:root {
  
  --primary: #6366f1;
  --primary-dark: #4f46e5;
  --primary-darker: #4338ca;
  --primary-light: #e0e7ff;
  --primary-lighter: #f5f3ff;
  
  --secondary: #64748b;
  --secondary-dark: #475569;
  --secondary-light: #f1f5f9;
  
  --success: #10b981;
  --success-dark: #059669;
  --success-light: #d1fae5;
  
  --warning: #f59e0b;
  --warning-dark: #d97706;
  --warning-light: #fef3c7;
  
  --danger: #ef4444;
  --danger-dark: #dc2626;
  --danger-light: #fee2e2;
  
  --info: #3b82f6;
  --info-dark: #2563eb;
  --info-light: #dbeafe;
  
  
  --gray-50: #f8fafc;
  --gray-100: #f1f5f9;
  --gray-200: #e2e8f0;
  --gray-300: #cbd5e1;
  --gray-400: #94a3b8;
  --gray-500: #64748b;
  --gray-600: #475569;
  --gray-700: #334155;
  --gray-800: #1e293b;
  --gray-900: #0f172a;
  
  
  --surface-0: rgba(255, 255, 255, 0.9);
  --surface-50: rgba(248, 250, 252, 0.9);
  --surface-100: rgba(241, 245, 249, 0.9);
  --surface-200: rgba(226, 232, 240, 0.9);
  --surface-300: rgba(203, 213, 225, 0.9);
  
  
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  
  
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-2xl: 1.5rem;
  --radius-full: 9999px;
  
  
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
  --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
  
  
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-normal: 300ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 500ms cubic-bezier(0.4, 0, 0.2, 1);
  
  
  --font-sans: 'Inter', system-ui, -apple-system, sans-serif;
  --font-mono: 'JetBrains Mono', ui-monospace, monospace;
  
  
  --container-max: 1280px;
  --container-padding: var(--space-8);

  --matrix-primary: #6366f1;
  --matrix-bg: #fff;
  --matrix-bg-alt: #f7f8fa;
  --matrix-border: #e0e7ff;
  --matrix-radius: 16px;
  --matrix-shadow: 0 2px 12px rgba(99,102,241,0.07);
  --matrix-contrast-bg: #000;
  --matrix-contrast-fg: #fff;
  --matrix-focus: #f9c846;
}


.dark-theme {
  --primary: #8b9cff;
  --primary-dark: #5a6ee6;
  --primary-darker: #3a4bb3;
  --primary-light: #23263a;
  --primary-lighter: #181a20;
  --info: #60a5fa;
  --info-dark: #2563eb;
  --info-light: #334155;
  --success: #22d3a8;
  --success-dark: #14b89a;
  --success-light: #134e4a;
  --warning: #fbbf24;
  --warning-dark: #f59e0b;
  --warning-light: #78350f;
  --danger: #f87171;
  --danger-dark: #dc2626;
  --danger-light: #7f1d1d;
  --surface-0: #181a20;
  --surface-50: #23263a;
  --surface-100: #23263a;
  --surface-200: #23263a;
  --surface-300: #232634;
  --gray-50: #181a20;
  --gray-100: #f3f4f6;
  --gray-200: #e0e7ef;
  --gray-300: #cbd5e1;
  --gray-400: #94a3b8;
  --gray-500: #64748b;
  --gray-600: #475569;
  --gray-700: #334155;
  --gray-800: #23263a;
  --gray-900: #181a20;
}

.dark-theme, .dark-theme body {
  color: #f3f4f6 !important;
  background: var(--dark-bg, #181a20) !important;
}
.dark-theme .container,
.dark-theme .card,
.dark-theme .result-container,
.dark-theme .math-display,
.dark-theme .form-label,
.dark-theme .form-control,
.dark-theme .btn,
.dark-theme .card-header,
.dark-theme .card-body,
.dark-theme .lead,
.dark-theme .subtitle,
.dark-theme .text-secondary,
.dark-theme .text-muted,
.dark-theme .text-info,
.dark-theme .text-success,
.dark-theme .text-danger,
.dark-theme .text-warning,
.dark-theme .text-primary {
  color: #f3f4f6 !important;
}
.dark-theme .text-secondary,
.dark-theme .lead,
.dark-theme .subtitle,
.dark-theme .text-muted {
  color: #b3b8c5 !important;
}
.dark-theme .form-label,
.dark-theme label {
  color: #e0e3ea !important;
}
.dark-theme .form-control,
.dark-theme input,
.dark-theme textarea,
.dark-theme select {
  color: #f3f4f6 !important;
  background: #232634 !important;
  border-color: #353a4a !important;
}
.dark-theme .form-control:focus,
.dark-theme input:focus,
.dark-theme textarea:focus,
.dark-theme select:focus {
  color: #fff !important;
  background: #232634 !important;
  border-color: #6366f1 !important;
}
.dark-theme .btn,
.dark-theme .btn-primary,
.dark-theme .btn-success,
.dark-theme .btn-info,
.dark-theme .btn-outline,
.dark-theme .btn-light {
  color: #fff !important;
  background: #353a4a !important;
  border-color: #6366f1 !important;
}
.dark-theme .btn:hover,
.dark-theme .btn:focus {
  background: #6366f1 !important;
  color: #fff !important;
}
.dark-theme .card,
.dark-theme .card-header,
.dark-theme .card-body {
  background: rgba(30,32,40,0.95) !important;
  color: #f3f4f6 !important;
  border-color: #353a4a !important;
}
.dark-theme .result-container {
  background: #232634 !important;
  color: #f3f4f6 !important;
  border-color: #6366f1 !important;
}
.dark-theme .math-display {
  color: #fff !important;
}
.dark-theme .examples-container button,
.dark-theme .examples-container .btn {
  color: #fff !important;
  background: #353a4a !important;
  border-color: #6366f1 !important;
}
.dark-theme .examples-container button:hover {
  background: #6366f1 !important;
  color: #fff !important;
}
.dark-theme .toast {
  background: #232634 !important;
  color: #fff !important;
  border-color: #6366f1 !important;
}
.dark-theme .toast .toast-icon {
  color: #8b9cff !important;
}
.dark-theme .form-hint {
  color: #b3b8c5 !important;
}
.dark-theme .explanation-box {
  background: #232634 !important;
  color: #f3f4f6 !important;
}
.dark-theme .vertex,
.dark-theme .vertex.visited {
  background: #6366f1 !important;
  color: #fff !important;
}
.dark-theme .vertex.current {
  background: #fbbf24 !important;
  color: #232634 !important;
}
.dark-theme .edge-list li {
  background: #232634 !important;
  color: #fff !important;
}
.dark-theme .degree-list li {
  color: #fff !important;
}
.dark-theme .property-name {
  color: #b3b8c5 !important;
}
.dark-theme .property-value {
  color: #fff !important;
}
.dark-theme .special-graph-card {
  background: #232634 !important;
  color: #f3f4f6 !important;
}
.dark-theme .tip-item {
  background: #232634 !important;
  color: #f3f4f6 !important;
}
.dark-theme .visualization-container {
  background: #232634 !important;
  color: #f3f4f6 !important;
}
.dark-theme .alert-error {
  background: #3b1f1f !important;
  color: #ffb4b4 !important;
  border-color: #c62828 !important;
}
.dark-theme .alert-success {
  background: #1f3b1f !important;
  color: #b4ffb4 !important;
  border-color: #2e7d32 !important;
}
.dark-theme .alert {
  color: #fff !important;
}
.dark-theme .modal-content {
  background: #232634 !important;
  color: #f3f4f6 !important;
}
.dark-theme .dropdown-menu {
  background: #232634 !important;
  color: #f3f4f6 !important;
}
.dark-theme .dropdown-item {
  color: #f3f4f6 !important;
}
.dark-theme .dropdown-item:hover {
  background: #353a4a !important;
  color: #fff !important;
}
.dark-theme .loader,
.dark-theme .spinner-border {
  border-top-color: #6366f1 !important;
  border-right-color: #6366f1 !important;
  border-bottom-color: #232634 !important;
  border-left-color: #232634 !important;
}
.dark-theme .fixed,
.dark-theme .bottom-4,
.dark-theme .end-0,
.dark-theme .p-3,
.dark-theme .z-50 {
  color: #fff !important;
}
.dark-theme .chatbot-widget,
.dark-theme #chatbot-toggle {
  background: #232634 !important;
  color: #f3f4f6 !important;
  border-color: #6366f1 !important;
}
.dark-theme .chatbot-header {
  background: #181a20 !important;
  color: #fff !important;
}
.dark-theme .chatbot-message.user {
  background: #353a4a !important;
  color: #fff !important;
}
.dark-theme .chatbot-message.ai {
  background: #6366f1 !important;
  color: #fff !important;
}
.dark-theme .chatbot-input {
  background: #232634 !important;
  color: #fff !important;
  border-color: #6366f1 !important;
}
.dark-theme .chatbot-input:focus {
  background: #232634 !important;
  color: #fff !important;
  border-color: #8b9cff !important;
}
.dark-theme .chatbot-footer {
  background: #181a20 !important;
  color: #b3b8c5 !important;
}
.dark-theme .chatbot-avatar {
  background: #353a4a !important;
  color: #fff !important;
}
.dark-theme .chatbot-badge {
  background: #353a4a !important;
  color: #8b9cff !important;
}
.dark-theme .simple-graph-viz,
.dark-theme .algorithm-viz {
  background: #232634 !important;
  color: #f3f4f6 !important;
}
.dark-theme .vis-network {
  background: #232634 !important;
}
.dark-theme .form-hint {
  color: #b3b8c5 !important;
}
.dark-theme .explanation-box h4 {
  color: #8b9cff !important;
}
.dark-theme .number-card {
  background: #232634 !important;
  color: #f3f4f6 !important;
}
.dark-theme .number-card .label {
  color: #b3b8c5 !important;
}
.dark-theme .number-card .value {
  color: #fff !important;
}
.dark-theme .step {
  border-bottom: 1px dashed #353a4a !important;
}
.dark-theme kbd {
  background: #353a4a !important;
  color: #fff !important;
  border: 1px solid #6366f1 !important;
}
.dark-theme .vertex-set .vertex {
  background: #353a4a !important;
  color: #fff !important;
}
.dark-theme .vertex-set .vertex.visited {
  background: #6366f1 !important;
  color: #fff !important;
}
.dark-theme .vertex-set .vertex.current {
  background: #fbbf24 !important;
  color: #232634 !important;
}


* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: var(--font-sans);
  line-height: 1.6;
  color: #1e293b;
  background-color: var(--gray-50);
  transition: var(--transition-normal);
  min-height: 100vh;
  background-image: 
    radial-gradient(at 0% 0%, #f5f3ff 0px, transparent 50%),
    radial-gradient(at 100% 100%, #dbeafe 0px, transparent 50%);
  background-attachment: fixed;
  padding-top: 3.5rem;
}


.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: var(--container-padding);
}


.top-nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.75rem 1.5rem;
    background: #23263a;
    color: #fff;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.25rem;
    font-weight: 600;
    color: #fff;
}

.nav-brand i {
    color: #4f46e5;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.nav-item {
    color: #fff;
    padding: 0.5rem;
    border-radius: 0.375rem;
    transition: all 0.2s ease;
    position: relative;
    text-decoration: none;
}

.nav-item:focus, .nav-item:hover {
    color: #fff;
    background: #6366f1;
}

.nav-item i {
    font-size: 1.125rem;
}


.nav-item::after {
    content: attr(title);
    position: absolute;
    bottom: -2rem;
    left: 50%;
    transform: translateX(-50%);
    padding: 0.25rem 0.5rem;
    background: #1e293b;
    color: white;
    font-size: 0.75rem;
    border-radius: 0.25rem;
    opacity: 0;
    visibility: hidden;
    transition: all 0.2s ease;
    white-space: nowrap;
}

.nav-item:hover::after {
    opacity: 1;
    visibility: visible;
}


.card {
  background: #fff;
  color: #1e293b;
  box-shadow: 0 4px 24px 0 rgba(80, 80, 120, 0.06);
  border: 1px solid var(--gray-200);
  margin-bottom: var(--space-8);
  overflow: hidden;
  transition: var(--transition-normal);
  border-radius: var(--radius-lg);
  position: relative;
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(to right, var(--primary), var(--info));
  opacity: 0;
  transition: var(--transition-normal);
}

.card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-2px);
}

.card:hover::before {
  opacity: 1;
}

.card-header {
  background: #f5f3ff;
  color: #1e293b;
  padding: var(--space-6);
  border-bottom: 1px solid var(--gray-200);
  position: relative;
  overflow: hidden;
}

.card-header::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(45deg, transparent, var(--primary-light), transparent);
  transform: translateX(-100%);
  transition: var(--transition-normal);
}

.card:hover .card-header::before {
  transform: translateX(100%);
}

.card-header h3 {
  margin: 0;
  font-size: 1.25rem;
  color: #1e293b;
  display: flex;
  align-items: center;
  gap: var(--space-2);
  position: relative;
  z-index: 1;
}

.card-body {
  padding: var(--space-6);
}


.form-container {
  max-width: 800px;
  margin: 0 auto;
}

.form-group {
  margin-bottom: var(--space-6);
}

.form-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--space-6);
  margin-bottom: var(--space-6);
}

label {
  display: block;
  margin-bottom: var(--space-2);
  font-weight: 500;
  color: #1e293b;
}

input[type="text"],
input[type="number"],
input[type="email"],
input[type="password"],
select,
textarea {
  width: 100%;
  padding: var(--space-3) var(--space-4);
  border: 2px solid var(--gray-300);
  border-radius: var(--radius-md);
  font-size: 1rem;
  transition: var(--transition-fast);
  background-color: var(--surface-0);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

input:focus,
select:focus,
textarea:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--primary-lighter);
}

.form-hint {
  font-size: 0.875rem;
  color: var(--gray-500);
  margin-top: var(--space-2);
}


.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-6);
  border: none;
  border-radius: var(--radius-md);
  font-size: 1rem;
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition-fast);
  text-decoration: none;
  position: relative;
  overflow: hidden;
  background: var(--primary);
  color: white;
}

.btn::before {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  width: 0;
  height: 0;
  background: rgba(255, 255, 255, 0.2);
  border-radius: 50%;
  transform: translate(-50%, -50%);
  transition: width 0.6s ease, height 0.6s ease;
}

.btn:hover {
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn:hover::before {
  width: 300%;
  height: 300%;
}

.btn-primary {
  background: linear-gradient(45deg, var(--primary), var(--info));
}

.btn-primary:hover {
  background: linear-gradient(45deg, var(--primary-dark), var(--info-dark));
}

.btn-outline {
  background: transparent;
  border: 2px solid var(--primary);
  color: var(--primary);
}

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


.result-container {
  background: #fff;
  color: #1e293b;
  box-shadow: 0 4px 24px 0 rgba(80, 80, 120, 0.06);
  border: 1px solid var(--gray-200);
  padding: var(--space-6);
  margin-top: var(--space-8);
  position: relative;
  overflow: hidden;
}

.result-container::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 4px;
  height: 100%;
  background: linear-gradient(to bottom, var(--primary), var(--info));
}

.result-container h3 {
  color: #1e293b;
  margin-top: 0;
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.math-display {
  font-family: var(--font-mono);
  background: var(--surface-50);
  padding: var(--space-4);
  border-radius: var(--radius-md);
  margin: var(--space-4) 0;
  overflow-x: auto;
  border: 1px solid var(--gray-200);
}


.visualization-container {
  margin-top: var(--space-8);
  padding: var(--space-6);
  background: #fff;
  color: #1e293b;
  box-shadow: 0 4px 24px 0 rgba(80, 80, 120, 0.06);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-lg);
  position: relative;
}

.visualization-container::after {
  content: '';
  position: absolute;
  bottom: 0;
  right: 0;
  width: 100px;
  height: 100px;
  background: radial-gradient(circle at bottom right, var(--primary-lighter), transparent 70%);
  opacity: 0.1;
  pointer-events: none;
}


.examples-container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--space-6);
  margin-top: var(--space-6);
}

.example-card {
  background: #fff;
  color: #1e293b;
  box-shadow: 0 4px 24px 0 rgba(80, 80, 120, 0.06);
  border: 1px solid var(--gray-200);
  padding: var(--space-6);
  transition: var(--transition-normal);
  border-radius: var(--radius-lg);
  position: relative;
  overflow: hidden;
}

.example-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(45deg, transparent, var(--primary-lighter), transparent);
  transform: translateX(-100%);
  transition: var(--transition-normal);
}

.example-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.example-card:hover::before {
  transform: translateX(100%);
}

.example-card h3 {
  color: #1e293b;
  margin-top: 0;
  font-size: 1.1rem;
  position: relative;
  z-index: 1;
}

.example-btn {
  margin-top: var(--space-4);
  width: 100%;
  position: relative;
  z-index: 1;
}


.theory-intro {
  background: #f5f3ff;
  color: #1e293b;
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  margin-bottom: var(--space-8);
  border: 1px solid var(--gray-200);
  position: relative;
  overflow: hidden;
}

.theory-intro::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%239C92AC' fill-opacity='0.05'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
  opacity: 0.1;
}

.theory-intro p {
  margin: 0 0 var(--space-4) 0;
  color: #1e293b;
  position: relative;
  z-index: 1;
}

.theory-intro ul {
  margin: 0;
  padding-left: var(--space-6);
  position: relative;
  z-index: 1;
}

.theory-intro li {
  margin-bottom: var(--space-2);
}


@media (max-width: 768px) {
  .container {
    padding: var(--space-4);
  }

  .navbar .container {
    padding: 0 var(--space-4);
  }

  .navbar-nav {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--surface-0);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    padding: var(--space-4);
    box-shadow: var(--shadow-md);
    border-top: 1px solid var(--gray-200);
  }

  .navbar-nav.active {
    display: flex;
    flex-direction: column;
    animation: slideDown 0.3s ease-out;
  }

  .page-title {
    margin-bottom: var(--space-8);
    padding: var(--space-4) 0;
  }

  .page-title h2 {
    font-size: 1.75rem;
  }

  .form-row {
    grid-template-columns: 1fr;
  }

  .card-header {
    padding: var(--space-4);
  }

  .card-body {
    padding: var(--space-4);
  }
}


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

@keyframes slideIn {
  from {
    opacity: 0;
    transform: translateX(-10px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

@keyframes slideDown {
  from {
    opacity: 0;
    transform: translateY(-10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.result-container {
  animation: fadeIn 0.3s ease-out;
}

.card {
  animation: slideIn 0.3s ease-out;
}


.footer {
  background: #23263a;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  color: #fff;
  padding: var(--space-12) 0;
  margin-top: var(--space-12);
  position: relative;
  overflow: hidden;
}

.footer::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(to right, transparent, var(--primary), transparent);
}

.footer .container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--space-8);
  position: relative;
  z-index: 1;
}

.footer h4 {
  color: var(--white);
  margin-bottom: var(--space-6);
  font-size: 1.1rem;
  position: relative;
  display: inline-block;
}

.footer h4::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 40px;
  height: 2px;
  background: linear-gradient(to right, var(--primary), var(--info));
}

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

.footer-links li {
  margin-bottom: var(--space-3);
}

.footer-links a {
  color: #b3b8c5;
  text-decoration: none;
  transition: var(--transition-fast);
  display: inline-block;
  position: relative;
}

.footer-links a::before {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 1px;
  background: linear-gradient(to right, var(--primary), var(--info));
  transition: var(--transition-fast);
}

.footer-links a:focus, .footer-links a:hover {
  color: var(--white);
  transform: translateX(4px);
}

.footer-links a:hover::before {
  width: 100%;
}


.text-center { text-align: center; }
.mt-1 { margin-top: var(--space-1); }
.mt-2 { margin-top: var(--space-2); }
.mt-3 { margin-top: var(--space-3); }
.mt-4 { margin-top: var(--space-4); }
.mt-5 { margin-top: var(--space-5); }
.mt-6 { margin-top: var(--space-6); }
.mt-8 { margin-top: var(--space-8); }
.mb-1 { margin-bottom: var(--space-1); }
.mb-2 { margin-bottom: var(--space-2); }
.mb-3 { margin-bottom: var(--space-3); }
.mb-4 { margin-bottom: var(--space-4); }
.mb-5 { margin-bottom: var(--space-5); }
.mb-6 { margin-bottom: var(--space-6); }
.mb-8 { margin-bottom: var(--space-8); }


.automata-container {
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    border-radius: 15px;
    padding: 20px;
    margin: 20px 0;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
}

.automata-container:hover {
    box-shadow: 0 12px 48px rgba(0, 0, 0, 0.15);
    transform: translateY(-2px);
}

.page-header {
    text-align: center;
    margin-bottom: 30px;
}

.page-header h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
    color: var(--primary);
}

.page-header .lead {
    font-size: 1.2rem;
    color: var(--text-secondary);
}

.automata-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
}

.automata-info {
    display: flex;
    gap: 20px;
}

.info-item {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 1.1rem;
    color: var(--text-primary);
}

.info-item i {
    color: var(--primary);
}

.automata-graph {
    position: relative;
    width: 100%;
    height: 500px;
    background: rgba(255, 255, 255, 0.05);
    border-radius: 10px;
    margin: 20px 0;
    overflow: hidden;
}

.automata-state {
    position: absolute;
    width: 60px;
    height: 60px;
    background: var(--surface);
    border: 2px solid var(--primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    color: var(--text-primary);
    cursor: pointer;
    transition: all 0.3s ease;
    z-index: 1;
}

.automata-state:hover {
    transform: scale(1.1);
    box-shadow: 0 0 20px rgba(var(--primary-rgb), 0.3);
}

.automata-state.active {
    background: var(--primary);
    color: white;
    animation: statePulse 1s infinite;
}

.automata-state.initial-state {
    border-width: 3px;
    border-color: var(--success);
}

.automata-state.final-state {
    border-width: 3px;
    border-color: var(--warning);
}

.automata-edge {
    stroke: var(--primary);
    stroke-width: 2;
    transition: all 0.3s ease;
}

.automata-edge:hover {
    stroke: var(--primary-dark);
    stroke-width: 3;
}

.automata-label {
    background: var(--surface);
    padding: 4px 8px;
    border-radius: 4px;
    font-size: 0.9rem;
    color: var(--text-primary);
    cursor: pointer;
    transition: all 0.3s ease;
}

.automata-label:hover {
    background: var(--primary);
    color: white;
    transform: scale(1.1);
}

.visualization-controls {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.visualization-controls .btn {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 8px 16px;
    border-radius: 8px;
    background: var(--surface);
    color: var(--text-primary);
    border: 1px solid var(--border);
    transition: all 0.3s ease;
}

.visualization-controls .btn:hover {
    background: var(--primary);
    color: white;
    transform: translateY(-2px);
}

.visualization-controls .btn.active {
    background: var(--primary);
    color: white;
}

.automata-input-section {
    margin: 20px 0;
}

.input-group {
    display: flex;
    gap: 10px;
    margin-bottom: 10px;
}

.input-group .form-control {
    flex: 1;
    padding: 10px 15px;
    border-radius: 8px;
    border: 1px solid var(--border);
    background: var(--surface);
    color: var(--text-primary);
    transition: all 0.3s ease;
}

.input-group .form-control:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 2px rgba(var(--primary-rgb), 0.2);
}

.simulation-result {
    padding: 15px;
    border-radius: 8px;
    margin-top: 10px;
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.1rem;
    opacity: 0;
    transform: translateY(-10px);
    transition: all 0.3s ease;
}

.simulation-result.show {
    opacity: 1;
    transform: translateY(0);
}

.simulation-result.accepted {
    background: rgba(var(--success-rgb), 0.1);
    color: var(--success);
}

.simulation-result.rejected {
    background: rgba(var(--error-rgb), 0.1);
    color: var(--error);
}

.automata-help {
    margin-top: 30px;
    padding: 20px;
    background: rgba(255, 255, 255, 0.05);
    border-radius: 10px;
}

.automata-help h3 {
    margin-bottom: 20px;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 10px;
}

.help-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
}

.help-item {
    padding: 20px;
    background: var(--surface);
    border-radius: 8px;
    text-align: center;
    transition: all 0.3s ease;
}

.help-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
}

.help-item i {
    font-size: 2rem;
    color: var(--primary);
    margin-bottom: 10px;
}

.help-item h4 {
    margin: 10px 0;
    color: var(--text-primary);
}

.help-item p {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.notification {
    position: fixed;
    top: 20px;
    right: 20px;
    padding: 15px 20px;
    border-radius: 8px;
    background: var(--surface);
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 10px;
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.1);
    z-index: 1000;
    opacity: 0;
    transform: translateX(100%);
    transition: all 0.3s ease;
}

.notification.show {
    opacity: 1;
    transform: translateX(0);
}

.notification.info {
    border-left: 4px solid var(--primary);
}

.notification.success {
    border-left: 4px solid var(--success);
}

.notification.warning {
    border-left: 4px solid var(--warning);
}

.notification.error {
    border-left: 4px solid var(--danger);
}

@keyframes statePulse {
    0% {
        box-shadow: 0 0 0 0 rgba(var(--primary-rgb), 0.4);
    }
    70% {
        box-shadow: 0 0 0 10px rgba(var(--primary-rgb), 0);
    }
    100% {
        box-shadow: 0 0 0 0 rgba(var(--primary-rgb), 0);
    }
}


@media (max-width: 768px) {
    .automata-container {
        padding: 15px;
    }

    .automata-graph {
        height: 400px;
    }

    .visualization-controls {
        justify-content: center;
    }

    .help-grid {
        grid-template-columns: 1fr;
    }

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

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


.dark-theme .automata-container {
    background: rgba(0, 0, 0, 0.2);
}

.dark-theme .automata-graph {
    background: rgba(0, 0, 0, 0.1);
}

.dark-theme .automata-state {
    background: var(--surface-dark);
}

.dark-theme .automata-label {
    background: var(--surface-dark);
}

.dark-theme .help-item {
    background: var(--surface-dark);
}


@media (hover: none) {
    .automata-state:hover,
    .automata-edge:hover,
    .automata-label:hover,
    .help-item:hover {
        transform: none;
    }

    .visualization-controls .btn:active {
        background: var(--primary);
        color: white;
    }
}


@media (prefers-contrast: high) {
    .automata-state {
        border-width: 3px;
    }

    .automata-edge {
        stroke-width: 3px;
    }

    .automata-label {
        border: 1px solid var(--text-primary);
    }
}


@media (prefers-reduced-motion: reduce) {
    .automata-container,
    .automata-state,
    .automata-edge,
    .automata-label,
    .help-item,
    .notification {
        transition: none;
    }

    .automata-state.active {
        animation: none;
    }
}


.zoom-controls {
    position: absolute;
    bottom: 20px;
    right: 20px;
    display: flex;
    flex-direction: column;
    gap: 10px;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.9);
    padding: 10px;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.zoom-controls .btn {
    width: 40px;
    height: 40px;
    padding: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    background: var(--primary);
    color: white;
    border: none;
    cursor: pointer;
    transition: all 0.3s ease;
}

.zoom-controls .btn:hover {
    background: var(--primary-dark);
    transform: scale(1.1);
}


.simulation-steps {
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin-top: 15px;
    max-height: 300px;
    overflow-y: auto;
    padding: 10px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 8px;
}

.simulation-step {
    display: flex;
    gap: 15px;
    padding: 10px;
    background: rgba(255, 255, 255, 0.05);
    border-radius: 6px;
    transition: all 0.3s ease;
}

.simulation-step:hover {
    background: rgba(255, 255, 255, 0.1);
    transform: translateX(5px);
}

.step-number {
    width: 30px;
    height: 30px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--primary);
    color: white;
    border-radius: 50%;
    font-weight: bold;
}

.step-details {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 5px;
}


.automata-state {
    transition: all 0.3s ease;
    cursor: grab;
}

.automata-state:active {
    cursor: grabbing;
}

.automata-state.dragging {
    opacity: 0.8;
    transform: scale(1.1);
}


.automata-edge {
    transition: all 0.3s ease;
}

.automata-edge:hover {
    stroke-width: 3px;
}


@keyframes stateTransition {
    0% {
        transform: scale(1);
        box-shadow: 0 0 0 0 rgba(var(--primary-rgb), 0.4);
    }
    50% {
        transform: scale(1.1);
        box-shadow: 0 0 0 10px rgba(var(--primary-rgb), 0);
    }
    100% {
        transform: scale(1);
        box-shadow: 0 0 0 0 rgba(var(--primary-rgb), 0);
    }
}

.state-transitioning {
    animation: stateTransition 1s ease;
}


@media (max-width: 768px) {
    .zoom-controls {
        bottom: 10px;
        right: 10px;
    }

    .zoom-controls .btn {
        width: 35px;
        height: 35px;
    }

    .simulation-steps {
        max-height: 200px;
    }
}


@media (hover: none) {
    .automata-state {
        cursor: pointer;
    }

    .zoom-controls .btn {
        padding: 8px;
    }
}


@media (prefers-contrast: high) {
    .automata-state {
        border-width: 3px;
    }

    .automata-edge {
        stroke-width: 3px;
    }

    .step-number {
        border: 2px solid white;
    }
}


@media (prefers-reduced-motion: reduce) {
    .automata-state,
    .automata-edge,
    .simulation-step,
    .zoom-controls .btn {
        transition: none;
    }

    .state-transitioning {
        animation: none;
    }
}


.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

h1 {
    text-align: center;
    color: #333;
    margin-bottom: 30px;
}

h2 {
    color: #444;
    margin-bottom: 20px;
}

.input-section, .test-section, .output-section {
    background: #fff;
    border-radius: 8px;
    padding: 20px;
    margin-bottom: 20px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.form-group {
    margin-bottom: 15px;
}

label {
    display: block;
    margin-bottom: 5px;
    color: #555;
    font-weight: 500;
}

input[type="text"], textarea {
    width: 100%;
    padding: 8px 12px;
    border: 1px solid #ddd;
    border-radius: 4px;
    font-size: 14px;
    transition: border-color 0.3s;
}

input[type="text"]:focus, textarea:focus {
    border-color: #2196f3;
    outline: none;
    box-shadow: 0 0 0 2px rgba(33, 150, 243, 0.2);
}

textarea {
    resize: vertical;
    min-height: 100px;
    font-family: monospace;
}

.example-buttons {
    display: flex;
    gap: 10px;
    margin-top: 15px;
}

button {
    background-color: #2196f3;
    color: white;
    border: none;
    padding: 10px 20px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 14px;
    transition: background-color 0.3s;
}

button:hover {
    background-color: #1976d2;
}

.example-dfa-button {
    background-color: #4caf50;
}

.example-dfa-button:hover {
    background-color: #388e3c;
}

#process-dfa-button {
    width: 100%;
    margin-top: 10px;
    font-weight: 500;
}

.result-box {
    background-color: #e3f2fd;
    border-radius: 4px;
    padding: 15px;
    margin-bottom: 20px;
}

.result-box p {
    margin: 5px 0;
}

.error-box {
    background-color: #ffebee;
    border-radius: 4px;
    padding: 15px;
    margin-bottom: 20px;
    color: #c62828;
}

#dfa-visualization {
    margin-top: var(--space-6);
    padding: var(--space-4);
    background: var(--surface-0);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    overflow: auto;
}

#dfa-visualization svg {
    display: block;
    margin: 0 auto;
}

.node circle {
    fill: var(--surface-0);
    stroke: var(--primary);
    stroke-width: 2px;
}

.node text {
    font-family: var(--font-sans);
    font-size: 14px;
    fill: var(--gray-800);
}

.node circle.start-state {
    stroke: var(--info);
    stroke-width: 3px;
}

.node circle.accept-state {
    stroke: var(--success);
    stroke-width: 3px;
}

.node circle.current-state {
    fill: var(--warning-light);
}

.edge path {
    stroke: var(--gray-400);
    stroke-width: 2px;
    fill: none;
}

.edge text {
    font-family: var(--font-sans);
    font-size: 12px;
    fill: var(--gray-600);
}

.trace {
    margin-top: var(--space-4);
    padding: var(--space-4);
    background: var(--surface-50);
    border-radius: var(--radius-md);
    font-family: var(--font-mono);
    font-size: 14px;
    color: var(--gray-700);
}

.accept {
    color: var(--success);
    font-weight: 600;
}

.reject {
    color: var(--danger);
    font-weight: 600;
}


@media (max-width: 768px) {
    .container {
        padding: 10px;
    }

    .example-buttons {
        flex-direction: column;
    }

    .example-dfa-button {
        width: 100%;
    }
}


.toast-container {
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 9999;
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
}

.toast {
    padding: var(--space-3) var(--space-4);
    border-radius: var(--radius-md);
    background: var(--surface-0);
    box-shadow: var(--shadow-lg);
    display: flex;
    align-items: center;
    gap: var(--space-2);
    min-width: 300px;
    max-width: 400px;
    animation: slideIn 0.3s ease-out;
}

.toast.success {
    border-left: 4px solid var(--success);
}

.toast.error {
    border-left: 4px solid var(--danger);
}

.toast.info {
    border-left: 4px solid var(--info);
}

.toast-icon {
    font-size: 1.2rem;
}

.toast.success .toast-icon {
    color: var(--success);
}

.toast.error .toast-icon {
    color: var(--danger);
}

.toast.info .toast-icon {
    color: var(--info);
}


.loader-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(255, 255, 255, 0.8);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 9999;
}

.loader {
    width: 48px;
    height: 48px;
    border: 4px solid var(--primary-light);
    border-bottom-color: var(--primary);
    border-radius: 50%;
    animation: rotation 1s linear infinite;
}

@keyframes rotation {
    0% {
        transform: rotate(0deg);
    }
    100% {
        transform: rotate(360deg);
    }
}


.dark-theme .loader-container {
    background: rgba(0, 0, 0, 0.8);
}

.dark-theme .toast {
    background: var(--surface-50);
    color: var(--gray-100);
}


.theme-toggle {
    position: fixed;
    bottom: var(--space-6);
    right: var(--space-6);
    width: 48px;
    height: 48px;
    border-radius: var(--radius-full);
    background: var(--surface-0);
    border: 1px solid var(--gray-200);
    box-shadow: var(--shadow-lg);
    cursor: pointer;
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition-normal);
}

.theme-toggle:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-xl);
}

.theme-toggle i {
    font-size: 1.25rem;
    color: var(--gray-600);
    transition: var(--transition-normal);
}

.theme-toggle .fa-sun {
    display: none;
}

.dark-theme .theme-toggle .fa-moon {
    display: none;
}

.dark-theme .theme-toggle .fa-sun {
    display: block;
}


.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    gap: 6px;
    background: none;
    border: none;
    padding: var(--space-2);
    cursor: pointer;
}

.mobile-menu-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background-color: var(--gray-600);
    transition: var(--transition-normal);
}

@media (max-width: 768px) {
    .mobile-menu-toggle {
        display: flex;
    }

    .navbar-nav {
        position: fixed;
        top: 72px;
        left: 0;
        right: 0;
        background: var(--surface-0);
        padding: var(--space-4);
        flex-direction: column;
        gap: var(--space-2);
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: var(--transition-normal);
    }

    .navbar-nav.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }
}


@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
}

@media (prefers-contrast: high) {
    :root {
        --primary: #0000ff;
        --primary-dark: #0000cc;
        --primary-light: #e6e6ff;
    }

    .card,
    .result-container,
    .visualization-container,
    .example-card {
        border: 2px solid var(--gray-800);
    }
}


@media print {
    .navbar,
    .footer,
    .theme-toggle,
    .mobile-menu-toggle {
        display: none;
    }

    .container {
        max-width: none;
        padding: 0;
    }

    .card {
        break-inside: avoid;
        box-shadow: none;
        border: 1px solid #000;
    }
}

.result-highlight {
  animation: resultPop 1.2s cubic-bezier(0.4, 0, 0.2, 1);
  box-shadow: 0 0 0 4px var(--primary-light), 0 2px 12px 0 rgba(99,102,241,0.15);
  border-color: var(--primary);
}
@keyframes resultPop {
  0% { box-shadow: 0 0 0 0 var(--primary-light); }
  40% { box-shadow: 0 0 0 8px var(--primary-light); }
  100% { box-shadow: 0 0 0 0 var(--primary-light); }
}
.form-loader {
  width: 2rem;
  height: 2rem;
  position: absolute;
  top: 10px;
  right: 10px;
  z-index: 10;
  display: inline-block;
}
.example-btn {
  font-weight: 600;
  border-width: 2px;
  border-radius: var(--radius-lg);
  transition: background 0.2s, color 0.2s, border 0.2s;
  box-shadow: 0 2px 8px 0 rgba(99,102,241,0.05);
}
.example-btn:focus, .example-btn:hover {
  background: var(--primary-light);
  color: var(--primary-dark);
  border-color: var(--primary-dark);
}
.card {
  margin-bottom: 2.5rem;
}
.result-container {
  margin-top: 1.5rem;
  margin-bottom: 1.5rem;
  transition: box-shadow 0.3s, border 0.3s;
}
.visually-hidden {
  display: none !important;
}

.top-nav.sticky-top {position:sticky;top:0;z-index:1050;background:var(--surface-0);box-shadow:0 2px 8px rgba(0,0,0,0.04);}
.mobile-menu-toggle {display:none;position:absolute;right:1rem;top:1rem;width:2.5rem;height:2.5rem;background:none;border:none;z-index:1100;flex-direction:column;justify-content:center;align-items:center;gap:0.3rem;}
.mobile-menu-toggle span {display:block;width:2rem;height:0.25rem;background:var(--primary);border-radius:2px;transition:all 0.2s;}
@media (max-width: 768px) {.mobile-menu-toggle {display:flex;}}
.fab-help {position:fixed;bottom:2.5rem;right:2.5rem;z-index:1200;background:var(--primary);color:#fff;border:none;border-radius:50%;width:3.5rem;height:3.5rem;box-shadow:0 4px 16px rgba(99,102,241,0.18);font-size:1.7rem;display:flex;align-items:center;justify-content:center;transition:background 0.2s,box-shadow 0.2s;}
.fab-help:focus,.fab-help:hover {background:var(--primary-dark);box-shadow:0 6px 24px rgba(99,102,241,0.28);outline:none;}
#globalLoader.global-loader-overlay {position:fixed;top:0;left:0;width:100vw;height:100vh;background:rgba(30,32,40,0.18);z-index:2000;display:flex;align-items:center;justify-content:center;}
#globalLoader .loader {width:64px;height:64px;border:8px solid #e0e7ff;border-top:8px solid var(--primary);border-radius:50%;animation:rotation 1s linear infinite;}
.toast-container {position:fixed;top:1.5rem;right:1.5rem;z-index:1300;display:flex;flex-direction:column;gap:1rem;}
.toast {background:var(--primary);color:#fff;padding:1rem 1.5rem;border-radius:var(--radius-lg);box-shadow:0 2px 8px rgba(99,102,241,0.12);font-size:1.1rem;display:flex;align-items:center;gap:0.8rem;min-width:220px;max-width:350px;opacity:0.98;transition:opacity 0.2s;}
.toast .toast-icon {font-size:1.4rem;}
.toast.success {background:var(--success);}
.toast.error {background:var(--danger);}
.toast.info {background:var(--info);}
@media (max-width: 768px) {.toast-container {top:0.5rem;right:0.5rem;gap:0.5rem;}.fab-help {bottom:1.2rem;right:1.2rem;width:2.7rem;height:2.7rem;font-size:1.2rem;}}

.visually-hidden.focusable {position: absolute;left: 0;top: 0;width: 1px;height: 1px;padding: 0;margin: 0;overflow: hidden;clip: rect(0,0,0,0);white-space: nowrap;border: 0;z-index: 2000;}
.visually-hidden.focusable:focus {position: static;width: auto;height: auto;clip: auto;overflow: visible;background: #fff;color: #23263a;padding: 0.5rem 1rem;border-radius: 4px;box-shadow: 0 2px 8px rgba(99,102,241,0.18);}

.chatbot-bubble, .chatbot-bubble-inner, .chatbot-msg-bot, .chatbot-msg-user {
    font-family: 'Inter', 'Segoe UI', Arial, sans-serif !important;
    font-size: 1.05em;
    line-height: 1.5;
    word-break: break-word;
}
.chatbot-bubble-inner code, .chatbot-bubble-inner pre, .chatbot-bubble code, .chatbot-bubble pre {
    font-family: 'JetBrains Mono', 'Fira Mono', 'Consolas', monospace !important;
    background: #f3f4f6;
    color: #23263a;
    border-radius: 0.3em;
    padding: 0.15em 0.4em;
    font-size: 0.98em;
}

/* OCR Modal Styles */
#imageToTextModal .modal-bg {background:rgba(0,0,0,0.3);z-index:2000;display:flex;align-items:center;justify-content:center;position:fixed;top:0;left:0;width:100vw;height:100vh;}
#imageToTextModal .modal-content {background:#fff;padding:2rem;border-radius:12px;max-width:400px;width:100%;position:relative;box-shadow:0 8px 32px rgba(0,0,0,0.18);}
#imageToTextModal .modal-content h3 {margin-bottom:1rem;}
#imageToTextModal .modal-content button {margin-bottom:0.5rem;}
#imageToTextModal .modal-content textarea {width:100%;margin-bottom:1rem;}
#imageToTextModal .modal-content img {max-width:100%;max-height:180px;border:1px solid #ccc;border-radius:6px;}
#imageToTextModal .modal-content #closeImageToTextModal {position:absolute;top:0.5rem;right:0.5rem;font-size:1.5rem;background:none;border:none;}

.dark-theme #imageToTextModal .modal-content {background:#23263a;color:#fff;}
.dark-theme #imageToTextModal .modal-content textarea {background:#181a29;color:#fff;}
.dark-theme #imageToTextModal .modal-content img {border:1px solid #444;}

/* === Adjacency Matrix Dedicated Styles === */
.matrix-card, .matrix-panel, .matrix-latex-panel, .matrix-analysis-panel, .matrix-graph-panel {
  background: var(--matrix-bg);
  border-radius: var(--matrix-radius);
  box-shadow: var(--matrix-shadow);
  border: 1.5px solid var(--matrix-border);
  padding: 1.5rem 1.5rem 1.2rem 1.5rem;
  margin-bottom: 2rem;
}
.matrix-section-title {
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--matrix-primary);
  margin-bottom: 1rem;
}
.matrix-controls {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.7rem;
}
.matrix-controls-group {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}
.matrix-controls .btn, .matrix-controls .form-check {
  margin-right: 0.5rem;
  margin-bottom: 0.5rem;
}
.matrix-controls .form-switch {
  margin-bottom: 0.5rem;
}
.matrix-controls label {
  font-weight: 500;
  color: var(--matrix-primary);
  margin-right: 0.5rem;
}
.matrix-controls input[type=range] {
  width: 120px;
  margin: 0 0.5rem;
}
.matrix-latex {
  font-size: 1.1rem;
  text-align: center;
  min-height: 2.5em;
}
.matrix-graph {
  min-width: 320px;
  min-height: 220px;
  overflow-x: auto;
}
.matrix-footer {
  margin-top: 2.5rem;
  text-align: center;
  color: var(--gray-500, #6b7280);
  font-size: 1.05rem;
  opacity: 0.85;
}
.matrix-title {
  font-size: 2.1rem;
  font-weight: 700;
  color: var(--matrix-primary);
  margin-bottom: 0.2rem;
  text-align: center;
}
.matrix-subtitle {
  font-size: 1.1rem;
  color: var(--gray-500, #6b7280);
  text-align: center;
  margin-bottom: 1.5rem;
}
.matrix-hot .htCore {
  background: var(--matrix-bg);
  border-radius: var(--matrix-radius);
}
.matrix-hot .htCore th, .matrix-hot .htCore td {
  border: 1px solid var(--matrix-border);
  font-size: 1.05rem;
  background: var(--matrix-bg);
  color: #23263a;
  transition: background 0.2s, color 0.2s;
}
.matrix-hot .htCore th {
  background: var(--matrix-bg-alt);
  color: var(--matrix-primary);
  font-weight: 600;
}
.matrix-hot .htCore td.ht-black {
  background: var(--matrix-primary);
  color: #fff;
}
.matrix-hot .htCore td:focus-visible {
  outline: 2px solid var(--matrix-focus);
  z-index: 2;
}
.matrix-hot .htCore td.error {
  background: #ffe0e0;
  color: #b91c1c;
}
.matrix-graph svg .node circle {
  stroke: #fff;
  stroke-width: 2;
  transition: stroke 0.2s, fill 0.2s;
}
.matrix-graph svg .node circle:focus-visible {
  outline: 2px solid var(--matrix-focus);
}
.matrix-graph svg .node circle.selected, .matrix-graph svg .node circle:hover {
  stroke: var(--matrix-primary);
  stroke-width: 3;
  filter: drop-shadow(0 0 6px var(--matrix-primary));
}
.matrix-graph svg .edge line {
  stroke: #999;
  stroke-opacity: 0.7;
  transition: stroke 0.2s;
}
.matrix-graph svg .edge line.selected, .matrix-graph svg .edge line:hover {
  stroke: var(--matrix-primary);
  stroke-width: 3;
}
.matrix-graph svg .edge text {
  font-size: 12px;
  fill: #333;
}
.matrix-graph svg .node text {
  font-size: 16px;
  font-weight: bold;
  fill: #fff;
  pointer-events: none;
}
.matrix-analysis-panel, .matrix-latex-panel, .matrix-graph-panel {
  background: var(--matrix-bg-alt);
  border-radius: 14px;
  padding: 1.2rem 1.5rem;
  margin-bottom: 2rem;
}
.matrix-analysis-panel {
  transition: background 0.2s, box-shadow 0.2s;
}
.matrix-analysis-panel[aria-live="polite"] {
  outline: none;
}
.matrix-card, .matrix-panel {
  transition: box-shadow 0.2s, background 0.2s;
}
.matrix-card:focus-within, .matrix-panel:focus-within {
  box-shadow: 0 4px 24px rgba(99,102,241,0.18);
}
.matrix-modal, .modal-bg {
  transition: opacity 0.2s;
}
.matrix-modal[aria-hidden="true"], .modal-bg[aria-hidden="true"] {
  opacity: 0;
  pointer-events: none;
}
.matrix-modal[aria-hidden="false"], .modal-bg[aria-hidden="false"] {
  opacity: 1;
}
.matrix-high-contrast {
  --matrix-bg: var(--matrix-contrast-bg);
  --matrix-bg-alt: #222;
  --matrix-primary: #f9c846;
  --matrix-border: #fff;
  --matrix-focus: #f9c846;
  --matrix-footer: #fff;
  color: var(--matrix-contrast-fg);
}
.matrix-high-contrast .matrix-card, .matrix-high-contrast .matrix-panel {
  background: var(--matrix-contrast-bg);
  color: var(--matrix-contrast-fg);
  border-color: #fff;
}
.matrix-high-contrast .matrix-latex, .matrix-high-contrast .matrix-section-title {
  color: #f9c846;
}
.matrix-high-contrast .matrix-hot .htCore th, .matrix-high-contrast .matrix-hot .htCore td {
  background: #111;
  color: #fff;
  border-color: #fff;
}
.matrix-high-contrast .matrix-hot .htCore td.ht-black {
  background: #f9c846;
  color: #000;
}
.matrix-high-contrast .matrix-graph svg .node circle {
  stroke: #fff;
  fill: #f9c846;
}
.matrix-high-contrast .matrix-graph svg .node text {
  fill: #000;
}
.matrix-high-contrast .matrix-graph svg .edge line {
  stroke: #fff;
}
.matrix-high-contrast .matrix-footer {
  color: #fff;
}
@media (max-width: 900px) {
  .matrix-card, .matrix-latex-panel, .matrix-analysis-panel, .matrix-graph-panel {
    padding: 1rem;
    border-radius: 10px;
  }
}
@media (max-width: 700px) {
  .matrix-title { font-size: 1.4rem; }
  .matrix-section-title { font-size: 1rem; }
  .matrix-controls { flex-direction: column; align-items: stretch; }
  .matrix-graph { min-width: 0; width: 100%; min-height: 120px; }
}
@media print {
  .matrix-card, .matrix-latex-panel, .matrix-analysis-panel, .matrix-graph-panel {
    box-shadow: none !important;
    background: #fff !important;
    color: #000 !important;
    border: 1px solid #000 !important;
  }
  .matrix-controls, .matrix-footer, .btn, .form-switch, .alert, .matrix-title, .matrix-subtitle { display: none !important; }
  body { background: #fff !important; }
}
.matrix-modal, .modal-bg {
  transition: opacity 0.2s;
}
.matrix-modal[aria-hidden="true"], .modal-bg[aria-hidden="true"] {
  opacity: 0;
  pointer-events: none;
}
.matrix-modal[aria-hidden="false"], .modal-bg[aria-hidden="false"] {
  opacity: 1;
}
.matrix-analysis-panel, .matrix-latex-panel, .matrix-graph-panel {
  transition: background 0.2s, box-shadow 0.2s;
}
.matrix-analysis-panel[aria-live="polite"] {
  outline: none;
}
.matrix-card, .matrix-panel {
  transition: box-shadow 0.2s, background 0.2s;
}
.matrix-card:focus-within, .matrix-panel:focus-within {
  box-shadow: 0 4px 24px rgba(99,102,241,0.18);
}