Change header backgrounds to use fewer different colors in web UI (#25577)

app/javascript/styles/mastodon/components.scss

@@ -3147,7 +3147,7 @@ $ui-header-height: 55px;
 .column-back-button {
   box-sizing: border-box;
   width: 100%;
-  background: lighten($ui-base-color, 4%);
+  background: $ui-base-color;
   border-radius: 4px 4px 0 0;
   color: $highlight-text-color;
   cursor: pointer;
@@ -3155,6 +3155,7 @@ $ui-header-height: 55px;
   font-size: 16px;
   line-height: inherit;
   border: 0;
+  border-bottom: 1px solid lighten($ui-base-color, 8%);
   text-align: unset;
   padding: 15px;
   margin: 0;
@@ -3167,7 +3168,7 @@ $ui-header-height: 55px;
 }
 
 .column-header__back-button {
-  background: lighten($ui-base-color, 4%);
+  background: $ui-base-color;
   border: 0;
   font-family: inherit;
   color: $highlight-text-color;
@@ -3202,7 +3203,7 @@ $ui-header-height: 55px;
   padding: 15px;
   position: absolute;
   inset-inline-end: 0;
-  top: -48px;
+  top: -50px;
 }
 
 .react-toggle {
@@ -3883,7 +3884,8 @@ a.status-card.compact:hover {
 .column-header {
   display: flex;
   font-size: 16px;
-  background: lighten($ui-base-color, 4%);
+  background: $ui-base-color;
+  border-bottom: 1px solid lighten($ui-base-color, 8%);
   border-radius: 4px 4px 0 0;
   flex: 0 0 auto;
   cursor: pointer;
@@ -3938,7 +3940,7 @@ a.status-card.compact:hover {
 }
 
 .column-header__button {
-  background: lighten($ui-base-color, 4%);
+  background: $ui-base-color;
   border: 0;
   color: $darker-text-color;
   cursor: pointer;
@@ -3946,16 +3948,15 @@ a.status-card.compact:hover {
   padding: 0 15px;
 
   &:hover {
-    color: lighten($darker-text-color, 7%);
+    color: lighten($darker-text-color, 4%);
   }
 
   &.active {
     color: $primary-text-color;
-    background: lighten($ui-base-color, 8%);
+    background: lighten($ui-base-color, 4%);
 
     &:hover {
       color: $primary-text-color;
-      background: lighten($ui-base-color, 8%);
     }
   }
 
@@ -3969,6 +3970,7 @@ a.status-card.compact:hover {
   max-height: 70vh;
   overflow: hidden;
   overflow-y: auto;
+  border-bottom: 1px solid lighten($ui-base-color, 8%);
   color: $darker-text-color;
   transition: max-height 150ms ease-in-out, opacity 300ms linear;
   opacity: 1;
@@ -3988,13 +3990,13 @@ a.status-card.compact:hover {
     height: 0;
     background: transparent;
     border: 0;
-    border-top: 1px solid lighten($ui-base-color, 12%);
+    border-top: 1px solid lighten($ui-base-color, 8%);
     margin: 10px 0;
   }
 }
 
 .column-header__collapsible-inner {
-  background: lighten($ui-base-color, 8%);
+  background: $ui-base-color;
   padding: 15px;
 }
 
@@ -4407,17 +4409,13 @@ a.status-card.compact:hover {
   color: $primary-text-color;
   margin-bottom: 4px;
   display: block;
-  background-color: $base-overlay-background;
-  text-transform: uppercase;
+  background-color: rgba($black, 0.45);
+  backdrop-filter: blur(10px) saturate(180%) contrast(75%) brightness(70%);
   font-size: 11px;
-  font-weight: 500;
-  padding: 4px;
+  text-transform: uppercase;
+  font-weight: 700;
+  padding: 2px 6px;
   border-radius: 4px;
-  opacity: 0.7;
-
-  &:hover {
-    opacity: 1;
-  }
 }
 
 .setting-toggle {
@@ -4477,6 +4475,7 @@ a.status-card.compact:hover {
 
 .follow_requests-unlocked_explanation {
   background: darken($ui-base-color, 4%);
+  border-bottom: 1px solid lighten($ui-base-color, 8%);
   contain: initial;
   flex-grow: 0;
 }
@@ -6161,6 +6160,7 @@ a.status-card.compact:hover {
   display: block;
   color: $white;
   background: rgba($black, 0.65);
+  backdrop-filter: blur(10px) saturate(180%) contrast(75%) brightness(70%);
   padding: 2px 6px;
   border-radius: 4px;
   font-size: 11px;
@@ -6838,24 +6838,6 @@ a.status-card.compact:hover {
       }
     }
   }
-
-  &.directory__section-headline {
-    background: darken($ui-base-color, 2%);
-    border-bottom-color: transparent;
-
-    a,
-    button {
-      &.active {
-        &::before {
-          display: none;
-        }
-
-        &::after {
-          border-color: transparent transparent darken($ui-base-color, 7%);
-        }
-      }
-    }
-  }
 }
 
 .filter-form {
@@ -7370,7 +7352,6 @@ noscript {
 
 .account__header {
   overflow: hidden;
-  background: lighten($ui-base-color, 4%);
 
   &.inactive {
     opacity: 0.5;
@@ -7392,6 +7373,7 @@ noscript {
     height: 145px;
     position: relative;
     background: darken($ui-base-color, 4%);
+    border-bottom: 1px solid lighten($ui-base-color, 8%);
 
     img {
       object-fit: cover;
@@ -7405,7 +7387,7 @@ noscript {
   &__bar {
     position: relative;
     padding: 0 20px;
-    border-bottom: 1px solid lighten($ui-base-color, 12%);
+    border-bottom: 1px solid lighten($ui-base-color, 8%);
 
     .avatar {
       display: block;
@@ -7414,7 +7396,7 @@ noscript {
 
       .account__avatar {
         background: darken($ui-base-color, 8%);
-        border: 2px solid lighten($ui-base-color, 4%);
+        border: 2px solid $ui-base-color;
       }
     }
   }