main_fonsize typo fix (#91)

diff --git a/inst/rmarkdown/templates/posterdown_betterland/resources/template.html b/inst/rmarkdown/templates/posterdown_betterland/resources/template.html
index d3f02cf..01b31f9 100644
--- a/inst/rmarkdown/templates/posterdown_betterland/resources/template.html
+++ b/inst/rmarkdown/templates/posterdown_betterland/resources/template.html
@@ -249,7 +249,7 @@
 }
 .main p {
 padding-top: 20%;
-font-size: $if(main_fonsize)$$main_textsize$$else$170px$endif$;
+font-size: $if(main_textsize)$$main_textsize$$else$170px$endif$;
 text-align: left;
 }
 .fab {