fix: update header styles and layout in default-base.css

- Corrected position property from 'absolute' to 'relative' for #header.
- Added flexbox properties to #header for better alignment and spacing.
- Introduced new styles for unraid-i18n-host and Downgrade icon rotation.
- Adjusted #menu position to 'sticky' for improved usability.

This change enhances the layout and responsiveness of the header and menu elements.

emhttp/plugins/dynamix/styles/default-base.css

@@ -358,9 +358,17 @@ textarea {
     border-bottom: 1px solid var(--input-border-color);
 }
 #header {
-    position: absolute;
-    top: 0;
-    left: 0;
+    position: relaitve;
+    z-index: 102 !important;
+    display: -webkit-box;
+    display: -ms-flexbox;
+    display: flex;
+    -webkit-box-pack: justify;
+    -ms-flex-pack: justify;
+    justify-content: space-between;
+    -webkit-box-align: center;
+    -ms-flex-align: center;
+    align-items: center;
     width: 100%;
     height: 91px;
     z-index: 102;
@@ -371,6 +379,27 @@ textarea {
     background-repeat: no-repeat;
 }
 
+#header unraid-i18n-host {
+    font-size: 16px;
+    margin-left: auto;
+    height: 100%;
+}
+
+/**
+ * Tools page, rotate the Downgrade icon to prevent needing to add a new icon to the icon font.
+ * The pseudo element is targeted here otherwise the rotation of the span would mess up spacing with the text.
+ */
+a[href="/Tools/Downgrade"] .icon-update:before {
+    display: inline-block; /* required otherwise the rotation won't work */
+    rotate: 180deg;
+}
+/* overriding #header .logo svg */
+#header .logo .partner-logo svg {
+    fill: var(--header-text-primary);
+    width: auto;
+    height: 28px;
+}
+
 #header.image { /* .image is conditionally added by DefaultPageLayout.php */
     background-image: var(--customer-header-background-image);
 }
@@ -436,10 +465,9 @@ div.title.shift {
     margin-top: -30px;
 }
 #menu {
-    position: absolute;
-    top: 90px;
-    left: 0;
-    right: 0;
+    position: sticky;
+    top: 0;
+    width: 100%;
     display: grid;
     grid-template-columns: auto max-content;
     z-index: 101;
@@ -1708,8 +1736,7 @@ span#wlan0 {
     }
 
     #header {
-        position: fixed;
-        height: 90px;
+        position: relative;
         z-index: 100;
         border-bottom: 1px solid var(--gray-600);
         box-sizing: border-box;