diff --git a/content/ai-system/_index.md b/content/ai-system/_index.md
index f955a4f..686080a 100644
--- a/content/ai-system/_index.md
+++ b/content/ai-system/_index.md
@@ -1,10 +1,11 @@
 +++
 title = "AI Systems & Infrastructure"
-sort_by = "date"
+sort_by = "weight"
 paginate_by = 10
 
 [extra]
 abbr = "AIsys"
+display_chapter = true
 +++
 
 Basics of streamlined interaction with AI systems, peripherals that enable such interaction, and deployment of AI systems on real-world infrastructure.
diff --git a/content/ai-system/advanced-apis/index.md b/content/ai-system/advanced-apis/index.md
index 8d5f547..50adff7 100644
--- a/content/ai-system/advanced-apis/index.md
+++ b/content/ai-system/advanced-apis/index.md
@@ -1,7 +1,11 @@
 +++
-title = "A.2-Advanced APIs in the Era of AI"
+title = "Advanced APIs in the Era of AI"
 date = 2025-09-11
 description = ""
+weight = 12
+
+[extra]
+chapter = "A.2"
 +++
 
 > **TL;DR:**
diff --git a/content/ai-system/advanced-deployment/index.md b/content/ai-system/advanced-deployment/index.md
index 873729e..45e1287 100644
--- a/content/ai-system/advanced-deployment/index.md
+++ b/content/ai-system/advanced-deployment/index.md
@@ -1,7 +1,11 @@
 +++
-title = "C.10-Advanced Deployment Strategies"
+title = "Advanced Deployment Strategies"
 date = 2025-11-08
 description = ""
+weight = 32
+
+[extra]
+chapter = "C.10"
 +++
 
 > **TL;DR:**
diff --git a/content/ai-system/ai-compute-hardware/index.md b/content/ai-system/ai-compute-hardware/index.md
index 8fd00d7..425d6e0 100644
--- a/content/ai-system/ai-compute-hardware/index.md
+++ b/content/ai-system/ai-compute-hardware/index.md
@@ -1,7 +1,11 @@
 +++
-title = "B.4-AI Compute Hardware"
+title = "AI Compute Hardware"
 date = 2025-09-25
 description = ""
+weight = 24
+
+[extra]
+chapter = "B.4"
 +++
 
 > **TL;DR:**
diff --git a/content/ai-system/api-fundamentals/index.md b/content/ai-system/api-fundamentals/index.md
index 7a4712c..16bff49 100644
--- a/content/ai-system/api-fundamentals/index.md
+++ b/content/ai-system/api-fundamentals/index.md
@@ -1,7 +1,11 @@
 +++
-title = "A.1-API Fundamentals"
+title = "API Fundamentals"
 date = 2025-09-03
 description = ""
+weight = 11
+
+[extra]
+chapter = "A.1"
 +++
 
 > **TL;DR:**
diff --git a/content/ai-system/cloud-deployment/index.md b/content/ai-system/cloud-deployment/index.md
index 9f7fdc6..7ba9f8f 100644
--- a/content/ai-system/cloud-deployment/index.md
+++ b/content/ai-system/cloud-deployment/index.md
@@ -1,7 +1,11 @@
 +++
-title = "B.6-Cloud Deployment"
+title = "Cloud Deployment"
 date = 2025-10-09
 description = ""
+weight = 26
+
+[extra]
+chapter = "B.6"
 +++
 
 > **TL;DR:**
diff --git a/content/ai-system/edge-self-hosted-deployment/index.md b/content/ai-system/edge-self-hosted-deployment/index.md
index b508410..8431079 100644
--- a/content/ai-system/edge-self-hosted-deployment/index.md
+++ b/content/ai-system/edge-self-hosted-deployment/index.md
@@ -1,7 +1,11 @@
 +++
-title = "B.7-Edge & Self-hosted Deployment"
+title = "Edge & Self-hosted Deployment"
 date = 2025-10-16
 description = ""
+weight = 27
+
+[extra]
+chapter = "B.7"
 +++
 
 > **TL;DR:** Cloud deployment isn't the only option. Learn about edge computing and self-hosted deployment: running AI systems closer to where data is generated or on your own hardware. Discover when these approaches make sense and how to implement them on devices like Raspberry Pi and home servers.
diff --git a/content/ai-system/exam/index.md b/content/ai-system/exam/index.md
index b462def..9aaa7fa 100644
--- a/content/ai-system/exam/index.md
+++ b/content/ai-system/exam/index.md
@@ -2,6 +2,10 @@
 title = "Exam Format"
 date = 2025-09-02
 description = ""
+weight = 50
+
+[extra]
+chapter = ""
 +++
 ## Modality and duration
 
diff --git a/content/ai-system/high-availability/index.md b/content/ai-system/high-availability/index.md
index 840bd58..b12bfd3 100644
--- a/content/ai-system/high-availability/index.md
+++ b/content/ai-system/high-availability/index.md
@@ -1,7 +1,11 @@
 +++
-title = "C.9-High Availability & Reliability"
+title = "High Availability & Reliability"
 date = 2025-10-26
 description = ""
+weight = 31
+
+[extra]
+chapter = "C.9"
 +++
 > **TL;DR:**
 > When your service goes down, users leave. Learn how to measure availability with industry-standard metrics (MTBF, MTTR), and implement practical strategies like redundancy and backups to keep your AI API running reliably.
diff --git a/content/ai-system/infrastructure-deployment/index.md b/content/ai-system/infrastructure-deployment/index.md
index c84ca27..76f9bd9 100644
--- a/content/ai-system/infrastructure-deployment/index.md
+++ b/content/ai-system/infrastructure-deployment/index.md
@@ -1,7 +1,11 @@
 +++
-title = "B-Infrastructure & Deployment of AI"
+title = "Infrastructure & Deployment of AI"
 date = 2025-09-25
 description = ""
+weight = 20
+
+[extra]
+chapter = "B"
 +++
 
 > **TL;DR:**
diff --git a/content/ai-system/interact-with-ai-systems/index.md b/content/ai-system/interact-with-ai-systems/index.md
index 06b38ff..e682261 100644
--- a/content/ai-system/interact-with-ai-systems/index.md
+++ b/content/ai-system/interact-with-ai-systems/index.md
@@ -1,7 +1,11 @@
 +++
-title = "A-Interact with AI Systems"
+title = "Interact with AI Systems"
 date = 2025-09-03
 description = ""
+weight = 10
+
+[extra]
+chapter = "A"
 +++
 > **TL;DR:**
 > Learn why standardized interactions between applications are essential for making AI models practical in real-world scenarios, moving beyond simple function calls to robust communication methods that work across different programming languages and distributed systems.
diff --git a/content/ai-system/introduction/index.md b/content/ai-system/introduction/index.md
index 0736b5c..2a96346 100644
--- a/content/ai-system/introduction/index.md
+++ b/content/ai-system/introduction/index.md
@@ -2,6 +2,10 @@
 title = "Introduction to AI Systems & Infrastructure"
 date = 2025-09-02
 description = ""
+weight = 1
+
+[extra]
+chapter = ""
 +++
 
 What is AI composed of, and how companies like OpenAI, Anthropic, Google, and Microsoft are pushing AI for millions of people around the globe to use (whether people want it or not)?
diff --git a/content/ai-system/mini-project/index.md b/content/ai-system/mini-project/index.md
index eb1d6d2..6f50a7b 100644
--- a/content/ai-system/mini-project/index.md
+++ b/content/ai-system/mini-project/index.md
@@ -1,7 +1,11 @@
 +++
-title = "B.8-Mini Project"
+title = "Mini Project"
 date = 2025-10-21
 description = ""
+weight = 28
+
+[extra]
+chapter = "B.8"
 +++
 Leveraging the knowledge from the [phase A and B](@/ai-system/_index.md) of this course (and optionally the advanced techniques from the phase C), we will develop and deploy a multi-functional AI API server in our mini project.
 
diff --git a/content/ai-system/packaging-containerization/index.md b/content/ai-system/packaging-containerization/index.md
index ff0b491..c894e94 100644
--- a/content/ai-system/packaging-containerization/index.md
+++ b/content/ai-system/packaging-containerization/index.md
@@ -1,7 +1,11 @@
 +++
-title = "B.5-Packaging & Containerization"
+title = "Packaging & Containerization"
 date = 2025-10-02
 description = ""
+weight = 25
+
+[extra]
+chapter = "B.5"
 +++
 
 > **TL;DR:**
diff --git a/content/ai-system/production-ready-systems/index.md b/content/ai-system/production-ready-systems/index.md
index 337be30..2ac79fd 100644
--- a/content/ai-system/production-ready-systems/index.md
+++ b/content/ai-system/production-ready-systems/index.md
@@ -1,7 +1,11 @@
 +++
-title = "C-Production-ready AI Systems"
+title = "Production-ready AI Systems"
 date = 2025-10-25
 description = ""
+weight = 30
+
+[extra]
+chapter = "C"
 +++
 Now you can deploy your AI system on different hardware infrastructures with ease, and also enable everyone in the world to access (and hopefully pay for) your AI services. Now you won't run into situations where your friends are calling you to play CS2 but your laptop is running an AI service so you cannot.
 
diff --git a/content/ai-system/wrap-ai-with-api/index.md b/content/ai-system/wrap-ai-with-api/index.md
index 414d6e6..7cfb139 100644
--- a/content/ai-system/wrap-ai-with-api/index.md
+++ b/content/ai-system/wrap-ai-with-api/index.md
@@ -1,7 +1,11 @@
 +++
-title = "A.3-Wrap AI Models with APIs"
+title = "Wrap AI Models with APIs"
 date = 2025-09-18
 description = ""
+weight = 13
+
+[extra]
+chapter = "A.3"
 +++
 > **TL;DR:**
 > Build your own APIs for serving AI models, covering everything from basic server setup and AI model integration to authentication, database-backed user management, and rate limiting—transforming you from an API consumer to an API producer.
diff --git a/content/dl4traj/_index.md b/content/dl4traj/_index.md
index b15d89d..e0aa699 100644
--- a/content/dl4traj/_index.md
+++ b/content/dl4traj/_index.md
@@ -1,11 +1,11 @@
 +++
 title = "Deep Learning for Trajectory"
-sort_by = "none"
+sort_by = "weight"
 paginate_by = 10
 
 [extra]
 abbr = "DL4traj"
-use_chapter_sort = true
+display_chapter = true
 +++
 
 Deep learning approaches for analysis and utilization of spatiotemporal trajectories.
diff --git a/content/dl4traj/end-to-end/index.md b/content/dl4traj/end-to-end/index.md
index df0d09f..83c8f04 100644
--- a/content/dl4traj/end-to-end/index.md
+++ b/content/dl4traj/end-to-end/index.md
@@ -2,6 +2,7 @@
 title = "End-to-end Learning of Trajectories"
 date = 2026-02-02
 description = ""
+weight = 2
 
 [extra]
 chapter = "2"
diff --git a/content/dl4traj/generation/index.md b/content/dl4traj/generation/index.md
index cc49d0b..72528d5 100644
--- a/content/dl4traj/generation/index.md
+++ b/content/dl4traj/generation/index.md
@@ -2,6 +2,7 @@
 title = "Trajectory Generation"
 date = 2026-02-04
 description = ""
+weight = 4
 
 [extra]
 chapter = "4"
diff --git a/content/dl4traj/introduction/index.md b/content/dl4traj/introduction/index.md
index 49705d3..86974b0 100644
--- a/content/dl4traj/introduction/index.md
+++ b/content/dl4traj/introduction/index.md
@@ -2,6 +2,7 @@
 title = "Introduction to Deep Learning for Trajectories"
 date = 2026-02-01
 description = ""
+weight = 1
 
 [extra]
 chapter = "1"
diff --git a/content/dl4traj/self-supervised/index.md b/content/dl4traj/self-supervised/index.md
index d6e95f5..2646e4a 100644
--- a/content/dl4traj/self-supervised/index.md
+++ b/content/dl4traj/self-supervised/index.md
@@ -2,6 +2,7 @@
 title = "Self-supervised Learning of Trajectories"
 date = 2026-02-03
 description = ""
+weight = 3
 
 [extra]
 chapter = "3"
diff --git a/sass/style.scss b/sass/style.scss
index fb0575d..bc6753d 100644
--- a/sass/style.scss
+++ b/sass/style.scss
@@ -144,7 +144,7 @@ ul, ol {
     }
 
     .chapter {
-      min-width: 2rem;
+      min-width: 2.2rem;
     }
 
     time {
diff --git a/templates/section.html b/templates/section.html
index 6f1b4da..d09a865 100644
--- a/templates/section.html
+++ b/templates/section.html
@@ -17,31 +17,25 @@
 {% else %}
 {% set pages = section.pages %}
 {% endif %}
-{% if section.extra.use_chapter_sort %}
-{% set pages = pages | sort(attribute="extra.chapter") %}
 {% for page in pages %}
     <li>
+        {% if section.extra.display_chapter %}
         <span class="chapter">{{ page.extra.chapter }}</span>
-        <a href="{{ page.permalink }}">{{ page.title }}</a>
-    </li>
-{% endfor %}
-{% else %}
-{% for page in pages %}
-    <li>
+        {% else %}
         <time datetime="{{ page.date }}">{{ page.date | date(format="%Y-%m-%d") }}</time>
+        {% endif %}
         <a href="{{ page.permalink }}">{{ page.title }}</a>
     </li>
 {% endfor %}
-{% endif %}
 </ul>
 
 {% if paginator %}
 <nav class="pagination">
     {% if paginator.previous %}
-        <a href="{{ paginator.previous }}">&larr; {% if section.extra.use_chapter_sort %}Previous{% else %}Newer{% endif %}</a>
+        <a href="{{ paginator.previous }}">&larr; {% if section.extra.display_chapter %}Previous{% else %}Newer{% endif %}</a>
     {% endif %}
     {% if paginator.next %}
-        <a href="{{ paginator.next }}">{% if section.extra.use_chapter_sort %}Next{% else %}Older{% endif %} &rarr;</a>
+        <a href="{{ paginator.next }}">{% if section.extra.display_chapter %}Next{% else %}Older{% endif %} &rarr;</a>
     {% endif %}
 </nav>
 {% endif %}