/* ============================================================
   DEAR Lab - Layout system
   12-column shell, full-bleed sections, editorial splits
   ============================================================ */

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

.shell--narrow { max-width: 1080px; }

/* --- Sections --- */
.section {
  position: relative;
  padding-block: var(--section-y);
}

.section--tight  { padding-block: clamp(3rem, 7vh, 5.5rem); }
.section--flush-top { padding-top: 0; }

.surface--ink    { background: var(--ink); }
.surface--deep   { background: var(--ink-deep); }
.surface--raised { background: var(--paper-warm); }
.surface--paper  { background: var(--paper); }
.surface--warm   { background: var(--paper-warm); }
.surface--bone   { background: var(--paper-warm); }

/* Grain is stronger on flat colour fields */
.surface--warm::before,
.surface--raised::before,
.surface--deep::before,
.surface--ink::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image: var(--grain);
  opacity: 0.4;
  mix-blend-mode: multiply;
  pointer-events: none;
}

.surface--deep::before,
.surface--raised::before { mix-blend-mode: overlay; opacity: 0.3; }

.section > .shell { position: relative; z-index: 1; }

/* --- Hairline rules as structure --- */
.rule {
  height: 1px;
  background: var(--line);
  border: 0;
}

.surface--ink .rule, .surface--deep .rule { background: var(--ink-line); }

/* --- The 12-column grid --- */
.grid {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: var(--stack-md) clamp(1rem, 2.5vw, 2.5rem);
}

.col-full { grid-column: 1 / -1; }
.col-1-4  { grid-column: 1 / span 4; }
.col-1-5  { grid-column: 1 / span 5; }
.col-1-6  { grid-column: 1 / span 6; }
.col-1-7  { grid-column: 1 / span 7; }
.col-2-10 { grid-column: 2 / span 9; }
.col-5-12 { grid-column: 5 / span 8; }
.col-6-12 { grid-column: 6 / span 7; }
.col-7-12 { grid-column: 7 / span 6; }
.col-8-12 { grid-column: 8 / span 5; }

/* --- Section head: marker in the margin, headline in the field --- */
.sect-head {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: var(--stack-sm) clamp(1rem, 2.5vw, 2.5rem);
  align-items: start;
  margin-bottom: var(--stack-xl);
}

.sect-head__marker {
  grid-column: 1 / span 2;
  padding-top: 0.6em;
}

.sect-head__body { grid-column: 3 / span 8; }

.sect-head__title {
  margin-top: var(--stack-sm);
}

.sect-head__lead { margin-top: var(--stack-md); }

/* --- Auto grids --- */
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: clamp(1rem, 2vw, 1.75rem);
}

.cards--wide {
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
}

/* --- Editorial split: sticky label column + flowing body --- */
.split {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: var(--stack-lg) clamp(1rem, 2.5vw, 2.5rem);
}

.split__aside {
  grid-column: 1 / span 3;
  position: sticky;
  top: calc(var(--nav-h) + 2rem);
  align-self: start;
}

.split__body { grid-column: 5 / span 8; }

/* --- Full-bleed figure --- */
.bleed {
  position: relative;
  width: 100vw;
  margin-inline: calc(50% - 50vw);
}

@media (max-width: 900px) {
  .sect-head__marker { grid-column: 1 / -1; padding-top: 0; }
  .sect-head__body   { grid-column: 1 / -1; }
  .sect-head         { margin-bottom: var(--stack-lg); }

  .col-1-4, .col-1-5, .col-1-6, .col-1-7,
  .col-2-10, .col-5-12, .col-6-12, .col-7-12, .col-8-12 { grid-column: 1 / -1; }

  .split__aside { grid-column: 1 / -1; position: static; }
  .split__body  { grid-column: 1 / -1; }
}