diff --git a/assets/theme-css/code-highlight.css b/assets/theme-css/code-highlight.css
index 818b3272..f9d8513c 100644
--- a/assets/theme-css/code-highlight.css
+++ b/assets/theme-css/code-highlight.css
@@ -306,7 +306,6 @@ html[data-theme="light"] {
   /* LineNumbersTable */
   .chroma .lnt {
     white-space: pre;
-    -webkit-user-select: none;
     user-select: none;
     margin-right: 0.4em;
     padding: 0 0.4em 0 0.4em;
@@ -315,7 +314,6 @@ html[data-theme="light"] {
   /* LineNumbers */
   .chroma .ln {
     white-space: pre;
-    -webkit-user-select: none;
     user-select: none;
     margin-right: 0.4em;
     padding: 0 0.4em 0 0.4em;
diff --git a/assets/theme-css/navbar.css b/assets/theme-css/navbar.css
index aa14aaf9..4650f5f3 100644
--- a/assets/theme-css/navbar.css
+++ b/assets/theme-css/navbar.css
@@ -54,8 +54,6 @@ a.navbar-item.nav-external::after,
   font-family: inherit;
   font-size: 1em;
   padding: 0;
-  -moz-appearance: none;
-  -webkit-appearance: none;
   appearance: none;
   background: 0 0;
   border: none;
diff --git a/assets/theme-css/sphinx-design/_button.scss b/assets/theme-css/sphinx-design/_button.scss
index f2cee5fb..98484261 100644
--- a/assets/theme-css/sphinx-design/_button.scss
+++ b/assets/theme-css/sphinx-design/_button.scss
@@ -23,9 +23,6 @@
     box-shadow 0.15s ease-in-out;
   vertical-align: middle;
   user-select: none;
-  -moz-user-select: none;
-  -ms-user-select: none;
-  -webkit-user-select: none;
 
   &:hover {
     text-decoration: none;
diff --git a/assets/theme-css/sphinx-design/_cards.scss b/assets/theme-css/sphinx-design/_cards.scss
index c4134b46..b8d52f7c 100644
--- a/assets/theme-css/sphinx-design/_cards.scss
+++ b/assets/theme-css/sphinx-design/_cards.scss
@@ -10,9 +10,7 @@
   border: 1px solid var(--sd-color-card-border);
   border-radius: 0.25rem;
   color: var(--sd-color-card-text);
-  display: -ms-flexbox;
   display: flex;
-  -ms-flex-direction: column;
   flex-direction: column;
   min-width: 0;
   position: relative;
@@ -30,7 +28,6 @@
 }
 
 .sd-card-body {
-  -ms-flex: 1 1 auto;
   flex: 1 1 auto;
   padding: 1rem 1rem;
 }
@@ -125,7 +122,6 @@
   width: 100%;
   display: flex;
   flex-wrap: nowrap;
-  -ms-flex-direction: row;
   flex-direction: row;
   overflow-x: hidden;
   scroll-snap-type: x mandatory;