/* ============================================
   MOBILE-OPTIMIZED UI/UX FOR 2026
   Based on latest best practices:
   - Minimalism & focus
   - Touch-friendly (48x48px minimum)
   - Better data visualization
   - Whitespace & breathing room
   - Accessibility (WCAG AA+)
   - Performance optimized
   ============================================ */

:root {
  /* Spacing System (8px base) */
  --space-xs: 0.5rem;   /* 8px */
  --space-sm: 1rem;     /* 16px */
  --space-md: 1.5rem;   /* 24px */
  --space-lg: 2rem;     /* 32px */
  --space-xl: 2.5rem;   /* 40px */
  --space-2xl: 3rem;    /* 48px */

  /* Typography (mobile-first) */
  --font-size-xs: 0.75rem;    /* 12px - labels only */
  --font-size-sm: 0.875rem;   /* 14px - secondary text */
  --font-size-base: 1rem;     /* 16px - body text */
  --font-size-lg: 1.125rem;   /* 18px - large body (accessibility) */
  --font-size-xl: 1.25rem;    /* 20px - headings */
  --font-size-2xl: 1.5rem;    /* 24px - large headings */
  --font-size-3xl: 1.875rem;  /* 30px - hero text */

  /* Line heights for readability */
  --line-height-tight: 1.4;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.75;

  /* Touch target minimums */
  --touch-target: 48px;
  --touch-target-sm: 44px;
}

/* ============================================
   GLOBAL STYLES
   ============================================ */

button:not([class]) {
  min-height: var(--touch-target);
  padding: var(--space-sm) var(--space-md);
  border-radius: 12px;
  transition: all 150ms ease;
}

input, select, textarea {
  font-size: var(--font-size-lg);
  min-height: var(--touch-target-sm);
  padding: var(--space-sm) var(--space-md);
}

/* Better focus indicators */
:focus-visible {
  outline: 2px solid var(--primary);
  outline-offset: 2px;
}

/* ============================================
   ACCESSIBILITY
   ============================================ */

@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}

@media (prefers-contrast: more) {
  button {
    border: 1px solid currentColor;
  }
}

/* ============================================
   PROGRESS INDICATORS
   ============================================ */

.progress-bar {
  width: 100%;
  height: 8px;
  background: var(--border);
  border-radius: 4px;
  overflow: hidden;
  margin-bottom: 1rem;
}

.progress-bar-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--primary), var(--accent));
  border-radius: 4px;
  transition: width 300ms ease;
}

/* ============================================
   MOBILE OPTIMIZATIONS
   ============================================ */

.page-content {
  max-width: 600px;
  margin: 0 auto;
  padding: 1.25rem 1rem calc(110px + env(safe-area-inset-bottom)) 1rem;
}

.card {
  border-radius: var(--radius-xl, 26px);
  padding: 1.4rem;
  margin-bottom: 1.25rem;
}

.nav-button {
  min-height: 50px;
}

/* Better list items */
.list-item {
  min-height: var(--touch-target);
  padding: 1rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* ============================================
   DATA VISUALIZATION
   ============================================ */

.stat-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1rem;
}

.stat-item {
  padding: 1rem;
  background: var(--surface-strong);
  border-radius: 12px;
  text-align: center;
}

.stat-value {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--primary);
}

/* ============================================
   RESPONSIVE
   ============================================ */

@media (max-width: 640px) {
  body {
    font-size: var(--font-size-lg);
  }

  h1 {
    font-size: 1.5rem;
  }

  .stat-grid {
    grid-template-columns: 1fr;
  }
}

/* ============================================
   COLLAPSIBLE SECTIONS (2026 UX)
   Reduce cognitive load by hiding secondary content
   ============================================ */

.collapsible-group {
  margin-bottom: 1.5rem;
}

[data-toggle="collapsible"] {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  border: none;
  cursor: pointer;
  transition: all var(--duration-fast) ease;
}

[data-toggle="collapsible"]:active {
  transform: scale(0.98);
}

.toggle-icon {
  display: inline-block;
  transition: transform var(--duration-normal) ease;
  margin-left: 0.75rem;
  font-size: 0.8rem;
  flex-shrink: 0;
}

.collapsible-content {
  transition: max-height var(--duration-normal) ease, opacity var(--duration-normal) ease;
  overflow: hidden;
}

/* Arrow icon rotation animation */
[aria-expanded="true"] .toggle-icon {
  transform: rotate(180deg);
}