diff --git a/python-book/src/ch01-introduction-and-motivation.md b/python-book/src/ch01-introduction-and-motivation.md
index f586f48..b9ab24c 100644
--- a/python-book/src/ch01-introduction-and-motivation.md
+++ b/python-book/src/ch01-introduction-and-motivation.md
@@ -404,6 +404,7 @@ graph LR
         PY_GIL --> PY_OS["OS / Hardware"]
     end
 
+    PY ~~~ RS
     subgraph RS["🦀 Rust"]
         direction TB
         RS_CODE["Your Code"] --> RS_NONE["No runtime overhead"]
diff --git a/python-book/src/ch04-control-flow.md b/python-book/src/ch04-control-flow.md
index 3988bc0..0c88084 100644
--- a/python-book/src/ch04-control-flow.md
+++ b/python-book/src/ch04-control-flow.md
@@ -218,6 +218,8 @@ flowchart LR
         P2 --> P4["result used later"]
         P3 --> P4
     end
+
+    Python ~~~ Rust
     subgraph Rust ["Rust — Expressions"]
         R1["let result = if cond"] --> R2["{ 'yes' }"]
         R1 --> R3["{ 'no' }"]
diff --git a/python-book/src/ch05-data-structures-and-collections.md b/python-book/src/ch05-data-structures-and-collections.md
index 7242470..4efc124 100644
--- a/python-book/src/ch05-data-structures-and-collections.md
+++ b/python-book/src/ch05-data-structures-and-collections.md
@@ -195,6 +195,7 @@ flowchart LR
         PH --> PHT["height: float obj"]
         PH --> PD["__dict__"]
     end
+    Python ~~~ Rust
     subgraph Rust ["Rust Struct (Stack)"]
         RW["width: f64<br/>(8 bytes)"] --- RH["height: f64<br/>(8 bytes)"]
     end
diff --git a/python-book/src/ch10-traits-and-generics.md b/python-book/src/ch10-traits-and-generics.md
index eb449fb..56a7dfe 100644
--- a/python-book/src/ch10-traits-and-generics.md
+++ b/python-book/src/ch10-traits-and-generics.md
@@ -322,6 +322,7 @@ flowchart TB
         VT --> I1["Article::summarize()"]
         VT --> I2["Tweet::summarize()"]
     end
+    Static ~~~ Dynamic
     style Static fill:#d4edda
     style Dynamic fill:#fff3cd
 ```
diff --git a/python-book/src/ch11-from-and-into-traits.md b/python-book/src/ch11-from-and-into-traits.md
index 30e67e3..09f77a5 100644
--- a/python-book/src/ch11-from-and-into-traits.md
+++ b/python-book/src/ch11-from-and-into-traits.md
@@ -63,7 +63,7 @@ let n: i32 = "42".parse()?;                    // Propagate error with ?
 ### The From/Into Relationship
 
 ```mermaid
-flowchart LR
+flowchart TB
     A["impl From&lt;A&gt; for B"] -->|"auto-generates"| B["impl Into&lt;B&gt; for A"]
     C["Celsius::from(Fahrenheit(212.0))"] ---|"same as"| D["Fahrenheit(212.0).into()"]
     style A fill:#d4edda
diff --git a/python-book/src/ch15-migration-patterns.md b/python-book/src/ch15-migration-patterns.md
index a39d528..492e839 100644
--- a/python-book/src/ch15-migration-patterns.md
+++ b/python-book/src/ch15-migration-patterns.md
@@ -251,7 +251,7 @@ let db_host = get_config()["database"]["host"].as_str().unwrap();
 ## Incremental Adoption Strategy
 
 ```mermaid
-flowchart LR
+flowchart TB
     A["1️⃣ Profile Python<br/>(find hotspots)"] --> B["2️⃣ Write Rust Extension<br/>(PyO3 + maturin)"]
     B --> C["3️⃣ Replace Python Call<br/>(same API)"]
     C --> D["4️⃣ Expand Gradually<br/>(more functions)"]