fix(nav): kill Bootstrap 5 navbar padding so bar matches zibll height

AKSRT loads BS5 (.navbar --bs-navbar-padding-y:.5rem) while zibll uses
BS3 without it; that alone added ~16px. Zero BS navbar pad, keep only
.header 8px 20px (mobile 0 8px), horizontal CTA margins, tighter mobile
logo/toggle row.

assets/css/frontend/nav/header-menu-buttons.css

@@ -43,7 +43,7 @@
   width: fit-content !important;
   max-width: fit-content !important;
   min-width: 0 !important;
-  margin: 0.4em !important;
+  margin: 0 0.4em !important;
   appearance: none;
   -webkit-appearance: none;
   cursor: pointer;

assets/css/frontend/nav/zib-navbar-core.css

@@ -57,6 +57,17 @@
     transition: 0.15s;
 }
 
+/* BS5 .navbar injects --bs-navbar-padding-y: .5rem; zibll (BS3) has no such pad */
+.header > .navbar,
+.header .navbar.navbar-top {
+    --bs-navbar-padding-y: 0;
+    --bs-navbar-padding-x: 0;
+    --bs-navbar-brand-padding-y: 0;
+    padding-top: 0 !important;
+    padding-bottom: 0 !important;
+    min-height: 0 !important;
+}
+
 .body-scroll .header {
     box-shadow: 0px 4px 10px var(--main-shadow);
 }
@@ -295,7 +306,7 @@ badge.top,
 .navbar-top .navbar-but .but {
     font-size: 0.8em;
     padding: 0.3em 1em !important;
-    margin: 0.4em;
+    margin: 0 0.4em;
     display: inline-flex !important;
     align-items: center;
     justify-content: center;