Use a system font stack instead of Open Sans

src/assets/styles/libs/_google-fonts/opensans.scss

@@ -1,49 +1,2 @@
 $fontdir: "../fonts" !default;
 
-@font-face {
-  font-family: 'Open Sans';
-  font-style: italic;
-  font-weight: 400;
-  src: local('Open Sans Italic'), local('OpenSans-Italic'), url('#{$fontdir}/OpenSans-Italic.ttf') format('truetype');
-  font-display: swap;
-}
-
-@font-face {
-  font-family: 'Open Sans';
-  font-style: italic;
-  font-weight: 600;
-  src: local('Open Sans SemiBold Italic'), local('OpenSans-SemiBoldItalic'), url(#{$fontdir}/OpenSans-SemiBoldItalic.ttf) format('truetype');
-  font-display: swap;
-}
-
-@font-face {
-  font-family: 'Open Sans';
-  font-style: italic;
-  font-weight: 800;
-  src: local('Open Sans ExtraBold Italic'), local('OpenSans-ExtraBoldItalic'), url(#{$fontdir}/OpenSans-ExtraBoldItalic.ttf) format('truetype');
-  font-display: swap;
-}
-
-@font-face {
-  font-family: 'Open Sans';
-  font-style: normal;
-  font-weight: 400;
-  src: local('Open Sans Regular'), local('OpenSans-Regular'), url(#{$fontdir}/OpenSans-Regular.ttf) format('truetype');
-  font-display: swap;
-}
-
-@font-face {
-  font-family: 'Open Sans';
-  font-style: normal;
-  font-weight: 600;
-  src: local('Open Sans SemiBold'), local('OpenSans-SemiBold'), url(#{$fontdir}/OpenSans-SemiBold.ttf) format('truetype');
-  font-display: swap;
-}
-
-@font-face {
-  font-family: 'Open Sans';
-  font-style: normal;
-  font-weight: 800;
-  src: local('Open Sans ExtraBold'), local('OpenSans-ExtraBold'), url(#{$fontdir}/OpenSans-ExtraBold.ttf) format('truetype');
-  font-display: swap;
-}

src/assets/styles/libs/_vars.scss

@@ -16,13 +16,13 @@
   $size: (
     element-height:   2.75em,
     element-margin:   2em,
-    letter-spacing:   0.075em,
+    letter-spacing:   0,
     letter-spacing-alt: 0.225em
   );
 
 // Font.
   $font: (
-    family:       ('Open Sans', Helvetica, sans-serif),
+    family:           (-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen-Sans,Ubuntu,Cantarell,"Helvetica Neue",sans-serif),
     family-fixed:     ('Courier New', monospace),
     weight:           400,
     weight-bold:      600,