diff --git a/src/SUMMARY.md b/src/SUMMARY.md
index 87525677670ad1b4cfc0d5bd4d9a9d502bcccd41..cf3fae587b275fd08e0e075a8b26bbc52bb38e47 100644
--- a/src/SUMMARY.md
+++ b/src/SUMMARY.md
@@ -1,13 +1,13 @@
 # Summary
 
 - [Introduction to embedded development](./ch1_00_introduction.md)
-    - [Introduction to the hardware](./ch1_01_hardware.md)
-    - [Introduction to the software](./ch1_02_software.md)
+  - [Introduction to the hardware](./ch1_01_hardware.md)
+  - [Introduction to the software](./ch1_02_software.md)
 - [Installation of toolchain](./ch2_00_installation.md)
-    - [Linux Toolchain setup](./ch2_01_linux_installation.md)
-    - [Windows Toolchain setup](./ch2_02_windows_installation.md)
-    - [Testing the toolchain](./ch2_03_testing_toolchain.md)
+  - [Linux Toolchain setup](./ch2_01_linux_installation.md)
+  - [Windows Toolchain setup](./ch2_02_windows_installation.md)
+  - [Testing the toolchain](./ch2_03_testing_toolchain.md)
 - [Exercises - learning by doing](./ch3_00_exercises.md)
-    - [Getting started with the hardware](./ch3_01_getting_started.md)
-    - [Blinking a LED](./ch3_02_blinky.md)
-    - [Serial port communication](./ch3_03_serial.md)
+  - [Getting started with the hardware](./ch3_01_getting_started.md)
+  - [Blinking a LED](./ch3_02_blinky.md)
+  - [Serial port communication](./ch3_03_serial.md)