:root {
  --ergonomic-bg: #0b1320;
  --ergonomic-surface: rgba(22, 33, 54, 0.65);
  --ergonomic-glow: #10b981;
  --ergonomic-glow-hover: #059669;
  --ergonomic-text: #f1f5f9;
  --ergonomic-text-muted: #94a3b8;
  --ergonomic-gradient: linear-gradient(135deg, #0b1320 0%, #172554 100%);
  --font-display: 'Montserrat', sans-serif;
  --font-body: 'Poppins', sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  padding: 0;
  overflow-x: hidden;
  background-color: var(--ergonomic-bg);
  color: var(--ergonomic-text);
  font-family: var(--font-body);
}

/* Scroll Gauge Indicator (CSS scroll-driven animation) */
.scroll-gauge-indicator {
  position: fixed;
  top: 0;
  left: 0;
  height: 3px;
  background: var(--ergonomic-glow);
  width: 100%;
  transform-origin: 0 50%;
  z-index: 100;
  animation: scroll-progress linear;
  animation-timeline: scroll();
}

@keyframes scroll-progress {
  from {
    transform: scaleX(0);
  }
  to {
    transform: scaleX(1);
  }
}

/* Scroll-Driven View Reveal Animation for Segments */
@keyframes fade-slide-in {
  from {
    opacity: 0.2;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

spine-layout-segment {
  animation: fade-slide-in linear both;
  animation-timeline: view();
  animation-range: entry 10% cover 30%;
}

/* Custom Semantic Container */
.sedentary-shell-box {
  width: 100%;
  max-width: 1200px;
  margin-left: auto;
  margin-right: auto;
}

/* Header styling */
.top-nav-panel {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(11, 19, 32, 0.85);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.nav-anchor-link {
  color: var(--ergonomic-text-muted);
  font-size: 0.875rem;
  transition: color 0.2s ease;
}

.nav-anchor-link:hover {
  color: var(--ergonomic-glow);
}

/* Glassmorphism Cards Neumorphism Depth Effects */
.posture-glass-card {
  box-shadow: 0 20px 40px -15px rgba(0, 0, 0, 0.5);
  transition: transform 0.3s ease, box-shadow 0.3s ease, border-color 0.3s ease;
}

.posture-glass-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 25px 50px -12px rgba(16, 185, 129, 0.15);
  border-color: rgba(16, 185, 129, 0.4) !important;
}

/* Action Button Style */
.action-glow-pill {
  transition: all 0.3s ease;
}

.action-glow-pill:hover {
  background: var(--ergonomic-glow-hover) !important;
  transform: translateY(-2px);
  box-shadow: 0 12px 28px -4px rgba(16, 185, 129, 0.5) !important;
}

/* Mobile Nav Toggle via CSS */
@media (max-width: 1023px) {
  .header-links-holder {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    width: 100%;
    flex-direction: column;
    background: var(--ergonomic-bg);
    padding: 1.5rem;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    gap: 1rem;
  }

  #mobile-toggle-checkbox:checked ~ .header-links-holder {
    display: flex;
  }
}