:root {
  /* Dynamic custom theme parameters - LIGHT variant on Vision Topic */
  --retina-cream-bg: #fdfbf7;
  --retina-soft-surface: #f3efe6;
  --retina-iris-accent: #1c3d5a;
  --retina-amber-glow: #b45309; /* AA compliant contrast contrast warm gold */
  --retina-deep-ink: #111827;
  --retina-muted-charcoal: #4b5563;
  --retina-glass-border: rgba(28, 61, 90, 0.1);
  --retina-gradient-shine: linear-gradient(135deg, #1c3d5a 0%, #2c5282 100%);
  
  /* Heading and Text choices */
  --font-display: 'Playfair Display', serif;
  --font-body: 'Poppins', sans-serif;

  /* Constraints parameters */
  --retina-radius: 16px; /* Soft border-radius-style */
  --retina-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.05), 0 4px 6px -2px rgba(0, 0, 0, 0.02); /* Raised shadow depth */
}

/* Global resets and standards */
html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  padding: 0;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

/* CSS Heading Case setting */
h1, h2, h3 {
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* Base structural spacings override values */
.iris-standard-padding {
  padding-top: 10dvh;
  padding-bottom: 10dvh;
}

/* Scroll position animation tracker (CSS-only) */
@keyframes progress-grow {
  to { width: 100%; }
}
.iris-scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  height: 4px;
  background: var(--retina-amber-glow);
  width: 0%;
  z-index: 100;
  animation: progress-grow linear;
  animation-timeline: scroll();
}

/* CSS scroll-driven reveals (Standard fallbacks configured) */
@keyframes slide-up {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}
.reveal {
  animation: slide-up 0.6s linear both;
  animation-timeline: view();
  animation-range: entry 0% entry 35%;
}

/* Hamburger toggle logic for Header */
#iris-nav-toggle:checked ~ .iris-nav-inner {
  display: flex !important;
}

@media (max-width: 767px) {
  .iris-nav-inner {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    width: 100%;
    background: var(--retina-cream-bg);
    border-bottom: 1px solid var(--retina-glass-border);
    padding: 1.5rem;
    box-shadow: var(--retina-shadow);
  }
}

/* Preset F Specific Elements */

/* Hero sizing */
.iris-hero-shield {
  height: 75vh;
  background-size: cover;
  background-position: center;
}

.iris-main-title {
  font-size: clamp(2.5rem, 6vw, 6.5rem);
}

/* Accordion features */
.pupil-accordion-card {
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}
.pupil-accordion-card:hover {
  transform: translateY(-4px);
}
.pupil-bg-number {
  position: absolute;
  right: -5%;
  bottom: -40%;
  font-size: 15rem;
  font-weight: 900;
  opacity: 0.04;
  line-height: 1;
  pointer-events: none;
  font-family: var(--font-display);
}

/* Editorial Drop cap */
.iris-drop-cap-column {
  margin-top: 1.5rem;
}
.iris-drop-cap {
  float: left;
  font-size: 4.8rem;
  line-height: 0.8;
  padding-top: 4px;
  padding-right: 12px;
  font-weight: bold;
}

/* CTA Ghost Button */
.macula-ghost-btn {
  display: inline-block;
  padding: 1rem 2.5rem;
  border: 1.5px solid white;
  color: white;
  text-transform: uppercase;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  border-radius: var(--retina-radius);
  transition: background 0.3s ease, color 0.3s ease;
}
.macula-ghost-btn:hover {
  background: white;
  color: var(--retina-iris-accent);
}

/* Testimonial structural quotes styling */
.sclera-testimonial-card:hover {
  transform: scale(1.01);
  transition: transform 0.4s ease;
}
.sclera-quote-symbol {
  position: absolute;
  top: -10px;
  left: 20px;
  font-size: 7rem;
  font-family: var(--font-display);
  opacity: 0.15;
  pointer-events: none;
}

/* Minimalist Form Inputs styling */
.iris-input-underline {
  background: transparent;
  border: none;
  border-bottom: 2px solid var(--retina-glass-border);
  padding: 0.75rem 0.25rem;
  font-size: 0.95rem;
  color: var(--retina-deep-ink);
  transition: border-color 0.3s ease;
}
.iris-input-underline:focus {
  outline: none;
  border-color: var(--retina-iris-accent);
}