optimise fonts

fonts are now loaded in a hierarchy:
- title: smallest, loads first, "riki's fluffy little house" characters only
- crit: loads next, contains ASCII + some other stuff, in weights 400-900 (for body text and headings)
- full: loads last, contains everything (italics & monospace too)

static/css/noncritical.css

@@ -15,6 +15,7 @@ dialog[open] {
 /* Command line */
 
 th-command-line {
+    font-family: var(--font-code);
     --recursive-mono: 1;
 
     display: none;
@@ -248,6 +249,7 @@ th-literate-program[data-mode="output"] {
 
 .th-syntax-highlighting span {
     &.comment {
+        --recursive-slnt: -8;
         font-style: oblique 8deg;
         color: var(--syntax-comment);
     }