:root {
  /* Site Theme: DARK with neon warming fiery accents */
  --thermal-coal: #0B0E14;     /* Deep dark background */
  --thermal-ash: #161B26;      /* High-contrast surface */
  --thermal-ember: #FF5A36;    /* Radiating fiery orange accent */
  --thermal-glow: #FFAE19;     /* Warm amber yellow */
  --thermal-frost: #F1F6FC;    /* Safe off-white / light text */
  --thermal-mist: #8A9CB4;     /* Muted secondary text */
  
  --thermal-gradient: linear-gradient(135deg, #FF5A36 0%, #FFAE19 100%);
  
  /* Fonts configuration based on choice */
  --font-display: 'Nunito', sans-serif;
  --font-body: 'Inter', sans-serif;
  
  /* Soft border radius style option */
  --thermal-radius: 16px;
  
  /* Deep shadows + spread */
  --thermal-shadow: 0 15px 35px rgba(0, 0, 0, 0.65), 0 5px 15px rgba(255, 90, 54, 0.15);
}

/* Base resets & transitions */
* {
  scroll-behavior: smooth;
  box-sizing: border-box;
}

body {
  margin: 0;
  padding: 0;
  overflow-x: hidden;
}

/* Scroll-driven animations (CSS only) */
@supports (animation-timeline: scroll()) {
  .scroll-progress-indicator {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: var(--thermal-gradient);
    z-index: 9999;
    transform-origin: 0 50%;
    animation: scaleProgress auto linear forwards;
    animation-timeline: scroll();
  }

  @keyframes scaleProgress {
    0% { transform: scaleX(0); }
    100% { transform: scaleX(1); }
  }
}

/* Fade in elements on viewport enter (Scroll-driven view animations) */
@supports (animation-timeline: view()) {
  .scroll-animate {
    animation: revealOnScroll auto linear forwards;
    animation-timeline: view();
    animation-range: entry 10% cover 35%;
  }

  @keyframes revealOnScroll {
    0% {
      opacity: 0;
      transform: translateY(30px);
    }
    100% {
      opacity: 1;
      transform: translateY(0);
    }
  }
}

/* Custom Navigation design & Hamburger */
.climate-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(11, 14, 20, 0.93);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.nav-anchor {
  position: relative;
  font-weight: 500;
  font-size: 0.95rem;
  padding: 0.5rem 1rem;
  transition: color 0.3s ease;
}

.nav-anchor::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  width: 0;
  height: 2px;
  background: var(--thermal-gradient);
  transition: width 0.3s ease, left 0.3s ease;
}

.nav-anchor:hover::after {
  width: 80%;
  left: 10%;
}

.nav-anchor:hover {
  color: var(--thermal-glow) !important;
}

/* Hamburger menu mechanics without JS */
#hamburger-btn span {
  display: block;
  width: 100%;
  height: 2px;
  background-color: var(--thermal-frost);
  border-radius: 2px;
  transition: all 0.3s ease-in-out;
}

#menu-toggle:checked ~ #hamburger-btn span:nth-child(1) {
  transform: translateY(9px) rotate(45deg);
  background-color: var(--thermal-ember);
}

#menu-toggle:checked ~ #hamburger-btn span:nth-child(2) {
  opacity: 0;
}

#menu-toggle:checked ~ #hamburger-btn span:nth-child(3) {
  transform: translateY(-9px) rotate(-45deg);
  background-color: var(--thermal-ember);
}

#menu-toggle:checked ~ .hearth-guide {
  display: flex !important;
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  background: var(--thermal-coal);
  flex-direction: column;
  padding: 2rem;
  border-bottom: 2px solid var(--thermal-ember);
  box-shadow: var(--thermal-shadow);
}

#menu-toggle:checked ~ .hearth-guide ul {
  flex-direction: column;
  gap: 1.5rem;
  width: 100%;
}

/* Card hover and interactive states */
.insulation-card {
  transition: transform 0.3s ease, box-shadow 0.3s ease, border-color 0.3s ease;
  border: 1px solid rgba(255, 255, 255, 0.05);
}

.insulation-card:hover {
  transform: translateY(-8px);
  box-shadow: 0 20px 40px rgba(255, 90, 54, 0.1), 0 8px 20px rgba(0, 0, 0, 0.7);
  border-color: rgba(255, 90, 54, 0.3);
}

/* Interactive custom styled form fields */
input:focus, textarea:focus {
  border-color: var(--thermal-ember) !important;
  box-shadow: 0 0 0 3px rgba(255, 90, 54, 0.25);
}

/* Utility classes wrapper styles */
.climate-capsule {
  width: 100%;
  margin-left: auto;
  margin-right: auto;
}

.ember-action {
  transition: transform 0.2s ease, filter 0.2s ease, box-shadow 0.2s ease;
}

.ember-action:hover {
  transform: scale(1.03);
  filter: brightness(1.1);
  box-shadow: 0 8px 25px rgba(255, 90, 54, 0.4);
}

/* Responsive adjusters for preset layouts */
@media (max-width: 768px) {
  .hearth-guide {
    display: none;
  }
}