diff --git a/extensions/odoo_theme/static/scss/_mixins.scss b/extensions/odoo_theme/static/scss/_mixins.scss
index 1f5b6200b..d8d7b0ec9 100644
--- a/extensions/odoo_theme/static/scss/_mixins.scss
+++ b/extensions/odoo_theme/static/scss/_mixins.scss
@@ -13,40 +13,13 @@
     left: $left;
 }
 
-@mixin o-transform-origin($x: 50%, $y: 50%, $z: 0){
-    -ms-transform-origin: $x $y $z;
-    -webkit-transform-origin: $x $y $z;
-    -moz-transform-origin: $x $y $z;
-    transform-origin: $x $y $z;
-}
-
-@mixin o-transition($property: all, $duration: 0s, $timing-function: ease, $transition-delay: 0s){
-    -webkit-transition: $property $duration $timing-function $transition-delay;
-    -moz-transition: $property $duration $timing-function $transition-delay;
-    -o-transition: $property $duration $timing-function $transition-delay;
-    transition: $property $duration $timing-function $transition-delay;
-}
-
 // Backgrounds
 // ------------------------------------------------------------------
 
 @mixin o-gradient($deg: 99deg , $startColor: $secondary, $endColor: #62495B, $startOffset: 10%, $endOffset: 90%){
     background: mix($startColor, $endColor);
-    background: -webkit-linear-gradient($deg, $startColor $startOffset, $endColor $endOffset);
-    background: -moz-linear-gradient($deg, $startColor $startOffset, $endColor $endOffset);
-    background: -ms-linear-gradient($deg, $startColor $startOffset, $endColor $endOffset);
-    background: -o-linear-gradient($deg, $startColor $startOffset, $endColor $endOffset);
     background: linear-gradient($deg, $startColor $startOffset, $endColor $endOffset);
 }
-
-@mixin o-transform($args){
-  -webkit-transform : $args;
-  -moz-transform    : $args;
-  -ms-transform     : $args;
-  -o-transform      : $args;
-  transform         : $args;
-}
-
 //-- add icon
 
 @mixin o-inline-icon($margin, $v-align: middle, $font-size: 1.5rem, $font-weight: $font-weight-normal) {
@@ -82,12 +55,12 @@
             background-repeat: no-repeat;
             opacity: 0;
             visibility: hidden;
-            @include o-transition(all, .5s, ease-out, .5s);
+            transition: all .5s ease-out 5s;
         }
         &:hover:after {
                 opacity: 1;
                 visibility: visible;
-                @include o-transition(all, .5s, ease-in, 5s);
+                transition: all .5s ease-in 5s;
         }
 }
 
diff --git a/extensions/odoo_theme/static/style.scss b/extensions/odoo_theme/static/style.scss
index 98506d4e1..640c38e19 100644
--- a/extensions/odoo_theme/static/style.scss
+++ b/extensions/odoo_theme/static/style.scss
@@ -138,7 +138,7 @@ header {
 
                 .btn {
                     @include o-position-absolute($top: 50%, $right: .5rem);
-                    @include o-transform (translateY(-50%)) ;
+                    transform: translateY(-50%);
 
                     padding: 0 $o-padding-xs;
                     font-size: 1.2rem;
@@ -164,7 +164,7 @@ header {
 
                     &:before {
                         @include o-position-absolute($top: 50%, $right: 3rem);
-                        @include o-transform (translateY(-50%)) ;
+                        transform: translateY(-50%);
                         content: $i-close;
                         @include o-inline-icon(auto, middle, 1.2rem);
                     }
@@ -222,13 +222,13 @@ header {
         z-index: 10;
         width: 90%;
         height: calc(100% - #{$o-headers-mobile-height});
+        transition: all, .3s;
         overflow-y: auto;
         padding-left: $o-padding-s;
         background-color: lighten($secondary, 70%) ;
         color: $secondary;
         font-weight: $font-weight-normal;
 
-        @include o-transition(all, .3s);
         @include font-size($font-size-sm);
         @include media-breakpoint-up(lg) {
             width: $o-side-nav-width;
@@ -354,10 +354,10 @@ header {
                     > i[class^="i-"] {
                         display: inline-block;
                         margin-right: .125rem;
-                        @include o-transition(rotate, .3s);
+                        transition: rotate, .3s;
                         font-size: .75rem;
                         &[aria-expanded="true"] {
-                            @include o-transform(rotate(90deg));
+                            transform: rotate(90deg);
                         }
                     }
                 }
@@ -366,7 +366,7 @@ header {
             &.o_active_toc_entry {
                 &:not(.toctree-l1) > .o_toc_entry_wrapper {
                     i[class^="i-"]:not(.collapsed) {
-                        @include o-transform(rotate(90deg));
+                        transform: rotate(90deg);
                     }
                 }
                 > a , > .o_toc_entry_wrapper a, > .o_toc_entry_wrapper i {
@@ -796,7 +796,7 @@ header {
                         visibility: hidden;
                         color: $o-gray-light;
                         opacity: 0;
-                        @include o-transition(all, .1s)
+                        transition: all, .1s;
                     }
                 }