diff --git a/index.qmd b/index.qmd
index 28878e5c..6c0955b4 100644
--- a/index.qmd
+++ b/index.qmd
@@ -1,7 +1,7 @@
 # Welcome {.unnumbered}
 
 This is the on-line version of work-in-progress **3rd edition** of "ggplot2: elegant graphics for data analysis" published by Springer.
-You can learn what's changed from the 2nd edition in the [Preface](#preface-3e).
+You can learn what's changed from the 2nd edition in the [Preface](#sec-preface-3e).
 
 While this book gives some details on the basics of ggplot2, its primary focus is explaining the Grammar of Graphics that ggplot2 uses, and describing the full details.
 It is not a [cookbook](https://r-graphics.org), and won't necessarily help you create any specific graphic that you need.
diff --git a/themes.qmd b/themes.qmd
index a899a29d..2e206f25 100644
--- a/themes.qmd
+++ b/themes.qmd
@@ -38,7 +38,7 @@ For example, imagine you've made the following plot of your data.
 #| label: motivation-1
 base <- ggplot(mpg, aes(cty, hwy, color = factor(cyl))) +
   geom_jitter() + 
-  geom_abline(colour = "grey50", size = 2)
+  geom_abline(colour = "grey50", linewidth = 2)
 base
 ```