body {
  min-height: 100vh;
  background: var(--color-bg);
  color: var(--color-text);
  font-size: 0.875rem;
  font-weight: 500;
  line-height: 1.6;
  text-rendering: optimizeLegibility;
}
body, button, input, select, textarea { font-family: inherit; }
h1, h2, h3 { font-weight: 500; }
strong { font-weight: 600; }
a { text-decoration-thickness: 1px; text-underline-offset: 3px; }
button, .button {
  display: inline-flex;
  min-height: 44px;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  border: 1px solid var(--color-input-line);
  border-radius: 0;
  background: var(--color-surface);
  color: var(--color-text);
  padding: 8px var(--space-4);
  font-size: 0.875rem;
  font-weight: 500;
  line-height: 1.4;
  text-align: center;
  text-decoration: none;
}
.button--primary { border-color: var(--color-accent); background: var(--color-accent); color: #ffffff; }
.button--secondary { background: var(--color-surface); }
.button--text { border-color: transparent; background: transparent; padding-inline: 0; color: var(--color-text-muted); text-decoration: underline; text-decoration-color: var(--color-line-strong); text-underline-offset: 4px; }
button:disabled, .button[aria-disabled="true"] { cursor: not-allowed; opacity: 0.5; }
:where(a, button, input, select, textarea, summary):focus-visible { outline: 2px solid var(--color-accent); outline-offset: 3px; }
::selection { background: var(--color-item-one); color: var(--color-text); }
input, textarea { caret-color: var(--color-text); }
.skip-link { position: fixed; z-index: 20; top: 12px; left: 12px; transform: translateY(-180%); background: var(--color-text); color: white; padding: 8px 16px; text-decoration: none; }
.skip-link:focus { transform: translateY(0); }
.panel__header { display: flex; min-height: 44px; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 4px var(--space-3); }
.panel__header h2, .lesson-note h2 { font-size: 1rem; line-height: 1.4; }
.panel__eyebrow, .lesson-intro__eyebrow, .sidebar__eyebrow { color: var(--color-text-muted); font-size: 0.8125rem; font-weight: 500; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation-duration: 0.01ms !important; animation-iteration-count: 1 !important; transition-duration: 0.01ms !important; }
}