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

:root {
  --bg: #0f1117;
  --surface: #1a1d27;
  --surface-hover: #22252f;
  --border: #2a2d3a;
  --text: #e4e4e7;
  --text-muted: #71717a;
  --primary: #3b82f6;
  --primary-hover: #2563eb;
  --success: #22c55e;
  --danger: #ef4444;
  --warning: #f59e0b;
  --radius: 8px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  display: flex;
  justify-content: center;
  padding: 2rem 1rem;
}

.container {
  width: 100%;
  max-width: 640px;
}

header {
  text-align: center;
  margin-bottom: 2rem;
}

h1 {
  font-size: 1.5rem;
  font-weight: 600;
  margin-bottom: 0.25rem;
}

.subtitle {
  color: var(--text-muted);
  font-size: 0.875rem;
}

.about-link {
  display: inline-block;
  margin-top: 0.5rem;
  color: var(--primary);
  text-decoration: none;
  font-size: 0.8rem;
}

.about-link:hover {
  text-decoration: underline;
}

/* Drop Zone */
.drop-zone {
  border: 2px dashed var(--border);
  border-radius: var(--radius);
  padding: 3rem 2rem;
  text-align: center;
  cursor: pointer;
  transition: border-color 0.2s, background 0.2s;
}

.drop-zone:hover,
.drop-zone.drag-over {
  border-color: var(--primary);
  background: rgba(59, 130, 246, 0.05);
}

.upload-icon {
  color: var(--text-muted);
  margin-bottom: 1rem;
}

.drop-zone-content p {
  color: var(--text-muted);
  margin-bottom: 0.75rem;
}

.drop-zone-or {
  display: block;
  color: var(--text-muted);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.75rem;
}

.file-input-label {
  display: inline-block;
  padding: 0.5rem 1.25rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 0.875rem;
  color: var(--text);
  cursor: pointer;
  transition: background 0.2s;
}

.file-input-label:hover {
  background: var(--surface-hover);
}

/* File Info */
.file-info {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
}

.file-info-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1rem;
}

.file-info-header h2 {
  font-size: 1rem;
  font-weight: 500;
  word-break: break-all;
}

.btn-clear {
  background: none;
  border: none;
  color: var(--text-muted);
  font-size: 1.5rem;
  cursor: pointer;
  padding: 0 0.25rem;
  line-height: 1;
}

.btn-clear:hover {
  color: var(--danger);
}

/* Stats */
.file-stats {
  display: flex;
  gap: 1rem;
  margin-bottom: 1.25rem;
}

.stat {
  flex: 1;
  background: var(--bg);
  border-radius: var(--radius);
  padding: 0.75rem;
  text-align: center;
}

.stat-label {
  display: block;
  font-size: 0.7rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.25rem;
}

.stat-value {
  font-size: 0.9rem;
  font-weight: 600;
}

/* Detected Info */
.detected-info {
  margin-bottom: 1.25rem;
  padding: 0.75rem;
  background: rgba(59, 130, 246, 0.06);
  border: 1px solid rgba(59, 130, 246, 0.15);
  border-radius: var(--radius);
}

.detected-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0.5rem;
}

.detected-item {
  text-align: center;
}

.detected-label {
  display: block;
  font-size: 0.65rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  margin-bottom: 0.15rem;
}

.detected-value {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--primary);
}

/* Options */
.options {
  margin-bottom: 1.25rem;
}

.options h3 {
  font-size: 0.875rem;
  font-weight: 500;
  margin-bottom: 0.75rem;
}

/* Stepover Info */
.stepover-info {
  display: flex;
  gap: 1.5rem;
  padding: 0.6rem 0.75rem;
  margin-bottom: 0.75rem;
  background: rgba(245, 158, 11, 0.08);
  border: 1px solid rgba(245, 158, 11, 0.2);
  border-radius: var(--radius);
  font-size: 0.8rem;
}

.stepover-detected,
.stepover-axis {
  color: var(--text-muted);
}

.stepover-info strong {
  color: var(--warning);
}

.section-heading {
  margin-top: 1rem;
  padding-top: 0.75rem;
  border-top: 1px solid var(--border);
}

.option-row {
  display: flex;
  gap: 0.75rem;
}

.option-row .option-group {
  flex: 1;
}

.option-group {
  margin-bottom: 0.75rem;
}

.option-group > label {
  display: block;
  font-size: 0.75rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.35rem;
}

.option-hint {
  font-size: 0.7rem;
  color: var(--text-muted);
  margin-top: 0.25rem;
  line-height: 1.4;
}

/* Selects */
.option-group select {
  width: 100%;
  padding: 0.55rem 0.75rem;
  background: var(--bg);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 0.85rem;
  font-family: inherit;
  appearance: none;
  -webkit-appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%2371717a' d='M2 4l4 4 4-4'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 0.75rem center;
  cursor: pointer;
  transition: border-color 0.2s;
}

.option-group select:hover {
  border-color: var(--primary);
}

.option-group select:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 2px rgba(59, 130, 246, 0.15);
}

.option-group select optgroup {
  color: var(--text-muted);
  font-style: normal;
  font-weight: 600;
  font-size: 0.8rem;
}

.option-group select option {
  color: var(--text);
  background: var(--bg);
  padding: 0.25rem;
}

/* Sliders */
.slider-row {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.slider-row input[type="range"] {
  flex: 1;
  height: 4px;
  -webkit-appearance: none;
  appearance: none;
  background: var(--border);
  border-radius: 2px;
  outline: none;
}

.slider-row input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--primary);
  cursor: pointer;
  border: 2px solid var(--bg);
}

.slider-row input[type="range"]::-moz-range-thumb {
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--primary);
  cursor: pointer;
  border: 2px solid var(--bg);
}

.slider-value {
  font-size: 0.8rem;
  font-weight: 600;
  min-width: 80px;
  text-align: right;
  white-space: nowrap;
}

/* Number inputs */
.number-input {
  width: 100%;
  padding: 0.55rem 0.75rem;
  background: var(--bg);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 0.85rem;
  font-family: inherit;
  transition: border-color 0.2s;
}

.number-input:hover {
  border-color: var(--primary);
}

.number-input:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 2px rgba(59, 130, 246, 0.15);
}

/* Checkboxes */
.checkbox-label {
  display: flex !important;
  align-items: center;
  gap: 0.5rem;
  cursor: pointer;
  text-transform: none !important;
  letter-spacing: normal !important;
  font-size: 0.85rem !important;
  color: var(--text) !important;
}

.checkbox-label input[type="checkbox"] {
  width: 16px;
  height: 16px;
  accent-color: var(--primary);
  cursor: pointer;
  flex-shrink: 0;
}

/* Buttons */
.actions {
  display: flex;
  gap: 0.75rem;
}

.btn {
  flex: 1;
  padding: 0.7rem 1.25rem;
  border: none;
  border-radius: var(--radius);
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  transition: background 0.2s, opacity 0.2s;
}

.btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

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

.btn-primary:hover:not(:disabled) {
  background: var(--primary-hover);
}

.btn-secondary {
  background: var(--surface-hover);
  color: var(--text);
  border: 1px solid var(--border);
}

.btn-secondary:hover {
  background: var(--border);
}

/* Result */
.result {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
}

.result h3 {
  font-size: 1rem;
  font-weight: 500;
  margin-bottom: 1rem;
  color: var(--success);
}

/* Detail Stats */
.detail-stats {
  margin-bottom: 1.25rem;
  padding: 0.75rem;
  background: var(--bg);
  border-radius: var(--radius);
}

.detail-row {
  display: flex;
  justify-content: space-between;
  padding: 0.35rem 0;
  font-size: 0.8rem;
}

.detail-row span:first-child {
  color: var(--text-muted);
}

.detail-row span:last-child {
  font-weight: 600;
}

/* Presets bar */
.presets-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem;
  padding: 0.6rem 0.75rem;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  margin-bottom: 1rem;
}

.presets-save,
.presets-load {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  flex-wrap: wrap;
}

.presets-save {
  flex: 1 1 auto;
  min-width: 180px;
}

.presets-load {
  flex: 2 1 auto;
  min-width: 200px;
}

.preset-name-input {
  flex: 1 1 0;
  min-width: 0;
  padding: 0.3rem 0.6rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 4px;
  color: var(--text);
  font-size: 0.8rem;
}

.preset-name-input:focus {
  outline: none;
  border-color: var(--primary);
}

.preset-select {
  flex: 1 1 0;
  min-width: 0;
  padding: 0.3rem 0.5rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 4px;
  color: var(--text);
  font-size: 0.8rem;
}

.btn-sm {
  padding: 0.3rem 0.7rem;
  font-size: 0.78rem;
  border: 1px solid var(--border);
  border-radius: 4px;
  background: var(--surface);
  color: var(--text);
  cursor: pointer;
  white-space: nowrap;
  transition: background 0.15s, border-color 0.15s;
}

.btn-sm:hover {
  background: var(--border);
}

.btn-preset-save {
  background: var(--primary);
  border-color: var(--primary);
  color: #fff;
}

.btn-preset-save:hover {
  background: var(--primary-hover);
  border-color: var(--primary-hover);
}

.btn-preset-delete {
  color: var(--danger);
  border-color: var(--danger);
  padding: 0.3rem 0.55rem;
}

.btn-preset-delete:hover {
  background: var(--danger);
  color: #fff;
}

/* Drop zone format hint */
.drop-zone-formats {
  font-size: 0.7rem;
  color: var(--text-muted);
  margin-top: -0.4rem;
  margin-bottom: 0.75rem;
  opacity: 0.7;
}

/* STL Settings Panel */
.stl-model-summary {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 0.15rem;
  font-weight: 400;
}

.stl-section-heading {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
  border-top: 1px solid var(--border);
  padding-top: 0.75rem;
  margin-top: 0.5rem;
  margin-bottom: 0.75rem;
}

.stl-model-stats {
  flex-wrap: wrap;
  margin-bottom: 0.5rem;
}

.stl-layer-count {
  color: var(--primary) !important;
  font-weight: 500;
}

/* STL Converting Notice */
.stl-converting {
  text-align: center;
  padding: 2.5rem 1rem;
  color: var(--text-muted);
  font-size: 0.95rem;
}

.stl-converting-inner {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
}

.stl-spinner {
  display: inline-block;
  width: 18px;
  height: 18px;
  border: 2px solid var(--border);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: stl-spin 0.8s linear infinite;
  flex-shrink: 0;
}

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

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

/* Footer */
footer {
  text-align: center;
  margin-top: 2rem;
}

footer p {
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* Responsive */
@media (max-width: 480px) {
  .option-row {
    flex-direction: column;
    gap: 0;
  }

  .file-stats {
    flex-wrap: wrap;
  }

  .detected-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}