:root {
      --bmi-underweight: #3b82f6;
      --bmi-normal: #22ab5a;
      --bmi-overweight: #f5a60f;
      --bmi-obese: #dc3232;
    }
    body {
      background: linear-gradient(135deg, #f0f4ff 0%, #e8f0fe 50%, #f5f0ff 100%);
      min-height: 100vh;
      font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
    }
    .card-glass {
      background: rgba(255,255,255,0.85);
      backdrop-filter: blur(16px);
      border: 1px solid rgba(255,255,255,0.6);
      border-radius: 1rem;
      box-shadow: 0 8px 32px rgba(0,0,0,0.08);
    }
    .hero-icon {
      width: 64px;
      height: 64px;
      border-radius: 1rem;
      background: rgba(99,102,241,0.1);
      display: inline-flex;
      align-items: center;
      justify-content: center;
      font-size: 1.8rem;
      color: #6366f1;
    }
    .gender-btn {
      flex: 1;
      padding: 0.6rem 1rem;
      border: 2px solid #e2e8f0;
      border-radius: 0.75rem;
      background: #fff;
      cursor: pointer;
      transition: all 0.2s;
      font-weight: 600;
    }
    .gender-btn:hover { 
        border-color: #6366f1; 
    }
    .gender-btn.active {
      border-color: #6366f1;
      background: rgba(99,102,241,0.08);
      color: #6366f1;
    }
    .unit-toggle {
    display: flex;       
    background: #f1f5f9;  
    border-radius: 0.5rem;
    overflow: hidden;
    padding: 4px;
    gap: 4px;
    font-weight: 600;
    }
    .unit-toggle button {
    flex: 1;     
    border: none;
    background: transparent;
    font-size: 0.9rem;          
    padding: 0.55rem 1rem;
    border-radius: 0.4rem;
    cursor: pointer;
    transition: all 0.2s;
    }
    .unit-toggle button:hover { 
        border-color: #6366f1; 
    }
    .unit-toggle button.active {
        background: #6366f1;
        color: #fff;
        box-shadow: 0 2px 8px rgba(99,102,241,0.3);
    }
        #heightMetric .form-range,
        #weightMetric .form-range,
        .form-range{
        flex: 3;
    }
    #heightMetric .form-control,
    #weightMetric .form-control,
    #age{
    flex: 1;
    max-width: 70px;
    border-radius: 0.5rem;
    }

    #heightMetric span,
    #weightMetric span,
    #ageDisplay{
    min-width: 20px;
    font-size: 17px;
    color: #6c757d; 
    }
    label{
      font-weight: 700;
    }
    .btn-calculate {
      background: linear-gradient(135deg, #6366f1, #8b5cf6);
      border: none;
      color: #fff;
      font-weight: 700;
      padding: 0.75rem;
      border-radius: 0.75rem;
      width: 100%;
      font-size: 1rem;
      transition: transform 0.2s, box-shadow 0.2s;
    }
    .btn-calculate:hover {
      transform: translateY(-1px);
      box-shadow: 0 6px 20px rgba(99,102,241,0.35);
      color: #fff;
    }
    .btn-reset {
      background: transparent;
      border: 2px solid #e2e8f0;
      font-weight: 600;
      padding: 0.75rem;
      border-radius: 0.75rem;
      width: 100%;
      transition: all 0.2s;
    }
    .btn-reset:hover { border-color: #cbd5e1; }
    .result-section {
      animation: slideUp 0.5s ease-out;
    }
    .bmi-big {
      font-size: 3.5rem;
      font-weight: 900;
      line-height: 1;
    }
    .category-badge {
      display: inline-flex;
      align-items: center;
      gap: 0.4rem;
      padding: 0.35rem 0.8rem;
      border-radius: 2rem;
      font-weight: 700;
      font-size: 0.85rem;
    }
    .info-badge {
      display: inline-flex;
      align-items: center;
      gap: 0.3rem;
      padding: 0.25rem 0.65rem;
      border-radius: 2rem;
      background: #f1f5f9;
      font-size: 0.8rem;
      color: #64748b;
      font-weight: 500;
    }
    .gauge-bar {
      height: 14px;
      border-radius: 7px;
       background: linear-gradient(
          90deg,
          #3b82f6  0%,    #3b82f6  28.3%,
          #22ab5a  28.3%, #22ab5a  50%,
          #f5a60f  50%,   #f5a60f  66.7%,
          #dc3232  66.7%, #dc3232  100%
        );
      position: relative;
      overflow: visible;
    }
    .gauge-needle {
      position: absolute;
      top: 50%;
      width: 5px;
      height: 32px;
      background: #1e293b;
      border-radius: 3px;
      transition: left 0.8s cubic-bezier(0.34, 1.56, 0.64, 1);
      transform: translateY(-50%, -50%);
      box-shadow: 0 0 4px rgba(0,0,0,0.4);
      z-index: 10;
    }
    .gauge-labels {
      display: flex;
      justify-content: space-between;
      font-size: 0.7rem;
      color: #94a3b8;
      font-weight: 600;
      margin-top: 8px;
    }
    .gauge-wrapper{
     position: relative;
        margin: 1.5rem 0 0.25rem;
        padding: 12px 0;
    }
    .range-bar-container {
      margin-bottom: 0.5rem;
    }
    .range-label {
      display: flex;
      justify-content: space-between;
      font-size: 0.95rem;
      margin-bottom: 0.3rem;
      font-weight: 600;
    }
    .range-label span:last-child {
      font-size: 0.9rem;
   }
   .range-track {
        height: 10px;
        border-radius: 5px;
        background: #e2e8f0;
        overflow: hidden;
      }
      .range-fill {
        height: 100%;
        border-radius: 5px;
      }

    .range-bar {
      height: 8px;
      border-radius: 4px;
      position: relative;
    }
    .tip-card {
      background: #f0fdf4;
      border: 1px solid #bbf7d0;
      border-radius: 0.75rem;
      padding: 1rem;
    }
    .tip-card.warning {
      background: #fffbeb;
      border-color: #fde68a;
    }
    .tip-card.danger {
      background: #fef2f2;
      border-color: #fecaca;
    }
    .tip-card.info {
      background: #eff6ff;
      border-color: #bfdbfe;
    }
    .form-range::-webkit-slider-thumb { background: #6366f1; }
    .form-range::-moz-range-thumb { background: #6366f1; }
    @keyframes slideUp {
      from { opacity: 0; transform: translateY(20px); }
      to { opacity: 1; transform: translateY(0); }
    }