.heating-wrapper {
    --p: #6366f1;
    --gas: #f97316;
    --aero: #10b981;
    --air: #3b82f6;
    
    width: 100%;
    max-width: 1000px;
    margin: 2rem auto;
    padding: 0 1rem;
    color: var(--text-main);
  }

  .main-card {
    background: var(--bg-surface);
    border: 1px solid var(--border-color);
    border-radius: 32px;
    padding: 2.5rem;
    box-shadow: 0 20px 50px rgba(0, 0, 0, 0.05);
  }

  .section-header {
    margin-bottom: 2rem;
  }

  .section-title {
    font-size: 1.25rem;
    font-weight: 900;
    margin: 0;
  }

  .section-desc {
    font-size: 0.9rem;
    color: var(--text-muted);
    margin: 0.5rem 0 0;
  }

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

  .input-group {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
  }

  .input-group label {
    font-size: 0.75rem;
    font-weight: 800;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-muted);
  }

  .input-helper {
    font-size: 0.75rem;
    color: var(--text-muted);
    margin: -0.25rem 0 0.25rem;
    opacity: 0.8;
  }

  .input-wrapper {
    position: relative;
    display: flex;
    align-items: center;
  }

  .input-wrapper input,
  .input-wrapper select {
    width: 100%;
    padding: 1rem 1.25rem;
    border-radius: 16px;
    border: 2px solid var(--border-color);
    background: var(--bg-muted);
    color: var(--text-main);
    font-size: 1rem;
    font-weight: 700;
    outline: none;
    transition: all 0.2s;
    appearance: none;
  }

  .input-wrapper select {
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 24 24' stroke='%2394a3b8'%3E%3Cpath stroke-linecap='round' stroke-linejoin='round' stroke-width='2' d='M19 9l-7 7-7-7'%3E%3C/path%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 1.25rem center;
    background-size: 1.25rem;
  }

  .input-wrapper input:focus,
  .input-wrapper select:focus {
    border-color: var(--p);
    box-shadow: 0 0 0 4px rgba(99, 102, 241, 0.1);
  }

  .input-unit {
    position: absolute;
    right: 1.25rem;
    font-weight: 700;
    color: var(--text-muted);
    font-size: 0.85rem;
    pointer-events: none;
  }

  .results-section {
    padding-top: 3rem;
    border-top: 1px solid var(--border-color);
  }

  .comparison-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1.5rem;
    margin-top: 2rem;
  }

  @media (max-width: 900px) {
    .comparison-grid {
      grid-template-columns: 1fr;
    }
  }

  .system-card {
    background: var(--bg-muted);
    border-radius: 24px;
    padding: 2rem;
    border: 1px solid var(--border-color);
    position: relative;
    overflow: hidden;
    transition: transform 0.3s;
  }

  .system-card:hover {
    transform: translateY(-4px);
  }

  .system-card::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0;
    height: 4px;
  }

  .system-card.gas::before { background: var(--gas); }
  .system-card.aero::before { background: var(--aero); }
  .system-card.air::before { background: var(--air); }

  .saving-badge {
    position: absolute;
    top: 1rem;
    right: 1rem;
    background: var(--aero);
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 100px;
    font-size: 0.65rem;
    font-weight: 800;
    text-transform: uppercase;
    display: none;
  }

  .saving-badge.visible {
    display: block;
    animation: bounce-in 0.5s cubic-bezier(0.18, 0.89, 0.32, 1.28);
  }

  .card-header {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 2rem;
  }

  .icon-box {
    width: 44px;
    height: 44px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
  }

  .gas .icon-box {
    background: rgba(249, 115, 22, 0.1);
    color: var(--gas);
  }
  .aero .icon-box {
    background: rgba(16, 185, 129, 0.1);
    color: var(--aero);
  }
  .air .icon-box {
    background: rgba(59, 130, 246, 0.1);
    color: var(--air);
  }

  .card-title {
    font-weight: 800;
    font-size: 1.1rem;
  }

  .cost-display {
    text-align: center;
    margin-bottom: 2rem;
  }

  .cost-label {
    display: block;
    font-size: 0.7rem;
    font-weight: 700;
    color: var(--text-muted);
    text-transform: uppercase;
    margin-bottom: 0.5rem;
  }

  .annual-cost {
    font-size: 2.25rem;
    font-weight: 900;
    letter-spacing: -0.02em;
  }

  .specs-list {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    padding-top: 1.5rem;
    border-top: 1px dashed var(--border-color);
  }

  .spec-item {
    display: flex;
    justify-content: space-between;
    font-size: 0.85rem;
  }

  .spec-label {
    color: var(--text-muted);
  }
  .spec-value {
    font-weight: 700;
  }

  @keyframes pop {
    0% { transform: scale(1); }
    50% { transform: scale(1.05); }
    100% { transform: scale(1); }
  }

  .animate-pop {
    animation: pop 0.2s ease-out;
  }

  @keyframes bounce-in {
    0% {
      transform: scale(0.3);
      opacity: 0;
    }
    50% {
      transform: scale(1.05);
      opacity: 1;
    }
    70% { transform: scale(0.9); }
    100% { transform: scale(1); }
  }