:root {
  --bg-color: #121212;
  --panel-bg: #1e1e1e;
  --card-bg: #2a2a2a;
  --text-primary: #e0e0e0;
  --text-secondary: #aaaaaa;
  --accent-color: #4a90e2;
  --accent-hover: #357abd;
  --border-color: #333333;
  --error-color: #ff5252;
  
  --spacing-sm: 8px;
  --spacing-md: 16px;
  --spacing-lg: 24px;
  --border-radius: 8px;
  --font-main: 'Segoe UI', system-ui, sans-serif;
}

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

body {
  background-color: var(--bg-color);
  color: var(--text-primary);
  font-family: var(--font-main);
  line-height: 1.5;
  height: 100vh;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

header {
  height: 60px;
  background-color: var(--panel-bg);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--spacing-lg);
  flex-shrink: 0;
}

header h1 {
  font-size: 1.2rem;
  font-weight: 600;
  letter-spacing: 0.5px;
}

.app-container {
  display: flex;
  flex: 1;
  overflow: hidden;
  height: calc(100vh - 60px);
}

.panel {
  padding: var(--spacing-md);
  overflow-y: auto;
  border-right: 1px solid var(--border-color);
}

/* Scrollbar styling */
.panel::-webkit-scrollbar {
  width: 8px;
}
.panel::-webkit-scrollbar-track {
  background: transparent;
}
.panel::-webkit-scrollbar-thumb {
  background-color: #444;
  border-radius: 4px;
}

.panel-left { width: 350px; flex-shrink: 0; }
.panel-center { width: 400px; flex-shrink: 0; }
.panel-right { flex: 1; display: flex; flex-direction: column; }

h2 {
  font-size: 1.1rem;
  margin-bottom: var(--spacing-sm);
  color: var(--text-primary);
  border-bottom: 2px solid var(--border-color);
  padding-bottom: 4px;
}

.panel-desc {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: var(--spacing-md);
}

/* Forms & Controls */
.control-group {
  margin-bottom: var(--spacing-lg);
}

.control-group label {
  display: block;
  font-size: 0.9rem;
  margin-bottom: 4px;
  color: var(--text-secondary);
}

.control-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 8px;
}

.control-row.inline {
  justify-content: flex-start;
  gap: var(--spacing-md);
}

.control-row.small {
  margin-bottom: 4px;
}

.control-row.small label, .control-row.micro label {
  font-size: 0.8rem;
}

input[type="text"],
input[type="number"],
select,
textarea {
  width: 100%;
  background: var(--bg-color);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
  border-radius: 4px;
  padding: 6px 8px;
  font-family: inherit;
  font-size: 0.9rem;
  outline: none;
  transition: border-color 0.2s;
}

input[type="text"]:focus,
textarea:focus,
select:focus {
  border-color: var(--accent-color);
}

select { cursor: pointer; }

textarea {
  resize: vertical;
  min-height: 100px;
  font-family: 'Consolas', 'Courier New', monospace;
  font-size: 1.1rem;
  letter-spacing: 2px;
}

input[type="range"] {
  flex: 1;
  margin: 0 8px;
  accent-color: var(--accent-color);
}
.val-display { min-width: 3ch; text-align: right; font-size: 0.8rem; color: var(--text-secondary); }

.control-row > input[type="number"],
.control-row > select {
  width: 120px;
}

/* Button Styles */
.btn {
  background: var(--card-bg);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
  border-radius: 4px;
  padding: 6px 12px;
  cursor: pointer;
  font-size: 0.85rem;
  transition: all 0.2s;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.btn:hover { background: #3a3a3a; }

.btn.primary {
  background: var(--accent-color);
  color: #fff;
  border: none;
  font-weight: bold;
}
.btn.primary:hover { background: var(--accent-hover); }

.btn.outline { border-color: var(--accent-color); color: var(--accent-color); }
.btn.outline:hover { background: rgba(74, 144, 226, 0.1); }

.btn.tiny { padding: 2px 6px; font-size: 0.75rem; }
.w-full { width: 100%; }

.icon-btn { padding: 4px; border: none; background: transparent; opacity: 0.7; }
.icon-btn:hover { opacity: 1; background: rgba(255,255,255,0.1); }

/* Cell List */
.cell-list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.cell-item {
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  padding: 8px;
  display: grid;
  grid-template-columns: 80px 1fr;
  grid-template-rows: auto auto;
  gap: 8px;
}

/* Empty cell styling hint */
.cell-item.is-empty { border: 1px dashed var(--border-color); opacity: 0.7; }
.cell-item.is-empty .cell-controls { opacity: 0.5; pointer-events: none; }

.cell-header {
  grid-column: 1 / -1;
  display: flex;
  align-items: center;
  gap: 8px;
  padding-bottom: 4px;
  border-bottom: 1px solid var(--border-color);
}

.cell-badge {
  background: var(--bg-color);
  border: 1px solid #555;
  border-radius: 4px;
  padding: 2px 8px;
  font-weight: bold;
  font-family: monospace;
  font-size: 1.1rem;
  color: var(--accent-color);
}

.upload-btn {
  background: var(--accent-color);
  color: #fff;
  padding: 2px 8px;
  border-radius: 4px;
  font-size: 0.75rem;
  cursor: pointer;
}
.upload-btn:hover { background: var(--accent-hover); }

.cell-preview-box {
  width: 70px;
  height: 70px;
  background: #000;
  border: 1px solid #444;
  border-radius: 4px;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  position: relative;
}

.empty-state { font-size: 0.7rem; color: #666; }
.cell-thumb-canvas { width: 100%; height: 100%; object-fit: contain; }

.cell-controls { font-size: 0.8rem; }
.color-adjust-details { margin-top: 4px; background: rgba(0,0,0,0.2); padding: 4px; border-radius: 4px; }
.color-adjust-details summary { cursor: pointer; color: var(--text-secondary); margin-bottom: 4px; }

/* Settings Cards */
.settings-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-md);
}

.settings-card {
  background: var(--card-bg);
  border-radius: var(--border-radius);
  padding: 12px;
  border: 1px solid var(--border-color);
}

.settings-card h3 {
  font-size: 0.95rem;
  margin-bottom: 12px;
  color: var(--accent-color);
}

.checkbox-label {
  display: flex;
  align-items: center;
  gap: 8px;
  cursor: pointer;
  user-select: none;
}

.divider {
  border: none;
  border-top: 1px solid var(--border-color);
  margin: 12px 0;
}

.double-grout-group {
  padding-left: 16px;
  border-left: 2px solid var(--border-color);
  margin-top: 8px;
  transition: opacity 0.2s;
}

/* Pattern Helpers */
.pattern-helpers { margin-bottom: 8px; display: flex; flex-direction: column; gap: 8px; }
.helper-buttons { display: flex; flex-wrap: wrap; gap: 4px; }
.helper-btn {
  background: var(--card-bg); border: 1px solid #444; color: #ccc;
  width: 24px; height: 24px; border-radius: 4px; cursor: pointer;
  font-family: monospace; font-size: 1rem;
}
.helper-btn:hover { background: var(--accent-color); border-color: var(--accent-color); color: #fff; }

.template-buttons { display: flex; gap: 8px; }
.error-msg { color: var(--error-color); font-size: 0.85rem; margin-top: 4px; min-height: 20px;}

/* Preview Area */
.preview-actions {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--spacing-md);
  padding-bottom: var(--spacing-sm);
  border-bottom: 1px solid var(--border-color);
}

.preview-container {
  flex: 1;
  background-color: #000;
  background-image: 
    linear-gradient(45deg, #111 25%, transparent 25%, transparent 75%, #111 75%, #111), 
    linear-gradient(45deg, #111 25%, transparent 25%, transparent 75%, #111 75%, #111);
  background-size: 20px 20px;
  background-position: 0 0, 10px 10px;
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  overflow: auto;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
}

#preview-canvas {
  box-shadow: 0 4px 12px rgba(0,0,0,0.5);
  max-width: 100%;
  max-height: 100%;
  object-fit: contain; /* Ensure it scales down if too large, while full size goes to canvas attributes */
}

/* Responsive adjustment if window shrinks */
@media (max-width: 1200px) {
  .panel-left { width: 300px; }
  .panel-center { width: 350px; }
}

/* Crop Modal */
.modal-overlay {
  position: fixed;
  top: 0; left: 0; right: 0; bottom: 0;
  background: rgba(0, 0, 0, 0.85);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 9999;
}

.modal-content.crop-modal-content {
  background: var(--panel-bg);
  width: 90vw;
  height: 90vh;
  border-radius: var(--border-radius);
  display: flex;
  flex-direction: column;
  overflow: hidden;
  border: 1px solid var(--border-color);
  box-shadow: 0 10px 30px rgba(0,0,0,0.5);
}

.modal-header {
  padding: 12px var(--spacing-md);
  background: var(--card-bg);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.modal-header h3 { font-size: 1.1rem; color: var(--text-primary); margin: 0; }
.btn-close-modal { font-size: 1.2rem; cursor: pointer; color: var(--text-secondary); background: none; border: none; }
.btn-close-modal:hover { color: #fff; }

.modal-toolbar {
  padding: 8px var(--spacing-md);
  background: #222;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  justify-content: space-between;
}

.crop-canvas-container {
  flex: 1;
  background-color: #111;
  background-image: 
    linear-gradient(45deg, #1a1a1a 25%, transparent 25%, transparent 75%, #1a1a1a 75%, #1a1a1a), 
    linear-gradient(45deg, #1a1a1a 25%, transparent 25%, transparent 75%, #1a1a1a 75%, #1a1a1a);
  background-size: 20px 20px;
  background-position: 0 0, 10px 10px;
  overflow: hidden;
  display: flex;
  position: relative;
  cursor: crosshair;
}

#crop-canvas {
  margin: auto;
  box-shadow: 0 0 20px rgba(0,0,0,0.8);
  transform-origin: center center;
}