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+# Mermaid Diagram Rendering Test
+
+Test file to verify Gitea renders mermaid diagrams correctly.
+Delete this file after confirming.
+
+---
+
+## Test 1: HAProxy Architecture (flowchart, top-down)
+
+Original: `notes/haproxy-guide.md` lines 13-44
+
+```mermaid
+flowchart TD
+    client["Client / LAN Traffic"]
+    vip["UPLINK VIP Address\n192.168.103.200"]
+    ovnlb["OVN Load Balancer\n(distributes to HA pair\nfor failover)"]
+    ha1["HAProxy 01\n10.10.10.50\n(container)"]
+    ha2["HAProxy 02\n10.10.10.51\n(container)"]
+    ng1["nginx-01\n.60 :80"]
+    ng2["nginx-02\n.61 :80"]
+    ng3["nginx-03\n.62 :80"]
+
+    client --> vip --> ovnlb
+    ovnlb --> ha1
+    ovnlb --> ha2
+    ha1 --> ng1
+    ha1 --> ng2
+    ha1 --> ng3
+    ha2 --> ng1
+    ha2 --> ng2
+    ha2 --> ng3
+
+    style vip fill:#4a90d9,color:#fff
+    style ovnlb fill:#7b68ee,color:#fff
+    style ha1 fill:#2ecc71,color:#fff
+    style ha2 fill:#2ecc71,color:#fff
+    style ng1 fill:#e67e22,color:#fff
+    style ng2 fill:#e67e22,color:#fff
+    style ng3 fill:#e67e22,color:#fff
+```
+
+---
+
+## Test 2: Bridge Topology (subgraphs for nodes)
+
+Original: `notes/networking-guide.md` lines 81-100
+
+```mermaid
+flowchart TD
+    subgraph node1["Node 1 (net-node-01)"]
+        br1["incusbr0\n10.0.0.1/24"]
+        c1["c1\n.202"]
+        c2["c2\n.40"]
+        nat1["NAT → ens18\n192.168.1.209"]
+        c1 --- br1
+        c2 --- br1
+        br1 --> nat1
+    end
+
+    subgraph node2["Node 2 (net-node-02)"]
+        br2["incusbr0\n10.0.0.1/24"]
+        c3["c3\n.52"]
+        nat2["NAT → ens18\n192.168.1.150"]
+        c3 --- br2
+        br2 --> nat2
+    end
+
+    nat1 --- lan
+    nat2 --- lan
+    lan(("LAN\n192.168.1.0/24"))
+
+    node1 ~~~ node2
+
+    linkStyle 5 stroke:red,stroke-dasharray:5
+    linkStyle 6 stroke:red,stroke-dasharray:5
+```
+
+> **Key point:** Each node has its own bridge with the same subnet. The
+> bridges are NOT connected to each other.
+
+---
+
+## Test 3: OVN Topology (control plane + nodes + tunnels)
+
+Original: `notes/networking-guide.md` lines 196-227
+
+```mermaid
+flowchart TD
+    subgraph cp["OVN Control Plane"]
+        ovnc["ovn-central\novn-northd + ovsdb-server\nNB: tcp:192.168.1.209:6641\nSB: tcp:192.168.1.209:6642"]
+    end
+
+    subgraph n1["Node 1 (net-node-01)"]
+        ctrl1["ovn-controller\novs-vswitchd"]
+        oc1["c1 (.2)"]
+        oc2["c2 (.3)"]
+        ls1["OVN logical switch\n10.10.10.0/24"]
+        oc1 --- ls1
+        oc2 --- ls1
+        ctrl1 ~~~ ls1
+    end
+
+    subgraph n2["Node 2 (net-node-02)"]
+        ctrl2["ovn-controller\novs-vswitchd"]
+        oc3["c3 (.4)"]
+        ls2["OVN logical switch\n10.10.10.0/24"]
+        oc3 --- ls2
+        ctrl2 ~~~ ls2
+    end
+
+    subgraph n3["Node 3 (net-node-03)"]
+        ctrl3["ovn-controller\novs-vswitchd"]
+        oc4["c4 (.5)"]
+        ls3["OVN logical switch\n10.10.10.0/24"]
+        oc4 --- ls3
+        ctrl3 ~~~ ls3
+    end
+
+    ovnc -->|proxy devices| ctrl1
+    ovnc -->|proxy devices| ctrl2
+    ovnc -->|proxy devices| ctrl3
+
+    ls1 <-->|Geneve tunnel\n192.168.1.209| ls2
+    ls2 <-->|Geneve tunnel\n192.168.1.150| ls3
+    ls1 <-->|Geneve tunnel\n192.168.1.13| ls3
+
+    lan(("LAN\n192.168.1.0/24"))
+    n1 --- lan
+    n2 --- lan
+    n3 --- lan
+```
+
+---
+
+## Test 4: Geneve Tunnel Mesh
+
+Original: `notes/ovn-deep-dive.md` lines 331-349
+
+```mermaid
+graph LR
+    n1(("oc-node-01\n.140"))
+    n2(("oc-node-02\n.141"))
+    n3(("oc-node-03\n.142"))
+
+    n1 <-->|"Geneve\nUDP 6081\nBFD ✓"| n2
+    n2 <-->|"Geneve\nUDP 6081\nBFD ✓"| n3
+    n1 <-->|"Geneve\nUDP 6081\nBFD ✓"| n3
+
+    style n1 fill:#3498db,color:#fff
+    style n2 fill:#2ecc71,color:#fff
+    style n3 fill:#e74c3c,color:#fff
+```
+
+---
+
+## Test 5: OVS Bridge Architecture (per-node)
+
+Original: `notes/ovn-deep-dive.md` lines 305-313
+
+```mermaid
+flowchart LR
+    subgraph provider["incusovn7 (provider bridge)"]
+        nic["incusovn7 ← physical NIC"]
+        intport["incusovn7b ← internal port"]
+        patch1["patch-...-to-br-int"]
+    end
+
+    subgraph integration["br-int (integration bridge)"]
+        veth["veth* ← instance NICs"]
+        ovntun["ovn-* ← Geneve tunnels"]
+        patch2["patch-br-int-to-..."]
+        brint["br-int ← internal port"]
+    end
+
+    patch1 <-->|"patch port"| patch2
+
+    style provider fill:#e8f4fd,stroke:#3498db
+    style integration fill:#eafaf1,stroke:#2ecc71
+```
+
+---
+
+## Test 6: Operations Center Architecture
+
+Original: `notes/operations-center-guide.md` lines 12-45
+
+```mermaid
+flowchart TD
+    subgraph proxmox["Proxmox VE Host (pve)\nIntel i9-13900HK · 64 GiB · 20 cores"]
+        subgraph cluster["Incus Cluster (OVN Geneve · net-prod 10.10.10.0/24)"]
+            n1["oc-node-01\nVMID 400\n4c/8G/64G\n.140\novn-central"]
+            n2["oc-node-02\nVMID 401\n4c/8G/50G\n.141"]
+            n3["oc-node-03\nVMID 402\n4c/8G/50G\n.142"]
+        end
+        oc["oc-server\nVMID 920 · 2c/4G/50G\n.120\nhttps://192.168.102.120\nWeb UI + CLI + REST API"]
+    end
+
+    vmbr0["vmbr0 (VLAN 69)\n192.168.100.0/22\nGateway: 192.168.100.1"]
+    ext["OVN External IPs\n192.168.103.200-210\nLB: .201 · Fwd: .202"]
+
+    proxmox --- vmbr0
+    cluster -.->|"OVN external"| ext
+
+    style proxmox fill:#f5f5f5,stroke:#333
+    style cluster fill:#e8f4fd,stroke:#3498db
+    style oc fill:#fff3cd,stroke:#e67e22
+    style n1 fill:#d4edda,stroke:#28a745
+    style n2 fill:#d4edda,stroke:#28a745
+    style n3 fill:#d4edda,stroke:#28a745
+```