/* ── Base Styles ── */

body {
  font-family: var(--font-sans);
  font-size: var(--text-base);
  font-weight: var(--weight-normal);
  color: var(--text-primary);
  background-color: var(--surface-1);
  line-height: var(--leading-normal);
  letter-spacing: var(--tracking-normal);
  overflow: hidden;
}

/* ── Typography ── */

h1 {
  font-size: var(--text-3xl);
  font-weight: var(--weight-bold);
  letter-spacing: var(--tracking-tight);
  line-height: var(--leading-tight);
  color: var(--text-primary);
}

h2 {
  font-size: var(--text-2xl);
  font-weight: var(--weight-semibold);
  letter-spacing: var(--tracking-tight);
  line-height: var(--leading-tight);
  color: var(--text-primary);
}

h3 {
  font-size: var(--text-xl);
  font-weight: var(--weight-semibold);
  line-height: var(--leading-tight);
  color: var(--text-primary);
}

h4 {
  font-size: var(--text-md);
  font-weight: var(--weight-semibold);
  line-height: var(--leading-tight);
  color: var(--text-primary);
}

h5 {
  font-size: var(--text-base);
  font-weight: var(--weight-medium);
  line-height: var(--leading-tight);
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: var(--tracking-wide);
}

small {
  font-size: var(--text-sm);
  color: var(--text-secondary);
}

code {
  font-family: var(--font-mono);
  font-size: 0.9em;
  background: var(--surface-2);
  padding: 0.15em 0.4em;
  border-radius: var(--radius-sm);
}

/* ── Links ── */

a:not(.btn) {
  color: var(--color-primary);
  transition: color var(--duration-fast) var(--ease-out);
}

a:not(.btn):hover {
  color: var(--color-primary-light);
}

/* ── Selection ── */

::placeholder {
  color: var(--text-tertiary);
}

/* ── Dividers ── */

hr {
  border: none;
  height: 1px;
  background: var(--border-subtle);
  margin: var(--space-6) 0;
}

/* ── Skeleton / Loading ── */

@keyframes shimmer {
  0% { background-position: -200% 0; }
  100% { background-position: 200% 0; }
}

.skeleton {
  background: linear-gradient(
    90deg,
    var(--surface-2) 25%,
    var(--surface-3) 50%,
    var(--surface-2) 75%
  );
  background-size: 200% 100%;
  animation: shimmer 1.5s ease-in-out infinite;
  border-radius: var(--radius-md);
}

/* ── Fade In ── */

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(16px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes scaleIn {
  from { opacity: 0; transform: scale(0.95); }
  to { opacity: 1; transform: scale(1); }
}

@keyframes slideInLeft {
  from { opacity: 0; transform: translateX(-12px); }
  to { opacity: 1; transform: translateX(0); }
}

.animate-fade-in {
  animation: fadeIn var(--duration-normal) var(--ease-out) both;
}

.animate-fade-in-up {
  animation: fadeInUp var(--duration-slow) var(--ease-out) both;
}

.animate-scale-in {
  animation: scaleIn var(--duration-normal) var(--ease-out) both;
}

/* Stagger children */
.stagger-children > * {
  animation: fadeInUp var(--duration-slow) var(--ease-out) both;
}

.stagger-children > *:nth-child(1) { animation-delay: 0ms; }
.stagger-children > *:nth-child(2) { animation-delay: 50ms; }
.stagger-children > *:nth-child(3) { animation-delay: 100ms; }
.stagger-children > *:nth-child(4) { animation-delay: 150ms; }
.stagger-children > *:nth-child(5) { animation-delay: 200ms; }
.stagger-children > *:nth-child(6) { animation-delay: 250ms; }
.stagger-children > *:nth-child(7) { animation-delay: 300ms; }
.stagger-children > *:nth-child(8) { animation-delay: 350ms; }
.stagger-children > *:nth-child(9) { animation-delay: 400ms; }
.stagger-children > *:nth-child(10) { animation-delay: 450ms; }

/* ── Page Transition ── */

.page-enter {
  animation: fadeIn var(--duration-slow) var(--ease-out) both;
}

/* ── Visually Hidden (SR only) ── */

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}