/* ==========================================================================
   SheetBox: Visual Excel Formula Sheet Builder Stylesheet
   Layout: Left 1/5th (Toolbox), Center 3/5ths (Canvas & Sheet), Right 1/5th (Properties)
   ========================================================================== */

:root, [data-theme="minimalist"] {
  --bg-app: #FBFBF9;
  --bg-panel: #FFFFFF;
  --bg-panel-subtle: #F5F5F3;
  --bg-card: #FFFFFF;
  --bg-card-hover: #F8F8F6;
  --border-color: #E6E4DE;
  --border-color-focus: #1B365D;
  --text-main: #1C1917;
  --text-muted: #78716C;
  --text-dim: #A8A29E;

  --primary: #1B365D;
  --primary-hover: #12243F;
  --primary-light: rgba(27, 54, 93, 0.08);

  --success: #15803D;
  --success-bg: rgba(21, 128, 61, 0.1);
  --danger: #DC2626;
  --warning: #D97706;

  --node-inp-border: #D97706;
  --node-calc-border: #6D28D9;
  --node-out-border: #15803D;
  --node-unit-border: #0284C7;

  --excel-green: #107C41;
  --excel-green-hover: #0E6B38;

  /* GUI Canvas Variables - Minimalist Theme */
  --canvas-bg: #F8F8F5;
  --canvas-grid-dot: #D4D0C5;
  --canvas-grid-opacity: 0.75;
  --canvas-node-bg: #FFFFFF;
  --canvas-node-border: #E5E3DC;
  --canvas-node-hover-border: #A8A29E;
  --canvas-node-shadow: 0 4px 14px rgba(0, 0, 0, 0.05), 0 1px 3px rgba(0, 0, 0, 0.03);

  --canvas-node-val-bg: #F5F5F2;
  --canvas-node-val-border: #E8E6E0;
  --canvas-node-val-text: #1C1917;

  --canvas-calc-banner-bg: #FAF5FF;
  --canvas-calc-banner-border: #E9D5FF;
  --canvas-calc-banner-text: #581C87;
  --canvas-calc-result-bg: #F5F3FF;
  --canvas-calc-result-border: #DDD6FE;

  --canvas-group-bg: rgba(0, 0, 0, 0.015);
  --canvas-group-border: #D1CEC7;
  --canvas-group-hover-border: #9CA3AF;
  --canvas-group-badge-bg: #EAE8E3;
  --canvas-group-badge-text: #57534E;

  --canvas-wire: #475569;
  --canvas-wire-hover: #1E293B;
  --canvas-wire-selected: #D97706;
  --canvas-group-wire: #1B365D;
  --canvas-group-wire-hover: #2563EB;

  --canvas-port-dot-in: #1B365D;
  --canvas-port-dot-out: #15803D;
  --canvas-port-dot-calc-in: #6D28D9;
  --canvas-port-dot-calc-out: #15803D;

  --canvas-node-header-inp-bg: #FEF3C7;
  --canvas-node-header-inp-title: #78350F;
  --canvas-node-header-inp-badge: #FDE68A;
  --canvas-node-header-inp-badge-text: #92400E;

  --canvas-node-header-out-bg: #DCFCE7;
  --canvas-node-header-out-title: #14532D;
  --canvas-node-header-out-badge: #BBF7D0;
  --canvas-node-header-out-badge-text: #166534;

  --canvas-node-header-calc-bg: #EDE9FE;
  --canvas-node-header-calc-title: #4C1D95;
  --canvas-node-header-calc-badge: #DDD6FE;
  --canvas-node-header-calc-badge-text: #5B21B6;

  --canvas-node-header-unit-bg: #E0F2FE;
  --canvas-node-header-unit-title: #0C4A6E;
  --canvas-node-header-unit-badge: #BAE6FD;
  --canvas-node-header-unit-badge-text: #075985;
}

[data-theme="modern"] {
  --bg-app: #0F172A;
  --bg-panel: #1E293B;
  --bg-panel-subtle: #0F172A;
  --bg-card: #273549;
  --bg-card-hover: #334155;
  --border-color: #334155;
  --border-color-focus: #3B82F6;
  --text-main: #F8FAFC;
  --text-muted: #94A3B8;
  --text-dim: #64748B;
  
  --primary: #2563EB;
  --primary-hover: #1D4ED8;
  --primary-light: rgba(37, 99, 235, 0.15);
  
  --success: #10B981;
  --success-bg: rgba(16, 185, 129, 0.15);
  --danger: #EF4444;
  --warning: #F59E0B;
  
  --node-inp-border: #F59E0B;
  --node-calc-border: #8B5CF6;
  --node-out-border: #10B981;
  --node-unit-border: #38BDF8;

  --excel-green: #107C41;
  --excel-green-hover: #0E6B38;

  /* GUI Canvas Variables - Modern Theme */
  --canvas-bg: #0B1120;
  --canvas-grid-dot: #334155;
  --canvas-grid-opacity: 0.6;
  --canvas-node-bg: #1E293B;
  --canvas-node-border: #334155;
  --canvas-node-hover-border: #64748B;
  --canvas-node-shadow: 0 4px 16px rgba(0, 0, 0, 0.3);

  --canvas-node-val-bg: rgba(15, 23, 42, 0.6);
  --canvas-node-val-border: #334155;
  --canvas-node-val-text: #F8FAFC;

  --canvas-calc-banner-bg: rgba(15, 23, 42, 0.7);
  --canvas-calc-banner-border: #334155;
  --canvas-calc-banner-text: #C4B5FD;
  --canvas-calc-result-bg: rgba(139, 92, 246, 0.1);
  --canvas-calc-result-border: rgba(139, 92, 246, 0.25);

  --canvas-group-bg: rgba(15, 23, 42, 0.35);
  --canvas-group-border: rgba(59, 130, 246, 0.45);
  --canvas-group-hover-border: rgba(96, 165, 250, 0.7);
  --canvas-group-badge-bg: rgba(255, 255, 255, 0.2);
  --canvas-group-badge-text: #FFFFFF;

  --canvas-wire: #3B82F6;
  --canvas-wire-hover: #60A5FA;
  --canvas-wire-selected: #F59E0B;
  --canvas-group-wire: #38BDF8;
  --canvas-group-wire-hover: #7DD3FC;

  --canvas-port-dot-in: #3B82F6;
  --canvas-port-dot-out: #10B981;
  --canvas-port-dot-calc-in: #A78BFA;
  --canvas-port-dot-calc-out: #10B981;

  --canvas-node-header-inp-bg: rgba(245, 158, 11, 0.12);
  --canvas-node-header-inp-title: var(--text-main);
  --canvas-node-header-inp-badge: rgba(245, 158, 11, 0.25);
  --canvas-node-header-inp-badge-text: #F59E0B;

  --canvas-node-header-out-bg: rgba(16, 185, 129, 0.12);
  --canvas-node-header-out-title: var(--text-main);
  --canvas-node-header-out-badge: rgba(16, 185, 129, 0.25);
  --canvas-node-header-out-badge-text: #10B981;

  --canvas-node-header-calc-bg: rgba(139, 92, 246, 0.12);
  --canvas-node-header-calc-title: var(--text-main);
  --canvas-node-header-calc-badge: rgba(139, 92, 246, 0.25);
  --canvas-node-header-calc-badge-text: #A78BFA;

  --canvas-node-header-unit-bg: rgba(2, 132, 199, 0.12);
  --canvas-node-header-unit-title: var(--text-main);
  --canvas-node-header-unit-badge: rgba(2, 132, 199, 0.25);
  --canvas-node-header-unit-badge-text: #0284C7;
}

[data-theme="dark"] {
  --bg-app: #121212;
  --bg-panel: #1A1A1A;
  --bg-panel-subtle: #161616;
  --bg-card: #202020;
  --bg-card-hover: #2A2A2A;
  --border-color: #2D2D2D;
  --border-color-focus: #60A5FA;
  --text-main: #EEEEEE;
  --text-muted: #9E9E9E;
  --text-dim: #666666;
  
  --primary: #3B82F6;
  --primary-hover: #2563EB;
  --primary-light: rgba(59, 130, 246, 0.2);
  
  --success: #22C55E;
  --success-bg: rgba(34, 197, 94, 0.15);
  --danger: #F87171;
  --warning: #FBBF24;
  
  --node-inp-border: #FBBF24;
  --node-calc-border: #A78BFA;
  --node-out-border: #22C55E;
  --node-unit-border: #38BDF8;

  --excel-green: #16A34A;
  --excel-green-hover: #15803D;

  /* GUI Canvas Variables - Dark Theme */
  --canvas-bg: #141414;
  --canvas-grid-dot: #2A2A2A;
  --canvas-grid-opacity: 0.85;
  --canvas-node-bg: #1E1E1E;
  --canvas-node-border: #2E2E2E;
  --canvas-node-hover-border: #4A4A4A;
  --canvas-node-shadow: 0 6px 20px rgba(0, 0, 0, 0.5), 0 2px 6px rgba(0, 0, 0, 0.35);

  --canvas-node-val-bg: #171717;
  --canvas-node-val-border: #2B2B2B;
  --canvas-node-val-text: #EEEEEE;

  --canvas-calc-banner-bg: #221D30;
  --canvas-calc-banner-border: #3D2D5E;
  --canvas-calc-banner-text: #DDD6FE;
  --canvas-calc-result-bg: #1E1E1E;
  --canvas-calc-result-border: #2E2E2E;

  --canvas-group-bg: rgba(255, 255, 255, 0.03);
  --canvas-group-border: rgba(255, 255, 255, 0.2);
  --canvas-group-hover-border: rgba(255, 255, 255, 0.4);
  --canvas-group-badge-bg: rgba(255, 255, 255, 0.15);
  --canvas-group-badge-text: #EEEEEE;

  --canvas-wire: #60A5FA;
  --canvas-wire-hover: #93C5FD;
  --canvas-wire-selected: #FBBF24;
  --canvas-group-wire: #93C5FD;
  --canvas-group-wire-hover: #BFDBFE;

  --canvas-port-dot-in: #3B82F6;
  --canvas-port-dot-out: #22C55E;
  --canvas-port-dot-calc-in: #A78BFA;
  --canvas-port-dot-calc-out: #22C55E;

  --canvas-node-header-inp-bg: rgba(251, 191, 36, 0.12);
  --canvas-node-header-inp-title: #FDE68A;
  --canvas-node-header-inp-badge: rgba(251, 191, 36, 0.25);
  --canvas-node-header-inp-badge-text: #FBBF24;

  --canvas-node-header-out-bg: rgba(34, 197, 94, 0.12);
  --canvas-node-header-out-title: #BBF7D0;
  --canvas-node-header-out-badge: rgba(34, 197, 94, 0.25);
  --canvas-node-header-out-badge-text: #22C55E;

  --canvas-node-header-calc-bg: rgba(167, 139, 250, 0.12);
  --canvas-node-header-calc-title: #DDD6FE;
  --canvas-node-header-calc-badge: rgba(167, 139, 250, 0.25);
  --canvas-node-header-calc-badge-text: #A78BFA;

  --canvas-node-header-unit-bg: rgba(56, 189, 248, 0.12);
  --canvas-node-header-unit-title: #BAE6FD;
  --canvas-node-header-unit-badge: rgba(56, 189, 248, 0.25);
  --canvas-node-header-unit-badge-text: #38BDF8;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background-color: var(--bg-app);
  color: var(--text-main);
  height: 100vh;
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

/* Typography & Helpers */
.font-mono { font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace; }
.font-bold { font-weight: 700; }
.font-semibold { font-weight: 600; }
.text-xs { font-size: 0.75rem; }
.text-sm { font-size: 0.875rem; }
.text-muted { color: var(--text-muted); }
.text-danger { color: var(--danger); }
.text-success { color: var(--success); }
.text-center { text-align: center; }
.text-right { text-align: right; }
.mb-1 { margin-bottom: 0.25rem; }
.mb-2 { margin-bottom: 0.5rem; }
.mt-1 { margin-top: 0.25rem; }
.mt-2 { margin-top: 0.5rem; }

/* Top Navigation Bar */
.app-header {
  height: 54px;
  background-color: var(--bg-panel);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 1rem;
  z-index: 50;
  flex-shrink: 0;
}

.header-brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.brand-logo-icon {
  width: 32px;
  height: 32px;
  background: linear-gradient(135deg, #2563EB, #10B981);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.95rem;
  font-weight: 800;
  letter-spacing: -0.5px;
  color: white;
  box-shadow: 0 2px 8px rgba(37, 99, 235, 0.4);
}

.brand-title-group {
  display: flex;
  flex-direction: column;
}

.brand-name {
  font-size: 0.95rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.brand-tag {
  font-size: 0.65rem;
  background: rgba(59, 130, 246, 0.2);
  color: #60A5FA;
  padding: 0.1rem 0.4rem;
  border-radius: 999px;
  font-weight: 600;
}

.project-title-display {
  font-size: 0.75rem;
  color: var(--text-muted);
  font-weight: 500;
}

.header-controls {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

/* Main 3-Column Layout */
.app-main-layout {
  flex: 1;
  display: flex;
  height: calc(100vh - 54px - 140px);
  min-height: 0;
  overflow: hidden;
}

/* Bottom Ad Space & Support Footer */
.app-ad-footer {
  height: 140px;
  background-color: var(--bg-panel);
  border-top: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 1.5rem;
  flex-shrink: 0;
  position: relative;
  z-index: 40;
  box-sizing: border-box;
}

.ad-space-area {
  flex: 1;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
}

.ad-footer-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-left: auto;
  flex-shrink: 0;
}

.ad-footer-actions .btn {
  text-decoration: none;
  height: 24px;
  box-sizing: border-box;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 0.7rem;
  padding: 0.2rem 0.55rem;
  border-radius: 6px;
}

/* Left 1/5th (Toolbox & Equations) */
.col-left-toolbox {
  width: 20%;
  min-width: 260px;
  max-width: 320px;
  background-color: var(--bg-panel);
  border-right: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  height: 100%;
  overflow: hidden;
  z-index: 20;
}

/* Center 3/5ths (Canvas & Live Sheet) */
.col-center-workspace {
  flex: 1;
  background-color: var(--bg-app);
  display: flex;
  flex-direction: column;
  height: 100%;
  overflow: hidden;
  position: relative;
}

/* Right 1/5th (Properties Manager) */
.col-right-properties {
  width: 20%;
  min-width: 260px;
  max-width: 340px;
  background-color: var(--bg-panel);
  border-left: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  height: 100%;
  overflow: hidden;
  z-index: 20;
}

/* Section Headers */
.panel-header {
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  background-color: var(--bg-panel);
  flex-shrink: 0;
}

.panel-title {
  font-size: 0.825rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.panel-scrollable {
  flex: 1;
  overflow-y: auto;
  padding: 0.85rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

/* Toolbox Block Cards */
.toolbox-section-label {
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.4rem;
}

.toolbox-blocks-grid {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.draggable-toolbox-block {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 0.6rem 0.75rem;
  cursor: grab;
  user-select: none;
  transition: all 0.15s ease;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.draggable-toolbox-block:hover {
  background-color: var(--bg-card-hover);
  border-color: #475569;
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
}

.draggable-toolbox-block:active {
  cursor: grabbing;
}

.tb-block-left {
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.tb-icon {
  width: 26px;
  height: 26px;
  border-radius: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.8rem;
  font-weight: bold;
}

.tb-icon-inp { background: rgba(245, 158, 11, 0.2); color: #F59E0B; }
.tb-icon-out { background: rgba(16, 185, 129, 0.2); color: #10B981; }
.tb-icon-calc { background: rgba(139, 92, 246, 0.2); color: #A78BFA; }
.tb-icon-grp { background: rgba(37, 99, 235, 0.2); color: #2563EB; font-size: 0.85rem; }

.tb-block-text {
  display: flex;
  flex-direction: column;
}

.tb-block-title {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-main);
}

.tb-block-subtitle {
  font-size: 0.68rem;
  color: var(--text-muted);
}

.drag-handle {
  color: var(--text-dim);
  font-size: 0.9rem;
}

/* Equations Library */
.library-search-box {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.equation-list {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  overflow-y: auto;
}

.equation-item-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 6px;
  padding: 0.55rem 0.65rem;
  cursor: grab;
  transition: all 0.15s ease;
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
}

.equation-item-card:hover {
  background: var(--bg-card-hover);
  border-color: #64748B;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

.eq-item-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.eq-item-title {
  color: var(--text-main);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 170px;
}

.eq-item-badge {
  background: rgba(100, 116, 139, 0.25);
  color: var(--text-muted);
  padding: 0.1rem 0.35rem;
  border-radius: 4px;
}

.eq-item-formula {
  background: var(--canvas-calc-banner-bg);
  border: 1px solid var(--canvas-calc-banner-border);
  padding: 0.25rem 0.4rem;
  border-radius: 4px;
  color: var(--canvas-calc-banner-text);
  overflow-x: auto;
  white-space: nowrap;
}

.eq-item-meta {
  display: flex;
  justify-content: space-between;
  color: var(--text-dim);
}

.eq-item-actions {
  display: flex;
  justify-content: flex-end;
}

/* Center Workspace Top Bar */
.workspace-toolbar {
  height: 44px;
  background-color: var(--bg-panel);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 0.85rem;
  flex-shrink: 0;
  z-index: 10;
}

.view-toggle-group {
  display: flex;
  background-color: var(--bg-panel-subtle);
  padding: 2px;
  border-radius: 6px;
  border: 1px solid var(--border-color);
}

.view-toggle-btn {
  background: transparent;
  border: none;
  color: var(--text-muted);
  font-size: 0.75rem;
  font-weight: 600;
  padding: 0.3rem 0.75rem;
  border-radius: 4px;
  cursor: pointer;
  transition: all 0.15s ease;
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.view-toggle-btn:hover {
  color: var(--text-main);
}

.view-toggle-btn.active {
  background-color: var(--primary);
  color: white;
  box-shadow: 0 1px 4px rgba(37, 99, 235, 0.3);
}

.canvas-action-controls {
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.toolbar-separator {
  width: 1px;
  height: 18px;
  background-color: var(--border-color);
  margin: 0 2px;
}

.canvas-action-controls button:disabled {
  opacity: 0.35;
  cursor: not-allowed;
  pointer-events: none;
}

/* Workspace Split Container */
.center-work-area {
  flex: 1;
  display: flex;
  flex-direction: column;
  position: relative;
  overflow: hidden;
}

.workspace-canvas-panel {
  flex: 1;
  position: relative;
  overflow: hidden;
  height: 100%;
}

.workspace-sheet-panel {
  display: none;
  flex: 1;
  height: 100%;
  background: #FFFFFF;
  color: #111827;
  overflow: hidden;
}

/* View Mode Toggles */
.center-work-area.view-canvas-only .workspace-canvas-panel {
  display: block;
  height: 100%;
}
.center-work-area.view-canvas-only .workspace-sheet-panel {
  display: none;
}

.center-work-area.view-sheet-only .workspace-canvas-panel {
  display: none;
}
.center-work-area.view-sheet-only .workspace-sheet-panel {
  display: block;
  height: 100%;
}

.center-work-area.view-split .workspace-canvas-panel {
  display: block;
  height: 52%;
  border-bottom: 2px solid var(--border-color);
}
.center-work-area.view-split .workspace-sheet-panel {
  display: block;
  height: 48%;
}

/* Flowchart Canvas */
.canvas-viewport {
  width: 100%;
  height: 100%;
  position: relative;
  overflow: hidden;
  user-select: none;
  background-color: var(--canvas-bg);
  transition: background-color 0.2s ease;
}

.canvas-grid-layer {
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image: radial-gradient(circle, var(--canvas-grid-dot) 1.2px, transparent 1.2px);
  background-size: 24px 24px;
  opacity: var(--canvas-grid-opacity, 0.7);
  transition: opacity 0.2s ease;
}

.canvas-world {
  position: absolute;
  top: 0;
  left: 0;
  transform-origin: 0 0;
  width: 10000px;
  height: 10000px;
  pointer-events: none;
}

.canvas-svg-layer {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  overflow: visible;
  pointer-events: auto;
}

.canvas-blocks-layer {
  position: absolute;
  top: 0;
  left: 0;
  pointer-events: auto;
}

/* Canvas Node Cards */
.canvas-node {
  position: absolute;
  width: 250px;
  background-color: var(--canvas-node-bg);
  border-radius: 10px;
  border: 1.5px solid var(--canvas-node-border);
  box-shadow: var(--canvas-node-shadow);
  cursor: default;
  transition: border-color 0.15s, box-shadow 0.15s, background-color 0.2s ease;
  pointer-events: auto;
}

.canvas-node:hover {
  border-color: var(--canvas-node-hover-border);
}

.canvas-node.selected {
  border-color: var(--primary);
  box-shadow: 0 0 0 2px var(--primary-light), 0 8px 24px rgba(0, 0, 0, 0.15);
}

.canvas-node.node-input.selected {
  border-color: var(--node-inp-border);
  box-shadow: 0 0 0 2px rgba(245, 158, 11, 0.35);
}

.canvas-node.node-output.selected {
  border-color: var(--node-out-border);
  box-shadow: 0 0 0 2px rgba(21, 128, 61, 0.35);
}

.canvas-node.node-calculation.selected {
  border-color: var(--node-calc-border);
  box-shadow: 0 0 0 2px rgba(109, 40, 217, 0.35);
}

.canvas-node.node-unit_conversion.selected {
  border-color: var(--node-unit-border);
  box-shadow: 0 0 0 2px rgba(2, 132, 199, 0.35);
}

.unit-header { background: var(--canvas-node-header-unit-bg); }
.unit-badge { background: var(--canvas-node-header-unit-badge); color: var(--canvas-node-header-unit-badge-text); }
.unit-title {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--canvas-node-header-unit-title);
}
.tb-icon-unit { background: #0284C7; color: white; }

.unit-ports-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.5rem 0.35rem;
  position: relative;
}
.unit-in-side, .unit-out-side {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  position: relative;
}
.unit-arrow-center {
  color: var(--text-dim);
  font-size: 0.9rem;
  font-weight: bold;
}

/* Group Arrow Ports on Center of Each Edge (matching reference image) */
.group-arrow-port {
  position: absolute;
  background: #FFFFFF;
  border: 1px solid #1E293B;
  border-radius: 2px;
  color: #1E293B;
  font-size: 0.55rem;
  line-height: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  z-index: 20;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.25);
  transition: background-color 0.15s ease, border-color 0.15s ease, color 0.15s ease;
}

.group-arrow-port svg {
  display: block;
  width: 6px;
  height: 6px;
  pointer-events: none;
  flex-shrink: 0;
}

[data-theme="dark"] .group-arrow-port,
[data-theme="modern"] .group-arrow-port {
  background: #FFFFFF;
  border: 1px solid #0F172A;
  color: #0F172A;
}

.group-arrow-port:hover {
  background: var(--primary, #1B365D);
  border-color: var(--primary, #1B365D);
  color: #FFFFFF;
}

[data-theme="dark"] .group-arrow-port:hover,
[data-theme="modern"] .group-arrow-port:hover {
  background: #3B82F6;
  border-color: #60A5FA;
  color: #FFFFFF;
}

/* Disabled snapping arrow ports: do not respond to cursor hovering */
.group-arrow-port.port-disabled,
.group-arrow-port.port-disabled:hover {
  pointer-events: none !important;
  opacity: 0.25 !important;
  cursor: not-allowed !important;
  background: #FFFFFF !important;
  border-color: #1E293B !important;
  color: #1E293B !important;
}

[data-theme="dark"] .group-arrow-port.port-disabled,
[data-theme="modern"] .group-arrow-port.port-disabled,
[data-theme="dark"] .group-arrow-port.port-disabled:hover,
[data-theme="modern"] .group-arrow-port.port-disabled:hover {
  pointer-events: none !important;
  opacity: 0.25 !important;
  cursor: not-allowed !important;
  background: #FFFFFF !important;
  border-color: #0F172A !important;
  color: #0F172A !important;
}

/* Specific edge proportions matching the reference image */
.port-group-left {
  width: 12px;
  height: 22px;
  left: -14px;
  top: 50%;
  transform: translateY(-50%);
}

.port-group-right {
  width: 12px;
  height: 22px;
  right: -14px;
  top: 50%;
  transform: translateY(-50%);
}

.port-group-top {
  width: 22px;
  height: 12px;
  top: -14px;
  left: 50%;
  transform: translateX(-50%);
}

.port-group-bottom {
  width: 22px;
  height: 12px;
  bottom: -14px;
  left: 50%;
  transform: translateX(-50%);
}

/* Group Connector Wires (Twice as thick as block wires: 6px vs 3px) */
.group-wire-hitbox {
  fill: none;
  stroke: transparent;
  stroke-width: 22px;
  cursor: pointer;
}
.group-wire-path {
  fill: none;
  stroke: var(--canvas-group-wire);
  stroke-width: 6px;
  stroke-linecap: round;
  stroke-linejoin: round;
  cursor: pointer;
  transition: stroke 0.15s;
}
.group-wire-path:hover {
  stroke: var(--canvas-group-wire-hover);
}
.group-wire-path.selected {
  stroke: var(--canvas-wire-selected);
}

.temp-group-wire {
  fill: none;
  stroke: var(--canvas-group-wire);
  stroke-width: 6px;
  stroke-linecap: round;
  stroke-linejoin: round;
  stroke-dasharray: 6 6;
  pointer-events: none;
}

.props-section-locked {
  opacity: 0.4;
  pointer-events: none;
  filter: grayscale(0.6);
}
.unit-symbol-display {
  background: var(--bg-panel-subtle);
  border: 1px solid var(--border-color);
  border-radius: 6px;
  padding: 0.4rem 0.6rem;
  font-size: 0.85rem;
  color: var(--text-main);
}

.node-header {
  padding: 0.55rem 0.75rem;
  border-top-left-radius: 8px;
  border-top-right-radius: 8px;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: grab;
}

.node-header:active {
  cursor: grabbing;
}

.input-header { background: var(--canvas-node-header-inp-bg); }
.input-header .var-title { color: var(--canvas-node-header-inp-title); font-weight: 700; }
.input-badge { background: var(--canvas-node-header-inp-badge); color: var(--canvas-node-header-inp-badge-text); }

.output-header { background: var(--canvas-node-header-out-bg); }
.output-header .var-title { color: var(--canvas-node-header-out-title); font-weight: 700; }
.output-badge { background: var(--canvas-node-header-out-badge); color: var(--canvas-node-header-out-badge-text); }

.calc-header { background: var(--canvas-node-header-calc-bg); }
.calc-header .calc-title { color: var(--canvas-node-header-calc-title); font-weight: 700; }
.calc-badge { background: var(--canvas-node-header-calc-badge); color: var(--canvas-node-header-calc-badge-text); }

.header-left {
  display: flex;
  align-items: center;
  gap: 0.45rem;
  overflow: hidden;
}

.type-badge {
  font-size: 0.65rem;
  font-weight: 700;
  padding: 0.15rem 0.35rem;
  border-radius: 4px;
  letter-spacing: 0.04em;
}

.var-title {
  font-size: 0.85rem;
  color: var(--text-main);
}

.calc-title {
  font-size: 0.8rem;
  color: var(--text-main);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 140px;
}

.node-action-btn {
  background: transparent;
  border: none;
  color: var(--text-dim);
  cursor: pointer;
  padding: 2px 4px;
  border-radius: 4px;
  font-size: 0.75rem;
}

.node-action-btn:hover {
  color: var(--danger);
  background: rgba(239, 68, 68, 0.15);
}

.node-body {
  padding: 0.65rem 0.75rem;
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
}

.node-desc {
  font-size: 0.72rem;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.node-value-row {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  background: var(--canvas-node-val-bg);
  padding: 0.3rem 0.45rem;
  border-radius: 6px;
  border: 1px solid var(--canvas-node-val-border);
  color: var(--canvas-node-val-text);
  transition: background-color 0.2s ease, border-color 0.2s ease;
}

.node-value-display {
  color: var(--canvas-node-val-text);
}

.node-value-input {
  flex: 1;
  background: transparent;
  border: none;
  color: var(--canvas-node-val-text);
  font-size: 0.85rem;
  text-align: right;
  width: 60px;
  outline: none;
}

.output-value-highlight {
  background: rgba(16, 185, 129, 0.1);
  border-color: rgba(16, 185, 129, 0.3);
}

.computed-val {
  flex: 1;
  text-align: right;
  font-size: 0.9rem;
  color: var(--canvas-computed-val-text, var(--success));
  font-weight: 700;
}

.node-unit-badge {
  font-size: 0.7rem;
  color: var(--canvas-unit-badge-text, var(--text-muted));
  background: var(--canvas-unit-badge-bg);
  border: 1px solid var(--border-color);
  padding: 0.1rem 0.35rem;
  border-radius: 4px;
}

.node-formula-hint {
  color: var(--canvas-formula-hint-text, var(--primary));
  background: var(--canvas-formula-hint-bg, var(--primary-light));
  padding: 0.2rem 0.4rem;
  border-radius: 4px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* Snapped Blocks Stacking & Badges */
.block-stack-order-badge {
  font-size: 0.65rem;
  font-weight: 700;
  padding: 0.05rem 0.35rem;
  border-radius: 999px;
  background: var(--canvas-group-badge-bg);
  color: var(--canvas-group-badge-text);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 14px;
  line-height: 1.2;
  margin-left: 0.3rem;
  vertical-align: middle;
}

.canvas-node.has-block-under {
  border-bottom-left-radius: 0 !important;
  border-bottom-right-radius: 0 !important;
}

.canvas-node.has-block-above {
  border-top-left-radius: 0 !important;
  border-top-right-radius: 0 !important;
}

.canvas-node.has-block-above .node-header {
  border-top-left-radius: 0 !important;
  border-top-right-radius: 0 !important;
}

/* Operation Node Internal layout */
.canvas-node.node-calculation {
  width: 290px;
}

.calc-formula-banner {
  background: var(--canvas-calc-banner-bg);
  border: 1px solid var(--canvas-calc-banner-border);
  padding: 0.4rem 0.6rem;
  border-radius: 6px;
  color: var(--canvas-calc-banner-text);
  font-size: 0.85rem;
  text-align: center;
  min-height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow-x: auto;
  transition: background-color 0.2s ease, border-color 0.2s ease, color 0.2s ease;
}

/* Canvas Groups Layer & Box */
.canvas-groups-layer {
  position: absolute;
  top: 0;
  left: 0;
  pointer-events: auto;
}

.canvas-group-box {
  position: absolute;
  border: 2px dashed var(--canvas-group-border);
  border-radius: 12px;
  background: var(--canvas-group-bg);
  pointer-events: auto;
  transition: border-color 0.15s, box-shadow 0.15s, background-color 0.2s ease;
}

.canvas-group-box:hover {
  border-color: var(--canvas-group-hover-border);
}

.canvas-group-box.selected {
  border-style: solid;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--primary-light);
}

.canvas-group-empty-state {
  position: absolute;
  inset: 32px 0 0 0;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-muted);
  font-size: 0.76rem;
  font-style: italic;
  pointer-events: none;
  text-align: center;
  padding: 12px;
  opacity: 0.65;
  user-select: none;
}

.canvas-group-header {
  height: 28px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 0.75rem;
  border-top-left-radius: 10px;
  border-top-right-radius: 10px;
  cursor: grab;
  user-select: none;
}

.canvas-group-header:active {
  cursor: grabbing;
}

.canvas-group-title {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.canvas-group-badge {
  font-size: 0.65rem;
  padding: 0.05rem 0.35rem;
  border-radius: 999px;
  background: var(--canvas-group-badge-bg);
  color: var(--canvas-group-badge-text);
}

.modal-latex-preview-box {
  background: var(--canvas-calc-banner-bg);
  border: 1px solid var(--canvas-calc-banner-border);
  padding: 0.5rem;
  border-radius: 6px;
  min-height: 38px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.95rem;
  color: var(--canvas-calc-banner-text);
}

.calc-ports-container {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin: 0.3rem 0;
  gap: 0.5rem;
}

.calc-inputs-list {
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
  flex: 1;
}

.calc-input-row {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  position: relative;
  padding-left: 0.5rem;
}

.calc-port-label {
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--text-main);
}

.calc-port-desc {
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 100px;
}

.calc-output-section {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  position: relative;
  padding-right: 0.5rem;
}

.calc-output-label {
  font-size: 0.8rem;
  font-weight: 700;
  color: #34D399;
}

.calc-result-badge {
  background: var(--canvas-calc-result-bg);
  border: 1px solid var(--canvas-calc-result-border);
  padding: 0.3rem 0.5rem;
  border-radius: 6px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.8rem;
  transition: background-color 0.2s ease, border-color 0.2s ease;
}

/* Port Sockets & Dots */
.port-socket {
  position: absolute;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: crosshair;
  z-index: 10;
  transition: transform 0.15s ease;
}

.port-socket:hover {
  /* No scale animation / movement on hover */
}

.port-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background-color: var(--canvas-port-dot-in);
  border: 2px solid var(--canvas-node-bg);
  box-shadow: 0 0 5px rgba(0, 0, 0, 0.3);
  transition: background-color 0.15s ease, border-color 0.15s ease, box-shadow 0.15s ease;
}

.port-out {
  right: -9px;
  top: 50%;
  transform: translateY(-50%);
}

.port-in {
  left: -9px;
  top: 50%;
  transform: translateY(-50%);
}

.port-out .port-dot { background-color: var(--canvas-port-dot-out); }
.port-in .port-dot { background-color: var(--canvas-port-dot-in); }

.port-in-calc {
  left: -19px;
  top: 50%;
  transform: translateY(-50%);
}

.port-in-calc .port-dot {
  background-color: var(--canvas-port-dot-calc-in);
  box-shadow: 0 0 6px var(--canvas-port-dot-calc-in);
}

.port-out-calc {
  right: -19px;
  top: 50%;
  transform: translateY(-50%);
}

.port-out-calc .port-dot {
  background-color: var(--canvas-port-dot-calc-out);
  box-shadow: 0 0 6px var(--canvas-port-dot-calc-out);
}

/* Hover color changes for equation and variable ports */
.port-in-calc:hover .port-dot {
  background-color: #C084FC !important;
  box-shadow: 0 0 10px rgba(192, 132, 252, 0.95) !important;
  border-color: #FFFFFF !important;
}

.port-out-calc:hover .port-dot {
  background-color: #34D399 !important;
  box-shadow: 0 0 10px rgba(52, 211, 153, 0.95) !important;
  border-color: #FFFFFF !important;
}

.port-in:hover .port-dot {
  background-color: #60A5FA !important;
  box-shadow: 0 0 10px rgba(96, 165, 250, 0.95) !important;
  border-color: #FFFFFF !important;
}

.port-out:hover .port-dot {
  background-color: #34D399 !important;
  box-shadow: 0 0 10px rgba(52, 211, 153, 0.95) !important;
  border-color: #FFFFFF !important;
}

/* SVG Connection Wires */
.wire-hitbox {
  fill: none;
  stroke: transparent;
  stroke-width: 16px;
  cursor: pointer;
}

.wire-path {
  fill: none;
  stroke: var(--canvas-wire);
  stroke-width: 2.5px;
  transition: stroke 0.15s, stroke-width 0.15s;
}

.wire-path:hover {
  stroke: var(--canvas-wire-hover);
  stroke-width: 4px;
}

.wire-path.selected {
  stroke: var(--canvas-wire-selected);
  stroke-width: 4px;
  filter: drop-shadow(0 0 6px rgba(245, 158, 11, 0.8));
}

#group-arrow-marker path {
  fill: var(--canvas-group-wire) !important;
  transition: fill 0.2s ease;
}

.wire-flow {
  display: none !important;
}

@keyframes wire-flow-anim {
  from { stroke-dashoffset: 14; }
  to { stroke-dashoffset: 0; }
}

.temp-wire {
  fill: none;
  stroke: var(--success);
  stroke-width: 2.5px;
  stroke-dasharray: 5 5;
  pointer-events: none;
}

/* ==========================================================================
   Visual Formula Sheet Preview (Excel Grid View)
   ========================================================================== */
.sheet-preview-wrapper {
  display: flex;
  flex-direction: column;
  height: 100%;
  background-color: #F8FAFC;
}

.excel-formula-bar {
  height: 34px;
  background-color: #F1F5F9;
  border-bottom: 1px solid #CBD5E1;
  display: flex;
  align-items: center;
  padding: 0 0.5rem;
  gap: 0.5rem;
  flex-shrink: 0;
}

.excel-name-box {
  width: 55px;
  height: 24px;
  background: white;
  border: 1px solid #CBD5E1;
  border-radius: 3px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: ui-monospace, monospace;
  font-size: 0.75rem;
  font-weight: 700;
  color: #334155;
}

.excel-fx-icon {
  font-family: "Georgia", serif;
  font-style: italic;
  font-weight: bold;
  color: #64748B;
  font-size: 0.85rem;
}

.excel-formula-input {
  flex: 1;
  height: 24px;
  background: white;
  border: 1px solid #CBD5E1;
  border-radius: 3px;
  padding: 0 0.5rem;
  font-family: ui-monospace, monospace;
  font-size: 0.8rem;
  color: #1E293B;
  outline: none;
}

.excel-formula-input:focus {
  border-color: #2563EB;
}

.excel-grid-viewport {
  flex: 1;
  overflow: auto;
  background: white;
}

.excel-table {
  border-collapse: collapse;
  table-layout: fixed;
  background: white;
  color: #1E293B;
  font-size: 11px;
}

.excel-corner-cell {
  width: 38px;
  background: #F1F5F9;
  border: 1px solid #CBD5E1;
}

.excel-col-header {
  height: 22px;
  background: #F1F5F9;
  border: 1px solid #CBD5E1;
  font-size: 11px;
  font-weight: 600;
  color: #475569;
  text-align: center;
  min-width: 80px;
}

.excel-row-header {
  width: 38px;
  background: #F1F5F9;
  border: 1px solid #CBD5E1;
  font-size: 10px;
  font-weight: 600;
  color: #475569;
  text-align: center;
}

.excel-cell {
  height: 24px;
  border: 1px solid #E2E8F0;
  padding: 2px 6px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  cursor: cell;
}

.excel-cell.excel-cell-active {
  outline: 2px solid #107C41;
  outline-offset: -2px;
  z-index: 5;
  position: relative;
}

.excel-banner-input {
  background: #EBF3FA !important;
  color: #1A365D;
  font-weight: bold;
  text-align: center;
  font-size: 12px;
  border: 1px solid #B0C4DE;
}

.excel-banner-output {
  background: #E6F4EA !important;
  color: #137333;
  font-weight: bold;
  text-align: center;
  font-size: 12px;
  border: 1px solid #A8DAB5;
}

.excel-sec-header {
  font-weight: bold;
  font-size: 11px;
  padding-left: 8px;
}

.excel-th-cell {
  background: #F0F4F8;
  font-weight: bold;
  color: #334155;
  border-bottom: 2px solid #B0C4DE;
}

.excel-inline-edit {
  width: 100%;
  height: 100%;
  border: none;
  background: transparent;
  font-family: inherit;
  font-size: inherit;
  font-weight: bold;
  text-align: right;
  outline: none;
  color: #000000;
}

.excel-output-cell {
  color: #000000;
  cursor: pointer;
}

/* ==========================================================================
   Properties Panel Controls
   ========================================================================== */
.props-section {
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
  padding-bottom: 0.85rem;
  border-bottom: 1px solid var(--border-color);
}

.props-section-title {
  font-size: 0.725rem;
  font-weight: 700;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.props-badge-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.form-label {
  font-size: 0.72rem;
  color: var(--text-muted);
  font-weight: 500;
}

.form-control {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 6px;
  color: var(--text-main);
  padding: 0.4rem 0.6rem;
  font-size: 0.8rem;
  outline: none;
  transition: border-color 0.15s;
}

.form-control:focus {
  border-color: var(--border-color-focus);
}

.form-control-xs {
  padding: 0.25rem 0.4rem;
  font-size: 0.72rem;
}

.color-picker-row {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.color-picker-input {
  width: 32px;
  height: 32px;
  border-radius: 6px;
  border: 1px solid var(--border-color);
  background: transparent;
  cursor: pointer;
  padding: 0;
}

.color-presets-row {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  margin-top: 0.2rem;
}

.color-chip {
  width: 20px;
  height: 20px;
  border-radius: 4px;
  border: 1px solid #64748B;
  cursor: pointer;
  transition: transform 0.1s;
}

.color-chip:hover {
  transform: scale(1.2);
}

.computed-readout {
  background: rgba(16, 185, 129, 0.15);
  border: 1px solid rgba(16, 185, 129, 0.3);
  padding: 0.4rem 0.6rem;
  border-radius: 6px;
  color: #34D399;
  font-size: 0.9rem;
}

.excel-formula-readout {
  background: rgba(59, 130, 246, 0.15);
  border: 1px solid rgba(59, 130, 246, 0.3);
  padding: 0.4rem 0.6rem;
  border-radius: 6px;
  color: #60A5FA;
  font-size: 0.8rem;
  word-break: break-all;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0.4rem;
}

.stat-pill {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  padding: 0.4rem 0.6rem;
  border-radius: 6px;
  display: flex;
  flex-direction: column;
}

.stat-num {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--primary-light);
  color: #60A5FA;
}

.stat-lbl {
  font-size: 0.65rem;
  color: var(--text-dim);
  text-transform: uppercase;
}

.calc-ports-list-ui {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.calc-port-item {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 6px;
  padding: 0.4rem 0.5rem;
}


/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.35rem;
  border: none;
  border-radius: 6px;
  font-size: 0.8rem;
  font-weight: 600;
  padding: 0.4rem 0.75rem;
  cursor: pointer;
  transition: all 0.15s ease;
  user-select: none;
}

.btn-sm { padding: 0.35rem 0.6rem; font-size: 0.75rem; }
.btn-xs { padding: 0.2rem 0.45rem; font-size: 0.7rem; height: 24px; box-sizing: border-box; line-height: 1; }
.btn-block { width: 100%; }

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

.btn-excel {
  background-color: var(--excel-green);
  color: white;
}
.btn-excel:hover {
  background-color: var(--excel-green-hover);
  box-shadow: 0 2px 8px rgba(16, 124, 65, 0.4);
}

.btn-subtle {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-muted);
}
.btn-subtle:hover {
  background-color: var(--bg-card-hover);
  color: var(--text-main);
}

.btn-danger {
  background-color: rgba(239, 68, 68, 0.2);
  color: #F87171;
  border: 1px solid rgba(239, 68, 68, 0.4);
}
.btn-danger:hover {
  background-color: #EF4444;
  color: white;
}

.btn-link {
  background: transparent;
  border: none;
  padding: 0;
}

.badge {
  display: inline-block;
  padding: 0.15rem 0.4rem;
  border-radius: 999px;
  font-weight: 600;
}

.badge-subtle {
  background: rgba(100, 116, 139, 0.2);
  color: var(--text-muted);
}

/* Modals */
.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.7);
  backdrop-filter: blur(4px);
  z-index: 100;
  display: none;
  align-items: center;
  justify-content: center;
}

.modal-backdrop.show {
  display: flex;
}

.modal-dialog {
  background: var(--bg-panel);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  width: 90%;
  max-width: 580px;
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.6);
  display: flex;
  flex-direction: column;
  max-height: 85vh;
  overflow: hidden;
  animation: modal-pop 0.2s cubic-bezier(0.16, 1, 0.3, 1);
}

@keyframes modal-pop {
  from { opacity: 0; transform: scale(0.95); }
  to { opacity: 1; transform: scale(1); }
}

.modal-header {
  padding: 1rem 1.25rem;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.modal-title {
  font-size: 1.05rem;
  font-weight: 700;
}

.modal-close-btn {
  background: transparent;
  border: none;
  color: var(--text-muted);
  font-size: 1.2rem;
  cursor: pointer;
}

.modal-body {
  padding: 1.25rem;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.modal-footer {
  padding: 0.85rem 1.25rem;
  border-top: 1px solid var(--border-color);
  display: flex;
  justify-content: flex-end;
  gap: 0.5rem;
  background: var(--bg-panel-subtle);
}

.modal-ports-list {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.modal-ports-header,
.modal-port-row {
  display: grid;
  grid-template-columns: 75px 45px 1fr 75px 75px;
  gap: 0.4rem;
  align-items: center;
}

.modal-ports-header {
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--text-muted);
  padding: 0.2rem 0.2rem;
  border-bottom: 1px solid var(--border-color);
  margin-bottom: 0.2rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.modal-test-box {
  background: var(--bg-panel-subtle);
  border: 1px solid var(--border-color);
  padding: 0.6rem 0.8rem;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.input-row-flex {
  display: flex;
  gap: 0.5rem;
}

/* Custom Scrollbar */
::-webkit-scrollbar {
  width: 6px;
  height: 6px;
}
::-webkit-scrollbar-track {
  background: rgba(0, 0, 0, 0.1);
}
::-webkit-scrollbar-thumb {
  background: #475569;
  border-radius: 3px;
}
::-webkit-scrollbar-thumb:hover {
  background: #64748B;
}

/* Groups Manager in Properties Panel */
.group-item-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 6px;
  padding: 0.45rem 0.6rem;
  transition: border-color 0.15s;
}

.group-item-row:hover {
  border-color: var(--border-color-focus);
}

.group-item-left {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.group-color-dot {
  width: 14px;
  height: 14px;
  border-radius: 3px;
  border: 1px solid rgba(255, 255, 255, 0.3);
  display: inline-block;
  flex-shrink: 0;
}

.group-member-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
}

.group-member-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  padding: 0.2rem 0.45rem;
  border-radius: 4px;
  font-size: 0.72rem;
  font-family: ui-monospace, monospace;
}

/* Sheet Manager in Properties Panel */
.sheet-item-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 6px;
  padding: 0.45rem 0.6rem;
  transition: border-color 0.15s;
}

.sheet-item-card:hover {
  border-color: var(--border-color-focus);
}

.sheet-num-label {
  font-weight: 700;
  font-size: 0.75rem;
  color: var(--text-main);
  white-space: nowrap;
}

.sheet-title-input {
  font-size: 0.8rem;
  padding: 0.25rem 0.5rem;
  height: 28px;
}

.sheet-name-warning {
  color: #EF4444;
  font-size: 0.72rem;
  line-height: 1.2;
}

/* Excel Sheet Tabs in Sheet Preview */
.excel-sheet-tabs-bar {
  height: 32px;
  background: #F1F5F9;
  border-top: 1px solid #CBD5E1;
  display: flex;
  align-items: center;
  padding: 0 0.5rem;
  gap: 4px;
  overflow-x: auto;
  flex-shrink: 0;
}

[data-theme="dark"] .excel-sheet-tabs-bar,
[data-theme="modern"] .excel-sheet-tabs-bar {
  background: #1E293B;
  border-top-color: #334155;
}

.excel-sheet-tab {
  padding: 4px 12px;
  font-size: 0.75rem;
  font-weight: 600;
  cursor: pointer;
  border: 1px solid #CBD5E1;
  border-bottom: none;
  border-radius: 4px 4px 0 0;
  background: #E2E8F0;
  color: #475569;
  white-space: nowrap;
  user-select: none;
  transition: background 0.15s, color 0.15s;
}

[data-theme="dark"] .excel-sheet-tab,
[data-theme="modern"] .excel-sheet-tab {
  background: #0F172A;
  border-color: #334155;
  color: #94A3B8;
}

.excel-sheet-tab:hover {
  background: #EDF2F7;
  color: #1E293B;
}

[data-theme="dark"] .excel-sheet-tab:hover,
[data-theme="modern"] .excel-sheet-tab:hover {
  background: #1E293B;
  color: #F8FAFC;
}

.excel-sheet-tab.active {
  background: #FFFFFF;
  color: #0F172A;
  border-top: 2px solid #2563EB;
  font-weight: 700;
}

[data-theme="dark"] .excel-sheet-tab.active,
[data-theme="modern"] .excel-sheet-tab.active {
  background: #334155;
  color: #38BDF8;
  border-top: 2px solid #38BDF8;
}

/* ==========================================
   AUTHENTICATION & TIER SYSTEM STYLES
   ========================================== */

/* Top Center Auth Controls */
.app-header {
  position: relative; /* Ensure absolute positioning for center auth */
}

.header-center-auth {
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 60;
  pointer-events: auto;
}

.auth-buttons-group,
.auth-user-group {
  display: flex;
  align-items: center;
  gap: 0.45rem;
}

.google-icon {
  display: inline-block;
  vertical-align: middle;
  margin-right: 0.25rem;
}

.user-profile-pill {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  padding: 0.2rem 0.6rem;
  border-radius: 999px;
  font-size: 0.72rem;
  cursor: pointer;
  transition: all 0.15s ease;
  user-select: none;
}

.user-profile-pill:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-color-focus);
}

.user-avatar-circle {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--primary);
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.65rem;
  font-weight: 700;
  text-transform: uppercase;
}

.user-email-text {
  color: var(--text-main);
  font-weight: 600;
  max-width: 130px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.tier-pill {
  font-size: 0.62rem;
  font-weight: 700;
  padding: 0.05rem 0.4rem;
  border-radius: 999px;
  letter-spacing: 0.02em;
}

.tier-pill.tier-free {
  background: rgba(59, 130, 246, 0.15);
  color: #3B82F6;
  border: 1px solid rgba(59, 130, 246, 0.3);
}

.tier-pill.tier-premium {
  background: rgba(245, 158, 11, 0.2);
  color: #D97706;
  border: 1px solid rgba(245, 158, 11, 0.45);
}

/* Gold background behind the text "SB" for premium tier users */
.brand-logo-icon.premium {
  background: linear-gradient(135deg, #F59E0B 0%, #D97706 50%, #B45309 100%) !important;
  box-shadow: 0 2px 10px rgba(217, 119, 6, 0.55), inset 0 1px 1px rgba(255, 255, 255, 0.4) !important;
  border: 1px solid rgba(251, 191, 36, 0.6) !important;
  color: #FFFFFF !important;
  text-shadow: 0 1px 2px rgba(0, 0, 0, 0.3);
}

/* Open Project Modal & Saved Projects List */
.quota-box {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 0.75rem 1rem;
  margin-bottom: 1rem;
}

.quota-header-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.78rem;
  font-weight: 600;
  margin-bottom: 0.4rem;
}

.quota-progress-track {
  height: 6px;
  border-radius: 999px;
  background: var(--border-color);
  overflow: hidden;
}

.quota-progress-fill {
  height: 100%;
  border-radius: 999px;
  background: var(--primary);
  transition: width 0.3s ease;
}

.quota-progress-fill.near-limit {
  background: #F59E0B;
}

.quota-progress-fill.at-limit {
  background: #EF4444;
}

.saved-projects-scroll {
  max-height: 380px;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.saved-project-card {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.65rem 0.85rem;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  transition: all 0.15s ease;
}

.saved-project-card:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-color-focus);
}

.saved-proj-left {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
  flex: 1;
  min-width: 0;
}

.saved-proj-title {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--text-main);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.saved-proj-meta {
  font-size: 0.72rem;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.saved-proj-actions {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  margin-left: 0.75rem;
  flex-shrink: 0;
}

/* Auth Modal Styling */
.btn-google-large {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.6rem;
  width: 100%;
  padding: 0.6rem 1rem;
  font-size: 0.85rem;
  font-weight: 600;
  border-radius: 8px;
  background: #FFFFFF;
  color: #1F2937;
  border: 1px solid #D1D5DB;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
  cursor: pointer;
  transition: all 0.15s ease;
}

.btn-google-large:hover {
  background: #F9FAFB;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.15);
}

.tier-upgrade-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 0.85rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.tier-upgrade-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* Floating Toast Notification */
.sheetbox-toast {
  position: fixed;
  bottom: 24px;
  right: 24px;
  background: #1E293B;
  color: #F8FAFC;
  padding: 0.65rem 1rem;
  border-radius: 8px;
  font-size: 0.8rem;
  font-weight: 600;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.3);
  border: 1px solid rgba(255, 255, 255, 0.1);
  z-index: 9999;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  animation: toast-slide-up 0.25s cubic-bezier(0.16, 1, 0.3, 1);
  transition: opacity 0.3s ease, transform 0.3s ease;
}

.sheetbox-toast.toast-success {
  border-left: 4px solid #10B981;
}

.sheetbox-toast.toast-warning {
  border-left: 4px solid #F59E0B;
}

@keyframes toast-slide-up {
  from {
    opacity: 0;
    transform: translateY(16px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
}