Optimize comment input section on markdown page on mobile

ui/scss/component/_comment-create.scss

@@ -112,6 +112,23 @@ $thumbnailWidthSmall: 1rem;
     }
   }
 
+  @media (max-width: $breakpoint-small) {
+    .MuiTextField-root {
+      .button--primary {
+        .button__content {
+          .icon {
+            stroke: var(--color-primary-contrast);
+            margin-left: 1px;
+            margin-right: -1px;
+          }
+        }
+      }
+      textarea#create__comment {
+        box-shadow: unset;
+      }
+    }
+  }
+
   @media (min-width: $breakpoint-small) {
     fieldset-section + .section {
       margin-top: var(--spacing-m);

ui/scss/component/_main.scss

@@ -199,6 +199,29 @@ body {
     @media (min-width: $breakpoint-small) {
       padding: var(--spacing-m);
     }
+
+    @media (max-width: $breakpoint-small) {
+      margin-top: 0;
+      .card {
+        padding: 0;
+        .card__first-pane {
+          .card__main-actions {
+            .button--alt:last-of-type {
+              top: -1px;
+              float: right;
+              margin-right: 0;
+            }
+            .comment__sort {
+              .button--alt:last-of-type {
+                top: unset;
+                float: unset;
+                margin-right: unset;
+              }
+            }
+          }
+        }
+      }
+    }
   }
 
   .file-page__info {

ui/scss/init/_gui.scss

@@ -1052,6 +1052,11 @@ img {
   }
 }
 
+// Remove resize icon in textareas
+::-webkit-resizer {
+  display: none;
+}
+
 // Remove tap focus on mobile devices
 input,
 textarea,