I'm trying to modify the fonts in my document so that normal text comes up in Calluna, and maths comes up in Computer Modern Bright.
My preamble goes something like this:
\documentclass{article}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{ifxetex}
\ifxetex
\usepackage{fontspec}
\usepackage{unicode-math}
\setmainfont{Calluna}
\setmathfont{Asana Math}
%\setmathfont[range=\mathup]{CMU Bright Medium}
%\setmathfont[range=\mathbfup]{CMU Bright SemiBold}
%\setmathfont[range=\mathbfit]{CMU Bright SemiBold}
%\setmathfont[range=\mathit]{CMU Bright Medium Oblique}
\else
\usepackage[T1]{fontenc}
\usepackage{cmbright}
\fi
I've gotten to this stage after looking at other examples on this site that appeared to work for other people.
All the \setmathfont commands are commented out because they gave me an error "font-not-found". Currently, Asana Math is working (for some reason). Other fonts like Latin Modern Math do not.
Calluna is one of my system fonts and comes up fine.
How should I proceed in order to set the maths font to CM Bright? Also, what exactly does the package unicode-math do?

