.shell {
  max-width: var(--content-max);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.measure {
  max-width: var(--measure);
}

.section {
  padding-block: var(--section-space);
}

.section--tight {
  padding-block: clamp(3rem, 6vw, 6rem);
}

.surface-dark {
  background: var(--surface-dark);
  color: var(--text-on-dark);
}

.surface-dark .muted { color: var(--text-on-dark-muted); }
.surface-light .muted,
.muted { color: var(--text-on-light-muted); }

.grid-12 {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: clamp(1rem, 2vw, 2rem);
}

.grid-8 {
  display: grid;
  grid-template-columns: repeat(8, 1fr);
  gap: clamp(1rem, 2vw, 2rem);
}

.grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1rem;
}

@media (max-width: 900px) {
  .grid-12, .grid-8 { grid-template-columns: repeat(4, 1fr); }
}

.split {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: clamp(2rem, 5vw, 5rem);
  align-items: start;
}

@media (max-width: 900px) {
  .split { grid-template-columns: 1fr; }
}

.split--narrow-right {
  grid-template-columns: 1.4fr 1fr;
}

@media (max-width: 900px) {
  .split--narrow-right { grid-template-columns: 1fr; }
}

.full-bleed {
  width: 100%;
}

.stack {
  display: flex;
  flex-direction: column;
}

.stack > * + * { margin-top: var(--gap, 1rem); }

.row {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--gap, 1rem);
}

.eyebrow {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--size-label);
  letter-spacing: var(--tracking-label);
  text-transform: uppercase;
  color: var(--green-700);
  margin-bottom: 1rem;
}

.surface-dark .eyebrow { color: var(--green-500); }

.rule {
  border: 0;
  border-top: var(--border-width) solid var(--border-on-light);
  margin: 0;
}

.surface-dark .rule { border-top-color: var(--border-on-dark); }

.sticky-rail {
  position: sticky;
  top: calc(var(--header-height, 88px) + 2rem);
  align-self: start;
}

@media (max-width: 900px) {
  .sticky-rail { position: static; }
}