feat(ui): enable username background and update member list styling

Uncomment and refine CSS for username backgrounds in headers and member lists, including opacity and positioning adjustments. Remove timestamp opacity transitions for cleaner UI.

Author: sang765

themes/main.css

@@ -301,37 +301,6 @@ button.button__67645 {
 [class^=appMount_] [class^=layers_] [class^=layer_]:has([class^=standardSidebarView_]) {
     border: 1px solid hsl(var(--accent-hsl));
 }
-/* Username Background */
-/***
-.headerText_c19a55:not(:has(.roleDot_c19a55)) .username_c19a55::before {
-    content: '';
-    inline-size: calc(100% + 0px);
-    block-size: 100%;
-    border-radius: 5px;
-    background-color: currentColor;
-    opacity: 0.3;
-    position: absolute;
-    margin-block-start: 1px;
-    z-index: -1;
-    margin-inline-start: -3px;
-}
-.headerText_c19a55:has(.roleDot_c19a55) .username_c19a55::before {
-    content: '';
-    inline-size: calc(100% + 29px);
-    block-size: 100%;
-    border-radius: 5px;
-    background-color: currentColor;
-    opacity: 0.3;
-    position: absolute;
-    margin-block-start: 1px;
-    padding: 1;
-    z-index: -1;
-    margin-inline-start: -27px;
-}
-.headerText_c19a55>span {
-    margin-inline-start: 3px;
-}
-***/
 /* Jump To Present Bar Revamp */
 [class*="jumpToPresentBar"] {
     display: contents;
@@ -530,26 +499,33 @@ button.button__67645 {
     -webkit-animation: fadeIn 0.5s ease forwards;
     animation: fadeIn 0.5s ease forwards;
 }
+/* Username Background */
+.headerText_c19a55 .username_c19a55:not([style^="--custom-gradient-color"])::before {
+    content: '';
+    inline-size: calc(100% + 0px);
+    block-size: 100%;
+    border-radius: 5px;
+    background-color: currentColor;
+    opacity: 0.3;
+    position: absolute;
+    z-index: -1;
+}
 /*Role color background in memberlist*/
-.member__5d473 span.username__703b9::after {
+.member__5d473:not(:has([style^="--custom-gradient-color"])) span.username__703b9::after {
     content: "";
-    border-radius: 10px;
+    border-radius: 5px;
     background: currentColor;
-    min-width: 243px;
-    inline-size: 100%;
+    inline-size: calc(100% + 0px);
     block-size: 100%;
     position: absolute;
-    opacity: 0.11;
-    inset-inline-start: -9px;
+    opacity: 0.3;
+    inset-inline-start: 0px;
     inset-block-start: 0;
     transition: opacity .2s ease;
 }
 .member__5d473 {
     border-radius: 10px;
 }
-.member__5d473:hover span.username__703b9::after {
-    opacity: 0.3;
-}
 /*Remove the Avatar Decorations Banner in user profile popups*/
 .containerWrapper_e18107 {
     display: none
@@ -693,16 +669,6 @@ h3.name__29444.container_cc72c1 {
 .wrapper_c19a55.cozy_c19a55 {
     transition: ease-in-out 0.25s;
 }
-[class*=timestampInline_] {
-    opacity: 0;
-    transition: 0.25s;
-}
-[class*=message_]:hover [class*=timestampInline_],
-[class*=messageGroupWrapper_]:hover [class*=timestampInline_],
-[class*=messageContainer_]:hover [class*=timestampInline_],
-[class*=message_]:hover [class*=timestampInline_] {
-    opacity: 1;
-}
 /* Anti Image Like Video */
 div[class="iconWrapper__6eb54"] {
     background-color: hsla(var(--accent-hsl), 0.45);