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

:root {
  --bg: #0f0f1a;
  --surface: rgba(20, 20, 40, 0.92);
  --border: rgba(100, 120, 255, 0.25);
  --accent: #6c7fff;
  --accent-hover: #8a94ff;
  --text: #e0e0f0;
  --text-muted: #7a7a9a;
  --danger: #ff6b6b;
  --radius: 10px;
  --font: system-ui, -apple-system, sans-serif;
}

html, body {
  height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  overflow: hidden;
}

/* ── Utility ── */
.hidden { display: none !important; }

/* ── Drop Zone ── */
#dropzone {
  position: fixed;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg);
  transition: background 0.2s;
  z-index: 10;
}

#dropzone.drag-over {
  background: rgba(108, 127, 255, 0.08);
}

#dropzone.drag-over .dropzone-inner {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(108, 127, 255, 0.2);
}

.dropzone-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
  padding: 60px 80px;
  border: 2px dashed var(--border);
  border-radius: 20px;
  text-align: center;
  transition: border-color 0.2s, box-shadow 0.2s;
  max-width: 480px;
  width: 90%;
}

.dropzone-icon {
  width: 72px;
  height: 72px;
  color: var(--accent);
  opacity: 0.8;
}

.dropzone-icon svg {
  width: 100%;
  height: 100%;
}

h1 {
  font-size: 1.8rem;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.subtitle {
  color: var(--text-muted);
  font-size: 0.95rem;
}

.formats {
  color: var(--text-muted);
  font-size: 0.8rem;
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  justify-content: center;
}

.formats span {
  background: rgba(108, 127, 255, 0.12);
  border: 1px solid var(--border);
  padding: 2px 8px;
  border-radius: 4px;
  font-family: monospace;
  font-size: 0.82rem;
  color: var(--accent);
}

/* ── Viewer ── */
#viewer {
  position: fixed;
  inset: 0;
}

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

/* ── Controls Panel ── */
#controls-panel {
  position: fixed;
  top: 16px;
  right: 16px;
  width: 240px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  display: flex;
  flex-direction: column;
  gap: 10px;
  z-index: 20;
}

.panel-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 8px;
}

#file-info {
  display: flex;
  flex-direction: column;
  gap: 4px;
  min-width: 0;
}

#file-name {
  font-size: 0.85rem;
  font-weight: 600;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 170px;
}

#format-badge, #fold-format-badge, #gen-badge {
  font-size: 0.7rem;
  font-family: monospace;
  background: rgba(108, 127, 255, 0.15);
  border: 1px solid var(--border);
  color: var(--accent);
  padding: 1px 6px;
  border-radius: 4px;
  align-self: flex-start;
}

#mesh-stats {
  font-size: 0.75rem;
  color: var(--text-muted);
  line-height: 1.6;
}

.panel-divider {
  height: 1px;
  background: var(--border);
}

.panel-actions {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.panel-select {
  display: flex;
  flex-direction: column;
  gap: 5px;
  font-size: 0.72rem;
  color: var(--text-muted);
}

.panel-select select {
  width: 100%;
  padding: 7px 8px;
  font: inherit;
  font-size: 0.78rem;
  color: var(--text);
  background: var(--surface-2, rgba(255, 255, 255, 0.04));
  border: 1px solid var(--border);
  border-radius: 6px;
  cursor: pointer;
}

.panel-select select:hover {
  border-color: var(--accent);
}

.panel-select select:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}

/* The popup list is drawn by the OS, so force readable colours there too. */
.panel-select select option,
.panel-select select optgroup {
  background: #16161f;
  color: #e8e8f0;
}

/* Section heading, matching .panel-select / .panel-slider label typography. */
.panel-label {
  font-size: 0.72rem;
  color: var(--text-muted);
}

/* Three equal numeric fields on one row — the X/Y/Z orientation entry. */
.panel-triple {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 6px;
}

.panel-triple label {
  display: flex;
  align-items: center;
  gap: 4px;
  font-size: 0.72rem;
  color: var(--text-muted);
}

.panel-triple input {
  width: 100%;
  min-width: 0;
  padding: 5px 4px;
  font: inherit;
  font-size: 0.74rem;
  color: var(--text);
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--border);
  border-radius: 6px;
}

.panel-triple input:hover { border-color: var(--accent); }
.panel-triple input:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}

.panel-slider {
  display: flex;
  flex-direction: column;
  gap: 5px;
  font-size: 0.72rem;
  color: var(--text-muted);
}

.panel-slider input[type="range"] {
  accent-color: var(--accent);
  cursor: pointer;
  height: 4px;
  width: 100%;
}

.panel-help {
  display: flex;
  flex-direction: column;
  gap: 2px;
  font-size: 0.7rem;
  color: var(--text-muted);
  border-top: 1px solid var(--border);
  padding-top: 8px;
}

/* ── Buttons ── */
.btn-primary {
  background: var(--accent);
  color: #fff;
  border: none;
  padding: 10px 28px;
  border-radius: 8px;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s, transform 0.1s;
}

.btn-primary:hover { background: var(--accent-hover); }
.btn-primary:active { transform: scale(0.97); }

.btn-secondary {
  background: rgba(108, 127, 255, 0.1);
  color: var(--text);
  border: 1px solid var(--border);
  padding: 7px 12px;
  border-radius: 6px;
  font-size: 0.8rem;
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s;
  text-align: left;
}

.btn-secondary:hover {
  background: rgba(108, 127, 255, 0.2);
  border-color: var(--accent);
}

.btn-secondary.active {
  background: rgba(108, 127, 255, 0.25);
  border-color: var(--accent);
  color: var(--accent);
}

.btn-icon {
  background: none;
  border: none;
  color: var(--text-muted);
  font-size: 1rem;
  cursor: pointer;
  padding: 2px 4px;
  border-radius: 4px;
  line-height: 1;
  transition: color 0.15s, background 0.15s;
  flex-shrink: 0;
}

.btn-icon:hover {
  color: var(--danger);
  background: rgba(255, 107, 107, 0.1);
}

/* ── Loading ── */
#loading {
  position: fixed;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 16px;
  background: rgba(15, 15, 26, 0.75);
  backdrop-filter: blur(4px);
  z-index: 30;
  font-size: 0.9rem;
  color: var(--text-muted);
}

.spinner {
  width: 40px;
  height: 40px;
  border: 3px solid rgba(108, 127, 255, 0.2);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* ── Error Toast ── */
#error-toast {
  position: fixed;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%);
  background: rgba(255, 107, 107, 0.15);
  border: 1px solid rgba(255, 107, 107, 0.4);
  color: #ffaaaa;
  padding: 10px 20px;
  border-radius: 8px;
  font-size: 0.85rem;
  z-index: 50;
  backdrop-filter: blur(8px);
  animation: fadeIn 0.2s ease;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateX(-50%) translateY(8px); }
  to   { opacity: 1; transform: translateX(-50%) translateY(0); }
}

/* ── Fold section (inside dropzone) ── */
.fold-section {
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
}

.fold-divider {
  width: 100%;
  height: 1px;
  background: var(--border);
}

.fold-label {
  color: var(--text-muted);
  font-size: 0.85rem;
}

.fold-hint {
  color: var(--text-muted);
  font-size: 0.75rem;
  text-align: center;
  min-height: 1em;
}

.fold-hint.error { color: var(--danger); }

.fold-input-row {
  display: flex;
  gap: 8px;
  width: 100%;
}

/* The select and the input are alternatives -- only one is ever visible -- so
   they share a look; whichever one you get should not feel like a different
   control. */
#fold-folder-input,
#fold-folder-select {
  flex: 1;
  background: rgba(108, 127, 255, 0.07);
  border: 1px solid var(--border);
  color: var(--text);
  border-radius: 6px;
  padding: 8px 12px;
  font-size: 0.85rem;
  font-family: var(--font);
  outline: none;
  transition: border-color 0.15s;
}

#fold-folder-input:focus,
#fold-folder-select:focus {
  border-color: var(--accent);
}

/* The native menu is drawn by the OS, so its options need a colour of their own
   or a dark-theme dropdown shows dark text on a dark background. */
#fold-folder-select option {
  background: var(--bg);
  color: var(--text);
}

#fold-folder-input::placeholder {
  color: var(--text-muted);
}

/* ── Fold viewer ── */
#fold-viewer {
  position: fixed;
  inset: 0;
}

#fold-canvas {
  display: block;
  width: 100%;
  height: 100%;
}

#fold-controls-panel {
  position: fixed;
  top: 16px;
  right: 16px;
  width: 240px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  display: flex;
  flex-direction: column;
  gap: 10px;
  z-index: 20;
  /* With the environment section this panel exceeds a laptop viewport. Wheel events
     over the panel never reach OrbitControls (bound to the canvas, a lower sibling),
     so scrolling here cannot fight the camera zoom. */
  max-height: calc(100vh - 32px);
  overflow-y: auto;
  overscroll-behavior: contain;
  scrollbar-width: thin;
  scrollbar-color: var(--border) transparent;
}

/* The OS scrollbar is light-on-light against --surface. Literal rgba rather than a
   new --surface-2: that name is referenced by .panel-select but never defined, so
   declaring it would silently restyle the existing LED-effect dropdown. */
#fold-controls-panel::-webkit-scrollbar { width: 8px; }
#fold-controls-panel::-webkit-scrollbar-track { background: transparent; }
#fold-controls-panel::-webkit-scrollbar-thumb {
  background: rgba(100, 120, 255, 0.35);
  border-radius: 4px;
}
#fold-controls-panel::-webkit-scrollbar-thumb:hover { background: var(--accent); }

#fold-file-info {
  display: flex;
  flex-direction: column;
  gap: 4px;
  min-width: 0;
}

#fold-folder-name {
  font-size: 0.85rem;
  font-weight: 600;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 170px;
}

#fold-stats {
  font-size: 0.75rem;
  color: var(--text-muted);
  line-height: 1.6;
}

/* ── Animation bar ── */
#fold-anim-bar {
  position: fixed;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  align-items: center;
  gap: 12px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 10px 16px;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  z-index: 20;
  min-width: 360px;
}

#fold-slider {
  flex: 1;
  accent-color: var(--accent);
  cursor: pointer;
  height: 4px;
}

#fold-percent {
  font-size: 0.8rem;
  color: var(--text-muted);
  min-width: 36px;
  text-align: right;
  font-variant-numeric: tabular-nums;
}

/* ── Fold loading overlay ── */
#fold-loading {
  position: fixed;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 16px;
  background: rgba(15, 15, 26, 0.75);
  backdrop-filter: blur(4px);
  z-index: 30;
  font-size: 0.9rem;
  color: var(--text-muted);
}

/* ── PCB generation panel ── */
/* Top-left, mirroring #controls-panel, so it never overlaps the right-hand
   panels of either viewer. Above #loading (30), below #error-toast (50). */
#gen-panel {
  position: fixed;
  top: 16px;
  left: 16px;
  width: 288px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  display: flex;
  flex-direction: column;
  gap: 10px;
  z-index: 40;
}

#gen-panel.state-warn  { border-color: rgba(255, 190, 80, 0.45); }
#gen-panel.state-error { border-color: rgba(255, 107, 107, 0.4); }

#gen-info {
  display: flex;
  flex-direction: column;
  gap: 4px;
  min-width: 0;
}

#gen-title {
  font-size: 0.85rem;
  font-weight: 600;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 210px;
}

#gen-row {
  display: flex;
  align-items: center;
  gap: 8px;
}

.spinner-sm {
  width: 16px;
  height: 16px;
  border-width: 2px;
  flex-shrink: 0;
}

#gen-panel.done .spinner-sm,
#gen-panel.state-error .spinner-sm { display: none; }

#gen-stage {
  font-size: 0.75rem;
  color: var(--text-muted);
  line-height: 1.6;
}

#gen-bar {
  height: 4px;
  background: rgba(108, 127, 255, 0.15);
  border-radius: 2px;
  overflow: hidden;
}

#gen-bar-fill {
  height: 100%;
  width: 0;
  background: var(--accent);
  transition: width 0.3s ease;
}

#gen-panel.state-error #gen-bar-fill { background: var(--danger); }

#gen-log {
  font-family: monospace;
  font-size: 0.68rem;
  line-height: 1.5;
  color: var(--text-muted);
  white-space: pre-wrap;
  word-break: break-word;
  max-height: 120px;
  overflow-y: auto;
}

#gen-log:empty { display: none; }