improvement(dark-mode): Improve colors in dark mode

.gitignore

@@ -133,3 +133,5 @@ dmypy.json
 
 # Jupyter Book
 _build/
+
+book/_config.yml.bak

book/_static/fix_alert_dark_mode.css

+html[data-theme="dark"] .alert {
+  --bs-alert-bg: #132119;
+  --bs-alert-color: #d1e7dd;
+}

book/_static/image_dark_mode.css

+html[data-theme="dark"] main img:not(.only-dark):not(.dark-light) {
+  filter: invert(1) hue-rotate(180deg);
+}