Does static templates support using pathto()?

[liborjelinek]

I have a static template, e.g., main.css.jinja. From it, I need to refer to a static file. To prevent hard-coding paths, I wish to use pathto(). For example, to add arrow icon to external links:

a.external::after {
   display: inline-block;
   content: url("{{ pathto('_static/icons/arrow.svg', 1) }}");
   width: 1cap;
   height: 1cap;
   margin-left: 0.25em;
}

But it ends with an error

WARNING: Failed to copy a file in the theme's 'static' directory: <PATH_TO_THEME>/static/styles/main.css.jinja: UndefinedError("'pathto' is undefined")