While working on my custom Anki cards for learning Japanese and Turkish, I found that my font of choice for Japanese - IPAex - was not properly supporting glyphs used by Turkish, like ğ.

To fix this i am using a property of the @font-face rule which limits custom fonts to source their glyphs from a subset of the unicode range and force fallback to the next font in the set.

@font-face {
    font-family: "IPAexGothic";
    src:
        local("IPAexGothic"),
        url("_ipaexg.ttf");
    unicode-range:
        U+0020-007F,
        U+3000-303f,
        U+3040-309f,
        U+30a0-30ff,
        U+ff00-ffef,
        U+4e00-9faf;
}

.card {
    font-family:
        IPAexGothic,
        Noto Sans,
        sans;
}