* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  /* Prevent blue highlight on tap (mobile) */
  -webkit-tap-highlight-color: transparent;
  -webkit-touch-callout: none;
}

html,
body {
  width: 100%;
  height: 100%;
  overflow: hidden;
  font-family: Arial, sans-serif;
  /* Prevent text selection on canvas */
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
}

/* Collapsible Toolbar */
.toolbar {
  position: fixed;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  z-index: 100;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.toolbar.collapsed .toolbar-content {
  transform: translateY(-100%);
  opacity: 0;
  pointer-events: none;
}

.toolbar-content {
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  border-radius: 0 0 16px 16px;
  padding: 12px;
  display: flex;
  gap: 12px;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
  opacity: 1;
  transition: all 0.4s cubic-bezier(0.68, -0.55, 0.265, 1.55);
  transform: translateY(0);
  margin-bottom: 0;
}

/* Hamburger Menu Button (Top Right - Independent) */
.hamburger-menu-btn {
  position: fixed;
  top: 20px;
  right: 20px;
  z-index: 150;
  width: 50px;
  height: 50px;
  background: #6366f1;
  color: white;
  border: none;
  border-radius: 12px;
  cursor: pointer;
  box-shadow: 0 4px 14px rgba(41, 16, 185, 0.3);
  display: none;
  align-items: center;
  justify-content: center;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.hamburger-menu-btn:hover {
  background: #4f46e5;
  box-shadow: 0 6px 20px rgba(41, 16, 185, 0.3);
  transform: translateY(-2px);
}

.hamburger-menu-btn:active {
  background: #4f46e5;
  transform: translateY(0) scale(0.95);
}

/* Hamburger Icon Container */
.hamburger-icon {
  width: 24px;
  height: 18px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  align-items: center;
  position: relative;
}

/* Hamburger Lines */
.hamburger-line {
  width: 100%;
  height: 2.5px;
  background: white;
  border-radius: 2px;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  transform-origin: center;
}

/* Hamburger → X Animation */
.hamburger-menu-btn.open .hamburger-line:nth-child(1) {
  transform: translateY(7.75px) rotate(45deg);
}

.hamburger-menu-btn.open .hamburger-line:nth-child(2) {
  opacity: 0;
  transform: scaleX(0);
}

.hamburger-menu-btn.open .hamburger-line:nth-child(3) {
  transform: translateY(-7.75px) rotate(-45deg);
}

/* Hamburger Dropdown - True Dropdown Style */
.hamburger-dropdown {
  position: fixed;
  top: 80px;
  right: 20px;
  z-index: 150;
  display: none;
  flex-direction: column;
  gap: 10px;
  opacity: 0;
  transform: translateY(-10px);
  pointer-events: none;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.hamburger-dropdown.show {
  opacity: 1;
  transform: translateY(0);
  pointer-events: all;
}

.hamburger-dropdown-content {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.dropdown-item {
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  padding: 12px 16px;
  border-radius: 12px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
  display: flex;
  flex-direction: column;
  gap: 8px;
  transition: all 0.3s ease;
}

.dropdown-item:hover {
  box-shadow: 0 6px 16px rgba(0, 0, 0, 0.15);
  transform: translateX(-2px);
}

.dropdown-label {
  font-size: 11px;
  font-weight: 600;
  color: #6b7280;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 4px;
}

/* Mobile Graph Direction Toggle */
.mobile-graph-direction-toggle {
  background: white;
  border: none;
  border-radius: 12px;
  padding: 10px 14px;
  cursor: pointer;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  display: flex;
  align-items: center;
  gap: 12px;
  font-family: Arial, sans-serif;
  width: 100%;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
}

.mobile-graph-direction-toggle:hover {
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.12);
  transform: translateY(-1px);
}

.mobile-graph-direction-toggle:active {
  transform: translateY(0) scale(0.98);
}

.mobile-toggle-slider {
  width: 48px;
  height: 28px;
  background: #6366f1;
  border-radius: 14px;
  position: relative;
  transition: background 0.3s ease;
  display: flex;
  align-items: center;
  padding: 0 4px;
  flex-shrink: 0;
}

.mobile-graph-direction-toggle.undirected .mobile-toggle-slider {
  background: #10b981;
}

.mobile-toggle-slider::before {
  content: "";
  position: absolute;
  width: 20px;
  height: 20px;
  background: white;
  border-radius: 50%;
  transition: transform 0.3s cubic-bezier(0.68, -0.55, 0.265, 1.55);
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
  left: 4px;
}

.mobile-graph-direction-toggle.undirected .mobile-toggle-slider::before {
  transform: translateX(20px);
}

.mobile-toggle-icon-directed,
.mobile-toggle-icon-undirected {
  width: 16px;
  height: 16px;
  position: absolute;
  stroke: white;
  transition: opacity 0.3s ease;
}

.mobile-toggle-icon-directed {
  left: 6px;
  opacity: 1;
}

.mobile-toggle-icon-undirected {
  right: 6px;
  opacity: 0;
}

.mobile-graph-direction-toggle.undirected .mobile-toggle-icon-directed {
  opacity: 0;
}

.mobile-graph-direction-toggle.undirected .mobile-toggle-icon-undirected {
  opacity: 1;
}

.mobile-toggle-label {
  font-size: 14px;
  font-weight: 600;
  color: #333;
  flex: 1;
}

.mobile-toggle-label::before {
  content: "Di";
}

.mobile-graph-direction-toggle.undirected .mobile-toggle-label::before {
  content: "Undi";
}

/* Mobile Algorithm Selector */
.mobile-algorithm-selector {
  width: 100%;
  padding: 10px 14px;
  border: none;
  border-radius: 8px;
  font-size: 14px;
  font-weight: 600;
  background: white;
  cursor: pointer;
  transition: all 0.3s ease;
  font-family: Arial, sans-serif;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
}

.mobile-algorithm-selector:hover {
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.12);
  transform: translateY(-1px);
}

.mobile-algorithm-selector:focus {
  outline: none;
  box-shadow: 0 4px 12px rgba(99, 102, 241, 0.2);
}

/* Mobile Algorithm Button */
.mobile-algorithm-btn {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 12px 20px;
  background: #6366f1;
  color: white;
  border: none;
  border-radius: 10px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  font-family: Arial, sans-serif;
  box-shadow: 0 2px 8px rgba(99, 102, 241, 0.3);
}

.mobile-algorithm-btn:hover {
  background: #4f46e5;
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(99, 102, 241, 0.4);
}

.mobile-algorithm-btn:active {
  transform: translateY(0);
  background: #4338ca;
}

.mobile-algorithm-btn.running {
  background: #ef4444;
}

.mobile-algorithm-btn.running:hover {
  background: #dc2626;
}

.mobile-algorithm-btn .btn-icon {
  width: 16px;
  height: 16px;
}

.mobile-algorithm-btn.disabled {
  opacity: 0.5;
  cursor: not-allowed;
  pointer-events: none;
}

.toolbar-toggle {
  background: #6366f1;
  color: white;
  border: none;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  cursor: pointer;
  box-shadow: 0 4px 14px rgba(99, 102, 241, 0.4);
  transition: all 0.4s cubic-bezier(0.68, -0.55, 0.265, 1.55);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-top: 8px;
  position: relative;
}

.toolbar.collapsed .toolbar-toggle {
  margin-top: -60px;
  box-shadow: 0 6px 18px rgba(99, 102, 241, 0.5);
}

.toolbar-toggle:hover {
  background: #4f46e5;
  box-shadow: 0 6px 20px rgba(99, 102, 241, 0.6);
  transform: scale(1.15);
}

.toolbar.collapsed .toolbar-toggle:hover {
  transform: scale(1.15);
}

.toolbar-toggle:active {
  transform: scale(0.9);
  background: #4338ca;
}

.toolbar.collapsed .toolbar-toggle:active {
  transform: scale(0.9);
}

.toggle-icon {
  width: 20px;
  height: 20px;
  transition: transform 0.4s cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

.toolbar.collapsed .toggle-icon {
  transform: rotate(180deg);
}

.toolbar-btn {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px 20px;
  font-size: 15px;
  font-weight: 600;
  border: none;
  border-radius: 12px;
  cursor: pointer;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  font-family: Arial, sans-serif;
  white-space: nowrap;
  position: relative;
  overflow: hidden;
}

.toolbar-btn::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(255, 255, 255, 0.2);
  transform: translateX(-100%);
  transition: transform 0.3s ease;
}

.toolbar-btn:hover::before {
  transform: translateX(0);
}

.toolbar-btn svg {
  width: 20px;
  height: 20px;
  stroke-width: 2.5;
  transition: transform 0.3s ease;
}

.toolbar-btn:hover svg {
  transform: scale(1.1) rotate(5deg);
}

.toolbar-btn:active {
  transform: scale(0.95);
}

/* Disabled state for toolbar buttons */
.toolbar-btn.disabled {
  opacity: 0.5;
  cursor: not-allowed;
  pointer-events: none;
}

.toolbar-btn.disabled:hover::before {
  transform: translateX(-100%);
}

.toolbar-btn.disabled svg {
  opacity: 0.6;
}

#addNodeBtn {
  background: #2563eb;
  color: white;
  box-shadow: 0 4px 14px rgba(37, 99, 235, 0.3);
}

#addNodeBtn:hover {
  background: #1d4ed8;
  box-shadow: 0 6px 20px rgba(37, 99, 235, 0.4);
  transform: translateY(-2px);
}

#addNodeBtn:active {
  background: #1e40af;
  transform: translateY(0) scale(0.95);
}

#resetBtn {
  background: #ef4444;
  color: white;
  box-shadow: 0 4px 14px rgba(239, 68, 68, 0.3);
}

#resetBtn:hover {
  background: #dc2626;
  box-shadow: 0 6px 20px rgba(239, 68, 68, 0.4);
  transform: translateY(-2px);
}

#resetBtn:active {
  background: #b91c1c;
  transform: translateY(0) scale(0.95);
}

#graph {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  /* Prevent blue highlight on mobile tap */
  -webkit-tap-highlight-color: transparent;
  -webkit-touch-callout: none;
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
  /* Prevent context menu on long press */
  touch-action: pan-x pan-y;
}

#graph canvas {
  -webkit-tap-highlight-color: transparent;
  -webkit-touch-callout: none;
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
}

/* Graph Direction Toggle (Next to Toolbar) */
.graph-direction-toggle {
  position: fixed;
  top: 20px;
  left: 20px;
  z-index: 100;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  border: none;
  border-radius: 30px;
  padding: 8px 20px 8px 12px;
  cursor: pointer;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  display: flex;
  align-items: center;
  gap: 12px;
  font-family: Arial, sans-serif;
}

.graph-direction-toggle:hover {
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.15);
  transform: translateY(-2px);
}

.graph-direction-toggle:active {
  transform: translateY(0) scale(0.98);
}

.toggle-slider {
  width: 48px;
  height: 28px;
  background: #6366f1;
  border-radius: 14px;
  position: relative;
  transition: background 0.3s ease;
  display: flex;
  align-items: center;
  padding: 0 4px;
}

.graph-direction-toggle.undirected .toggle-slider {
  background: #10b981;
}

.toggle-slider::before {
  content: "";
  position: absolute;
  width: 20px;
  height: 20px;
  background: white;
  border-radius: 50%;
  transition: transform 0.3s cubic-bezier(0.68, -0.55, 0.265, 1.55);
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
  left: 4px;
}

.graph-direction-toggle.undirected .toggle-slider::before {
  transform: translateX(20px);
}

.toggle-icon-directed,
.toggle-icon-undirected {
  width: 16px;
  height: 16px;
  position: absolute;
  stroke: white;
  transition: opacity 0.3s ease;
}

.toggle-icon-directed {
  left: 6px;
  opacity: 1;
}

.toggle-icon-undirected {
  right: 6px;
  opacity: 0;
}

.graph-direction-toggle.undirected .toggle-icon-directed {
  opacity: 0;
}

.graph-direction-toggle.undirected .toggle-icon-undirected {
  opacity: 1;
}

.toggle-label {
  font-size: 14px;
  font-weight: 600;
  color: #333;
  min-width: 75px;
}

.toggle-label::before {
  content: "Di";
}

.graph-direction-toggle.undirected .toggle-label::before {
  content: "Undi";
}

/* Custom Popup Styles */
.popup-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(4px);
  display: none;
  justify-content: center;
  align-items: center;
  z-index: 1000;
  animation: fadeIn 0.2s ease;
}

.popup-overlay.show {
  display: flex;
}

.popup-dialog {
  background: white;
  border-radius: 16px;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
  width: 90%;
  max-width: 450px;
  overflow: hidden;
  display: none;
  animation: slideUp 0.3s ease;
}

.popup-dialog.show {
  display: block;
}

.popup-header {
  padding: 24px 24px 16px;
  border-bottom: 1px solid #e0e0e0;
}

.popup-title {
  font-size: 20px;
  font-weight: 700;
  color: #333;
  margin: 0;
}

.popup-body {
  padding: 24px;
}

.popup-body p {
  font-size: 16px;
  color: #555;
  line-height: 1.6;
  margin: 0 0 16px 0;
}

.popup-input {
  width: 100%;
  padding: 12px 16px;
  font-size: 16px;
  border: 2px solid #e0e0e0;
  border-radius: 8px;
  outline: none;
  transition: border-color 0.3s ease;
  font-family: Arial, sans-serif;
  /* Allow text selection in inputs */
  -webkit-user-select: text;
  -moz-user-select: text;
  -ms-user-select: text;
  user-select: text;
}

.popup-input:focus {
  border-color: #667eea;
}

.popup-textarea {
  width: 100%;
  padding: 12px 16px;
  font-size: 14px;
  border: 2px solid #e0e0e0;
  border-radius: 8px;
  outline: none;
  transition: border-color 0.3s ease;
  font-family: "Courier New", monospace;
  resize: vertical;
  line-height: 1.5;
  /* Allow text selection in textarea */
  -webkit-user-select: text;
  -moz-user-select: text;
  -ms-user-select: text;
  user-select: text;
}

.popup-textarea:focus {
  border-color: #667eea;
}

.popup-textarea[readonly] {
  background-color: #f5f5f5;
  cursor: text;
}

.popup-footer {
  padding: 16px 24px 24px;
  display: flex;
  gap: 12px;
  justify-content: flex-end;
}

.popup-btn {
  padding: 12px 28px;
  font-size: 15px;
  font-weight: 600;
  border: none;
  border-radius: 10px;
  cursor: pointer;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  font-family: Arial, sans-serif;
}

.popup-btn-primary {
  background: #2563eb;
  color: white;
  box-shadow: 0 4px 14px rgba(37, 99, 235, 0.3);
}

.popup-btn-primary:hover {
  background: #1d4ed8;
  transform: translateY(-2px);
  box-shadow: 0 6px 18px rgba(37, 99, 235, 0.4);
}

.popup-btn-primary:active {
  background: #1e40af;
  transform: translateY(0);
}

.popup-btn-secondary {
  background: #f5f5f5;
  color: #666;
}

.popup-btn-secondary:hover {
  background: #e0e0e0;
}

.popup-btn-secondary:active {
  background: #d0d0d0;
}

@keyframes fadeIn {
  from {
    opacity: 0;
  }

  to {
    opacity: 1;
  }
}

@keyframes slideUp {
  from {
    transform: translateY(40px);
    opacity: 0;
  }

  to {
    transform: translateY(0);
    opacity: 1;
  }
}

/* Responsive Design */
@media (max-width: 768px) {
  /* Show hamburger menu button on mobile */
  .hamburger-menu-btn {
    display: flex !important;
  }

  /* Show hamburger dropdown on mobile */
  .hamburger-dropdown {
    display: flex;
  }

  /* Hide desktop algorithm controls on mobile */
  .algorithm-controls {
    display: none !important;
  }

  /* Hide desktop graph direction toggle on mobile */
  .graph-direction-toggle {
    display: none !important;
  }
  /* Subtle left shift for toolbar on mobile */
  .toolbar {
    left: 45%;
  }

  /* Convert toolbar to 2x2 grid on mobile */
  .toolbar-content {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 8px;
    padding: 10px;
    max-width: 400px;
  }

  .toolbar-btn {
    width: 100%;
    justify-content: center;
    padding: 10px 14px;
    font-size: 13px;
  }

  .toolbar-btn svg {
    width: 18px;
    height: 18px;
  }
  .toolbar-toggle {
    width: 36px;
    height: 36px;
  }

  .toolbar.collapsed .toolbar-toggle {
    margin-top: -120px;
  }

  .toggle-icon {
    width: 18px;
    height: 18px;
  }

  /* Adjust dropdown position for mobile */
  .hamburger-dropdown {
    right: 10px;
    top: 80px;
  }
  .hamburger-menu-btn {
    top: 10px;
    right: 10px;
    width: 46px;
    height: 46px;
  }

  .hamburger-icon {
    width: 22px;
    height: 16px;
  }

  .hamburger-line {
    height: 2px;
  }

  .hamburger-menu-btn.open .hamburger-line:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
  }

  .hamburger-menu-btn.open .hamburger-line:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
  }

  .dropdown-item {
    padding: 10px 14px;
  }

  .popup-dialog {
    width: 95%;
    max-width: 320px;
  }

  .popup-body {
    padding: 20px;
  }

  .popup-btn {
    padding: 10px 20px;
    font-size: 14px;
  }
}

@media (max-width: 480px) {
  /* Extra small mobile adjustments */
  .toolbar {
    left: 42%;
  }

  .toolbar-content {
    max-width: 320px;
    gap: 6px;
    padding: 8px;
  }

  .toolbar-btn {
    padding: 8px 10px;
    font-size: 12px;
  }

  .toolbar-btn span {
    font-size: 12px;
  }

  .toolbar-btn svg {
    width: 16px;
    height: 16px;
  }
  .toolbar-toggle {
    width: 32px;
    height: 32px;
  }

  .toolbar.collapsed .toolbar-toggle {
    margin-top: -70px;
  }

  .toggle-icon {
    width: 16px;
    height: 16px;
  }

  .hamburger-menu-btn {
    width: 42px;
    height: 42px;
    top: 8px;
    right: 8px;
  }

  .hamburger-menu-btn svg {
    width: 20px;
    height: 20px;
  }

  .hamburger-dropdown {
    top: 60px;
    right: 8px;
  }

  .dropdown-item {
    padding: 8px 12px;
  }

  .popup-title {
    font-size: 18px;
  }

  .popup-body p {
    font-size: 14px;
  }

  .help-panel {
    border-radius: 12px 12px 0 0;
    max-height: 60vh;
  }

  .help-panel-header {
    padding: 16px 18px;
  }

  .help-panel-header h3 {
    font-size: 19px;
  }

  .help-panel-close {
    width: 32px;
    height: 32px;
    font-size: 24px;
  }

  .help-panel-content {
    padding: 16px;
  }

  .help-section {
    padding: 12px 14px;
    margin-bottom: 16px;
    border-radius: 10px;
  }

  .help-section h4 {
    font-size: 15px;
    margin-bottom: 12px;
    padding-bottom: 8px;
  }

  .help-section li {
    font-size: 13px;
    padding: 8px 0;
    padding-left: 18px;
  }
  .help-panel-toggle {
    width: 48px;
    height: 48px;
    bottom: 12px;
    right: 12px;
  }

  .help-panel-toggle svg {
    width: 22px;
    height: 22px;
  }

  .watermark {
    font-size: 11px;
    padding: 5px 12px;
    bottom: 12px;
  }

  .watermark-text {
    font-size: 11px;
  }

  .watermark-year {
    font-size: 11px;
  }
}

/* Help Panel Toggle Button (Bottom Right) */
.help-panel-toggle {
  position: fixed;
  bottom: 20px;
  right: 20px;
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background: #6366f1;
  color: white;
  border: none;
  cursor: pointer;
  box-shadow: 0 4px 14px rgba(99, 102, 241, 0.4);
  transition: all 0.4s cubic-bezier(0.68, -0.55, 0.265, 1.55);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 150;
}

.help-panel-toggle:hover {
  background: #4f46e5;
  transform: scale(1.15);
  box-shadow: 0 6px 20px rgba(99, 102, 241, 0.6);
}

.help-panel-toggle:active {
  transform: scale(0.9);
  background: #4338ca;
}

.help-panel-toggle svg {
  width: 28px;
  height: 28px;
  transition: transform 0.3s ease;
}

.help-panel.active ~ .help-panel-toggle svg {
  transform: rotate(180deg);
}

.help-panel-toggle.hidden {
  display: none;
}

/* Panels Toggle Button (Bottom Right - Mobile Algo Running) */
.panels-toggle {
  position: fixed;
  bottom: 20px;
  right: 20px;
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background: #10b981;
  color: white;
  border: none;
  cursor: pointer;
  box-shadow: 0 4px 14px rgba(16, 185, 129, 0.4);
  transition: all 0.4s cubic-bezier(0.68, -0.55, 0.265, 1.55);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 150;
}

.panels-toggle:hover {
  background: #059669;
  transform: scale(1.15);
  box-shadow: 0 6px 20px rgba(16, 185, 129, 0.6);
}

.panels-toggle:active {
  transform: scale(0.9);
  background: #047857;
}

.panels-toggle svg {
  width: 24px;
  height: 24px;
}

.panels-toggle.hidden {
  display: none;
}

/* Panels Dropdown (Mobile Algo Running) */
.panels-dropdown {
  position: fixed;
  bottom: 90px;
  right: 20px;
  z-index: 150;
  display: flex;
  flex-direction: column;
  gap: 10px;
  opacity: 0;
  transform: translateY(10px);
  pointer-events: none;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.panels-dropdown.show {
  opacity: 1;
  transform: translateY(0);
  pointer-events: all;
}

.panels-dropdown.hidden {
  display: none;
}

.panels-dropdown-item {
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  padding: 12px 16px;
  border-radius: 12px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
  display: flex;
  align-items: center;
  gap: 10px;
  border: none;
  cursor: pointer;
  transition: all 0.3s ease;
  font-family: Arial, sans-serif;
  font-size: 14px;
  font-weight: 600;
  color: #333;
  min-width: 180px;
}

.panels-dropdown-item:hover {
  box-shadow: 0 6px 16px rgba(0, 0, 0, 0.15);
  transform: translateX(-4px);
  background: white;
}

.panels-dropdown-item:active {
  transform: translateX(-2px) scale(0.98);
}

.panels-dropdown-item svg {
  width: 20px;
  height: 20px;
  color: #6366f1;
  flex-shrink: 0;
}

.panels-dropdown-item span {
  flex: 1;
  text-align: left;
}

/* Help Panel */
.help-panel {
  position: fixed;
  bottom: 0;
  right: 20px;
  width: 420px;
  max-height: 75vh;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  border-radius: 20px 20px 0 0;
  box-shadow: 0 -8px 32px rgba(0, 0, 0, 0.15);
  transform: translateY(calc(100% + 20px));
  transition: transform 0.4s cubic-bezier(0.68, -0.55, 0.265, 1.55),
    box-shadow 0.3s ease;
  z-index: 140;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  border: 1px solid rgba(255, 255, 255, 0.3);
}

.help-panel.active {
  transform: translateY(0);
  box-shadow: 0 -10px 40px rgba(0, 0, 0, 0.2);
}

.help-panel-header {
  background: linear-gradient(135deg, #6366f1 0%, #4f46e5 100%);
  color: white;
  padding: 20px 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  position: relative;
  overflow: hidden;
}

.help-panel-header::before {
  content: "";
  position: absolute;
  top: -50%;
  right: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(
    circle,
    rgba(255, 255, 255, 0.1) 0%,
    transparent 70%
  );
  pointer-events: none;
}

.help-panel-header h3 {
  margin: 0;
  font-size: 22px;
  font-weight: 700;
  letter-spacing: 0.5px;
  position: relative;
  z-index: 1;
}

.help-panel-close {
  background: rgba(255, 255, 255, 0.2);
  border: none;
  color: white;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  cursor: pointer;
  font-size: 26px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.3s cubic-bezier(0.68, -0.55, 0.265, 1.55);
  line-height: 1;
  padding: 0;
  position: relative;
  z-index: 1;
}

.help-panel-close:hover {
  background: rgba(255, 255, 255, 0.3);
  transform: rotate(90deg) scale(1.1);
}

.help-panel-close:active {
  transform: rotate(90deg) scale(0.9);
}

.help-panel-content {
  padding: 24px;
  overflow-y: auto;
  flex: 1;
  background: rgba(255, 255, 255, 0.5);
}

.help-section {
  margin-bottom: 28px;
  background: rgba(255, 255, 255, 0.7);
  backdrop-filter: blur(10px);
  border-radius: 12px;
  padding: 16px 18px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
  transition: all 0.3s ease;
  border: 1px solid rgba(255, 255, 255, 0.5);
}

.help-section:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
  background: rgba(255, 255, 255, 0.85);
}

.help-section:last-child {
  margin-bottom: 0;
}

.help-section h4 {
  margin: 0 0 14px 0;
  font-size: 17px;
  font-weight: 700;
  color: #1f2937;
  display: flex;
  align-items: center;
  gap: 10px;
  padding-bottom: 10px;
  border-bottom: 2px solid rgba(99, 102, 241, 0.1);
}

.section-icon {
  width: 22px;
  height: 22px;
  color: #6366f1;
  flex-shrink: 0;
  transition: transform 0.3s ease;
}

.help-section:hover .section-icon {
  transform: scale(1.1);
}

.help-section ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

.help-section li {
  padding: 10px 0;
  font-size: 14px;
  color: #4b5563;
  line-height: 1.7;
  position: relative;
  padding-left: 20px;
  transition: all 0.2s ease;
}

.help-section li::before {
  content: "•";
  position: absolute;
  left: 4px;
  color: #6366f1;
  font-size: 18px;
  font-weight: bold;
  transition: transform 0.2s ease;
}

.help-section li:hover {
  color: #1f2937;
  transform: translateX(4px);
}

.help-section li:hover::before {
  transform: scale(1.3);
}

.help-section li strong {
  color: #6366f1;
  font-weight: 700;
}

/* Scrollbar styling for help panel */
.help-panel-content::-webkit-scrollbar {
  width: 8px;
}

.help-panel-content::-webkit-scrollbar-track {
  background: rgba(0, 0, 0, 0.03);
  border-radius: 4px;
  margin: 8px 0;
}

.help-panel-content::-webkit-scrollbar-thumb {
  background: rgba(99, 102, 241, 0.3);
  border-radius: 4px;
  transition: background 0.2s ease;
}

.help-panel-content::-webkit-scrollbar-thumb:hover {
  background: rgba(99, 102, 241, 0.5);
}

/* Watermark */
.watermark {
  position: fixed;
  bottom: 15px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  color: rgba(0, 0, 0, 0.25);
  pointer-events: none;
  z-index: 10;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, sans-serif;
  user-select: none;
  background: rgba(255, 255, 255, 0.5);
  backdrop-filter: blur(8px);
  padding: 6px 14px;
  border-radius: 20px;
  border: 1px solid rgba(0, 0, 0, 0.08);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
}

.watermark-text {
  font-weight: 400;
  letter-spacing: 0.3px;
}

.watermark-text strong {
  font-weight: 600;
  color: rgba(0, 0, 0, 0.35);
}

.watermark-separator {
  color: rgba(0, 0, 0, 0.2);
  font-size: 10px;
}

.watermark-year {
  font-weight: 500;
  color: rgba(0, 0, 0, 0.3);
}

/* Responsive adjustments for help panel */
@media (max-width: 768px) {
  .help-panel {
    right: 10px;
    left: 10px;
    width: auto;
    max-height: 65vh;
    border-radius: 16px 16px 0 0;
  }
  .help-panel-toggle {
    bottom: 15px;
    right: 15px;
    width: 50px;
    height: 50px;
  }

  .help-panel-toggle svg {
    width: 24px;
    height: 24px;
  }

  .help-panel-content {
    padding: 20px;
  }

  .help-section {
    padding: 14px 16px;
    margin-bottom: 20px;
  }

  /* Graph Direction Toggle - Mobile adjustments */
  .graph-direction-toggle {
    top: 10px;
    left: 10px;
    padding: 6px 16px 6px 10px;
    gap: 10px;
  }

  .toggle-slider {
    width: 42px;
    height: 24px;
  }

  .toggle-slider::before {
    width: 18px;
    height: 18px;
    left: 3px;
  }

  .graph-direction-toggle.undirected .toggle-slider::before {
    transform: translateX(18px);
  }

  .toggle-icon-directed,
  .toggle-icon-undirected {
    width: 14px;
    height: 14px;
  }

  .toggle-icon-directed {
    left: 5px;
  }

  .toggle-icon-undirected {
    right: 5px;
  }

  .toggle-label {
    font-size: 13px;
    min-width: 65px;
  }
}

/* Algorithm Controls */
.algorithm-controls {
  position: fixed;
  top: 20px;
  right: 20px;
  z-index: 100;
  display: flex;
  gap: 12px;
  align-items: center;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  padding: 12px 16px;
  border-radius: 12px;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
}

.algorithm-selector {
  padding: 8px 16px;
  border: 2px solid #e0e0e0;
  border-radius: 8px;
  font-size: 14px;
  font-weight: 600;
  background: white;
  cursor: pointer;
  transition: all 0.3s ease;
  font-family: Arial, sans-serif;
}

.algorithm-selector:hover {
  border-color: #6366f1;
}

.algorithm-selector:focus {
  outline: none;
  border-color: #6366f1;
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.algorithm-btn {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 20px;
  background: #6366f1;
  color: white;
  border: none;
  border-radius: 8px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  font-family: Arial, sans-serif;
}

.algorithm-btn:hover {
  background: #4f46e5;
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(99, 102, 241, 0.4);
}

.algorithm-btn:active {
  transform: translateY(0);
}

.algorithm-btn.running {
  background: #ef4444;
}

.algorithm-btn.running:hover {
  background: #dc2626;
}

.algorithm-btn .btn-icon {
  width: 16px;
  height: 16px;
}

.algorithm-btn.disabled {
  opacity: 0.5;
  cursor: not-allowed;
  pointer-events: none;
}

/* Step Controller */
.step-controller {
  position: fixed;
  bottom: 20px;
  left: 50%;
  z-index: 100;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  padding: 16px 24px;
  border-radius: 16px;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.15);
  min-width: 600px;
  transition: opacity 0.3s ease, transform 0.3s ease;
  opacity: 1;
  transform: translateX(-50%) translateY(0);
  pointer-events: auto;
}

.step-controller.hidden {
  opacity: 0;
  transform: translateX(-50%) translateY(6px);
  pointer-events: none;
}

.step-controls {
  display: flex;
  gap: 12px;
  align-items: center;
  justify-content: center;
  margin-bottom: 12px;
}

.step-btn {
  width: 40px;
  height: 40px;
  border: none;
  background: #f3f4f6;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all 0.3s ease;
}

.step-btn:hover {
  background: #e5e7eb;
  transform: scale(1.1);
}

.step-btn:active {
  transform: scale(0.95);
}

.step-btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
  transform: none !important;
}

.step-btn svg {
  width: 20px;
  height: 20px;
}

.step-btn.play-btn {
  background: #6366f1;
  color: white;
  width: 48px;
  height: 48px;
}

.step-btn.play-btn:hover {
  background: #4f46e5;
}

.step-btn.play-btn.playing {
  background: #ef4444;
}

.step-btn.play-btn.playing:hover {
  background: #dc2626;
}

/* Play/Pause icon visibility */
.play-icon,
.pause-icon {
  transition: opacity 0.2s ease;
}

.play-icon.hidden,
.pause-icon.hidden {
  display: none;
}

.step-info {
  padding: 0 16px;
  font-size: 14px;
  font-weight: 600;
  color: #333;
  min-width: 120px;
  text-align: center;
}

.speed-control {
  display: flex;
  align-items: center;
  gap: 8px;
  padding-left: 16px;
  border-left: 2px solid #e5e7eb;
}

.speed-control label {
  font-size: 13px;
  font-weight: 600;
  color: #666;
}

.speed-control input[type="range"] {
  width: 100px;
  height: 4px;
  background: #e5e7eb;
  border-radius: 2px;
  outline: none;
  -webkit-appearance: none;
  appearance: none;
}

.speed-control input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 16px;
  height: 16px;
  background: #6366f1;
  border-radius: 50%;
  cursor: pointer;
}

.speed-control input[type="range"]::-moz-range-thumb {
  width: 16px;
  height: 16px;
  background: #6366f1;
  border-radius: 50%;
  cursor: pointer;
  border: none;
}

#speedValue {
  font-size: 13px;
  font-weight: 600;
  color: #6366f1;
  min-width: 40px;
}

.step-description {
  text-align: center;
  font-size: 13px;
  color: #666;
  padding: 8px 16px;
  background: #f9fafb;
  border-radius: 8px;
  line-height: 1.5;
}

/* Path Visualizer */
.path-visualizer {
  position: fixed;
  top: 90px;
  right: 20px;
  z-index: 100;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  padding: 12px 16px;
  border-radius: 12px;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
  display: flex;
  align-items: center;
  gap: 12px;
}

.path-visualizer.hidden {
  display: none;
}

.path-visualizer label {
  font-size: 14px;
  font-weight: 600;
  color: #333;
}

.path-selector {
  padding: 8px 16px;
  border: 2px solid #e0e0e0;
  border-radius: 8px;
  font-size: 14px;
  background: white;
  cursor: pointer;
  transition: all 0.3s ease;
  font-family: Arial, sans-serif;
  min-width: 150px;
}

.path-selector:hover {
  border-color: #6366f1;
}

.path-selector:focus {
  outline: none;
  border-color: #6366f1;
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

/* Result Panel */
.result-panel {
  position: fixed;
  bottom: 20px;
  right: 20px;
  z-index: 100;
  background: rgba(255, 255, 255, 0.98);
  backdrop-filter: blur(10px);
  border-radius: 16px;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.15);
  max-width: 500px;
  max-height: 400px;
  overflow: hidden;
  transition: opacity 0.3s ease, transform 0.3s ease;
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}

.result-panel.hidden {
  opacity: 0;
  transform: translateY(6px);
  pointer-events: none;
}

.result-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 16px 20px;
  border-bottom: 2px solid #e5e7eb;
  background: linear-gradient(135deg, #6366f1 0%, #4f46e5 100%);
  color: white;
}

.result-header h3 {
  margin: 0;
  font-size: 16px;
  font-weight: 700;
}

.close-result-btn {
  background: rgba(255, 255, 255, 0.2);
  border: none;
  color: white;
  font-size: 24px;
  width: 32px;
  height: 32px;
  border-radius: 8px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.3s ease;
  line-height: 1;
}

.close-result-btn:hover {
  background: rgba(255, 255, 255, 0.3);
}

.result-content {
  padding: 16px;
  overflow-y: auto;
  max-height: 340px;
}

.result-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
}

.result-table thead {
  background: #f9fafb;
  position: sticky;
  top: 0;
}

.result-table th {
  padding: 10px 12px;
  text-align: left;
  font-weight: 700;
  color: #374151;
  border-bottom: 2px solid #e5e7eb;
}

.result-table td {
  padding: 10px 12px;
  border-bottom: 1px solid #f3f4f6;
  color: #4b5563;
}

.result-table tr:hover {
  background: #f9fafb;
}

.result-table td:nth-child(1) {
  font-weight: 600;
  color: #6366f1;
}

.result-table td:nth-child(2) {
  font-family: "Courier New", monospace;
  font-weight: 600;
}

.result-table td:nth-child(3) {
  font-size: 12px;
}

.result-table td:nth-child(4) {
  text-align: center;
}

.reachable-yes {
  color: #10b981;
  font-weight: 600;
}

.reachable-no {
  color: #ef4444;
  font-weight: 600;
}

/* Mobile Responsive */
@media (max-width: 768px) {
  .algorithm-controls {
    top: 10px;
    right: 10px;
    padding: 8px 12px;
    gap: 8px;
  }

  .algorithm-selector,
  .algorithm-btn {
    font-size: 12px;
    padding: 6px 12px;
  }

  .step-controller {
    min-width: calc(100% - 40px);
    bottom: 10px;
    padding: 12px 16px;
  }

  .step-controls {
    flex-wrap: wrap;
    gap: 8px;
  }

  .speed-control {
    flex-basis: 100%;
    border-left: none;
    border-top: 2px solid #e5e7eb;
    padding: 8px 0 0 0;
    justify-content: center;
  }
  .path-visualizer {
    top: 10px;
    left: 10px;
    right: auto;
    padding: 10px;
    max-width: calc(100% - 130px);
  }

  .result-panel {
    bottom: 10px;
    right: 10px;
    left: 10px;
    max-width: none;
  }
}

/* ========================================
   Step Table Window (Draggable/Resizable)
   ======================================== */

.step-table-window {
  position: fixed;
  left: 20px;
  top: 120px;
  width: 450px;
  max-width: 90vw;
  max-height: 600px;
  z-index: 95;
  background: rgba(255, 255, 255, 0.98);
  backdrop-filter: blur(10px);
  border-radius: 8px;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.15);
  display: flex;
  flex-direction: column;
  overflow: hidden;
  transition: opacity 0.3s ease, transform 0.3s ease;
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}

.step-table-window.hidden {
  opacity: 0;
  transform: translateY(6px);
  pointer-events: none;
}

.step-table-window.collapsed .step-table-body {
  display: none;
}

.step-table-window.collapsed {
  max-height: 60px;
}

/* Header */
.step-table-header {
  background: linear-gradient(135deg, #6366f1 0%, #4f46e5 100%);
  color: white;
  cursor: move;
  user-select: none;
}

.step-table-title-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 12px 16px;
}

.step-table-title {
  margin: 0;
  font-size: 15px;
  font-weight: 700;
  display: flex;
  align-items: center;
  gap: 8px;
}

.step-table-controls {
  display: flex;
  gap: 8px;
}

.step-table-control-btn {
  background: rgba(255, 255, 255, 0.2);
  border: none;
  color: white;
  width: 28px;
  height: 28px;
  border-radius: 6px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s ease;
  font-size: 18px;
  line-height: 1;
}

.step-table-control-btn:hover {
  background: rgba(255, 255, 255, 0.3);
  transform: scale(1.05);
}

.step-table-control-btn svg {
  width: 16px;
  height: 16px;
}

.step-table-window.collapsed #stepTableCollapse svg {
  transform: rotate(180deg);
}

/* Body */
.step-table-body {
  flex: 1;
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

.step-table-scroll {
  overflow: auto;
  max-height: 520px;
  position: relative;
}

.step-table-scroll::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}

.step-table-scroll::-webkit-scrollbar-track {
  background: #f3f4f6;
  border-radius: 4px;
}

.step-table-scroll::-webkit-scrollbar-thumb {
  background: #d1d5db;
  border-radius: 4px;
}

.step-table-scroll::-webkit-scrollbar-thumb:hover {
  background: #9ca3af;
}

/* Table */
.step-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 12px;
  table-layout: auto;
}

.step-table thead {
  background: #f9fafb;
  position: sticky;
  top: 0;
  z-index: 10;
}

.step-table th {
  padding: 10px 8px;
  text-align: center;
  font-weight: 700;
  color: #374151;
  border: 1px solid #e5e7eb;
  white-space: nowrap;
  min-width: 70px;
  background: #f9fafb;
}

.step-table th.step-index-col {
  min-width: 50px;
  background: #eef2ff;
  color: #4f46e5;
  position: sticky;
  left: 0;
  z-index: 11;
}

.step-table tbody tr {
  transition: background-color 0.2s ease;
}

.step-table tbody tr:nth-child(even) {
  background: #f9fafb;
}

.step-table tbody tr:hover {
  background: #eef2ff;
}

.step-table tbody tr.current-step {
  background: #dbeafe !important;
  box-shadow: inset 0 0 0 2px #3b82f6;
}

.step-table tbody tr.previous-step {
  opacity: 0.6;
}

.step-table td {
  padding: 8px 6px;
  text-align: center;
  border: 1px solid #e5e7eb;
  color: #4b5563;
  font-family: "Courier New", monospace;
  font-size: 11px;
  white-space: nowrap;
  transition: all 0.3s ease;
}

.step-table td.step-index {
  font-weight: 700;
  color: #4f46e5;
  background: #f3f4f6;
  position: sticky;
  left: 0;
  z-index: 5;
}

.step-table td.chosen-node {
  background: #fef3c7;
  font-weight: 700;
  position: relative;
}

.step-table td.chosen-node::after {
  content: "★";
  position: absolute;
  top: 2px;
  right: 4px;
  color: #f59e0b;
  font-size: 10px;
}

.step-table td.updated-node {
  background: #d1fae5;
  border-color: #10b981;
  animation: pulse-green 0.5s ease;
}

.step-table td.checked-node {
  background: #fef3c7;
  border-color: #f59e0b;
}

.step-table td.highlighted-column {
  background: #fef3c7;
}

.step-table td.infinity-value {
  color: #9ca3af;
  font-style: italic;
}

.step-table td.empty-value {
  color: #d1d5db;
}

.step-table td.visited-node {
  color: #9ca3af;
  font-weight: 600;
  background: #f3f4f6;
}

/* Resize Handle */
.step-table-resize-handle {
  position: absolute;
  bottom: 0;
  right: 0;
  width: 20px;
  height: 20px;
  cursor: nwse-resize;
  background: linear-gradient(
    135deg,
    transparent 0%,
    transparent 50%,
    #d1d5db 50%,
    #d1d5db 100%
  );
  border-radius: 0 0 16px 0;
  opacity: 0.5;
  transition: opacity 0.2s ease;
}

.step-table-resize-handle:hover {
  opacity: 1;
}

/* Animations */
@keyframes pulse-green {
  0%,
  100% {
    background: #d1fae5;
  }
  50% {
    background: #6ee7b7;
  }
}

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

.step-table tbody tr {
  animation: fade-in 0.3s ease;
}

/* Mobile Responsive */
@media (max-width: 768px) {
  .step-table-window {
    left: 10px;
    right: 10px;
    width: auto;
    max-width: none;
    top: 80px;
  }

  .step-table th,
  .step-table td {
    padding: 6px 4px;
    font-size: 10px;
    min-width: 50px;
  }

  .step-table th.step-index-col {
    min-width: 40px;
  }
}