Add Manrope variable font (#118)

Manrope is an open-source modern sans-serif font family.

Makefile

@@ -7,10 +7,11 @@ $(PROJ).pdf: lkmpg.tex
 	pdflatex -shell-escape $< 2>/dev/null >/dev/null
 	rm -rf _minted-$(PROJ)
 
-html: lkmpg.tex html.cfg
+html: lkmpg.tex html.cfg assets/Manrope_variable.ttf
 	sed $ 's/\t/    /g' lkmpg.tex > lkmpg-for-ht.tex
 	make4ht --shell-escape --utf8 --format html5 --config html.cfg --output-dir html  lkmpg-for-ht.tex "fn-in"
 	ln -sf lkmpg-for-ht.html html/index.html
+	cp assets/Manrope_variable.ttf html/Manrope_variable.ttf
 	rm -f  lkmpg-for-ht.tex lkmpg-for-ht.xref lkmpg-for-ht.tmp lkmpg-for-ht.html lkmpg-for-ht.css lkmpg-for-ht.4ct lkmpg-for-ht.4tc lkmpg-for-ht.dvi lkmpg-for-ht.lg lkmpg-for-ht.idv lkmpg*.svg lkmpg-for-ht.log lkmpg-for-ht.aux
 	rm -rf _minted-$(PROJ) _minted-lkmpg-for-ht
 
@@ -21,4 +22,4 @@ clean:
 	rm -f *.dvi *.aux *.log *.ps *.pdf *.out lkmpg.bbl lkmpg.blg lkmpg.lof lkmpg.toc
 	rm -rf html
 
-.PHONY: html
+.PHONY: html

html.cfg

@@ -7,6 +7,11 @@
     overflow-x: hidden;
 }}
 
+\Css{@font-face {
+  font-family: Manrope;
+  src: url(Manrope_variable.ttf);
+}}
+
 \Css{body {
     max-width: 55rem;
     box-sizing: border-box;
@@ -24,6 +29,7 @@ color: \#0060DF;
 
 \Css{p, a {
 font-size: 1.2rem;
+font-family: Manrope;
 }}
 
 \Css{p + pre {