch-shadow: error
-  no-cond-assign: error
-  no-console:
-  - warn
-  - allow:
-    - error
-    - warn
-  no-fallthrough: error
-  no-irregular-whitespace: error
-  no-mixed-spaces-and-tabs: warn
-  no-nested-ternary: warn
-  no-trailing-spaces: warn
-  no-undef: error
-  no-unreachable: error
-  no-unused-expressions: error
-  no-unused-vars:
-  - error
-  - vars: all
-    args: after-used
-    ignoreRestSiblings: true
-  object-curly-spacing:
-  - error
-  - always
-  padded-blocks:
-  - error
-  - classes: always
-  quotes:
-  - error
-  - single
-  semi: error
-  strict: off
-  valid-typeof: error
-
-  react/jsx-boolean-value: error
-  react/jsx-closing-bracket-location:
-  - error
-  - line-aligned
-  react/jsx-curly-spacing: error
-  react/jsx-equals-spacing: error
-  react/jsx-first-prop-new-line:
-  - error
-  - multiline-multiprop
-  react/jsx-indent:
-  - error
-  - 2
-  react/jsx-no-bind: error
-  react/jsx-no-duplicate-props: error
-  react/jsx-no-undef: error
-  react/jsx-tag-spacing: error
-  react/jsx-uses-react: error
-  react/jsx-uses-vars: error
-  react/jsx-wrap-multilines: error
-  react/no-multi-comp: off
-  react/no-string-refs: error
-  react/prop-types: error
-  react/self-closing-comp: error
-
-  jsx-a11y/accessible-emoji: warn
-  jsx-a11y/alt-text: warn
-  jsx-a11y/anchor-has-content: warn
-  jsx-a11y/anchor-is-valid:
-  - warn
-  - components:
-    - Link
-    - NavLink
-    specialLink:
-    - to
-    aspect:
-    - noHref
-    - invalidHref
-    - preferButton
-  jsx-a11y/aria-activedescendant-has-tabindex: warn
-  jsx-a11y/aria-props: warn
-  jsx-a11y/aria-proptypes: warn
-  jsx-a11y/aria-role: warn
-  jsx-a11y/aria-unsupported-elements: warn
-  jsx-a11y/heading-has-content: warn
-  jsx-a11y/html-has-lang: warn
-  jsx-a11y/iframe-has-title: warn
-  jsx-a11y/img-redundant-alt: warn
-  jsx-a11y/interactive-supports-focus: warn
-  jsx-a11y/label-has-for: off
-  jsx-a11y/mouse-events-have-key-events: warn
-  jsx-a11y/no-access-key: warn
-  jsx-a11y/no-distracting-elements: warn
-  jsx-a11y/no-noninteractive-element-interactions:
-  - warn
-  - handlers:
-    - onClick
-  jsx-a11y/no-onchange: warn
-  jsx-a11y/no-redundant-roles: warn
-  jsx-a11y/no-static-element-interactions:
-  - warn
-  - handlers:
-    - onClick
-  jsx-a11y/role-has-required-aria-props: warn
-  jsx-a11y/role-supports-aria-props: off
-  jsx-a11y/scope: warn
-  jsx-a11y/tabindex-no-positive: warn
-
-  import/extensions:
-  - error
-  - always
-  - js: never
-  import/newline-after-import: error
-  import/no-extraneous-dependencies:
-  - error
-  - devDependencies:
-    - "config/webpack/**"
-    - "app/javascript/mastodon/test_setup.js"
-    - "app/javascript/**/__tests__/**"
-  import/no-unresolved: error
-  import/no-webpack-loader-syntax: error
-
-  promise/catch-or-return: error
diff --git a/package.json b/package.json
index a7f2fd157a5be7..15d9f085a86e41 100644
--- a/package.json
+++ b/package.json
@@ -10,8 +10,8 @@
     "build:production": "cross-env RAILS_ENV=production NODE_ENV=production ./bin/webpack",
     "manage:translations": "node ./config/webpack/translationRunner.js",
     "start": "node ./streaming/index.js",
-    "test": "npm run test:lint && npm run test:jest",
-    "test:lint": "eslint -c .eslintrc.yml --ext=js app/javascript/ config/webpack/ streaming/",
+    "test": "${npm_execpath} run test:lint && ${npm_execpath} run test:jest",
+    "test:lint": "eslint --ext=js .",
     "test:jest": "cross-env NODE_ENV=test jest --coverage"
   },
   "repository": {
diff --git a/postcss.config.js b/postcss.config.js
index 84701e4ade38bd..1c820c3181b19f 100644
--- a/postcss.config.js
+++ b/postcss.config.js
@@ -1,13 +1,7 @@
-module.exports = {
+module.exports = ({ env }) => ({
   plugins: {
-    autoprefixer: {
-      browsers: [
-        'last 2 versions',
-        'IE >= 11',
-        'iOS >= 9',
-      ],
-    },
+    autoprefixer: {},
     'postcss-object-fit-images': {},
-    cssnano: {},
+    cssnano: env === 'production' ? {} : false,
   },
-};
+});
diff --git a/vendor/assets/javascripts/.keep b/vendor/.keep
similarity index 100%
rename from vendor/assets/javascripts/.keep
rename to vendor/.keep
diff --git a/vendor/assets/stylesheets/.keep b/vendor/assets/stylesheets/.keep
deleted file mode 100644
index e69de29bb2d1d6..00000000000000