diff --git a/Chapter_8.Rmd b/Chapter_8.Rmd
index b7f08f7..a5b4a06 100644
--- a/Chapter_8.Rmd
+++ b/Chapter_8.Rmd
@@ -137,3 +137,5 @@ for (i in seq_along(population_sizes)) {
 mtext("Number of people", side = 2, outer = TRUE, line = 0.2)
 par(old_par)
 ```
+
+If the  skill level is transmitted culturally  from these skilled individual to the next generation, we can then add different type of social transmission process to then get prediction about on the spread (and retention) of skills within the population.
diff --git a/book.css b/book.css
index 3dec9f7..c58a929 100644
--- a/book.css
+++ b/book.css
@@ -93,7 +93,7 @@ body,
 
 .book .book-body .page-wrapper .page-inner section.normal {
   color: var(--ink);
-  font-size: 1.02rem;
+  font-size: 1.5rem;
   line-height: 1.75;
 }
 
@@ -157,7 +157,73 @@ body,
 }
 
 .book .book-body .page-wrapper .page-inner section.normal pre code {
-  color: #e9e2d6;
+  color: #f7f3e8;
+  background: transparent;
+}
+
+.book .book-body .page-wrapper .page-inner section.normal :not(pre) > code {
+  padding: 0.12em 0.35em;
+  color: #7a3526;
+  background: #f1e5d2;
+  border: 1px solid #dfcdb2;
+  border-radius: 3px;
+}
+
+/* High-contrast syntax colours for Pandoc and highlight.js output. */
+.book section.normal pre code .kw,
+.book section.normal pre code .cf,
+.book section.normal pre code .hljs-keyword,
+.book section.normal pre code .hljs-selector-tag {
+  color: #ffd166;
+  font-weight: 600;
+}
+
+.book section.normal pre code .fu,
+.book section.normal pre code .bu,
+.book section.normal pre code .hljs-title,
+.book section.normal pre code .hljs-built_in {
+  color: #73daca;
+}
+
+.book section.normal pre code .st,
+.book section.normal pre code .ch,
+.book section.normal pre code .vs,
+.book section.normal pre code .ss,
+.book section.normal pre code .hljs-string {
+  color: #b8e986;
+}
+
+.book section.normal pre code .dv,
+.book section.normal pre code .bn,
+.book section.normal pre code .fl,
+.book section.normal pre code .cn,
+.book section.normal pre code .hljs-number,
+.book section.normal pre code .hljs-literal {
+  color: #ffad7d;
+}
+
+.book section.normal pre code .co,
+.book section.normal pre code .do,
+.book section.normal pre code .an,
+.book section.normal pre code .cv,
+.book section.normal pre code .hljs-comment {
+  color: #b7c4c1;
+  font-style: italic;
+}
+
+.book section.normal pre code .op,
+.book section.normal pre code .sc,
+.book section.normal pre code .hljs-operator,
+.book section.normal pre code .hljs-punctuation {
+  color: #f4d6a0;
+}
+
+.book section.normal pre code .va,
+.book section.normal pre code .at,
+.book section.normal pre code .dt,
+.book section.normal pre code .hljs-variable,
+.book section.normal pre code .hljs-attr {
+  color: #9ecbff;
 }
 
 .book .book-body .page-wrapper .page-inner section.normal table {