:root {
  --primary: #007bff;
  --primary-dark: #0056b3;
  --secondary: #6c757d;
  --success: #28a745;
  --danger: #dc3545;
  --warning: #ffc107;
  --info: #17a2b8;
  --light: #f8f9fa;
  --dark: #343a40;
  --white: #ffffff;
  --gray-100: #f8f9fa;
  --gray-200: #e9ecef;
  --gray-300: #dee2e6;
  --gray-400: #ced4da;
  --gray-500: #adb5bd;
  --gray-600: #6c757d;
  --gray-700: #495057;
  --gray-800: #343a40;
  --gray-900: #212529;
}

* {
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  font-size: 16px;
  line-height: 1.6;
  color: var(--gray-800);
  background-color: var(--light);
}

/* NAVBAR */
.navbar {
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
  position: sticky;
  top: 0;
  z-index: 1000;
}

.navbar-brand {
  font-weight: 600;
  letter-spacing: 1px;
}

.btn-outline-light:hover {
  background-color: rgba(255, 255, 255, 0.2);
}

/* OFFCANVAS MENU */
.offcanvas {
  width: 280px !important;
}

.offcanvas-header {
  border-bottom: 1px solid var(--gray-300);
  background-color: var(--light);
}

.offcanvas-body {
  padding: 0;
}

.list-group-item {
  border: none;
  border-bottom: 1px solid var(--gray-200);
  padding: 12px 16px;
  font-size: 15px;
}

.list-group-item:last-child {
  border-bottom: none;
}

.list-group-item a {
  color: var(--gray-800);
  text-decoration: none;
  transition: color 0.2s;
}

.list-group-item a:hover {
  color: var(--primary);
  font-weight: 500;
}

.list-group-item form {
  margin: 0;
}

/* CONTAINERS */
.container {
  max-width: 1200px;
}

/* CARDS */
.card {
  border: 1px solid var(--gray-200);
  border-radius: 8px;
  transition: all 0.3s ease;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

.card-header {
  border-bottom: 1px solid var(--gray-200);
  background-color: var(--light);
  font-weight: 600;
  padding: 16px;
}

.card-body {
  padding: 20px;
}

.card-title {
  margin-bottom: 12px;
  font-weight: 600;
  color: var(--gray-900);
}

.card-text {
  color: var(--gray-700);
  margin-bottom: 12px;
}

/* BUTTONS */
.btn {
  border-radius: 6px;
  font-weight: 500;
  transition: all 0.2s;
  text-decoration: none;
}

.btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

.btn-primary {
  background-color: var(--primary);
  border-color: var(--primary);
}

.btn-primary:hover {
  background-color: var(--primary-dark);
  border-color: var(--primary-dark);
}

.btn-danger {
  background-color: var(--danger);
  border-color: var(--danger);
}

.btn-success {
  background-color: var(--success);
  border-color: var(--success);
}

.btn-outline-primary {
  color: var(--primary);
  border-color: var(--primary);
}

.btn-outline-primary:hover {
  background-color: var(--primary);
  color: white;
}

/* FORMS */
.form-control,
.form-select,
textarea {
  border: 1px solid var(--gray-300);
  border-radius: 6px;
  padding: 10px 12px;
  font-size: 15px;
  transition: border-color 0.2s, box-shadow 0.2s;
}

.form-control:focus,
.form-select:focus,
textarea:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(0, 123, 255, 0.1);
  outline: none;
}

.form-label {
  font-weight: 500;
  color: var(--gray-800);
  margin-bottom: 8px;
  display: block;
}

input[type="date"],
input[type="email"],
input[type="password"],
input[type="text"] {
  width: 100%;
}

/* TABLES */
.table {
  background-color: white;
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
}

.table thead {
  background-color: var(--gray-100);
  font-weight: 600;
}

.table-dark thead {
  background-color: var(--gray-800);
  color: white;
}

.table-hover tbody tr:hover {
  background-color: var(--gray-50);
}

.table td,
.table th {
  padding: 12px 16px;
  border-color: var(--gray-200);
}

.table-striped tbody tr:nth-child(odd) {
  background-color: var(--gray-50);
}

/* ALERTS */
.alert {
  border: none;
  border-left: 4px solid var(--gray-400);
  border-radius: 6px;
  padding: 16px;
  margin-bottom: 16px;
}

.alert-success {
  background-color: #d4edda;
  color: #155724;
  border-left-color: var(--success);
}

.alert-danger {
  background-color: #f8d7da;
  color: #721c24;
  border-left-color: var(--danger);
}

.alert-warning {
  background-color: #fff3cd;
  color: #856404;
  border-left-color: var(--warning);
}

.alert-info {
  background-color: #d1ecf1;
  color: #0c5460;
  border-left-color: var(--info);
}

/* CHAT MESSAGES */
#messages-container {
  background-color: white;
  border: 1px solid var(--gray-200);
  border-radius: 8px;
  padding: 16px;
  scroll-behavior: smooth;
}

.message {
  background-color: var(--gray-50);
  border-left: 4px solid var(--primary);
  padding: 12px;
  margin-bottom: 12px;
  border-radius: 4px;
  word-wrap: break-word;
  line-height: 1.5;
}

.message strong {
  color: var(--gray-900);
  display: block;
  margin-bottom: 4px;
}

.message small {
  color: var(--gray-600);
  font-size: 12px;
}

.message p {
  margin: 8px 0 0 0;
  color: var(--gray-800);
}

.message.own {
  background-color: #e7f3ff;
  border-left-color: var(--success);
}

/* INPUT GROUP */
.input-group {
  margin-top: 16px;
  display: flex;
  gap: 8px;
}

.input-group textarea {
  flex: 1;
  font-family: inherit;
}

.input-group button {
  flex-shrink: 0;
  padding: 10px 24px;
}

/* TEXT UTILITIES */
.text-muted {
  color: var(--gray-600) !important;
}

.text-muted-small {
  color: var(--gray-600);
  font-size: 13px;
}

.text-center {
  text-align: center;
}

.text-decoration-none {
  text-decoration: none;
}

.text-decoration-none:hover {
  text-decoration: underline;
}

.lead {
  font-size: 18px;
  font-weight: 300;
  color: var(--gray-700);
}

/* SPACING */
.mb-0 { margin-bottom: 0 !important; }
.mb-1 { margin-bottom: 0.25rem !important; }
.mb-2 { margin-bottom: 0.5rem !important; }
.mb-3 { margin-bottom: 1rem !important; }
.mb-4 { margin-bottom: 1.5rem !important; }
.mb-5 { margin-bottom: 3rem !important; }

.mt-3 { margin-top: 1rem !important; }
.mt-4 { margin-top: 1.5rem !important; }
.mt-5 { margin-top: 3rem !important; }

.ms-2 { margin-left: 0.5rem !important; }
.ms-3 { margin-left: 1rem !important; }

.p-2 { padding: 0.5rem !important; }
.p-3 { padding: 1rem !important; }
.p-4 { padding: 1.5rem !important; }

/* ROWS & COLUMNS */
.row {
  display: flex;
  flex-wrap: wrap;
  margin-right: -12px;
  margin-left: -12px;
}

.col-md-4,
.col-md-6,
.col-md-8,
.col-md-10,
.col-md-12 {
  padding-right: 12px;
  padding-left: 12px;
  margin-bottom: 20px;
}

.col-md-4 { flex: 0 0 33.333%; }
.col-md-6 { flex: 0 0 50%; }
.col-md-8 { flex: 0 0 66.667%; }
.col-md-10 { flex: 0 0 83.333%; }
.col-md-12 { flex: 0 0 100%; }

.mx-auto {
  margin-left: auto !important;
  margin-right: auto !important;
}

.w-100 {
  width: 100% !important;
}

/* BORDER STYLES */
.border {
  border: 1px solid var(--gray-300) !important;
}

.border-start {
  border-left: 1px solid var(--gray-300) !important;
}

.border-success {
  border-color: var(--success) !important;
}

.border-primary {
  border-color: var(--primary) !important;
}

/* HEADINGS */
h1, h2, h3, h4, h5, h6 {
  color: var(--gray-900);
  font-weight: 600;
  line-height: 1.3;
}

h1 { font-size: 32px; margin-bottom: 24px; }
h2 { font-size: 28px; margin-bottom: 20px; }
h3 { font-size: 24px; margin-bottom: 16px; }
h4 { font-size: 20px; margin-bottom: 12px; }
h5 { font-size: 18px; margin-bottom: 12px; }
h6 { font-size: 16px; margin-bottom: 8px; }

/* SECTION TITLES */
section h2 {
  border-bottom: 2px solid var(--gray-200);
  padding-bottom: 12px;
  margin-bottom: 16px;
}

/* LIST STYLES */
ul, ol {
  margin-bottom: 16px;
  margin-left: 20px;
}

ul li, ol li {
  margin-bottom: 8px;
  color: var(--gray-800);
}

.list-unstyled {
  list-style: none;
  padding: 0;
  margin: 0;
}

.list-unstyled li {
  margin-left: 0;
}

.list-group {
  border-radius: 8px;
  overflow: hidden;
  border: 1px solid var(--gray-300);
}

.list-group-item {
  background-color: white;
  border: 1px solid var(--gray-300);
  padding: 12px 16px;
}

.list-group-item:first-child {
  border-top-left-radius: 8px;
  border-top-right-radius: 8px;
}

.list-group-item:last-child {
  border-bottom-left-radius: 8px;
  border-bottom-right-radius: 8px;
}

.list-group-item strong {
  color: var(--gray-900);
}

.list-group-numbered {
  counter-reset: section;
}

.list-group-numbered .list-group-item::before {
  counter-increment: section;
  content: counter(section) ". ";
  font-weight: 600;
  color: var(--primary);
}

/* RESPONSIVE */
@media (max-width: 768px) {
  .container {
    padding: 0 12px;
  }

  .col-md-4,
  .col-md-6,
  .col-md-8,
  .col-md-10,
  .col-md-12 {
    flex: 0 0 100%;
  }

  .mx-auto {
    margin-left: 0 !important;
    margin-right: 0 !important;
  }

  h1 { font-size: 28px; }
  h2 { font-size: 24px; }
  h3 { font-size: 20px; }

  #messages-container {
    height: 300px !important;
  }

  .input-group {
    flex-direction: column;
  }

  .input-group button {
    width: 100%;
  }

  .table-responsive {
    overflow-x: auto;
  }

  .offcanvas {
    width: 100% !important;
  }
}

@media (max-width: 576px) {
  body {
    font-size: 14px;
  }

  .container {
    padding: 0 8px;
  }

  h1 { font-size: 24px; margin-bottom: 16px; }
  h2 { font-size: 20px; margin-bottom: 12px; }
  h3 { font-size: 18px; }

  .card {
    margin-bottom: 16px;
  }

  .btn {
    padding: 10px 16px;
    font-size: 14px;
  }

  .btn-lg {
    padding: 12px 24px;
    font-size: 16px;
  }

  .navbar-brand {
    font-size: 18px;
  }
}

/* BACKGROUND COLORS */
.bg-light {
  background-color: var(--light) !important;
}

.bg-dark {
  background-color: var(--dark) !important;
  color: white;
}

.bg-primary {
  background-color: var(--primary) !important;
  color: white;
}

.bg-success {
  background-color: var(--success) !important;
  color: white;
}

.bg-danger {
  background-color: var(--danger) !important;
  color: white;
}

.bg-info {
  background-color: var(--info) !important;
  color: white;
}

/* MISC */
.hr {
  border: none;
  border-top: 1px solid var(--gray-300);
  margin: 8px 0;
}

.rounded {
  border-radius: 8px;
}

.small {
  font-size: 13px;
}

.d-block {
  display: block;
}

.d-inline {
  display: inline;
}

.d-flex {
  display: flex;
}

.gap-3 {
  gap: 1rem;
}

/* ANIMATIONS */
@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.fade-in {
  animation: fadeIn 0.3s ease-in-out;
}

/* SCROLLBAR */
::-webkit-scrollbar {
  width: 8px;
}

::-webkit-scrollbar-track {
  background: var(--gray-100);
}

::-webkit-scrollbar-thumb {
  background: var(--gray-400);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--gray-500);
}

/* FOCUS STATES */
*:focus-visible {
  outline: 2px solid var(--primary);
  outline-offset: 2px;
}

button:focus-visible,
.btn:focus-visible {
  outline: 2px solid var(--primary);
  outline-offset: 2px;
}