diff --git a/core/modules/system/css/system.admin.css b/core/modules/system/css/system.admin.css
index 3eeb445..dc31d95 100644
--- a/core/modules/system/css/system.admin.css
+++ b/core/modules/system/css/system.admin.css
@@ -132,7 +132,7 @@ small .admin-link:after {
   cursor: default;
 }
 .system-modules td {
-  padding-left: 0;
+  padding-left: 0; /* LTR */
 }
 
 @media screen and (max-width: 40em) {
@@ -370,5 +370,8 @@ small .admin-link:after {
   padding: 0 0 0 0.7em;
 }
 .system-themes-admin-form {
-  clear: left;
+  clear: left; /* LTR */
+}
+[dir="rtl"] .system-themes-admin-form {
+  clear: right;
 }
diff --git a/core/modules/system/css/system.diff.css b/core/modules/system/css/system.diff.css
index 251ff57..0f123cd 100644
--- a/core/modules/system/css/system.diff.css
+++ b/core/modules/system/css/system.diff.css
@@ -14,7 +14,12 @@
 
 .diff-inline-legend span,
 .diff-inline-legend label {
-  margin-right:5px;
+  margin-right:5px; /* LTR */
+}
+[dir="rtl"] .diff-inline-legend span,
+[dir="rtl"] .diff-inline-legend label {
+  margin-left: 5px;
+  margin-right: 0;
 }
 
 /**
@@ -53,10 +58,16 @@ table.diff .even, table.diff .odd {
   border: none;
 }
 table.diff .diff-prevlink {
-  text-align: left;
+  text-align: left; /* LTR */
+}
+[dir="rtl"] table.diff .diff-prevlink {
+   text-align: right;
 }
 table.diff .diff-nextlink {
-  text-align: right;
+  text-align: right; /* LTR */
+}
+[dir="rtl"] table.diff .diff-nextlink {
+  text-align: left;
 }
 table.diff .diff-section-title,
 table.diff  .diff-section-title {
@@ -88,7 +99,11 @@ table.diff .diff-content {
   width: 50%;
 }
 table.diff th {
-  padding-right: inherit;
+  padding-right: inherit; /* LTR */
+}
+[dir="rtl"] table.diff th {
+  padding-right: 0;
+  padding-left: inherit;
 }
 table.diff td div {
   overflow: auto;
diff --git a/core/modules/system/css/system.maintenance.css b/core/modules/system/css/system.maintenance.css
index b6456c6..8b142cc 100644
--- a/core/modules/system/css/system.maintenance.css
+++ b/core/modules/system/css/system.maintenance.css
@@ -41,7 +41,11 @@
 }
 
 #edit-connection-settings-change-connection-type {
-  margin: 2.6em 0.5em 0 1em;
+  margin: 2.6em 0.5em 0 1em; /* LTR */
+}
+[dir="rtl"] #edit-connection-settings-change-connection-type {
+  margin-left: 0.5em;
+  margin-right: 1em;
 }
 
 /**
diff --git a/core/modules/system/css/system.module.css b/core/modules/system/css/system.module.css
index b38c5e5..db2d032 100644
--- a/core/modules/system/css/system.module.css
+++ b/core/modules/system/css/system.module.css
@@ -128,9 +128,12 @@ a.tabledrag-handle:focus .handle {
   width: 40px;
 }
 .touch a.tabledrag-handle .handle {
-  background-position: 40% 19px;
+  background-position: 40% 19px; /* LTR */
   height: 21px;
 }
+[dir="rtl"] .touch a.tabledrag-handle .handle {
+  background-position: right 40% top 19px;
+}
 .touch .draggable.drag a.tabledrag-handle .handle {
   background-position: 50% -32px;
 }
@@ -254,7 +257,7 @@ tr .ajax-progress-throbber .throbber {
 /* Full screen  throbber */
 .ajax-progress-fullscreen {
   /* Can't do center:50% middle: 50%, so approximate it for a typical window size. */
-  left: 49%;
+  left: 49%; /* LTR */
   position: fixed;
   top: 48.5%;
   z-index: 1000;
@@ -268,6 +271,10 @@ tr .ajax-progress-throbber .throbber {
   padding: 4px;
   width: 24px;
 }
+[dir="rtl"] .ajax-progress-fullscreen {
+  left: auto;
+  right: 49%;
+}
 
 /**
  * Inline items.
diff --git a/core/modules/system/css/system.theme.css b/core/modules/system/css/system.theme.css
index f7af1e4..9803fdc 100644
--- a/core/modules/system/css/system.theme.css
+++ b/core/modules/system/css/system.theme.css
@@ -74,7 +74,12 @@ label.option {
 }
 .form-type-radio .description,
 .form-type-checkbox .description {
-  margin-left: 2.4em;
+  margin-left: 2.4em; /* LTR */
+}
+[dir="rtl"] .form-type-radio .description,
+[dir="rtl"] .form-type-checkbox .description {
+  margin-left: 0;
+  margin-right: 2.4em;
 }
 .marker {
   color: #e00;
@@ -220,7 +225,7 @@ summary {
 .collapse-processed > summary:before {
   background: url(../../../misc/menu-expanded.png) 0px 100% no-repeat; /* LTR */
   content: "";
-  float: left;
+  float: left; /* LTR */
   height: 1em;
   width: 1em;
 }
@@ -309,7 +314,7 @@ th.checkbox {
       #0094f0 100% );
   background-size: 40px 40px;
   margin-top: -1px;
-  margin-left: -1px;
+  margin-left: -1px; /* LTR */
   padding: 0 1px;
   height: 16px;
   border-radius: 10em;
@@ -318,6 +323,11 @@ th.checkbox {
   -webkit-transition: width 0.5s ease-out;
   transition: width 0.5s ease-out;
 }
+[dir="rtl"] .progress__bar {
+  margin-left: 0;
+  margin-right: -1px;
+  animation-direction: reverse;
+}
 
 /**
  * Progress bar animations.
@@ -371,7 +381,12 @@ ul.menu a.active {
 ul.inline,
 ul.links.inline {
   display: inline;
-  padding-left: 0;
+  padding-left: 0; /* LTR */
+}
+[dir="rtl"] ul.inline,
+[dir="rtl"] ul.links.inline {
+  padding-right: 0;
+  padding-left: 15px;
 }
 ul.inline li {
   display: inline;
@@ -592,6 +607,7 @@ form .field-multiple-table .field-multiple-drag .tabledrag-handle {
   padding-right: .5em; /*LTR*/
 }
 [dir="rtl"] form .field-multiple-table .field-multiple-drag .tabledrag-handle {
+  padding-right: 0;
   padding-left: .5em;
 }
 form .field-add-more-submit {