/* Landing page CSS for Keycube Heatmap 3D
   ─────────────────────────────────────────
   Design approach: Full-screen immersive 3D scene with overlay UI.
   Integrated with keycube.io design system.
   
   CSS architecture references:
   - CSS Grid overlay technique: https://css-tricks.com/positioning-overlay-content-with-css-grid/
   - Glassmorphism effect: https://css.glass/
   - Modern button design: https://moderncss.dev/css-button-styling-guide/
*/

/* ─── Reset & Base ─── */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body, html {
  width: 100%;
  height: 100%;
  overflow: hidden;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', sans-serif;
  background: #ffffff;
  color: #1a1a2e;
}

/* ─── Keycube-style Header ─── */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 100;
  background: rgba(253, 253, 253, 0.92);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(0, 0, 0, 0.08);
  border-top: 5px solid #43AAD6; /* Research color from keycube.io */
}

.header-wrapper {
  max-width: 800px;
  margin: 0 auto;
  padding: 0.6rem 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.site-title {
  display: flex;
  align-items: center;
  text-decoration: none;
}

.site-logo {
  height: 28px;
}

.site-nav {
  display: flex;
  gap: 1.25rem;
}

.site-nav .nav-link {
  font-size: 0.95rem;
  color: #111;
  text-decoration: none;
  transition: color 0.2s;
}

.site-nav .nav-link:hover {
  color: #43AAD6;
}

.site-nav .nav-link.active {
  color: #43AAD6;
  font-weight: 600;
}

/* ─── Keycube-style Footer ─── */
.site-footer {
  position: fixed;
  bottom: 0;
  left: 0;
  width: 100%;
  z-index: 100;
  background: rgba(253, 253, 253, 0.92);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-top: 1px solid rgba(0, 0, 0, 0.08);
  padding: 0.75rem 1.5rem;
}

.footer-wrapper {
  max-width: 800px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.footer-text {
  font-size: 0.8rem;
  color: #828282;
  margin: 0;
}

.footer-links {
  display: flex;
  gap: 0.5rem;
  align-items: center;
}

.footer-links a {
  font-size: 0.8rem;
  color: #43AAD6;
  text-decoration: none;
}

.footer-links a:hover {
  text-decoration: underline;
}

.footer-links .separator {
  color: #ccc;
}

/* ─── 3D Canvas Background ─── */
#landing-canvas {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 0;
}

/* ─── Overlay Container ─── */
/* Uses CSS Grid to center content over the 3D scene */
.landing-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 10;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  pointer-events: none; /* Allow mouse events to pass through to 3D scene */
  padding-top: 60px; /* Account for fixed header */
  padding-bottom: 50px; /* Account for fixed footer */
}

/* ─── Title Section ─── */
.landing-title {
  text-align: center;
  margin-bottom: 2rem;
  pointer-events: auto;
}

.landing-title h1 {
  font-size: 2.8rem;
  font-weight: 700;
  letter-spacing: 2px;
  color: #1a1a2e;
  text-shadow: 0 0 30px rgba(74, 158, 255, 0.2);
  margin-bottom: 0.5rem;
}

.landing-title .subtitle {
  font-size: 1rem;
  color: rgba(0, 0, 0, 0.5);
  font-weight: 300;
  letter-spacing: 1px;
}

/* ─── Navigation Buttons Container ─── */
/* Buttons are centered and overlaid on the keycube model */
.nav-buttons {
  display: flex;
  gap: 1.5rem;
  pointer-events: auto;
  flex-wrap: wrap;
  justify-content: center;
  padding: 0 1rem;
}

/* ─── Navigation Button ─── 
   Glassmorphism effect for modern translucent look.
   Ref: https://css.glass/ 
   Each button corresponds to a visualization mode. */
.nav-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  width: 180px;
  height: 120px;
  padding: 12px 16px;
  box-sizing: border-box;
  border: 1px solid rgba(0, 0, 0, 0.1);
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.7);
  /* Glassmorphism backdrop blur - https://developer.mozilla.org/en-US/docs/Web/CSS/backdrop-filter */
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  color: #1a1a2e;
  text-decoration: none;
  cursor: pointer;
  transition: all 0.4s cubic-bezier(0.25, 0.46, 0.45, 0.94);
  position: relative;
  overflow: hidden;
  text-align: center;
}

.nav-btn::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(
    90deg,
    transparent,
    rgba(255, 255, 255, 0.05),
    transparent
  );
  transition: left 0.6s ease;
}

.nav-btn:hover::before {
  left: 100%;
}

.nav-btn:hover {
  border-color: rgba(0, 0, 0, 0.2);
  background: rgba(255, 255, 255, 0.9);
  transform: translateY(-4px);
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.1), 0 0 20px rgba(74, 158, 255, 0.1);
}

/* ─── Button Icon ─── */
.nav-btn .btn-icon {
  font-size: 2rem;
  margin-bottom: 0.4rem;
  transition: transform 0.3s ease;
  line-height: 1;
}

.nav-btn:hover .btn-icon {
  transform: scale(1.15);
}

/* ─── Button Label ─── */
.nav-btn .btn-label {
  font-size: 0.95rem;
  font-weight: 600;
  letter-spacing: 1px;
  text-transform: uppercase;
  text-align: center;
}

/* ─── Button Description ─── */
.nav-btn .btn-desc {
  font-size: 0.65rem;
  color: rgba(0, 0, 0, 0.45);
  margin-top: 0.25rem;
  letter-spacing: 0.5px;
  text-align: center;
  line-height: 1.3;
  max-width: 100%;
}

/* ─── Individual Button Accent Colors ─── */
/* Each mode has its own accent to visually distinguish them */
.nav-btn.preference-btn {
  border-color: rgba(255, 107, 107, 0.3);
}
.nav-btn.preference-btn:hover {
  border-color: rgba(255, 107, 107, 0.6);
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.1), 0 0 25px rgba(255, 107, 107, 0.15);
}
.nav-btn.preference-btn .btn-icon {
  color: #ff6b6b;
}

.nav-btn.reachability-btn {
  border-color: rgba(81, 207, 102, 0.3);
}
.nav-btn.reachability-btn:hover {
  border-color: rgba(81, 207, 102, 0.6);
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.1), 0 0 25px rgba(81, 207, 102, 0.15);
}
.nav-btn.reachability-btn .btn-icon {
  color: #51cf66;
}

/* ─── Responsive Design ─── */
/* Mobile-first adjustments
   Ref: https://developer.mozilla.org/en-US/docs/Learn/CSS/CSS_layout/Responsive_Design */

@media (max-width: 768px) {
  .site-header {
    border-top-width: 3px;
  }

  .header-wrapper {
    padding: 0.5rem 1rem;
  }

  .site-logo {
    height: 24px;
  }

  .site-nav {
    gap: 0.75rem;
  }

  .site-nav .nav-link {
    font-size: 0.85rem;
  }

  .footer-wrapper {
    flex-direction: column;
    text-align: center;
  }

  .footer-text {
    font-size: 0.7rem;
  }

  .landing-title h1 {
    font-size: 1.8rem;
    letter-spacing: 1px;
  }

  .landing-title .subtitle {
    font-size: 0.8rem;
  }

  .nav-buttons {
    gap: 1rem;
  }

  .nav-btn {
    width: 140px;
    height: 100px;
  }

  .nav-btn .btn-icon {
    font-size: 1.6rem;
  }

  .nav-btn .btn-label {
    font-size: 0.8rem;
  }

  .nav-btn .btn-desc {
    font-size: 0.6rem;
  }
}

@media (max-width: 480px) {
  .site-nav .nav-link {
    font-size: 0.75rem;
  }

  .landing-title h1 {
    font-size: 1.4rem;
  }

  .nav-buttons {
    flex-direction: column;
    align-items: center;
    gap: 0.8rem;
  }

  .nav-btn {
    width: 200px;
    height: 80px;
    flex-direction: row;
    gap: 0.8rem;
    padding: 0 1.2rem;
  }

  .nav-btn .btn-icon {
    font-size: 1.4rem;
    margin-bottom: 0;
  }

  .nav-btn .btn-label {
    font-size: 0.75rem;
  }
}