enhance: add a font for markup MathML

Assisted-by: Copilot Coding Agent:GPT-5

Co-authored-by: bircni <75789103+bircni@users.noreply.github.com>

web_src/css/markup/content.css

@@ -5,6 +5,16 @@
   overflow-wrap: break-word;
 }
 
+@font-face {
+  font-family: NewComputerModernMath;
+  src: local("NewComputerModernMath"), url("../../fonts/NewCMMath-Book.woff2") format("woff2");
+}
+
+.markup math {
+  font-family: NewComputerModernMath, "Latin Modern Math", "STIX Two Math", "Cambria Math", math;
+  font-size-adjust: ex-height 0.52;
+}
+
 .markup > *:first-child {
   margin-top: 0 !important;
 }

web_src/fonts/GUST-FONT-LICENSE.txt

@@ -0,0 +1,28 @@
+% This is version 1.0, dated 22 June 2009, of the GUST Font License.
+% (GUST is the Polish TeX Users Group, http://www.gust.org.pl)
+%
+% For the most recent version of this license see
+% http://www.gust.org.pl/fonts/licenses/GUST-FONT-LICENSE.txt
+% or
+% http://tug.org/fonts/licenses/GUST-FONT-LICENSE.txt
+%
+% This work may be distributed and/or modified under the conditions
+% of the LaTeX Project Public License, either version 1.3c of this
+% license or (at your option) any later version.
+%
+% Please also observe the following clause:
+% 1) it is requested, but not legally required, that derived works be
+%    distributed only after changing the names of the fonts comprising this
+%    work and given in an accompanying "manifest", and that the
+%    files comprising the Work, as listed in the manifest, also be given
+%    new names. Any exceptions to this request are also given in the
+%    manifest.
+%
+%    We recommend the manifest be given in a separate file named
+%    MANIFEST-<fontid>.txt, where <fontid> is some unique identification
+%    of the font family. If a separate "readme" file accompanies the Work,
+%    we recommend a name of the form README-<fontid>.txt.
+%
+% The latest version of the LaTeX Project Public License is in
+% http://www.latex-project.org/lppl.txt and version 1.3c or later
+% is part of all distributions of LaTeX version 2006/05/20 or later.