/* ── RESEARCH & TECHNOLOGY PAGE ──────────────────────── */

/* Hero */
.rt-hero {
  position: relative;
  background: var(--void);
  padding: 8rem 3rem 5rem;
  overflow: hidden;
  transition: background 0.3s;
}
.rt-hero .hero-grid-canvas {
  position: absolute;
  inset: 0; width: 100%; height: 100%;
  opacity: 0.3; pointer-events: none;
}
[data-theme="light"] .rt-hero .hero-grid-canvas { opacity: 0.15; }

.rt-hero-content { position: relative; z-index: 2; max-width: 680px; }

.rt-hero-title {
  font-family: var(--heading-font, Georgia, serif);
  font-size: clamp(38px, 5.5vw, 64px);
  font-weight: 300;
  line-height: 1.1;
  color: var(--champagne);
  margin-bottom: 1.25rem;
}
.rt-hero-title em { font-style: var(--heading-style, italic); color: var(--gold); }
.rt-hero-sub {
  font-size: 15px;
  font-weight: 300;
  color: var(--muted);
  max-width: 500px;
  line-height: 1.75;
}

/* Topic nav strip */
.rt-topics-nav {
  display: flex;
  border-top: 0.5px solid var(--border);
  border-bottom: 0.5px solid var(--border);
  background: var(--card);
  overflow-x: auto;
  transition: background 0.3s;
}
.rt-topic-btn {
  flex: 1;
  min-width: max-content;
  padding: 1rem 2rem;
  font-size: 10px;
  font-weight: 600;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--muted);
  text-decoration: none;
  border-right: 0.5px solid var(--border2);
  text-align: center;
  transition: color 0.2s, background 0.2s;
}
.rt-topic-btn:last-child { border-right: none; }
.rt-topic-btn:hover {
  color: var(--gold);
  background: var(--card2);
}

/* Topic sections */
.rt-topic-section {
  padding: 6rem 3rem;
  background: var(--void);
  transition: background 0.3s;
}
.rt-topic-section.rt-alt {
  background: var(--deep);
}

.rt-topic-inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 5rem;
  align-items: center;
  max-width: 1200px;
  margin: 0 auto;
}
.rt-topic-inner.rt-flip { }

.rt-desc {
  font-size: 14px;
  color: var(--muted);
  line-height: 1.85;
  margin-bottom: 1rem;
}

.rt-feature-list {
  list-style: none;
  padding: 0;
  margin: 1.5rem 0 0;
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}
.rt-feature-list li {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 13px;
  color: var(--text);
  border-left: 1px solid var(--border2);
  padding: 0.4rem 0 0.4rem 1rem;
  transition: border-color 0.2s;
}
.rt-feature-list li:hover { border-color: var(--gold-dim); }
.rt-feature-list li i {
  font-size: 16px;
  color: var(--gold-dim);
  flex-shrink: 0;
}

/* Image grids */
.rt-img-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2px;
}
.rt-img-tile {
  overflow: hidden;
  aspect-ratio: 4/3;
  background: var(--card);
}
.rt-img-tile.main-tile {
  grid-column: 1 / -1;
  aspect-ratio: 16/9;
}
.rt-img-tile img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: brightness(0.85);
  transition: transform 0.45s ease, filter 0.3s ease;
}
.rt-img-tile:hover img {
  transform: scale(1.04);
  filter: brightness(1);
}

/* 5-image grid for footpaths section */
.rt-grid-5 {
  grid-template-columns: 1fr 1fr 1fr;
}
.rt-grid-5 .main-tile {
  grid-column: 1 / -1;
}

/* Theme cities cards */
.rt-theme-cities-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2px;
}
.rt-theme-card {
  background: var(--card);
  border: 0.5px solid var(--border2);
  padding: 2rem 1.5rem;
  transition: background 0.2s, border-color 0.2s;
}
.rt-theme-card:hover {
  background: var(--card2);
  border-color: var(--gold-dim);
}
.rt-theme-icon {
  font-size: 24px;
  color: var(--gold-dim);
  margin-bottom: 0.75rem;
}
.rt-theme-icon i { font-size: 28px; }
.rt-theme-title {
  font-family: var(--heading-font, Georgia, serif);
  font-size: 20px;
  font-weight: 300;
  color: var(--champagne);
  margin-bottom: 0.5rem;
}
.rt-theme-desc {
  font-size: 12px;
  color: var(--muted);
  line-height: 1.65;
}

/* CTA section */
.rt-cta-section {
  background: var(--panel);
  padding: 6rem 3rem;
  text-align: center;
  transition: background 0.3s;
}
.rt-cta-inner { max-width: 620px; margin: 0 auto; }
.rt-cta-sub {
  font-size: 14px;
  color: var(--muted);
  line-height: 1.75;
  margin: 1rem 0 2.5rem;
}
.rt-cta-actions {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}

/* Responsive */
@media (max-width: 900px) {
  .rt-topic-inner {
    grid-template-columns: 1fr;
    gap: 3rem;
  }
  .rt-topic-inner.rt-flip .rt-topic-gallery { order: -1; }
  .rt-theme-cities-grid { grid-template-columns: 1fr; }
}

@media (max-width: 720px) {
  .rt-hero { padding: 6rem 1.25rem 4rem; }
  .rt-topic-section { padding: 4rem 1.25rem; }
  .rt-cta-section { padding: 4rem 1.25rem; }
  .rt-grid-5 { grid-template-columns: 1fr 1fr; }
}