:root {
  --bg: #0f1115;
  --surface: #171a21;
  --surface-2: #1f242e;
  --border: #2a303d;
  --text: #eef1f6;
  --muted: #939cad;
  --accent: #3b82f6;
  --accent-hover: #2563eb;
  --uv: #06b6d4;
  --laser: #f43f5e;
  --success: #10b981;
  --radius: 10px;
}

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

html, body {
  height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Inter, sans-serif;
  font-size: 13px;
  line-height: 1.4;
  overflow: hidden;
}

.app-shell {
  display: flex;
  flex-direction: column;
  height: 100vh;
}

/* Topbar */
.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 10px 18px;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
}

.brand-icon {
  width: 36px;
  height: 36px;
  border-radius: 9px;
  background: linear-gradient(135deg, #3b82f6, #06b6d4);
  display: grid;
  place-items: center;
  color: #fff;
}

.brand h1 {
  font-size: 15px;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.brand .subtitle {
  font-size: 11px;
  color: var(--muted);
}

.topbar-stats {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}

.stat-pill {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 4px 10px;
  display: flex;
  flex-direction: column;
}

.stat-label {
  font-size: 10px;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.stat-pill strong {
  font-size: 12px;
  font-weight: 600;
  color: var(--text);
}

/* Workspace */
.workspace {
  display: grid;
  grid-template-columns: 350px 1fr;
  flex: 1;
  min-height: 0;
}

/* Sidebar */
.sidebar {
  background: var(--surface);
  border-right: 1px solid var(--border);
  overflow-y: auto;
  padding: 12px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.panel-section {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 12px;
}

.section-header {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 10px;
}

.step-badge {
  width: 20px;
  height: 20px;
  border-radius: 6px;
  background: rgba(59, 130, 246, 0.18);
  color: #60a5fa;
  font-size: 11px;
  font-weight: 700;
  display: grid;
  place-items: center;
}

.section-header h2 {
  font-size: 13px;
  font-weight: 600;
}

/* Upload Zone */
.upload-zone {
  border: 1.5px dashed #3b4456;
  border-radius: 8px;
  padding: 14px 10px;
  text-align: center;
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s;
  background: rgba(15, 17, 21, 0.45);
}

.upload-zone:hover,
.upload-zone.dragover {
  border-color: var(--accent);
  background: rgba(59, 130, 246, 0.08);
}

.upload-content svg {
  color: var(--muted);
  margin-bottom: 4px;
}

.upload-content p {
  font-size: 12px;
  color: var(--text);
}

.upload-content p span {
  color: #60a5fa;
  text-decoration: underline;
}

.upload-content small {
  font-size: 11px;
  color: var(--muted);
}

.upload-loaded {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  text-align: left;
}

.file-name {
  font-weight: 600;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 135px;
}

.file-dims {
  font-size: 11px;
  color: var(--muted);
}

.btn-link {
  background: none;
  border: none;
  color: #60a5fa;
  cursor: pointer;
  font-size: 12px;
  font-weight: 600;
}

/* Controls */
.control-group {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

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

label {
  font-size: 12px;
  color: #cbd5e1;
}

.val-badge {
  font-size: 11px;
  font-weight: 600;
  color: #93c5fd;
  background: rgba(59, 130, 246, 0.14);
  padding: 1px 6px;
  border-radius: 4px;
}

input[type="number"],
select {
  width: 100%;
  background: var(--bg);
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: 6px;
  padding: 6px 8px;
  font-size: 12px;
  outline: none;
}

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

input[type="range"] {
  width: 100%;
  accent-color: var(--accent);
  cursor: pointer;
}

.control-row.two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
}

.seed-row {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 8px;
  align-items: end;
}

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

.checkbox-row input {
  width: 15px;
  height: 15px;
  accent-color: var(--accent);
}

.hint {
  display: block;
  font-size: 11px;
  color: var(--muted);
  margin-top: 3px;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  border: none;
  border-radius: 7px;
  padding: 8px 13px;
  font-size: 12px;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s, transform 0.05s;
}

.btn:active {
  transform: translateY(1px);
}

.btn-primary {
  background: var(--accent);
  color: #fff;
}

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

.btn-secondary {
  background: #282f3d;
  color: var(--text);
  border: 1px solid #353e50;
}

.btn-secondary:hover {
  background: #323a4b;
}

.btn-sm {
  padding: 6px 10px;
  font-size: 11.5px;
}

.btn-xs {
  padding: 4px 8px;
  font-size: 11px;
  border-radius: 5px;
  cursor: pointer;
}

.btn-full {
  width: 100%;
}

/* Download Grid */
.download-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
}

.btn-dl {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 9px 8px;
  text-align: left;
  color: var(--text);
  cursor: pointer;
  display: flex;
  flex-direction: column;
  gap: 2px;
  transition: border-color 0.15s, background 0.15s;
}

.btn-dl:hover {
  border-color: var(--accent);
  background: #141923;
}

.btn-dl strong {
  font-size: 12.5px;
  margin-top: 2px;
}

.btn-dl small {
  font-size: 10px;
  color: var(--muted);
}

.dl-tag {
  font-size: 9.5px;
  font-weight: 700;
  letter-spacing: 0.05em;
  padding: 1px 5px;
  border-radius: 4px;
  align-self: flex-start;
}

.tag-uv {
  background: rgba(6, 182, 212, 0.18);
  color: #22d3ee;
}

.tag-laser {
  background: rgba(244, 63, 94, 0.18);
  color: #fb7185;
}

/* Viewport */
.viewport-area {
  display: flex;
  flex-direction: column;
  min-width: 0;
  min-height: 0;
  background: #0b0d11;
}

.viewport-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 8px 14px;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  gap: 12px;
  flex-wrap: wrap;
}

.layer-toggles {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}

.toggle-chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 4px 9px;
  font-size: 11.5px;
  cursor: pointer;
  user-select: none;
}

.toggle-chip input {
  accent-color: var(--accent);
}

.zoom-controls {
  display: flex;
  align-items: center;
  gap: 6px;
}

.btn-icon {
  width: 26px;
  height: 26px;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: var(--surface-2);
  color: var(--text);
  font-size: 15px;
  cursor: pointer;
  display: grid;
  place-items: center;
}

.btn-icon:hover {
  background: #2b3242;
}

#zoomLabel {
  min-width: 44px;
  text-align: center;
  font-size: 12px;
  font-weight: 600;
}

.canvas-stage {
  position: relative;
  flex: 1;
  min-height: 0;
  overflow: hidden;
  background-image:
    linear-gradient(45deg, #12151c 25%, transparent 25%),
    linear-gradient(-45deg, #12151c 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, #12151c 75%),
    linear-gradient(-45deg, transparent 75%, #12151c 75%);
  background-size: 20px 20px;
  background-position: 0 0, 0 10px, 10px -10px, -10px 0;
  cursor: grab;
}

.canvas-stage:active {
  cursor: grabbing;
}

#previewCanvas {
  display: block;
  width: 100%;
  height: 100%;
}

.stage-hint {
  position: absolute;
  bottom: 10px;
  left: 50%;
  transform: translateX(-50%);
  background: rgba(15, 17, 21, 0.8);
  border: 1px solid var(--border);
  padding: 4px 10px;
  border-radius: 999px;
  font-size: 11px;
  color: var(--muted);
  pointer-events: none;
}

.status-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 6px 14px;
  background: var(--surface);
  border-top: 1px solid var(--border);
  font-size: 11.5px;
  color: var(--muted);
  gap: 12px;
}

.legend {
  display: flex;
  align-items: center;
  gap: 10px;
  white-space: nowrap;
}

.dot {
  display: inline-block;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  margin-right: 3px;
}

.dot-red { background: #ff0000; }
.dot-blue { background: #3b82f6; }
.dot-green { background: #22c55e; }

.toast {
  position: fixed;
  bottom: 42px;
  right: 20px;
  background: #1e293b;
  border: 1px solid #38bdf8;
  color: #f8fafc;
  padding: 10px 14px;
  border-radius: 8px;
  font-size: 12.5px;
  box-shadow: 0 10px 25px rgba(0,0,0,0.45);
  z-index: 999;
}

.hidden { display: none !important; }
.mt-6 { margin-top: 6px; }
.mt-8 { margin-top: 8px; }

@media (max-width: 960px) {
  html, body { overflow: auto; }
  .app-shell { height: auto; }
  .workspace { grid-template-columns: 1fr; }
  .canvas-stage { height: 60vh; }
  .topbar { flex-wrap: wrap; }
}