:root {
  /* Modern Theme Palette - Slate & Indigo */
  --bg-app: #f8fafc;
  --bg-panel: #ffffff;
  --bg-surface: #f1f5f9;
  --bg-input: #ffffff;
  
  --border-subtle: #e2e8f0;
  --border-active: #cbd5e1;
  --border-focus: #818cf8;
  
  --primary: #4f46e5;
  --primary-hover: #4338ca;
  --primary-gradient: linear-gradient(135deg, #4f46e5 0%, #6366f1 100%);
  --primary-light: #e0e7ff;
  
  --text-main: #0f172a;
  --text-muted: #64748b;
  --text-dim: #94a3b8;
  
  --success: #10b981;
  --warning: #f59e0b;
  --danger: #ef4444;

  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 20px;
  
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -1px rgba(0,0,0,0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1), 0 4px 6px -2px rgba(0,0,0,0.05);
  --shadow-glow: 0 4px 14px rgba(79, 70, 229, 0.3);
  
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', Consolas, monospace;
}

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

body {
  font-family: var(--font-sans);
  background: var(--bg-app);
  color: var(--text-main);
  height: 100vh;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  font-size: 14px;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

/* Scrollbar */
::-webkit-scrollbar {
  width: 6px;
  height: 6px;
}
::-webkit-scrollbar-track {
  background: transparent;
}
::-webkit-scrollbar-thumb {
  background: #cbd5e1;
  border-radius: 3px;
}
::-webkit-scrollbar-thumb:hover {
  background: #94a3b8;
}

/* Topbar */
.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 24px;
  height: 64px;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-subtle);
  flex-shrink: 0;
  z-index: 20;
}

.topbar-left {
  display: flex;
  align-items: center;
  gap: 16px;
}

.topbar-right {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 6px;
  border-radius: 999px;
  background: rgba(236, 253, 245, 0.9);
  border: 1px solid #a7f3d0;
  box-shadow: var(--shadow-sm);
}

.topbar h1 {
  font-size: 20px;
  font-weight: 800;
  background: var(--primary-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  letter-spacing: -0.5px;
}

.topbar-subtitle {
  font-size: 13px;
  color: var(--text-muted);
  padding-left: 16px;
  border-left: 2px solid var(--border-subtle);
  line-height: 1.2;
  font-weight: 500;
}

.topbar-link {
  font-size: 13px;
  color: var(--text-main);
  text-decoration: none;
  font-weight: 500;
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  background: var(--bg-surface);
  transition: all 0.2s;
  display: flex;
  align-items: center;
  gap: 6px;
  margin-left: 8px;
}
.topbar-link:hover {
  background: #d1fae5;
  color: #059669;
}

.topbar-status {
  font-size: 12px;
  font-weight: 600;
  padding: 6px 16px;
  border-radius: 99px;
  background: #ecfdf5;
  color: #065f46;
  border: 1px solid #a7f3d0;
  display: flex;
  align-items: center;
  gap: 8px;
  transition: all 0.3s;
  box-shadow: var(--shadow-sm);
}

.topbar-status::before {
  content: '';
  display: block;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: #34d399;
  box-shadow: 0 0 8px rgba(16, 185, 129, 0.35);
}

.topbar-status.active {
  background: #d1fae5;
  border-color: #a7f3d0;
  color: #047857;
  box-shadow: 0 6px 16px rgba(16, 185, 129, 0.22);
}
.topbar-status.active::before { background: #10b981; box-shadow: 0 0 10px rgba(16, 185, 129, 0.45); }

.topbar-status.processing {
  background: #fffbeb;
  border-color: #fde68a;
  color: #b45309;
}
.topbar-status.processing::before { background: #f59e0b; animation: pulse 1.5s infinite; }

.btn-ghost {
  font-size: 13px;
  font-weight: 600;
  color: #ffffff;
  text-decoration: none;
  padding: 6px 16px;
  border-radius: 99px;
  background: linear-gradient(135deg, #34d399 0%, #10b981 100%);
  border: 1px solid transparent;
  transition: all 0.2s;
  box-shadow: 0 10px 18px rgba(16, 185, 129, 0.28);
}
.btn-ghost:hover {
  transform: translateY(-1px);
  box-shadow: 0 14px 28px rgba(16, 185, 129, 0.35);
}

@keyframes pulse { 0%, 100% { opacity: 1; transform: scale(1); } 50% { opacity: 0.5; transform: scale(1.2); } }

/* Layout */
.app-layout {
  display: flex;
  flex: 1;
  overflow: hidden;
  padding: 0;
}

/* Panels */
.panel {
  width: 340px;
  flex-shrink: 0;
  background: var(--bg-panel);
  border-right: 1px solid var(--border-subtle);
  overflow-y: auto;
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 28px;
  box-shadow: 2px 0 10px rgba(0,0,0,0.02);
  z-index: 5;
}

.panel-right {
  border-right: none;
  border-left: 1px solid var(--border-subtle);
  box-shadow: -2px 0 10px rgba(0,0,0,0.02);
}

.panel-section {
  position: relative;
  animation: fadeIn 0.5s ease-out;
}
@keyframes fadeIn { from { opacity: 0; transform: translateY(5px); } to { opacity: 1; transform: translateY(0); } }

/* Special Section for Submit Button */
.section-submit {
  margin-top: 12px;
  padding-top: 32px;
  border-top: 1px solid var(--border-subtle);
}

.panel-section h3 {
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.8px;
  color: var(--text-muted);
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.panel-section h3::after {
  content: '';
  flex: 1;
  height: 1px;
  background: var(--border-subtle);
  opacity: 0.6;
}

.hint {
  font-size: 12px;
  color: var(--text-dim);
  margin-top: 6px;
  line-height: 1.4;
}

/* Guide Card */
.guide-card {
  background: linear-gradient(145deg, #f0fdf4 0%, #ffffff 100%);
  border: 1px solid #bbf7d0;
  border-radius: var(--radius-md);
  padding: 20px;
}
.guide-card h3 { color: #15803d; border: none; margin-bottom: 8px; }
.guide-card h3::after { display: none; }
.steps { padding-left: 20px; color: var(--text-muted); font-size: 13px; margin-bottom: 12px; }
.steps li { margin-bottom: 6px; }
.tips { list-style: none; padding: 0; margin-top: 12px; border-top: 1px dashed #bbf7d0; padding-top: 12px; }
.tips li { font-size: 12px; color: var(--text-muted); display: flex; gap: 8px; align-items: flex-start; margin-bottom: 4px; }
.tips li::before { content: '💡'; font-size: 10px; margin-top: 2px; }

/* Config Rows */
.config-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 12px;
}
.config-row label {
  color: var(--text-main);
  font-size: 13px;
  font-weight: 500;
}

/* Inputs */
input[type="text"],
input[type="number"],
.form-select {
  background: var(--bg-input);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  color: var(--text-main);
  padding: 8px 12px;
  font-size: 13px;
  font-family: inherit;
  transition: all 0.2s;
  box-shadow: var(--shadow-sm);
}
input[type="text"]:focus,
input[type="number"]:focus,
.form-select:focus {
  outline: none;
  border-color: var(--border-focus);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.15);
}
input[type="text"]:hover,
input[type="number"]:hover,
.form-select:hover {
  border-color: var(--border-active);
}

.num-input {
  width: 80px;
  text-align: right;
  font-family: var(--font-mono);
}

input[type="color"] {
  width: 36px;
  height: 36px;
  padding: 0;
  border: none;
  border-radius: 50%;
  cursor: pointer;
  background: none;
  transition: transform 0.2s;
}
input[type="color"]:hover { transform: scale(1.1); }
input[type="color"]::-webkit-color-swatch-wrapper { padding: 0; }
input[type="color"]::-webkit-color-swatch { border: 2px solid #fff; box-shadow: 0 0 0 1px var(--border-subtle); border-radius: 50%; }

/* Range Slider */
input[type="range"] {
  -webkit-appearance: none;
  width: 100%;
  background: transparent;
  height: 28px;
  cursor: pointer;
}
input[type="range"]::-webkit-slider-runnable-track {
  width: 100%;
  height: 6px;
  background: var(--bg-surface);
  border-radius: 3px;
  border: 1px solid var(--border-subtle);
}
input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  height: 18px;
  width: 18px;
  border-radius: 50%;
  background: var(--primary);
  margin-top: -7px;
  box-shadow: 0 2px 5px rgba(0,0,0,0.2);
  border: 2px solid #fff;
  transition: transform 0.1s, background 0.2s;
}
input[type="range"]::-webkit-slider-thumb:hover {
  transform: scale(1.15);
  background: var(--primary-hover);
}

/* Parameter Items */
.param-item {
  background: #fff;
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 16px;
  margin-bottom: 12px;
  box-shadow: var(--shadow-sm);
  transition: box-shadow 0.2s;
}
.param-item:hover { box-shadow: var(--shadow-md); border-color: var(--border-active); }
.param-head { display: flex; justify-content: space-between; margin-bottom: 4px; align-items: center; }
.param-title { font-weight: 600; font-size: 13px; color: var(--text-main); }
.param-desc { font-size: 11px; color: var(--text-dim); margin-bottom: 10px; }
.val-tag {
  font-size: 11px;
  font-family: var(--font-mono);
  background: var(--primary-light);
  color: var(--primary);
  padding: 2px 8px;
  border-radius: 6px;
  font-weight: 600;
}

/* Buttons */
.btn-primary {
  width: 100%;
  padding: 14px;
  border: none;
  border-radius: var(--radius-md);
  background: var(--primary-gradient);
  color: white;
  font-weight: 600;
  font-size: 15px;
  cursor: pointer;
  box-shadow: var(--shadow-glow);
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
}
.btn-primary:hover {
  filter: brightness(1.08);
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(79, 70, 229, 0.4);
}
.btn-primary:active { transform: translateY(0); }

/* New Ready State for Button */
.btn-primary.ready {
  background: linear-gradient(135deg, #4f46e5 0%, #7c3aed 100%);
  box-shadow: 0 4px 14px rgba(124, 58, 237, 0.4);
  animation: pulse-glow 2s infinite;
}
@keyframes pulse-glow {
  0% { box-shadow: 0 0 0 0 rgba(99, 102, 241, 0.6); }
  70% { box-shadow: 0 0 0 10px rgba(99, 102, 241, 0); }
  100% { box-shadow: 0 0 0 0 rgba(99, 102, 241, 0); }
}

.btn-sm {
  background: #fff;
  border: 1px solid var(--border-subtle);
  color: var(--text-main);
  padding: 8px 14px;
  border-radius: var(--radius-sm);
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s;
  width: 100%;
  box-shadow: var(--shadow-sm);
}
.btn-sm:hover {
  background: var(--bg-surface);
  border-color: var(--border-active);
  color: var(--primary);
  transform: translateY(-1px);
}

.btn-ghost {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 13px;
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  transition: all 0.2s;
  font-weight: 500;
}
.btn-ghost:hover { color: var(--primary); background: rgba(79, 70, 229, 0.05); }

.btn-row { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; margin-top: 12px; }

.btn-chip {
  background: #fff;
  border: 1px dashed var(--border-active);
  color: var(--text-muted);
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  font-size: 12px;
  cursor: pointer;
  transition: all 0.2s;
  box-shadow: var(--shadow-sm);
}
.btn-chip:hover {
  border-color: var(--primary);
  color: var(--primary);
  background: rgba(99, 102, 241, 0.03);
  transform: translateY(-1px);
}

/* Prim List */
.prim-card {
  display: flex;
  align-items: center;
  gap: 10px;
  background: #fff;
  border: 1px solid var(--border-subtle);
  padding: 10px;
  border-radius: var(--radius-sm);
  margin-bottom: 10px;
  box-shadow: var(--shadow-sm);
  animation: slideIn 0.2s ease-out;
}
@keyframes slideIn { from { opacity: 0; transform: translateX(-10px); } to { opacity: 1; transform: translateX(0); } }

.prim-card input[type="number"] {
  width: 52px;
  padding: 4px 6px;
  text-align: center;
}
.prim-tag {
  font-size: 11px;
  background: var(--bg-surface);
  padding: 4px 8px;
  border-radius: 6px;
  color: var(--text-muted);
  min-width: 40px;
  text-align: center;
  font-weight: 600;
  border: 1px solid var(--border-subtle);
}
.prim-x { color: var(--text-dim); font-size: 12px; }
.btn-del {
  background: none;
  border: none;
  color: var(--text-dim);
  cursor: pointer;
  padding: 6px;
  margin-left: auto;
  border-radius: 6px;
  transition: all 0.2s;
}
.btn-del:hover { color: var(--danger); background: #fef2f2; }

/* Drop Zone */
.drop-zone {
  background: #fff;
  border: 2px dashed var(--border-active);
  border-radius: var(--radius-lg);
  padding: 40px 20px;
  text-align: center;
  cursor: pointer;
  transition: all 0.3s;
  min-height: 200px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-sm);
}
.drop-zone.ready {
  border-color: var(--success);
  background: #f0fdf4;
  box-shadow: 0 0 0 4px rgba(16, 185, 129, 0.1);
}
.drop-zone.drag-over {
  border-color: var(--primary);
  background: var(--primary-light);
  transform: scale(1.02);
  box-shadow: 0 0 0 4px rgba(79, 70, 229, 0.2);
}
.drop-zone:hover {
  border-color: var(--primary);
  background: #f8fafc;
  transform: scale(1.01);
}
.drop-zone p { color: var(--text-muted); font-size: 14px; margin-bottom: 12px; }
.file-label { color: var(--primary); font-weight: 600; text-decoration: underline; text-underline-offset: 4px; }
.preview-img { max-height: 180px; max-width: 100%; border-radius: var(--radius-md); box-shadow: var(--shadow-md); margin-bottom: 12px; }

/* New Upload Ready Badge */
.upload-ready {
  margin-top: 12px;
  padding: 8px 16px;
  background: #dcfce7;
  color: #166534;
  border-radius: 20px;
  font-weight: 600;
  font-size: 13px;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  animation: popIn 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
  box-shadow: 0 2px 6px rgba(16, 185, 129, 0.2);
}
@keyframes popIn { from { transform: scale(0.9); opacity: 0; } to { transform: scale(1); opacity: 1; } }

/* Canvas Area */
.canvas-area {
  flex: 1;
  background: var(--bg-surface); /* Darker bg for contrast */
  position: relative;
  display: flex;
  flex-direction: column;
}

.canvas-wrap {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  background-image: radial-gradient(#e2e8f0 1px, transparent 1px);
  background-size: 20px 20px; /* Dot pattern */
  position: relative;
}

.canvas-wrap canvas {
  box-shadow: 0 20px 50px rgba(0,0,0,0.15);
  border: 1px solid rgba(0,0,0,0.05);
  background: #ffffff;
  border-radius: 4px;
}

.canvas-bar {
  height: 56px;
  background: #fff;
  border-top: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  padding: 0 24px;
  gap: 24px;
  font-size: 13px;
  color: var(--text-muted);
  box-shadow: 0 -2px 10px rgba(0,0,0,0.02);
  z-index: 10;
}

.canvas-bar label {
  display: flex;
  align-items: center;
  gap: 8px;
  cursor: pointer;
  user-select: none;
  font-weight: 500;
  color: var(--text-main);
  padding: 6px 10px;
  border-radius: 6px;
  transition: background 0.2s;
}
.canvas-bar label:hover { background: var(--bg-surface); }
.canvas-bar input[type="checkbox"] {
  accent-color: var(--primary);
  width: 16px;
  height: 16px;
}

/* Tooltip & Info */
.tooltip {
  position: absolute;
  background: rgba(15, 23, 42, 0.95);
  border: 1px solid rgba(255,255,255,0.1);
  backdrop-filter: blur(8px);
  color: #fff;
  padding: 10px 14px;
  border-radius: var(--radius-sm);
  font-size: 12px;
  font-family: var(--font-sans);
  box-shadow: 0 10px 25px rgba(0,0,0,0.2);
  z-index: 100;
  pointer-events: none;
  line-height: 1.6;
}
.tooltip b { color: #818cf8; }

.elem-info table {
  width: 100%;
  font-size: 13px;
  border-collapse: separate;
  border-spacing: 0 8px;
}
.elem-info td {
  padding: 4px 0;
  border-bottom: 1px solid var(--bg-surface);
}
.elem-info td:first-child { color: var(--text-muted); width: 40%; font-weight: 500; }
.elem-info td:last-child { color: var(--text-main); font-family: var(--font-mono); text-align: right; font-weight: 600; }

.empty-panel {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 160px;
  border: 2px dashed var(--border-active);
  border-radius: var(--radius-md);
  color: var(--text-dim);
  background: var(--bg-surface);
  text-align: center;
  padding: 20px;
}
.empty-panel p { color: var(--text-muted); font-weight: 600; margin-bottom: 6px; font-size: 14px; }
.empty-panel span { font-size: 12px; opacity: 0.8; }

/* Loading */
.loading-overlay {
  position: absolute;
  inset: 0;
  background: rgba(255, 255, 255, 0.8);
  backdrop-filter: blur(8px);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  z-index: 50;
}
.spinner {
  width: 50px;
  height: 50px;
  border: 4px solid #e2e8f0;
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 0.8s cubic-bezier(0.5, 0, 0.5, 1) infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* Utility */
[hidden] { display: none !important; }