phanpy/src/cloak-mode.css

body.cloak .name-text,
body.cloak .status .content-container,
body.cloak .account-container :is(header, main > *:not(.actions)) {
  text-decoration-thickness: 1.1em;
  text-decoration-line: line-through;
  text-rendering: optimizeSpeed;
}

body.cloak .status :is(img, video, audio),
body.cloak .avatar,
body.cloak .emoji,
body.cloak .header-banner {
  filter: contrast(0) !important;
  background-color: #000 !important;
}