:root {
  --bg: #121317;
  --panel: #1a1c22;
  --panel-elevated: #20232a;
  --border: #2b2e36;
  --border-subtle: #23262d;
  --text: #f2f2f5;
  --text-secondary: #b4b5bf;
  --muted: #71727d;
  --accent: #e08a4a;
  --accent-hover: #ec9958;
  --accent-soft: rgba(224, 138, 74, 0.16);
  --danger: #e0625a;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 18px;
  --shadow-lg: 0 24px 70px rgba(0, 0, 0, 0.5);
  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

.app {
  display: flex;
  height: 100vh;
}

.panel {
  width: 300px;
  flex-shrink: 0;
  background: var(--panel);
  border-right: 1px solid var(--border);
  padding: 28px 22px;
  overflow-y: auto;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 28px;
}

.logo-mark {
  flex-shrink: 0;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(224, 138, 74, 0.35);
}

.panel h1 {
  font-size: 16px;
  margin: 0;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.subtitle {
  margin: 2px 0 0;
  color: var(--muted);
  font-size: 12.5px;
}

.group {
  background: var(--panel-elevated);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 16px 16px 18px;
  margin-bottom: 16px;
}

.group h2 {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
  margin: 0 0 14px;
  font-weight: 600;
}

label {
  display: block;
  font-size: 13px;
  color: var(--text-secondary);
}

.label-row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  margin-bottom: 10px;
}

.label-row > span:first-child {
  color: var(--text);
  font-weight: 500;
}

.value-readout {
  color: var(--accent);
  font-weight: 600;
  font-variant-numeric: tabular-nums;
}

input[type="range"] {
  width: 100%;
  height: 4px;
  margin: 4px 0;
  border-radius: 2px;
  appearance: none;
  -webkit-appearance: none;
  background: linear-gradient(
    to right,
    var(--accent) 0%,
    var(--accent) var(--pct, 25%),
    var(--border) var(--pct, 25%),
    var(--border) 100%
  );
  outline: none;
  cursor: pointer;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 16px;
  height: 16px;
  margin-top: -6px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.5);
  transition: transform 0.12s ease, box-shadow 0.12s ease;
}

input[type="range"]::-webkit-slider-thumb:hover {
  transform: scale(1.15);
}

input[type="range"]:active::-webkit-slider-thumb {
  transform: scale(1.05);
  box-shadow: 0 0 0 6px var(--accent-soft);
}

input[type="range"]::-moz-range-track {
  height: 4px;
  border-radius: 2px;
  background: var(--border);
}

input[type="range"]::-moz-range-progress {
  height: 4px;
  border-radius: 2px;
  background: var(--accent);
}

input[type="range"]::-moz-range-thumb {
  width: 16px;
  height: 16px;
  border: none;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 1px 4px rgba(0, 0, 0, 0.5);
  cursor: pointer;
}

input[type="range"]:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 4px;
}

.actions {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 6px;
}

button {
  width: 100%;
  padding: 11px 14px;
  border: none;
  border-radius: var(--radius-sm);
  background: var(--accent);
  color: #171310;
  font-family: inherit;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.2);
  transition: background 0.12s ease, transform 0.08s ease, box-shadow 0.12s ease;
}

button:hover:not(:disabled) {
  background: var(--accent-hover);
  box-shadow: 0 4px 14px rgba(224, 138, 74, 0.3);
}

button:active:not(:disabled) {
  transform: translateY(1px);
}

button:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

button:disabled {
  opacity: 0.35;
  cursor: not-allowed;
  box-shadow: none;
}

button.secondary {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text-secondary);
  box-shadow: none;
}

button.secondary:hover:not(:disabled) {
  border-color: var(--muted);
  background: var(--panel-elevated);
  color: var(--text);
  box-shadow: none;
}

.status {
  font-size: 12px;
  color: var(--muted);
  margin-top: 14px;
  line-height: 1.5;
  word-break: break-word;
}

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

.stage {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 32px;
  overflow: auto;
  background:
    radial-gradient(circle at 25% 15%, rgba(224, 138, 74, 0.05), transparent 45%),
    var(--bg);
}

.drop-zone {
  width: 100%;
  max-width: 520px;
  aspect-ratio: 4 / 3;
  border: 2px dashed var(--border);
  border-radius: var(--radius-lg);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 10px;
  cursor: pointer;
  color: var(--muted);
  transition: border-color 0.15s, color 0.15s, background 0.15s;
}

.drop-zone:hover, .drop-zone.dragover {
  border-color: var(--accent);
  color: var(--text);
  background: var(--accent-soft);
}

.drop-icon {
  opacity: 0.7;
}

.drop-zone p {
  margin: 0;
  font-size: 14px;
}

.drop-zone .hint {
  font-size: 12.5px;
  color: var(--muted);
}

canvas#view {
  max-width: 100%;
  max-height: 100%;
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-lg);
  outline: 2px dashed transparent;
  outline-offset: -2px;
  transition: outline-color 0.15s, opacity 0.15s;
}

/* Feedback for dragging a replacement image over an already-loaded photo. */
.stage.dragover canvas#view {
  outline-color: var(--accent);
  opacity: 0.7;
}

.hidden { display: none !important; }