Revert "set header background to page color with blur"

This reverts commit 987022deb3.

css/style.css

@@ -481,19 +481,26 @@ button:active, .button-primary:active, .logo:active {
 /* Site header */
 
 .site-header {
+  display: flex;
+  align-items: center;
+  justify-content: center;
   position: sticky;
   top: 0;
-  z-index: 100;
-  display: flex;
-  justify-content: center;
-  margin-bottom: var(--spacing-3);
   padding-top: max(1px, env(safe-area-inset-top));
-  background:
-    color-mix(in srgb, var(--color-background) 60%, transparent);
-  -webkit-backdrop-filter: blur(6px) saturate(140%);
-  backdrop-filter: blur(6px) saturate(140%);
-
-  border-bottom: 1px solid color-mix(in srgb, var(--color-background) 10%, transparent);
+  z-index: 100;
+  background-image: linear-gradient(
+    180deg,
+    light-dark(var(--gradient-stop-1-light), var(--gradient-stop-1-dark)) 0%,
+    6%,
+    light-dark(var(--gradient-stop-2-light), var(--gradient-stop-2-dark)) 12%,
+    44%,
+    light-dark(var(--gradient-stop-3-light), var(--gradient-stop-3-dark)) 60%,
+    76%,
+    light-dark(var(--gradient-stop-4-light), var(--gradient-stop-4-dark)) 100%
+  );
+  /* background: rgb(255 255 255 / 0.88); */
+  /* backdrop-filter: blur(10px);
+  -webkit-backdrop-filter: blur(10px); */
 }
 
 .menu-bar {