Merge branch 'feature/slides-dumux-logo-background' into 'master'

Feature/slides dumux logo background

See merge request !172

slides/dumux_course_header.html

@@ -13,6 +13,10 @@ body {
 .reveal {
     font-family: var(--font-family), sans-serif;
     background-color: white;
+    background-image: url("https://dumux.org/images/logo.svg");
+    background-size: 15%;
+    background-repeat: no-repeat;
+    background-position: left 15px bottom 30px;
 }
 
 .reveal a {