Merge branch '5.3'

diff --cc wcfsetup/install/files/style/ui/reactions.scss
index 9be1530dfd7128ab637dcde03aa7ecfdb17ae46a,e09490111a6b12a387c178a59e4ea8cb0ef86b4c..12ae8bec60d4cd927a475037ebebf5ed92a0abed
--- 1/wcfsetup/install/files/style/ui/reactions.scss
--- 2/wcfsetup/install/files/style/ui/reactions.scss
+++ b/wcfsetup/install/files/style/ui/reactions.scss
@@@ -106,19 -106,19 +106,19 @@@
                        pointer-events: none;
                        position: absolute;
                        right: 0;
 -                      transition: opacity .12s linear;
 +                      transition: opacity 0.12s linear;
                }
 -              
 +
                &::after {
-                       background-image: linear-gradient(to bottom, transparent, $wcfContentBackground);
+                       background-image: linear-gradient(to bottom, transparentize($wcfContentBackground, 100%), $wcfContentBackground);
                        bottom: 0;
                }
                &.overflowBottom::after {
                        opacity: 1;
                }
 -              
 +
                &::before {
-                       background-image: linear-gradient(to top, transparent, $wcfContentBackground);
+                       background-image: linear-gradient(to top, transparentize($wcfContentBackground, 100%), $wcfContentBackground);
                        top: 0;
                }
                &.overflowTop::before {