refactor(api): Flatten API nav groups to single-tag items

Remove multi-tag groups (Administration, Concepts) and flatten to
single-tag groups for direct linking. Each API tag now renders as
a direct nav item instead of being nested under a parent group.

- Update api_nav_groups.yml to use single-tag groups only
- Delete Administration landing pages (not needed without nesting)
- Improve SCSS styling for API nav visibility and active states

assets/styles/layouts/_api-layout.scss

@@ -212,6 +212,21 @@
 ////////////////////////// API Navigation in Sidebar ///////////////////////////
 ////////////////////////////////////////////////////////////////////////////////
 
+// API navigation wrapper - controls visibility
+// Hidden by default, revealed via JS (localStorage) or on API pages
+.api-nav-wrapper {
+  display: none; // Hidden by default
+
+  &.is-revealed {
+    display: block; // Revealed via JS
+  }
+
+  // Always show on API pages (server-rendered with .api-reference class)
+  .api-reference & {
+    display: block;
+  }
+}
+
 // API navigation section added to the existing Hugo sidebar
 .api-nav {
   margin-top: 2rem;
@@ -245,14 +260,19 @@
       border: none;
       width: 100%;
       text-align: left;
-      font-size: inherit;
+      font-size: 1.2rem; // Match sidebar .nav-category > a (19.2px)
       font-family: inherit;
+      text-decoration: none; // For anchor version
 
       &:hover {
         color: $nav-category-hover;
       }
 
-      // Collapse/expand indicator
+      &.is-active {
+        color: $nav-active;
+      }
+
+      // Collapse/expand indicator (for button headers)
       &::before {
         content: "";
         display: inline-block;
@@ -263,6 +283,7 @@
         border-top: 4px solid transparent;
         border-bottom: 4px solid transparent;
         transition: transform 0.2s;
+        flex-shrink: 0;
       }
 
       &.is-open::before {
@@ -270,6 +291,12 @@
       }
     }
 
+    // For anchor headers, keep the ::before arrow (same as button)
+    // No special handling needed - anchor headers look the same as button headers
+    a#{&}-header {
+      // Same styling as button, arrow works via ::before
+    }
+
     &-items {
       list-style: none;
       padding-left: 2.5rem;
@@ -328,23 +355,43 @@
       &.delete { background-color: $r-curacao; color: #fff; }
     }
 
-    // Operation items with method badges and paths
-    &.api-nav-operation {
-      a {
-        display: flex;
-        align-items: center;
-        gap: 0.4rem;
-        font-size: 1rem; // Match sidebar nav-item font size (18px base)
+    // Tag items that link to tag pages
+    &.api-nav-tag {
+      > a {
+        font-weight: $medium;
       }
 
+      // Nested operations list under tag
+      .api-nav-operations {
+        list-style: none;
+        margin: 0.25rem 0 0.5rem;
+        padding-left: 0.75rem;
+
+        .api-nav-operation {
+          margin: 0.15rem 0;
+
+          a {
+            display: flex;
+            align-items: center;
+            gap: 0.4rem;
+            font-size: 0.85rem;
+            padding: 0.25rem 0;
+          }
+        }
+      }
+    }
+
+    // Operation items with method badges
+    &.api-nav-operation,
+    .api-nav-operation {
       .api-method {
         display: inline-block;
-        font-size: 0.6rem;
+        font-size: 0.55rem;
         font-weight: $bold;
         text-transform: uppercase;
-        padding: 0.15rem 0.3rem;
+        padding: 0.1rem 0.25rem;
         border-radius: 3px;
-        min-width: 2.2rem;
+        min-width: 2rem;
         text-align: center;
         flex-shrink: 0;
 
@@ -357,7 +404,7 @@
 
       .api-path {
         font-family: $code;
-        font-size: 0.9rem; // Slightly smaller than link text for hierarchy
+        font-size: 0.85rem;
         word-break: break-all;
         color: inherit;
       }

assets/styles/layouts/_sidebar.scss

@@ -255,6 +255,38 @@
         }
       }
     }
+
+    // API operation items within Hugo menu
+    .api-operation {
+      a {
+        display: flex;
+        align-items: center;
+        gap: 0.4rem;
+      }
+    }
+
+    .api-method {
+      font-size: 0.6rem;
+      font-weight: 700;
+      padding: 0.15rem 0.35rem;
+      border-radius: 3px;
+      text-transform: uppercase;
+      flex-shrink: 0;
+      line-height: 1;
+
+      &--get { background: #61affe; color: white; }
+      &--post { background: #49cc90; color: white; }
+      &--put { background: #fca130; color: white; }
+      &--delete { background: #f93e3e; color: white; }
+      &--patch { background: #50e3c2; color: white; }
+    }
+
+    // Non-link group labels (for multi-tag groups)
+    .nav-group-label {
+      color: $nav-item;
+      font-weight: $medium;
+      display: inline-block;
+    }
   }
 }
 

content/influxdb3/core/api/administration/_index.md

@@ -1,26 +0,0 @@
----
-title: Administration
-description: Endpoints for managing databases, tables, and tokens.
-type: api
-layout: list
-weight: 105
-isConceptual: true
----
-
-Use the Administration API to manage InfluxDB resources:
-
-<div class="children-links">
-
-### [Database](/influxdb3/core/api/database/)
-
-Create, list, and delete databases.
-
-### [Table](/influxdb3/core/api/table/)
-
-Create and delete tables within databases.
-
-### [Token](/influxdb3/core/api/token/)
-
-Manage authentication tokens for API access.
-
-</div>

content/influxdb3/enterprise/api/administration/_index.md

@@ -1,26 +0,0 @@
----
-title: Administration
-description: Endpoints for managing databases, tables, and tokens.
-type: api
-layout: list
-weight: 105
-isConceptual: true
----
-
-Use the Administration API to manage InfluxDB resources:
-
-<div class="children-links">
-
-### [Database](/influxdb3/enterprise/api/database/)
-
-Create, list, and delete databases.
-
-### [Table](/influxdb3/enterprise/api/table/)
-
-Create and delete tables within databases.
-
-### [Token](/influxdb3/enterprise/api/token/)
-
-Manage authentication tokens for API access.
-
-</div>

data/api_nav_groups.yml

@@ -1,55 +1,69 @@
 # API Navigation Groups
 # Defines sidebar navigation structure for API reference documentation
-# Tags are grouped by function/task for better UX
+# Single-tag groups render as direct links; multi-tag groups create nested menus
 #
 # Group fields:
 #   name: Display name in the navigation
 #   weight: Sort order (lower = higher)
 #   tags: List of tag names that belong to this group
-#   url: (optional) URL path suffix for the group page (relative to api/)
 
 groups:
-  - name: Concepts
+  - name: Quick start
     weight: 1
     tags:
       - Quick start
+
+  - name: Authentication
+    weight: 2
+    tags:
       - Authentication
+
+  - name: Headers and parameters
+    weight: 3
+    tags:
       - Headers and parameters
 
   - name: Write data
-    weight: 2
+    weight: 10
     tags:
       - Write data
 
   - name: Query data
-    weight: 3
+    weight: 11
     tags:
       - Query data
 
   - name: Cache data
-    weight: 4
+    weight: 12
     tags:
       - Cache data
 
-  - name: Administration
-    weight: 5
-    url: administration
+  - name: Database
+    weight: 20
     tags:
       - Database
+
+  - name: Table
+    weight: 21
+    tags:
       - Table
+
+  - name: Token
+    weight: 22
+    tags:
       - Token
 
-  - name: Processing Engine
-    weight: 6
+  - name: Processing engine
+    weight: 30
     tags:
       - Processing engine
 
-  - name: Server
-    weight: 7
+  - name: Server information
+    weight: 40
     tags:
       - Server information
 
-  - name: Compatibility
-    weight: 8
+  - name: Compatibility endpoints
+    weight: 50
     tags:
       - Compatibility endpoints