use hydra for heading, cleanup docs template

docs/main.typ

@@ -14,5 +14,8 @@
 
 #pagebreak()
 
+#lorem(100)
+#pagebreak()
+
 = Fazit
 #lorem(100)
\ No newline at end of file

docs/template.typ

-// The project function defines how your document looks.
-// It takes your content and some metadata and formats it.
-// Go ahead and customize it to your liking!
+#import "@preview/hydra:0.6.0": hydra
+
 #let project(title: "", subtitle: "", authors: (), logo: none, body) = {
 
   // Set the document's basic properties.
@@ -42,54 +41,19 @@
 
   set page(numbering: "I", number-align: center)
 
+  // Table of contents
+  outline(depth: 3)
+  pagebreak()
 
-/*let ht-first = state("page-first-section", [])
-  let ht-last = state("page-last-section", [])
-
-  set page(
-    header: {
-      locate(loc => {
-          // find first heading of level 1 on current page
-          let first-heading = query(
-            heading.where(level: 1), loc)
-            .find(h => h.location().page() == loc.page())
-          // find last heading of level 1 on current page
-          let last-heading = query(
-            heading.where(level: 1), loc)
-            .rev()
-            .find(h => h.location().page() == loc.page())
-          // test if the find function returned none (i.e. no headings on this page)
-          {
-            if not first-heading == none {
-              ht-first.update([
-                // change style here if update needed section per section
-                #first-heading.body
-              ])
-              ht-last.update([
-                // change style here if update needed section per section
-                #last-heading.body
-              ])
-
-              // if one or more headings on the page, use first heading
-              // change style here if update needed page per page
-              ht-first.display()
-            } else {
-              // no headings on the page, use last heading from variable
-              // change style here if update needed page per page
-              ht-last.display()
-            }
-          }
-        }
-      )
-
+  let show-header(ctx, candidates) = {
+    candidates.body
     v(-0.8em)
     line(length: 100%, stroke: 0.5pt)
   }
-  )*/
 
-  // Table of contents
-  outline(depth: 3)
-  pagebreak()
+  set page(header: context {
+    hydra(1, skip-starting: false, display: show-header)
+  })
 
   set page(numbering: "1")
   counter(page).update(1)