:root {
  --bg-canvas: #faf6ef;
  --bg-surface: #fffdf8;
  --bg-surface-elevated: #f4eee1;
  --text-primary: #2b211a;
  --text-muted: #6e5e52;
  --accent-primary: #c2562e;
  --accent-primary-hover: #a84723;
  --accent-secondary: #6b7a3a;
  --accent-secondary-hover: #55622d;
  --border-subtle: #e4dacb;
  --border-strong: #cfbeaa;
  --shadow-card: 0 4px 16px rgba(43, 33, 26, 0.06);
  --shadow-elevation: 0 10px 24px rgba(43, 33, 26, 0.1);
  --radius: 4px;
  --ease: cubic-bezier(0.16, 1, 0.3, 1);
}

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  background-color: var(--bg-canvas);
  color: var(--text-primary);
  scroll-behavior: smooth;
}

body {
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.65;
  color: var(--text-primary);
  background-color: var(--bg-canvas);
  overflow-wrap: anywhere;
  hyphens: auto;
  -webkit-font-smoothing: antialiased;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: var(--accent-primary);
  text-decoration: none;
  transition: color 0.2s var(--ease);
}

a:hover, a:focus-visible {
  color: var(--accent-primary-hover);
}

.link-underline {
  position: relative;
  display: inline-block;
  color: var(--accent-primary);
  font-weight: 700;
  text-decoration: none;
}

.link-underline::after {
  content: "";
  position: absolute;
  width: 100%;
  transform: scaleX(0);
  height: 2px;
  bottom: -2px;
  left: 0;
  background-color: var(--accent-primary);
  transform-origin: bottom right;
  transition: transform 0.25s var(--ease);
}

.link-underline:hover::after, .link-underline:focus-visible::after {
  transform: scaleX(1);
  transform-origin: bottom left;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  font-weight: 800;
  letter-spacing: -0.025em;
  line-height: 1.2;
  color: var(--text-primary);
  margin-bottom: 0.75rem;
}

h1 { font-size: clamp(2rem, 4vw + 1rem, 3.25rem); }
h2 { font-size: clamp(1.5rem, 2.5vw + 0.5rem, 2.25rem); margin-top: 1.5rem; }
h3 { font-size: 1.35rem; }
h4 { font-size: 1.15rem; }

p {
  margin-bottom: 1.25rem;
  color: var(--text-muted);
}

.prose {
  max-width: 72ch;
  margin-left: auto;
  margin-right: auto;
}

.prose p, .prose li {
  color: var(--text-primary);
  font-size: 1.05rem;
}

/* Header & Nav */
.site-header {
  position: relative;
  background-color: var(--bg-surface);
  border-bottom: 1px solid var(--border-subtle);
  padding: 1.25rem 1.5rem;
  z-index: 50;
}

.header-inner {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.header-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
}

.brand {
  font-size: 1.5rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  color: var(--accent-primary);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
}

.brand:hover {
  color: var(--accent-primary-hover);
}

.brand-dot {
  width: 10px;
  height: 10px;
  background-color: var(--accent-secondary);
  border-radius: var(--radius);
  display: inline-block;
}

.menu-toggle {
  display: none;
  background: none;
  border: 1px solid var(--border-subtle);
  font-size: 1.5rem;
  line-height: 1;
  padding: 0.35rem 0.75rem;
  border-radius: var(--radius);
  cursor: pointer;
  color: var(--text-primary);
}

.main-nav {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 1.5rem;
  flex-wrap: wrap;
}

.main-nav a {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-primary);
  padding: 0.35rem 0.5rem;
  border-bottom: 2px solid transparent;
}

.main-nav a:hover, .main-nav a.active {
  color: var(--accent-primary);
  border-bottom-color: var(--accent-primary);
}

/* Layout */
.wrapper {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

.section {
  padding: 4.5rem 0;
}

.section-tight {
  padding: 2.5rem 0;
}

.section-muted {
  background-color: var(--bg-surface-elevated);
  border-top: 1px solid var(--border-subtle);
  border-bottom: 1px solid var(--border-subtle);
}

.section-head {
  text-align: center;
  max-width: 72ch;
  margin: 0 auto 3rem;
}

.section-head p {
  font-size: 1.1rem;
}

.tag-eyebrow {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--accent-secondary);
  margin-bottom: 0.5rem;
}

/* Hero */
.hero {
  position: relative;
  min-height: 75vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 4rem 1.5rem;
  background-color: #1a1410;
  color: #fffdf8;
  overflow: hidden;
}

.hero-media {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.42;
}

.hero-overlay {
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at center, rgba(30, 20, 14, 0.65) 0%, rgba(18, 12, 8, 0.92) 100%);
}

.hero-content {
  position: relative;
  z-index: 2;
  max-width: 800px;
  margin: 0 auto;
}

.hero-content h1 {
  color: #ffffff;
  margin-bottom: 1.25rem;
}

.hero-content p {
  color: #e5ded4;
  font-size: 1.2rem;
  max-width: 65ch;
  margin: 0 auto 2rem;
}

.page-hero {
  padding: 4rem 1.5rem 3rem;
  background-color: var(--bg-surface-elevated);
  border-bottom: 1px solid var(--border-subtle);
}

.page-hero-inner {
  max-width: 900px;
  margin: 0 auto;
  text-align: center;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.85rem 1.75rem;
  border-radius: var(--radius);
  font-size: 1rem;
  font-weight: 700;
  border: none;
  cursor: pointer;
  transition: background-color 0.2s var(--ease), transform 0.15s var(--ease);
  text-decoration: none;
}

.btn-primary {
  background-color: var(--accent-primary);
  color: #ffffff;
}

.btn-primary:hover, .btn-primary:focus-visible {
  background-color: var(--accent-primary-hover);
  color: #ffffff;
  transform: translateY(-2px);
}

.btn-secondary {
  background-color: var(--accent-secondary);
  color: #ffffff;
}

.btn-secondary:hover {
  background-color: var(--accent-secondary-hover);
  color: #ffffff;
}

.btn-outline {
  background: transparent;
  border: 1px solid var(--accent-primary);
  color: var(--accent-primary);
}

.btn-outline:hover {
  background-color: var(--accent-primary);
  color: #ffffff;
}

/* Grids & Cards */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 2rem;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 2rem;
}

.card {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow-card);
  display: flex;
  flex-direction: column;
  transition: transform 0.25s var(--ease), box-shadow 0.25s var(--ease);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-elevation);
}

.card-media {
  position: relative;
  width: 100%;
  height: 220px;
  background-color: #2b211a;
  overflow: hidden;
}

.card-media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.4s var(--ease);
}

.card:hover .card-media img {
  transform: scale(1.03);
}

.card-badge {
  position: absolute;
  bottom: -10px;
  left: 1.25rem;
  background-color: var(--accent-primary);
  color: #ffffff;
  font-size: 0.75rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 0.25rem 0.65rem;
  border-radius: var(--radius);
  z-index: 2;
}

.badge-alt {
  background-color: var(--accent-secondary);
}

.card-body {
  padding: 1.75rem 1.5rem 1.5rem;
  flex: 1;
  display: flex;
  flex-direction: column;
}

.card-body h3 {
  margin-bottom: 0.5rem;
}

.card-body p {
  flex: 1;
  font-size: 0.95rem;
}

.card-footer {
  margin-top: 1rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border-subtle);
}

/* Feature Lead Block */
.feature-lead {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius);
  overflow: hidden;
  display: grid;
  grid-template-columns: 1.1fr 1fr;
  margin-bottom: 3.5rem;
  box-shadow: var(--shadow-card);
}

.feature-lead-media {
  position: relative;
  min-height: 380px;
}

.feature-lead-media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.feature-lead-badge {
  position: absolute;
  top: 1.25rem;
  left: 1.25rem;
  background-color: var(--accent-primary);
  color: #ffffff;
  font-size: 0.75rem;
  font-weight: 800;
  text-transform: uppercase;
  padding: 0.35rem 0.75rem;
  border-radius: var(--radius);
}

.feature-lead-body {
  padding: 2.5rem;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

/* Geological Process Diagram / Comparison Rows */
.process-steps {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1.5rem;
  margin: 2.5rem 0;
}

.step-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius);
  padding: 1.5rem;
  position: relative;
}

.step-number {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--accent-secondary);
  line-height: 1;
  margin-bottom: 0.75rem;
}

/* Table container */
.table-wrapper {
  overflow-x: auto;
  margin: 2rem 0;
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius);
}

table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.95rem;
}

th, td {
  padding: 1rem 1.25rem;
  border-bottom: 1px solid var(--border-subtle);
}

th {
  background-color: var(--bg-surface-elevated);
  font-weight: 800;
  color: var(--text-primary);
}

tr:last-child td {
  border-bottom: none;
}

/* Checklist */
.checklist {
  list-style: none;
  margin: 1.5rem 0;
}

.checklist li {
  position: relative;
  padding-left: 1.75rem;
  margin-bottom: 0.75rem;
  color: var(--text-primary);
}

.checklist li::before {
  content: "✓";
  position: absolute;
  left: 0;
  color: var(--accent-secondary);
  font-weight: 800;
}

.checklist-warning li::before {
  content: "!";
  color: var(--accent-primary);
}

/* Accordion FAQs */
.faq-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.faq-item {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius);
  overflow: hidden;
}

.faq-summary {
  padding: 1.25rem 1.5rem;
  font-weight: 700;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  user-select: none;
  list-style: none;
}

.faq-summary::-webkit-details-marker {
  display: none;
}

.faq-summary::after {
  content: "+";
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--accent-primary);
  transition: transform 0.2s var(--ease);
}

details[open] .faq-summary::after {
  content: "−";
}

.faq-content {
  padding: 0 1.5rem 1.5rem;
  color: var(--text-muted);
}

/* Contact / Speleological Tool */
.tool-box {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius);
  padding: 2rem;
  box-shadow: var(--shadow-card);
}

.form-group {
  margin-bottom: 1.25rem;
}

label {
  display: block;
  font-weight: 700;
  font-size: 0.9rem;
  margin-bottom: 0.35rem;
  color: var(--text-primary);
}

input, select, textarea {
  width: 100%;
  padding: 0.75rem 1rem;
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius);
  background-color: var(--bg-canvas);
  color: var(--text-primary);
  font-family: inherit;
  font-size: 0.95rem;
}

input:focus, select:focus, textarea:focus {
  outline: none;
  border-color: var(--accent-primary);
  background-color: #ffffff;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.status-box {
  margin-top: 1rem;
  padding: 0.75rem 1rem;
  border-radius: var(--radius);
  font-size: 0.9rem;
  display: none;
}

.status-box.visible {
  display: block;
}

.status-success {
  background: #edf3e5;
  color: #35471d;
  border: 1px solid #c2d8a4;
}

/* Footer */
.site-footer {
  background-color: #211913;
  color: #d6cbbf;
  padding: 4rem 1.5rem 2.5rem;
  border-top: 2px solid var(--accent-primary);
}

.footer-inner {
  max-width: 1200px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1.6fr 1fr;
  gap: 3rem;
}

.footer-brand .brand {
  color: #ffffff;
  font-size: 1.35rem;
  margin-bottom: 0.75rem;
}

.footer-brand p {
  color: #a89c8f;
  font-size: 0.9rem;
  margin-bottom: 0.5rem;
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}

.footer-links a {
  color: #d6cbbf;
  font-size: 0.95rem;
}

.footer-links a:hover {
  color: #ffffff;
}

.footer-copy {
  grid-column: 1 / -1;
  padding-top: 2rem;
  margin-top: 1.5rem;
  border-top: 1px solid #362920;
  font-size: 0.85rem;
  color: #8c7e72;
  text-align: center;
}

/* Responsive */
@media (max-width: 860px) {
  .feature-lead {
    grid-template-columns: 1fr;
  }
  .feature-lead-media {
    min-height: 260px;
  }
  .footer-inner {
    grid-template-columns: 1fr;
    gap: 2rem;
  }
}

@media (max-width: 768px) {
  .menu-toggle {
    display: block;
  }
  .main-nav {
    display: none;
    flex-direction: column;
    align-items: flex-start;
    padding: 1rem 0;
    gap: 0.5rem;
    border-top: 1px solid var(--border-subtle);
  }
  .main-nav.nav-open {
    display: flex;
  }
  .form-row {
    grid-template-columns: 1fr;
  }
}

@media (prefers-reduced-motion: reduce){*,*::before,*::after{animation-duration:.01ms!important;animation-iteration-count:1!important;transition-duration:.01ms!important;scroll-behavior:auto!important}}