:root {
    --primary-red: #C62828;
    --primary-red-hover: #B71C1C;
    --primary-red-light: #FFEBEE;
    --bg-light: #F8F9FA;
    --sidebar-width: 260px;
    --card-radius: 16px;
    --transition-speed: 0.25s;
  }

  body {
    font-family: 'Poppins', sans-serif;
    background-color: var(--bg-light);
    color: #333333;
    overflow-x: hidden;
  }

  /* Layout Structure */
  #app-wrapper {
    display: flex;
    min-height: 100vh;
  }

  /* Desktop Sidebar */
  #sidebar {
    width: var(--sidebar-width);
    background: #FFFFFF;
    border-right: 1px solid #EAEAEA;
    position: fixed;
    top: 0;
    bottom: 0;
    left: 0;
    z-index: 1000;
    transition: all var(--transition-speed) ease-in-out;
    display: flex;
    flex-direction: column;
  }

  /* Main Wrapper */
  #main-wrapper {
    flex: 1;
    margin-left: var(--sidebar-width);
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    transition: all var(--transition-speed) ease-in-out;
  }

  @media (max-width: 991.98px) {
    #sidebar {
      display: none;
    }
    #main-wrapper {
      margin-left: 0;
    }
  }

  /* Brand Header */
  .brand-box {
    padding: 1.5rem 1.25rem;
    display: flex;
    align-items: center;
    gap: 12px;
    border-bottom: 1px solid #F0F0F0;
  }

  .brand-logo {
    width: 42px;
    height: 42px;
    object-fit: contain;
  }

  .brand-title {
    font-weight: 700;
    font-size: 0.95rem;
    color: var(--primary-red);
    line-height: 1.2;
    margin: 0;
  }

  .brand-subtitle {
    font-size: 0.72rem;
    color: #757575;
    margin: 0;
  }

  /* Navigation Links */
  .nav-list {
    list-style: none;
    padding: 1rem 0.75rem;
    margin: 0;
    flex: 1;
  }

  .nav-item {
    margin-bottom: 4px;
  }

  .nav-link-custom {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 0.75rem 1rem;
    color: #616161;
    text-decoration: none;
    border-radius: 12px;
    font-weight: 500;
    font-size: 0.88rem;
    transition: all 0.2s ease;
  }

  .nav-link-custom i {
    font-size: 1.2rem;
  }

  .nav-link-custom:hover {
    background-color: var(--primary-red-light);
    color: var(--primary-red);
  }

  .nav-link-custom.active {
    background-color: var(--primary-red);
    color: #FFFFFF !important;
    box-shadow: 0 4px 12px rgba(198, 40, 40, 0.25);
  }

  /* Navbar */
  .top-navbar {
    height: 70px;
    background: #FFFFFF;
    border-bottom: 1px solid #EAEAEA;
    padding: 0 1.5rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    position: sticky;
    top: 0;
    z-index: 999;
  }

  /* Custom Cards & Glassmorphism */
  .card-custom {
    background: #FFFFFF;
    border: 1px solid rgba(0,0,0,0.05);
    border-radius: var(--card-radius);
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.03);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
  }

  .card-custom:hover {
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.06);
  }

  .glass-header {
    background: linear-gradient(135deg, var(--primary-red) 0%, #8E0000 100%);
    color: white;
    border-radius: var(--card-radius);
    padding: 1.75rem;
    box-shadow: 0 6px 18px rgba(198, 40, 40, 0.2);
  }

  /* Buttons */
  .btn-primary-custom {
    background-color: var(--primary-red);
    border-color: var(--primary-red);
    color: #FFFFFF;
    font-weight: 500;
    border-radius: 10px;
    padding: 0.6rem 1.2rem;
  }

  .btn-primary-custom:hover {
    background-color: var(--primary-red-hover);
    border-color: var(--primary-red-hover);
    color: #FFFFFF;
  }

  /* Loading Overlay */
  #loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(4px);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 9999;
  }

  .spinner-custom {
    width: 3rem;
    height: 3rem;
    color: var(--primary-red);
  }

  /* Print Optimization CSS */
  @media print {
    body {
      background-color: #FFFFFF !important;
      color: #000000 !important;
    }
    #sidebar, .top-navbar, footer, .no-print, #loading-overlay {
      display: none !important;
    }
    #main-wrapper {
      margin-left: 0 !important;
      padding: 0 !important;
    }
    .card-custom {
      border: none !important;
      box-shadow: none !important;
      padding: 0 !important;
    }
    .print-only {
      display: flex !important;
    }
    .table-bordered th, .table-bordered td {
      border: 1px solid #333 !important;
    }
  }