The current contents of my custom CSS field if anyone cares:

body, button, input {
  font-family: monospace, "Noto Mono";
  --radius: 0;
}

p, nav button, nav a.button {
  font-size: 11pt;
}

.notification {
  background: inherit;
  color: inherit;
  font-size: inherit;
}

button.primary, a.button.primary {
  background: var(--color-lowered);
  color: var(--color-primary);
}

button.primary:hover, a.button.primary:hover, button:not(nav *):hover, a.button:not(nav *):hover {
  background: var(--color-super-lowered)
}

nav, nav button, nav a.button, .pillmenu a, .sidenav a {
  padding: 0 0.75rem;
  border: none;
  height: unset;
}

nav button::before, nav a::before, .card:not(:has(form)) button, .card:not(:has(form)) a.button {
  border-radius: 0;
}

.pillmenu {
  border: none;
  border-radius: 0;
  --radius: 0;
}

.card, .card-nest, .card-nest .card:last-child {
  border: none;
}