Optimized webfonts

- Replaced ancient TTF fallback with less ancient WOFF fallback
- WOFF2 and WOFF fonts are now dehinted and subsetted
- Added CSS `format()` function to font-faces
- Added font-display rule

public/assets/css/style.css

@@ -9,20 +9,22 @@
 
 @font-face {
     font-family: "Roboto Mono";
-    font-weight: 400;
-    src: local("Roboto Mono Regular"),
-         local("RobotoMono-Regular"),
-         url("../fonts/RobotoMono-Regular.woff2"),
-         url("../fonts/RobotoMono-Regular.ttf");
+    font-weight: normal;
+    font-style: normal;
+    src: local("Roboto Mono Regular"), local("RobotoMono-Regular"),
+         url("../fonts/RobotoMono-Regular.woff2") format("woff2"),
+         url("../fonts/RobotoMono-Regular.woff") format("woff");
+    font-display: optional;
 }
 
 @font-face {
     font-family: "Roboto Mono";
-    font-weight: 700;
-    src: local("Roboto Mono Bold"),
-         local("RobotoMono-Bold"),
-         url("../fonts/RobotoMono-Bold.woff2"),
-         url("../fonts/RobotoMono-Bold.ttf");
+    font-weight: bold;
+    font-style: normal;
+    src: local("Roboto Mono Bold"), local("RobotoMono-Bold"),
+         url("../fonts/RobotoMono-Bold.woff2") format("woff2"),
+         url("../fonts/RobotoMono-Bold.woff") format("woff");
+    font-display: optional;
 }
 
 /* -- Cornerstones -- */