/* ==========================================================================
   Layout — page skeleton, container system, section rhythm, grids.
   Mobile-first. No horizontal overflow permitted at any breakpoint.
   ========================================================================== */

.site {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.site-main {
  flex: 1 1 auto;
}

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

@media (min-width: 768px) {
  .container {
    padding-inline: var(--gutter-tablet);
  }
}

@media (min-width: 1024px) {
  .container {
    padding-inline: var(--gutter-desktop);
  }
}

/* ---- Section rhythm ---- */
.section {
  padding-block: var(--space-2xl);
}

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

.section--muted {
  background: var(--color-surface-muted);
}

@media (min-width: 1024px) {
  .section {
    padding-block: var(--space-3xl);
  }
}

.section-head {
  max-width: 640px;
  margin-bottom: var(--space-xl);
}

.section-head p {
  margin-top: var(--space-xs);
}

/* ---- Grid helpers ---- */
.grid {
  display: grid;
  gap: var(--space-lg);
}

.grid--2 { grid-template-columns: 1fr; }
.grid--3 { grid-template-columns: 1fr; }
.grid--4 { grid-template-columns: 1fr; }

@media (min-width: 640px) {
  .grid--2 { grid-template-columns: repeat(2, 1fr); }
  .grid--4 { grid-template-columns: repeat(2, 1fr); }
}

@media (min-width: 900px) {
  .grid--3 { grid-template-columns: repeat(3, 1fr); }
  .grid--4 { grid-template-columns: repeat(4, 1fr); }
}

/* ---- Header ---- */
.site-header {
  border-bottom: 1px solid var(--color-border);
  background: var(--color-surface);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: var(--header-height);
  gap: var(--space-md);
}

/* ---- Footer ---- */
.site-footer {
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
  margin-top: var(--space-2xl);
}

.footer-grid {
  display: grid;
  gap: var(--space-xl);
  grid-template-columns: 1fr;
  padding-block: var(--space-2xl);
}

@media (min-width: 640px) {
  .footer-grid {
    grid-template-columns: 1.2fr repeat(3, 1fr);
  }
}

.footer-grid h2 {
  font-size: var(--fs-sm);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--color-text-secondary);
  margin-bottom: var(--space-sm);
}

.footer-links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.footer-links a {
  color: var(--color-text-primary);
  text-decoration: none;
  font-size: var(--fs-sm);
}

.footer-links a:hover {
  color: var(--color-primary);
  text-decoration: underline;
}

.footer-bottom {
  border-top: 1px solid var(--color-border);
  padding-block: var(--space-md);
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  justify-content: space-between;
  align-items: center;
  font-size: var(--fs-xs);
  color: var(--color-text-secondary);
}

/* ---- Tool workspace shell (structural only — Phase 02 fills logic) ---- */
.tool-workspace {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-lg);
}

@media (min-width: 900px) {
  .tool-workspace {
    grid-template-columns: 1fr 340px;
    align-items: start;
  }
  .tool-workspace--reverse {
    grid-template-columns: 340px 1fr;
  }
}

.tool-workspace__preview {
  order: 1;
}

.tool-workspace__controls {
  order: 2;
}

/* ---- Utility layout classes ---- */
.stack {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.cluster {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-sm);
}

.no-overflow-x {
  overflow-x: hidden;
}