/* Red-white (cool tone) palette */
  .bg-cool {
    background: linear-gradient(135deg, #fff5f5 0%, #ffffff 100%);
  }
  .bg-cool-1 {
    background: linear-gradient(135deg, #fff5f5 0%, #fff9f2 100%);
  }
  .text-cool {
    color: #c62828; /* đỏ rượu vang */
  }
  .text-cool-dark {
    color: #a61c1c; /* đỏ đậm hơn */
  }
  .btn-cool {
    background: #c62828;
    color: #fff;
    border: none;
  }
  .btn-cool:hover {
    background: #a61c1c;
    color: rgb(227, 221, 214);
  }
  .btn-outline-cool {
    border: 1px solid #c62828;
    color: #c62828;
  }
  .btn-outline-cool:hover {
    background: #c62828;
    color: #fff;
  }
  .input-group.modern-input .form-control {
    border-radius: 0 !important;
  }
  .input-group.modern-input .input-group-text {
    border-radius: .75rem 0 0 .75rem;
    color: #c62828;
  }
  .input-group.modern-input .btn {
    border-radius: 0 .75rem .75rem 0;
  }

  /* Responsive tweak */
  @media (max-width: 576px) {
    .bg-cool {
      padding: 2rem 1rem !important;
    }
    #qr-tools .form-select, 
    #qr-tools .form-control-color {
      width: 100%;
    }
  }

  /* QR Generator Styles */
  #qr-tools .card { border-radius: 1.25rem; }
  #qrPreviewFrame canvas { border-radius: 8px; }
  #qr-tools .form-control, 
  #qr-tools .form-select, 
  #qr-tools .btn { border-radius: .75rem; }
  #qr-tools .form-control-color { height: 42px; }

  /* Default: khung QR co giãn mượt */
  #qrPreviewFrame {
    width: clamp(240px, 80%, 360px);
    height: clamp(240px, 80vw, 360px);
    transition: width .2s ease, height .2s ease;
  }

  @media (max-width: 768px) {
    #qr-tools .p-4 { padding: 1.25rem !important; }
    #qrPreviewFrame { width: clamp(200px, 70vw, 280px); height: clamp(200px, 70vw, 280px); }
    #previewTitle { font-size: 1rem; }
    #previewUrl { font-size: .8rem; }
  }

  /* Hiệu ứng hover nổi khối */
  .hover-lift {
    transition: all 0.3s ease;
    border-radius: 16px;
  }
  .hover-lift:hover {
    transform: translateY(-6px);
    box-shadow: 0 12px 24px rgba(0,0,0,0.12);
  }
  #tools .icon i {
    transition: transform 0.3s ease;
  }
  #tools .card:hover .icon i {
    transform: scale(1.1);
  }

  /* Vietnam Map */
  #mapVN { 
    min-height: 360px; 
    height: 100%; 
    width: 100%; 
    display: block; 
  }
  #vn-map-explorer .card { border-radius: 12px; overflow: visible; }
  .province-tooltip { z-index: 99999; pointer-events: none; }

  #previewCanvas {
    display: block;
    margin: 0 auto;
    aspect-ratio: 9 / 16;
    width: 70%;          
    height: auto;
    max-width: 360px;    
    max-height: 75vh;
    border-radius: 12px;
    box-shadow: 0 8px 24px rgba(0,0,0,0.1);
  }

  /* Avatar */
  /* Custom modern slider */
  .styled-range {
    -webkit-appearance: none;
    height: 6px;
    border-radius: 6px;
    background: linear-gradient(90deg, #dc3545, #ff9800); /* đỏ -> cam */
    outline: none;
    transition: background 0.3s;
    cursor: pointer;
  }

  /* Thumb (nút trượt) */
  .styled-range::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 18px;
    height: 18px;
    border-radius: 50%;
    background: #fff;
    border: 2px solid #dc3545;
    box-shadow: 0 0 6px rgba(0,0,0,0.2);
    transition: transform 0.2s;
  }
  .styled-range::-webkit-slider-thumb:hover {
    transform: scale(1.2);
  }

  .styled-range::-moz-range-thumb {
    width: 18px;
    height: 18px;
    border-radius: 50%;
    background: #fff;
    border: 2px solid #dc3545;
    box-shadow: 0 0 6px rgba(0,0,0,0.2);
    cursor: pointer;
    transition: transform 0.2s;
  }
  .styled-range::-moz-range-thumb:hover {
    transform: scale(1.2);
  }