enable quarto book configuration with custom css

_quarto.yml

+project:
+  type: book
+  resources:
+    - "dimension_reduction.pdf"
+    - "clustering.pdf"
+    - "regression_multiple_testing.pdf"
+  output-dir: public/
+
+book:
+  title: "ENSL M1 BioScience - Machine Learning"
+  author:
+    - Franck Picard
+    - Laurent Modolo
+    - Ghislain Durif
+  date: "2023-10-16"
+  chapters:
+    - index.md
+    - part: 1_dimred.qmd
+      chapters: 
+        - text: Course
+          href: 1_dimred/course.qmd
+        - text: Practice
+          href: Practical_a.Rmd
+    - part: 2_clustering.qmd
+      chapters:
+        - text: Course
+          href: 2_clustering/course.qmd
+        - text: Practice
+          href: Practical_b.Rmd
+    - part: 3_linmod_multitest.qmd
+      chapters: 
+        - text: Course
+          href: 3_linmod_multitest/course.qmd
+        - text: Practice
+          href: Practical_c.Rmd
+    - part: 4_modsel_regul.qmd
+      chapters:
+        - text: Course
+          href: 4_modsel_regul/course.qmd
+        - text: Practice
+          href: Practical_d.Rmd
+    #- M1_biosciences_dimension_reduction/main.qmd
+  page-footer: 
+    center: "License: [CC BY-SA 4.0](http://creativecommons.org/licenses/by-sa/4.0/)"
+    right: "Made with [Quarto](https://quarto.org/)."
+  navbar:
+    search: true
+    right:
+      - icon: git
+        href: https://gitbio.ens-lyon.fr/LBMC/hub/formations/ens_m1_ml
+        text: Sources
+
+format:
+  html:
+    theme:
+      light: flatly
+      dark: darkly
+    css: styles.css
+  # pdf:
+  #   documentclass: scrreprt
+
+execute: 
+  cache: true

styles.css

+.pencadre {
+  border: 4px;
+  border-style: solid;
+  border-color: #034b6f;
+  background-color: #eef3f9;
+  padding: 1em;
+  text-align: left;
+  border-radius: 5px 4px 3px 2px;
+}
+
+.red_pencadre {
+  border: 6px;
+  border-style: solid;
+  border-color: #d53600;
+  background-color: #f9e9e7;
+  padding: 1em;
+  text-align: left;
+  border-radius: 5px 4px 3px 2px;
+}
+
+details {
+  border: 4px;
+  border-style: solid;
+  border-color: #999999;
+  background-color:  #f9f9f9;
+  padding-right: 1em;
+  padding-left: 1em;
+  text-align: left;
+  border-radius: 5px 4px 3px 2px;
+}