body {
  background-color: var(--color-bg);
  color: var(--color-fg);
  font-family: var(--font-body);
  font-size: var(--text-body);
  line-height: 1.75;
}

/* Invisible measurement point for the nav's scroll-state
   IntersectionObserver in js/main.js; carries no visual weight. */
.nav-scroll-sentinel {
  position: absolute;
  top: 20px;
  width: 1px;
  height: 1px;
  pointer-events: none;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: absolute;
  top: -40px;
  left: var(--space-sm);
  z-index: 200;
  background: var(--color-surface);
  color: var(--color-fg);
  padding: 10px 16px;
  border-radius: var(--radius-sm);
  font-family: var(--font-heading);
  font-size: 14px;
  font-weight: 600;
  transition: top var(--transition);
}

.skip-link:focus {
  top: var(--space-sm);
}

.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--container-pad);
}

.grad-line {
  height: 1px;
  background: var(--gradient-divider);
  opacity: 0.55;
}

.eyebrow {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-aqua);
  display: block;
  margin-bottom: var(--space-sm);
}

.section {
  padding-block: var(--space-2xl);
  scroll-margin-top: calc(var(--nav-height) + var(--space-md));
}

.section-head {
  margin-bottom: var(--space-xl);
}

::selection {
  background-color: var(--color-blue);
  color: var(--color-fg);
}

:focus-visible {
  outline: 2px solid var(--color-blue);
  outline-offset: 3px;
  border-radius: var(--radius-sm);
}