font-display
swap
custom font
を読み込むまでは、
system font
を表示する、というやつ
たぶん
https://developer.mozilla.org/en-US/docs/Web/CSS/@font-face/font-display
https://web.dev/font-display/?utm_source=lighthouse&utm_medium=devtools#how-to-avoid-showing-invisible-text
https://web.dev/avoid-invisible-text/#option-1:-use-font-display
#??
@font-face