/* ============================================================================
   f(x) → NATURE DS — Utilities & signature motifs
   Layout helpers, technical labels, grid background, crosshair frames, dividers.
   These carry the brutalist identity and are reused by every section.
   Depends on tokens.css.
   ============================================================================ */

/* --- Container & sections ------------------------------------------- */
.fd-container {
  width: 100%;
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: var(--space-6);
}
@media (max-width: 768px) {
  .fd-container { padding-inline: var(--space-4); }
}

.fd-section {
  padding-block: var(--space-20);
  border-top: var(--border-width) solid var(--border);
  scroll-margin-top: calc(var(--header-height) + var(--space-4));
}
.fd-section:first-of-type { border-top: 0; }

.fd-section__head {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  margin-bottom: var(--space-10);
}
.fd-section__title {
  font-size: var(--text-4xl);
  font-weight: var(--weight-black);
  letter-spacing: var(--tracking-tight);
  text-transform: uppercase;
}
.fd-section__lead {
  max-width: 62ch;
  color: var(--foreground-muted);
  font-size: var(--text-lg);
  line-height: var(--leading-relaxed);
}

/* --- Technical mono label (e.g. "[02] / COMPONENTS / BUTTONS") ------- */
.fd-label {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-mono);
  font-size: var(--text-2xs);
  font-weight: var(--weight-medium);
  letter-spacing: var(--tracking-label);
  text-transform: uppercase;
  color: var(--foreground-subtle);
}
.fd-label--accent { color: var(--accent-text); }
.fd-label__index { color: var(--accent-text); }
.fd-label__sep { color: var(--foreground-faint); }

/* --- Eyebrow + display helpers -------------------------------------- */
.fd-display { font-family: var(--font-display); font-weight: var(--weight-black); }
.fd-mono { font-family: var(--font-mono); }
.fd-text-muted { color: var(--foreground-muted); }
.fd-text-subtle { color: var(--foreground-subtle); }
.fd-text-accent { color: var(--accent-text); }

/* --- Signature grid background -------------------------------------- */
.fd-grid-bg {
  background-image:
    linear-gradient(var(--border-faint) var(--border-width), transparent var(--border-width)),
    linear-gradient(90deg, var(--border-faint) var(--border-width), transparent var(--border-width));
  background-size: var(--space-8) var(--space-8);
  background-position: center top;
}
.fd-grid-bg--fade {
  -webkit-mask-image: radial-gradient(ellipse 80% 70% at 50% 0%, #000 30%, transparent 80%);
  mask-image: radial-gradient(ellipse 80% 70% at 50% 0%, #000 30%, transparent 80%);
}

/* --- Crosshair frame: a bordered box with + markers at each corner --- */
.fd-frame {
  position: relative;
  border: var(--border-width) solid var(--border);
  background: var(--surface);
}
.fd-frame--crosshair::before,
.fd-frame--crosshair::after,
.fd-frame--crosshair > .fd-crosshair {
  pointer-events: none;
}
/* corner crosshair marks */
.fd-crosshair {
  position: absolute;
  width: 11px; height: 11px;
  z-index: 2;
}
.fd-crosshair::before,
.fd-crosshair::after {
  content: "";
  position: absolute;
  background: var(--accent);
}
.fd-crosshair::before { left: 50%; top: 0; width: var(--border-width); height: 100%; transform: translateX(-50%); }
.fd-crosshair::after  { top: 50%; left: 0; height: var(--border-width); width: 100%; transform: translateY(-50%); }
.fd-crosshair--tl { top: -6px; left: -6px; }
.fd-crosshair--tr { top: -6px; right: -6px; }
.fd-crosshair--bl { bottom: -6px; left: -6px; }
.fd-crosshair--br { bottom: -6px; right: -6px; }

/* --- Divider --------------------------------------------------------- */
.fd-divider {
  border: 0;
  border-top: var(--border-width) solid var(--border);
  margin-block: var(--space-8);
}
.fd-divider--dashed { border-top-style: dashed; }

/* --- Demo card: live example + meta (used across component sections) -- */
.fd-demo {
  border: var(--border-width) solid var(--border);
  background: var(--surface);
  margin-bottom: var(--space-8);
}
.fd-demo__title {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: var(--space-4);
  padding: var(--space-3) var(--space-4);
  border-bottom: var(--border-width) solid var(--border);
  background: var(--background-subtle);
}
.fd-demo__name {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: var(--tracking-wide);
  text-transform: uppercase;
  color: var(--foreground-muted);
}
.fd-demo__meta { font-family: var(--font-mono); font-size: var(--text-2xs); color: var(--foreground-faint); }
.fd-demo__stage {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-4);
  padding: var(--space-10) var(--space-6);
  min-height: 120px;
  background:
    radial-gradient(var(--border-faint) var(--border-width), transparent var(--border-width));
  background-size: 16px 16px;
}
.fd-demo__stage--column { flex-direction: column; align-items: flex-start; }
.fd-demo__stage--center { justify-content: center; }

/* --- Code snippet block --------------------------------------------- */
.fd-code {
  position: relative;
  border-top: var(--border-width) solid var(--border);
  background: var(--background);
}
.fd-code pre {
  margin: 0;
  padding: var(--space-4) var(--space-5);
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  line-height: var(--leading-relaxed);
  color: var(--foreground-muted);
}
.fd-code pre .tok-key { color: var(--accent-text); }
.fd-code pre .tok-str { color: var(--success-text); }
.fd-code pre .tok-com { color: var(--foreground-faint); }
.fd-code pre .tok-tag { color: var(--info-text); }
.fd-code__copy {
  position: absolute;
  top: var(--space-2);
  right: var(--space-2);
}

/* --- Component grid layout for sections ----------------------------- */
.fd-grid {
  display: grid;
  gap: var(--space-6);
}
.fd-grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.fd-grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.fd-grid--4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }
@media (max-width: 900px) {
  .fd-grid--3, .fd-grid--4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (max-width: 600px) {
  .fd-grid--2, .fd-grid--3, .fd-grid--4 { grid-template-columns: 1fr; }
}

.fd-stack { display: flex; flex-direction: column; }
.fd-row { display: flex; align-items: center; }
.fd-wrap { flex-wrap: wrap; }
.fd-gap-2 { gap: var(--space-2); }
.fd-gap-3 { gap: var(--space-3); }
.fd-gap-4 { gap: var(--space-4); }
.fd-gap-6 { gap: var(--space-6); }