diff --git a/app/code/Magento/Checkout/view/frontend/web/template/authentication.html b/app/code/Magento/Checkout/view/frontend/web/template/authentication.html
index 6c59936d60504f56b80a9bbd0f57e3121f8d1f2e..f6a1e6e73a2bfcdb356a85b00747775a7d094ed4 100644
--- a/app/code/Magento/Checkout/view/frontend/web/template/authentication.html
+++ b/app/code/Magento/Checkout/view/frontend/web/template/authentication.html
@@ -7,7 +7,7 @@
 <div class="authentication-wrapper" data-block="authentication" data-bind="visible: isActive()">
     <button
         type="button"
-        class="action-auth-toggle"
+        class="action action-auth-toggle"
         data-trigger="authentication">
         <span data-bind="text: $t('Sign In')"></span>
     </button>
diff --git a/app/code/Magento/Checkout/view/frontend/web/template/onepage.html b/app/code/Magento/Checkout/view/frontend/web/template/onepage.html
index 3a2622ab629b0c90ee8feb871f9707a2b3335a7e..51b80426e5dd4a8fc930916241602f4d28da9681 100644
--- a/app/code/Magento/Checkout/view/frontend/web/template/onepage.html
+++ b/app/code/Magento/Checkout/view/frontend/web/template/onepage.html
@@ -20,7 +20,7 @@
         <span class="estimated-price">$100.00</span>
     </div>
     <div class="minicart-wrapper">
-        <button type="button" class="action showcart action-showcart" data-toggle="opc-summary">
+        <button type="button" class="action showcart" data-toggle="opc-summary">
             <span class="counter qty">
                 <span class="counter-number">6</span>
             </span>
@@ -29,7 +29,7 @@
     <!-- Temp MAGETWO-36025 markup
     <button
         type="button"
-        class="action showcart action-showcart"
+        class="action showcart"
         data-toggle="opc-summary">
         <span data-bind="text: $t('View order summary')"></span>
     </button>-->
diff --git a/app/design/frontend/Magento/blank/Magento_Checkout/web/css/source/module/checkout/_authentication.less b/app/design/frontend/Magento/blank/Magento_Checkout/web/css/source/module/checkout/_authentication.less
index de193cdab2dfa30fb3e37f6cde3475642dd316ce..26c1ac83c04217bc2ad84483a5ec3b608cecf4ae 100644
--- a/app/design/frontend/Magento/blank/Magento_Checkout/web/css/source/module/checkout/_authentication.less
+++ b/app/design/frontend/Magento/blank/Magento_Checkout/web/css/source/module/checkout/_authentication.less
@@ -53,7 +53,7 @@
         }
         .actions-toolbar {
             margin-bottom: @indent__xs;
-            & > .secondary {
+            > .secondary {
                 padding-top: @indent__m;
                 text-align: left;
             }
@@ -87,7 +87,7 @@
                     .css(min-width, @block-auth__or-label__size);
                     background: @color-white;
                     border-radius: 50%;
-                    border: .1rem solid @color-gray-light5;
+                    border: 1px solid @color-gray-light5;
                     box-sizing: border-box;
                     color: @color-gray-light5;
                     content: attr(data-label);
@@ -117,12 +117,15 @@
         text-align: left;
         top: 100%;
         transform-origin: 0 0;
-        transform:  scale(1,0);
-        transition: transform linear .1s;
+        transform: scale(1,0);
+        transition: transform linear .1s, visibility 0s linear .1s;
+        visibility: hidden;
         width: 100%;
         &._show {
             .css(z-index, @dropdown-list__z-index);
-            transform:  scale(1,1);
+            transform: scale(1,1);
+            transition: transform linear .1s, visibility 0s linear 0s;
+            visibility: visible;
         }
     }
     .authentication-wrapper {
@@ -136,7 +139,7 @@
             margin-bottom: @indent__m;
         }
         .actions-toolbar {
-            & > .primary {
+            > .primary {
                 display: inline;
                 float: right;
                 margin-right: 0;
@@ -144,7 +147,7 @@
                     margin-right: 0;
                 }
             }
-            & > .secondary {
+            > .secondary {
                 float: left;
                 margin-right: 2rem;
                 padding-top: 1rem;
diff --git a/app/design/frontend/Magento/blank/Magento_Checkout/web/css/source/module/checkout/_order-summary.less b/app/design/frontend/Magento/blank/Magento_Checkout/web/css/source/module/checkout/_order-summary.less
index a38d9c6903325d31ae68911d3003330ca7f06f10..0cc46910745bc2c366c049f1fa689ca0c6a7c0e5 100644
--- a/app/design/frontend/Magento/blank/Magento_Checkout/web/css/source/module/checkout/_order-summary.less
+++ b/app/design/frontend/Magento/blank/Magento_Checkout/web/css/source/module/checkout/_order-summary.less
@@ -157,8 +157,9 @@
 }
 
 //
-//    Desktop
-//--------------------------------------
+//  Desktop
+//  _____________________________________________
+
 .media-width(@extremum, @break) when (@extremum = 'min') and (@break = @screen__m) {
     .opc-summary-wrapper {
         .modal-header {
diff --git a/app/design/frontend/Magento/luma/Magento_Checkout/web/css/source/module/checkout/_estimated-total.less b/app/design/frontend/Magento/luma/Magento_Checkout/web/css/source/module/checkout/_estimated-total.less
index b6414bdc53e461a8acc70b564e6bb3f43eab5f82..ef38e6bf14b181f0df82d36c63e47b7bbd9179ce 100644
--- a/app/design/frontend/Magento/luma/Magento_Checkout/web/css/source/module/checkout/_estimated-total.less
+++ b/app/design/frontend/Magento/luma/Magento_Checkout/web/css/source/module/checkout/_estimated-total.less
@@ -34,10 +34,12 @@
         }
 
         .minicart-wrapper {
-            .action-showcart {
-                .button-reset();
-                &:before {
-                    .css(color, @primary__color);
+            button {
+                &.action.showcart {
+                    .button-reset();
+                    &:before {
+                        .css(color, @primary__color);
+                    }
                 }
             }
         }
diff --git a/lib/web/css/source/components/_modals.less b/lib/web/css/source/components/_modals.less
index 95b777e245be442bc97819c01ee56b1fdf1215af..c19a66131c9b3957ce5461cd88f737e6dc691db7 100644
--- a/lib/web/css/source/components/_modals.less
+++ b/lib/web/css/source/components/_modals.less
@@ -105,10 +105,12 @@
 
 //
 
-body._has-modal {
-    width: 100%;
-    height: 100%;
-    overflow: hidden;
+body {
+    &._has-modal {
+        height: 100%;
+        overflow: hidden;
+        width: 100%;
+    }
 }
 
 // Modals overlay