/* ============================================================
   LAYOUT
   ============================================================ */

.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 var(--section-x);
}

.container--sm {
  max-width: var(--container-sm);
}

/* ---- Section ---- */
section {
  padding: var(--section-y) 0;
}

.section-header {
  margin-bottom: 3.5rem;
}

.section-eyebrow {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  color: var(--text-tertiary);
  margin-bottom: 0.75rem;
  text-transform: uppercase;
}

.section-title {
  font-family: var(--font-heading);
  font-size: clamp(1.75rem, 3.5vw, 2.5rem);
  font-weight: 700;
  letter-spacing: -0.025em;
  line-height: 1.2;
  color: var(--text-primary);
}

.section-subtitle {
  font-size: 1rem;
  color: var(--text-secondary);
  margin-top: 0.75rem;
  max-width: 560px;
  line-height: 1.7;
}

/* ---- Grid helpers ---- */
.grid-2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}

/* ---- Scroll Progress ---- */
.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  width: 0%;
  height: 2px;
  background: var(--accent);
  z-index: 1001;
  transition: width 0.1s linear;
}

/* ---- Preloader ---- */
.preloader {
  position: fixed;
  inset: 0;
  background: var(--bg-page);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 9999;
  transition: opacity 0.4s ease, visibility 0.4s ease;
}

.preloader.hidden {
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
}

.preloader-spinner {
  width: 24px;
  height: 24px;
  border: 2px solid var(--border);
  border-top-color: var(--text-primary);
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
}

/* ---- Back to Top ---- */
.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 40px;
  height: 40px;
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-secondary);
  font-size: 1rem;
  cursor: pointer;
  z-index: 100;
  opacity: 0;
  visibility: hidden;
  transform: translateY(8px);
  transition: all var(--transition);
  box-shadow: var(--shadow-sm);
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  background: var(--bg-elevated);
  color: var(--text-primary);
  box-shadow: var(--shadow-md);
}

@keyframes spin {
  to { transform: rotate(360deg); }
}