From 648b1b2ba83e4ad7103d1782594564bd99a2a681 Mon Sep 17 00:00:00 2001
From: Jon Froehlich <jonf@cs.uw.edu>
Date: Mon, 22 Jun 2026 14:03:03 -0700
Subject: [PATCH] Tier-0 V2.0 quick fixes: sitemap, robots.txt, LaTeX + nav
 fixes

- Enable jekyll-sitemap (bundled with github-pages) so /sitemap.xml is
  generated for search indexing; add robots.txt pointing to it (#72).
- Fix malformed LaTeX in advancedio/smoothing-input.md: a nested `$>$`
  inside a $$...$$ block broke MathJax; use a literal `>` to match the
  `if i = 1` case above it.
- Migrate esp32/esp32-ide.md from the old .btn "Back to" button to the
  standard card-style <nav class="lesson-nav">, matching the other esp32
  lessons (the nav script doesn't recognize the single back-button form).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
---
 _config.yml                   | 7 +++++++
 advancedio/smoothing-input.md | 2 +-
 esp32/esp32-ide.md            | 9 ++++++---
 robots.txt                    | 4 ++++
 4 files changed, 18 insertions(+), 4 deletions(-)
 create mode 100644 robots.txt

diff --git a/_config.yml b/_config.yml
index 260c7faa..00879a94 100644
--- a/_config.yml
+++ b/_config.yml
@@ -42,6 +42,13 @@ url: "https://makeabilitylab.github.io" # the base hostname & protocol for your
 # For copy button on code
 enable_copy_code_button: true
 
+# Jekyll plugins. jekyll-sitemap generates /sitemap.xml (submittable to search
+# engines) to help indexing. It ships with the github-pages gem and is on the
+# GitHub Pages plugin whitelist, so it works under both the legacy build and the
+# GitHub Actions build (#98).
+plugins:
+  - jekyll-sitemap
+
 # custom site variables
 arduino_github_baseurl: "https://makeabilitylab.github.io/physcomp/"
 comments: false
diff --git a/advancedio/smoothing-input.md b/advancedio/smoothing-input.md
index c3cfa7cf..76b6398d 100644
--- a/advancedio/smoothing-input.md
+++ b/advancedio/smoothing-input.md
@@ -204,7 +204,7 @@ $$
 S_{i} =
 \begin{cases}
     X_{1} & \text{if i = 1}\\
-    \alpha \cdot X_{i} + (1 - \alpha) \cdot S_{i-1} & \text{if i $>$ 1}
+    \alpha \cdot X_{i} + (1 - \alpha) \cdot S_{i-1} & \text{if i > 1}
 \end{cases}
 $$
 
diff --git a/esp32/esp32-ide.md b/esp32/esp32-ide.md
index 345188df..c2bd86b9 100644
--- a/esp32/esp32-ide.md
+++ b/esp32/esp32-ide.md
@@ -196,6 +196,9 @@ With your IDE set up, you're ready to start building ESP32 projects!
 
 Head back to [Lesson 1: Introduction to the ESP32](esp32.md) to learn about the hardware, or jump straight to [Lesson 2: Blinking an LED](led-blink.md) if you're ready to write code.
 
-<span class="fs-6">
-[Back to: Introduction to the ESP32](esp32.md){: .btn .btn-outline }
-</span>
\ No newline at end of file
+<nav class="lesson-nav" aria-label="Lesson navigation">
+  <a href="esp32.html" class="nav-prev">
+    <div class="nav-label">&larr; Previous Lesson</div>
+    <div class="nav-title">Introduction to the ESP32</div>
+  </a>
+</nav>
\ No newline at end of file
diff --git a/robots.txt b/robots.txt
new file mode 100644
index 00000000..872cd917
--- /dev/null
+++ b/robots.txt
@@ -0,0 +1,4 @@
+User-agent: *
+Allow: /
+
+Sitemap: https://makeabilitylab.github.io/physcomp/sitemap.xml