Safari > Settings > Advanced > Style sheet.

quiet-linkedin-grass.css

/* Quiet LinkedIn — Grass Edition */

main#workspace:has([data-testid="mainFeed"]) {
  display: block !important;
  position: relative !important;
  box-sizing: border-box !important;
  width: calc(100% - 48px) !important;
  min-height: 72vh !important;
  max-width: 1000px !important;
  margin: 24px auto !important;
  border-radius: 18px !important;
  overflow: hidden !important;
  background-color: #6f8f52 !important;
  background-image:
    linear-gradient(
      rgba(255, 255, 255, 0.15),
      rgba(255, 255, 255, 0.15)
    ),
    url("https://images.unsplash.com/photo-1617280137702-32e761be8b26?q=80&w=1887&auto=format&fit=crop") !important;
  background-size: cover !important;
  background-position: center !important;
  background-repeat: no-repeat !important;
  box-shadow: 0 6px 28px rgba(0, 0, 0, 0.12) !important;
}

/* Remove everything inside the feed workspace */
main#workspace:has([data-testid="mainFeed"]) > * {
  display: none !important;
}

main#workspace:has([data-testid="mainFeed"])::before {
  content: "Go outside.";
  position: absolute;
  top: 32px;
  left: 50%;
  transform: translateX(-50%);
  padding: 14px 22px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.78);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
  color: #111;
  font: 600 18px/1.2 -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  white-space: nowrap;
}

a[href="/feed/"],
a[href^="https://www.linkedin.com/feed/"] {
  opacity: 0.35 !important;
}