store side art as one ANSI file, render it with PHP (cached)

css/style.css

@@ -188,9 +188,9 @@ button {
 }
 
 /* ── side art ───────────────────────────────────────────────────────────
-   Full-height sakura in both margins: colored ASCII art (inc/art/left.html
-   and right.html, 104x88 characters), mirrored so the branches hang in from
-   the outer corners. Hidden when there's no margin. */
+   Full-height sakura in both margins: ANSI art (inc/art/sakura.ans, `cat`
+   it), turned into HTML by inc/art.php and mirrored for the right side so the
+   branches hang in from the outer corners. Hidden when there's no margin. */
 
 /* The art is drawn for .6em-wide characters; system monospaces range from
    .5em up, which squashes it. So it gets its own: JetBrains Mono's printable
@@ -219,14 +219,6 @@ button {
    ltr, or the bidi algorithm reorders runs of punctuation */
 .side-right { right: 0; direction: rtl; }
 .side-right > span { direction: ltr; unicode-bidi: isolate; }
-.side .a0 { color: #8c6068; }
-.side .a1 { color: #a07076; }
-.side .a2 { color: #ffb0cc; }
-.side .a3 { color: #ff96be; }
-.side .a4 { color: #f678ac; }
-.side .a5 { color: #ffd4e4; }
-.side .a6 { color: #e86098; }
-.side .a7 { color: #ffecbe; }
 
 /* the column's shadow: the art fades out under it instead of stopping dead
    beside the text. Eased falloff, as wide as about a third of the margin. */