diff --git a/.csslintrc b/.csslintrc
deleted file mode 100644
index 177e4fc..0000000
--- a/.csslintrc
+++ /dev/null
@@ -1,40 +0,0 @@
---errors=box-model,
-         display-property-grouping,
-         duplicate-background-images,
-         duplicate-properties,
-         empty-rules,
-         ids,
-         import,
-         important,
-         known-properties,
-         outline-none,
-         overqualified-elements,
-         qualified-headings,
-         shorthand,
-         star-property-hack,
-         text-indent,
-         underscore-property-hack,
-         unique-headings,
-         unqualified-attributes,
-         vendor-prefix,
-         zero-units
---ignore=adjoining-classes,
-         box-sizing,
-         bulletproof-font-face,
-         compatible-vendor-prefixes,
-         errors,
-         fallback-colors,
-         floats,
-         font-faces,
-         font-sizes,
-         gradients,
-         import-ie-limit,
-         order-alphabetical,
-         regex-selectors,
-         rules-count,
-         selector-max,
-         selector-max-approaching,
-         selector-newline,
-         universal-selector
---exclude-list=core/assets,
-               vendor
diff --git a/.stylelintrc.json b/.stylelintrc.json
new file mode 100644
index 0000000..f04c115
--- /dev/null
+++ b/.stylelintrc.json
@@ -0,0 +1,17 @@
+{
+  "rules": {
+    "block-no-empty": null,
+    "block-opening-brace-newline-after": "always",
+    "block-closing-brace-newline-before": "always",
+    "color-no-invalid-hex": true,
+    "indentation": 2,
+    "max-empty-lines": 2,
+    "declaration-empty-line-before": "never",
+    "unit-whitelist": ["deg", "em", "ex", "ms", "rem", "%", "s", "px"]
+  },
+  "ignoreFiles": [
+    "core/assets/vendor/**/*.css",
+    "core/tests/Drupal/Tests/Core/Asset/css_test_files/**/*.css"
+  ]
+}
+
diff --git a/core/misc/vertical-tabs.css b/core/misc/vertical-tabs.css
index ec5d3c1..fc83da5 100644
--- a/core/misc/vertical-tabs.css
+++ b/core/misc/vertical-tabs.css
@@ -8,8 +8,8 @@
   border: 1px solid #ccc;
 }
 [dir="rtl"] .vertical-tabs {
-   margin-left: 0;
-   margin-right: 15em;
+  margin-left: 0;
+  margin-right: 15em;
 }
 .vertical-tabs__menu {
   float: left; /* LTR */
diff --git a/core/modules/ckeditor/css/ckeditor.admin.css b/core/modules/ckeditor/css/ckeditor.admin.css
index 8b771c7..82b6c53 100644
--- a/core/modules/ckeditor/css/ckeditor.admin.css
+++ b/core/modules/ckeditor/css/ckeditor.admin.css
@@ -6,8 +6,6 @@
  * "moono".
  */
 
-
-
 .ckeditor-toolbar {
   border: 1px solid #b6b6b6;
   padding: 0.1667em 0.1667em 0.08em;
diff --git a/core/modules/image/css/editors/image.theme.css b/core/modules/image/css/editors/image.theme.css
index cb0c7f9..5016365 100644
--- a/core/modules/image/css/editors/image.theme.css
+++ b/core/modules/image/css/editors/image.theme.css
@@ -50,11 +50,13 @@
   border-color: white transparent transparent transparent;
 }
 
+/* stylelint-disable block-closing-brace-newline-before, block-opening-brace-newline-after */
 @keyframes quickedit-image-spin {
   0% {transform: rotate(0deg);}
   50% {transform: rotate(180deg);}
   100% {transform: rotate(360deg);}
 }
+/* stylelint-enable */
 
 .quickedit-image-text {
   text-align: center;
diff --git a/core/modules/outside_in/css/offcanvas.css b/core/modules/outside_in/css/offcanvas.css
index fb671db..7e3b168 100644
--- a/core/modules/outside_in/css/offcanvas.css
+++ b/core/modules/outside_in/css/offcanvas.css
@@ -6,18 +6,18 @@
  */
 /* Position the dialog-offcanvas tray container outside the right of the viewport. */
 .ui-dialog-offcanvas {
-    box-sizing: border-box;
-    height: 100%;
-    overflow: visible;
+  box-sizing: border-box;
+  height: 100%;
+  overflow: visible;
 }
 
 /* Wrap the form that's inside the dialog-offcanvas tray. */
 .ui-dialog-offcanvas .ui-dialog-content {
-    padding: 0 20px;
-    /* Prevent horizontal scrollbar. */
-    overflow-x: hidden;
-    overflow-y: auto;
+  padding: 0 20px;
+  /* Prevent horizontal scrollbar. */
+  overflow-x: hidden;
+  overflow-y: auto;
 }
 [dir="rtl"] .ui-dialog-offcanvas .ui-dialog-content {
-    text-align: right;
+  text-align: right;
 }
diff --git a/core/modules/outside_in/css/offcanvas.motion.css b/core/modules/outside_in/css/offcanvas.motion.css
index 1c06994..5bec16b 100644
--- a/core/modules/outside_in/css/offcanvas.motion.css
+++ b/core/modules/outside_in/css/offcanvas.motion.css
@@ -12,17 +12,17 @@
 
 /* Transition the dialog-offcanvas tray container, with 2s delay to match main canvas speed. */
 .ui-dialog-offcanvas .ui-dialog-content {
-    -webkit-transition: all .7s ease 2s;
-    -moz-transition: all .7s ease 2s;
-    transition: all .7s ease 2s;
+  -webkit-transition: all .7s ease 2s;
+  -moz-transition: all .7s ease 2s;
+  transition: all .7s ease 2s;
 }
 
 @media (max-width: 700px) {
-    .ui-dialog-offcanvas .ui-dialog-content {
-        -webkit-transition: all .7s ease;
-        -moz-transition: all .7s ease;
-        transition: all .7s ease;
-    }
+  .ui-dialog-offcanvas .ui-dialog-content {
+    -webkit-transition: all .7s ease;
+    -moz-transition: all .7s ease;
+    transition: all .7s ease;
+  }
 }
 
 .dialog-offcanvas__main-canvas {
diff --git a/core/modules/outside_in/css/outside_in.toolbar.css b/core/modules/outside_in/css/outside_in.toolbar.css
index 3f7e044..a199841 100644
--- a/core/modules/outside_in/css/outside_in.toolbar.css
+++ b/core/modules/outside_in/css/outside_in.toolbar.css
@@ -62,9 +62,9 @@ button.toolbar-icon.toolbar-icon-edit.toolbar-item:before:focus {
 }
 
 #toolbar-bar.js-outside-in-edit-mode button.toolbar-icon.toolbar-icon-edit.toolbar-item.is-active {
- background-image: none;
- color: #fff;
+  background-image: none;
+  color: #fff;
 }
 #toolbar-bar.js-outside-in-edit-mode button.toolbar-icon.toolbar-icon-edit.toolbar-item.is-active:hover {
- background-image: linear-gradient(to bottom, #0094f0, #0e69be);
+  background-image: linear-gradient(to bottom, #0094f0, #0e69be);
 }
diff --git a/core/modules/quickedit/css/quickedit.theme.css b/core/modules/quickedit/css/quickedit.theme.css
index 399db7a..db233c8 100644
--- a/core/modules/quickedit/css/quickedit.theme.css
+++ b/core/modules/quickedit/css/quickedit.theme.css
@@ -174,9 +174,9 @@
   padding: 0.1667em 0.2em;
 }
 
- /**
-  * Info toolgroup.
-  */
+/**
+ * Info toolgroup.
+ */
 .quickedit-toolbar-fullwidth {
   width: 100%;
 }
diff --git a/core/modules/system/css/system.admin.css b/core/modules/system/css/system.admin.css
index 913ce57..8d276f8 100644
--- a/core/modules/system/css/system.admin.css
+++ b/core/modules/system/css/system.admin.css
@@ -211,7 +211,7 @@ small .admin-link:after {
   background-color: transparent;
 }
 [dir="rtl"] .system-status-report__status-title {
-    padding: 10px 40px 10px 6px;
+  padding: 10px 40px 10px 6px;
 }
 .system-status-report__status-icon:before {
   content: "";
diff --git a/core/modules/views_ui/css/views_ui.admin.theme.css b/core/modules/views_ui/css/views_ui.admin.theme.css
index 460e75e..3aabe1f 100644
--- a/core/modules/views_ui/css/views_ui.admin.theme.css
+++ b/core/modules/views_ui/css/views_ui.admin.theme.css
@@ -158,7 +158,7 @@ details.box-padding {
 
 /* Hide 'remove' checkboxes. */
 .views-remove-checkbox {
-    display: none;
+  display: none;
 }
 
 /* sizes the labels of checkboxes and radio button to the height of the text */
diff --git a/core/themes/bartik/color/preview.css b/core/themes/bartik/color/preview.css
index ac561d3..48c124e 100644
--- a/core/themes/bartik/color/preview.css
+++ b/core/themes/bartik/color/preview.css
@@ -78,7 +78,7 @@
 }
 [dir="rtl"] .color-preview-sidebar,
 [dir="rtl"] .color-preview-content {
-    float: right;
+  float: right;
 }
 .color-preview-sidebar {
   margin-left: 15px; /* LTR */
diff --git a/core/themes/bartik/css/components/header.css b/core/themes/bartik/css/components/header.css
index 40ea0f0..7c7b8e5 100644
--- a/core/themes/bartik/css/components/header.css
+++ b/core/themes/bartik/css/components/header.css
@@ -21,7 +21,6 @@
   }
   .region-header .site-branding {
     float: left; /* LTR */
-   /* margin-bottom: 1.857em;*/
   }
   [dir="rtl"] .region-header .site-branding {
     float: right;
diff --git a/core/themes/classy/css/components/form.css b/core/themes/classy/css/components/form.css
index 15b8ec2..a3fd9d6 100644
--- a/core/themes/classy/css/components/form.css
+++ b/core/themes/classy/css/components/form.css
@@ -64,8 +64,8 @@ label.option {
 }
 [dir="rtl"] .form-type-radio .description,
 [dir="rtl"] .form-type-checkbox .description {
-   margin-left: 0;
-   margin-right: 2.4em;
+  margin-left: 0;
+  margin-right: 2.4em;
 }
 .marker {
   color: #e00;
diff --git a/core/themes/classy/css/components/progress.css b/core/themes/classy/css/components/progress.css
index 1fb80a6..476e4fd 100644
--- a/core/themes/classy/css/components/progress.css
+++ b/core/themes/classy/css/components/progress.css
@@ -18,26 +18,12 @@
   background: #057ec9;
   background-image:
     -webkit-linear-gradient( top, rgba(0, 0, 0, 0), rgba(0, 0, 0, 0.15) ),
-    -webkit-linear-gradient( left top,
-      #0094f0 0%,
-      #0094f0 25%,
-      #007ecc 25%,
-      #007ecc 50%,
-      #0094f0 50%,
-      #0094f0 75%,
-      #0094f0 100% );
+    -webkit-linear-gradient( left top, #0094f0 0%, #0094f0 25%, #007ecc 25%, #007ecc 50%, #0094f0 50%, #0094f0 75%, #0094f0 100% );
   background-image:
     -webkit-linear-gradient(top, rgba(0, 0, 0, 0), rgba(0, 0, 0, 0.15)), -webkit-linear-gradient(left top, #0094f0 0%, #0094f0 25%, #007ecc 25%, #007ecc 50%, #0094f0 50%, #0094f0 75%, #0094f0 100%);
   background-image:
     linear-gradient( to bottom, rgba(0, 0, 0, 0), rgba(0, 0, 0, 0.15) ),
-    linear-gradient( to right bottom,
-      #0094f0 0%,
-      #0094f0 25%,
-      #007ecc 25%,
-      #007ecc 50%,
-      #0094f0 50%,
-      #0094f0 75%,
-      #0094f0 100% );
+    linear-gradient( to right bottom, #0094f0 0%, #0094f0 25%, #007ecc 25%, #007ecc 50%, #0094f0 50%, #0094f0 75%, #0094f0 100% );
   background-size: 40px 40px;
   margin-top: -1px;
   margin-left: -1px; /* LTR */
@@ -60,6 +46,7 @@
 /**
  * Progress bar animations.
  */
+/* stylelint-disable block-closing-brace-newline-before, block-opening-brace-newline-after */
 @-webkit-keyframes animate-stripes {
   0% {background-position: 0 0, 0 0;} 100% {background-position: 0 0, -80px 0;}
 }
@@ -69,3 +56,4 @@
 @keyframes animate-stripes {
   0% {background-position: 0 0, 0 0;} 100% {background-position: 0 0, -80px 0;}
 }
+/* stylelint-enable */
diff --git a/core/themes/seven/css/components/entity-meta.css b/core/themes/seven/css/components/entity-meta.css
index 9877ec3..701e8dc 100644
--- a/core/themes/seven/css/components/entity-meta.css
+++ b/core/themes/seven/css/components/entity-meta.css
@@ -55,5 +55,5 @@
   text-shadow: 0 1px 0 white;
 }
 .entity-meta details .summary {
- display: none; /* Hide JS summaries. @todo Rethink summaries. */
+  display: none; /* Hide JS summaries. @todo Rethink summaries. */
 }
diff --git a/core/themes/seven/css/components/form.css b/core/themes/seven/css/components/form.css
index f3acc2c..fa644c0 100644
--- a/core/themes/seven/css/components/form.css
+++ b/core/themes/seven/css/components/form.css
@@ -255,7 +255,7 @@ select {
   select:focus,
   select:hover {
     background-image: url(../../../../misc/icons/333333/caret-down.svg),
-    -webkit-linear-gradient(top, #fcfcfa, #e9e9dd);
+      -webkit-linear-gradient(top, #fcfcfa, #e9e9dd);
     color: #1a1a1a;
   }
   select:hover {
diff --git a/core/themes/seven/css/components/jquery.ui/theme.css b/core/themes/seven/css/components/jquery.ui/theme.css
index dd81ec2..9bf07a7 100644
--- a/core/themes/seven/css/components/jquery.ui/theme.css
+++ b/core/themes/seven/css/components/jquery.ui/theme.css
@@ -91,6 +91,7 @@
   margin: 2px 0 0 3px;
 }
 /* positioning */
+/* stylelint-disable block-closing-brace-newline-before, block-opening-brace-newline-after */
 .ui-icon-carat-1-ne { background-position: -16px 0; }
 .ui-icon-carat-1-e { background-position: -32px 0; }
 .ui-icon-carat-1-se { background-position: -48px 0; }
@@ -264,7 +265,7 @@
 .ui-icon-gripsmall-diagonal-se { background-position: -64px -224px; }
 .ui-icon-grip-diagonal-se { background-position: -80px -224px; }
 .ui-icon-carat-1-n { background-position: 0 0; }
-
+/* stylelint-enable */
 /**
  * Accordion
  */
diff --git a/core/themes/seven/css/components/system-status-report.css b/core/themes/seven/css/components/system-status-report.css
index bfcd75c..7869fbd 100644
--- a/core/themes/seven/css/components/system-status-report.css
+++ b/core/themes/seven/css/components/system-status-report.css
@@ -22,7 +22,7 @@
 .system-status-report__entry--warning {
   background-color: transparent;
 }
-  /* Account for native and poly-filled details element */
+/* Account for native and poly-filled details element */
 .system-status-report__status-title {
   position: relative;
   padding: 1em 1em 1em 3em; /* LTR */
diff --git a/core/themes/seven/css/components/tabs.css b/core/themes/seven/css/components/tabs.css
index 28401b4..eff2773 100644
--- a/core/themes/seven/css/components/tabs.css
+++ b/core/themes/seven/css/components/tabs.css
@@ -123,7 +123,7 @@ li.tabs__tab a {
 }
 
 /* JS dependent styling */
- .is-collapse-enabled .tabs__trigger {
+.is-collapse-enabled .tabs__trigger {
   box-sizing: content-box;
   display: block;
   position: absolute;
diff --git a/core/themes/seven/css/components/views-ui.css b/core/themes/seven/css/components/views-ui.css
index 6849781..7278125 100644
--- a/core/themes/seven/css/components/views-ui.css
+++ b/core/themes/seven/css/components/views-ui.css
@@ -169,7 +169,7 @@ details.fieldset-no-legend {
  */
 
 .views-displays .secondary {
- text-align: left; /* LTR */
+  text-align: left; /* LTR */
 }
 [dir="rtl"] .views-displays .secondary {
   text-align: right;
diff --git a/core/themes/stable/css/ckeditor/ckeditor.admin.css b/core/themes/stable/css/ckeditor/ckeditor.admin.css
index 8b771c7..82b6c53 100644
--- a/core/themes/stable/css/ckeditor/ckeditor.admin.css
+++ b/core/themes/stable/css/ckeditor/ckeditor.admin.css
@@ -6,8 +6,6 @@
  * "moono".
  */
 
-
-
 .ckeditor-toolbar {
   border: 1px solid #b6b6b6;
   padding: 0.1667em 0.1667em 0.08em;
diff --git a/core/themes/stable/css/core/vertical-tabs.css b/core/themes/stable/css/core/vertical-tabs.css
index ec5d3c1..fc83da5 100644
--- a/core/themes/stable/css/core/vertical-tabs.css
+++ b/core/themes/stable/css/core/vertical-tabs.css
@@ -8,8 +8,8 @@
   border: 1px solid #ccc;
 }
 [dir="rtl"] .vertical-tabs {
-   margin-left: 0;
-   margin-right: 15em;
+  margin-left: 0;
+  margin-right: 15em;
 }
 .vertical-tabs__menu {
   float: left; /* LTR */
diff --git a/core/themes/stable/css/image/editors/image.theme.css b/core/themes/stable/css/image/editors/image.theme.css
index 5520758..549a56f 100644
--- a/core/themes/stable/css/image/editors/image.theme.css
+++ b/core/themes/stable/css/image/editors/image.theme.css
@@ -50,11 +50,13 @@
   border-color: white transparent transparent transparent;
 }
 
+/* stylelint-disable block-closing-brace-newline-before, block-opening-brace-newline-after */
 @keyframes quickedit-image-spin {
   0% {transform: rotate(0deg);}
   50% {transform: rotate(180deg);}
   100% {transform: rotate(360deg);}
 }
+/* stylelint-enable */
 
 .quickedit-image-text {
   text-align: center;
diff --git a/core/themes/stable/css/quickedit/quickedit.theme.css b/core/themes/stable/css/quickedit/quickedit.theme.css
index 399db7a..db233c8 100644
--- a/core/themes/stable/css/quickedit/quickedit.theme.css
+++ b/core/themes/stable/css/quickedit/quickedit.theme.css
@@ -174,9 +174,9 @@
   padding: 0.1667em 0.2em;
 }
 
- /**
-  * Info toolgroup.
-  */
+/**
+ * Info toolgroup.
+ */
 .quickedit-toolbar-fullwidth {
   width: 100%;
 }
diff --git a/core/themes/stable/css/system/system.admin.css b/core/themes/stable/css/system/system.admin.css
index cd92b1a..1919732 100644
--- a/core/themes/stable/css/system/system.admin.css
+++ b/core/themes/stable/css/system/system.admin.css
@@ -211,7 +211,7 @@ small .admin-link:after {
   background-color: transparent;
 }
 [dir="rtl"] .system-status-report__status-title {
-    padding: 10px 40px 10px 6px;
+  padding: 10px 40px 10px 6px;
 }
 .system-status-report__status-icon:before {
   content: "";
diff --git a/core/themes/stable/css/views_ui/views_ui.admin.theme.css b/core/themes/stable/css/views_ui/views_ui.admin.theme.css
index e4ac1e4..a5f86d8 100644
--- a/core/themes/stable/css/views_ui/views_ui.admin.theme.css
+++ b/core/themes/stable/css/views_ui/views_ui.admin.theme.css
@@ -158,7 +158,7 @@ details.box-padding {
 
 /* Hide 'remove' checkboxes. */
 .views-remove-checkbox {
-    display: none;
+  display: none;
 }
 
 /* sizes the labels of checkboxes and radio button to the height of the text */