/* ============================================================================
   Fira Sans — the shipped brand webfont.
   ============================================================================

   WHY THIS FILE EXISTS AT ALL. Frutiger LT Com is the Fraunhofer SIT brand
   typeface and remains the authority for *print* (real licensed TTFs live in the
   `reporting` repo). Its **web** licence could never be confirmed: the TTFs are
   licensed for the LaTeX build, and a desktop licence does not cover webfont
   embedding. A previous set of 11 unused woff2 files was removed from this repo
   for exactly that reason, and the design skill has said ever since: do not add
   @font-face without a real licensed file. This is that real licensed file.

   THE FACE. Fira Sans, by Erik Spiekermann and Ralph du Carrois (Carrois Corporate
   Design) for Mozilla and Telefónica. Humanist sans, drawn for legibility at small
   sizes on screens — the same functional brief that produced Frutiger for airport
   signage. Shares Frutiger's structural tells: double-storey `a`, single-storey
   `g`, wide open apertures on a/c/e/s, a very generous x-height, and slightly
   squarish round forms.

   THE LICENCE. SIL Open Font License 1.1 — `static/fonts/OFL.txt`, committed
   verbatim from upstream. Copyright (c) 2012-2015 The Mozilla Foundation and
   Telefonica S.A. The copyright line declares **no Reserved Font Name**, so the
   family may be served under its own name. OFL 1.1 explicitly permits embedding
   and redistribution with software, including commercially; the only bar is
   selling the font by itself. Self-hosting is therefore unambiguously allowed —
   which matters, because exercises run on a hospital LAN with no internet, so a
   Google Fonts CDN link is not an option. The files are the unmodified upstream
   woff2 builds from github.com/mozilla/Fira (`woff2/`), not a repackaging.

   WHY ONLY FOUR WEIGHTS. Frutiger ships four faces to the LaTeX build — Light,
   Roman, Bold, Black — and the design language is built on that set (see the
   weight-contrast rule: a heading and its subordinate line at the *same size*,
   Bold over Light). Fira Sans maps onto it exactly: Light 300 / Regular 400 /
   Bold 700 / Heavy 900. Weight mapping is upstream's own, from `fira.css` in the
   Mozilla repo — not guessed.

   The repo also declares 500, 600 and 800. Those are deliberately NOT shipped:
   CSS font matching resolves 500 -> 400, and 600/800 -> 700/900, which is exactly
   what the old Helvetica/Arial fallback already did with its two faces. So this
   file adds a real Light and a real Black where there were none, and changes
   nothing about how 500/600/800 render. Shipping two more files to buy a tier the
   design language never asked for is not worth 280 KB.

   font-display:swap — a projector in a room full of people must never show
   invisible text while a font loads. Fallback first, swap when ready.
   ========================================================================== */

@font-face {
  font-family: 'Fira Sans';
  src: url('/static/fonts/FiraSans-Light.woff2') format('woff2');
  font-weight: 300;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: 'Fira Sans';
  src: url('/static/fonts/FiraSans-Regular.woff2') format('woff2');
  font-weight: 400;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: 'Fira Sans';
  src: url('/static/fonts/FiraSans-Bold.woff2') format('woff2');
  font-weight: 700;
  font-style: normal;
  font-display: swap;
}

/* Upstream calls 900 "Heavy"; Google Fonts calls the same face "Black". It is the
   Frutiger Black slot. */
@font-face {
  font-family: 'Fira Sans';
  src: url('/static/fonts/FiraSans-Heavy.woff2') format('woff2');
  font-weight: 900;
  font-style: normal;
  font-display: swap;
}