:root {
  --bg-app: #ececef;
  --bg-preview: #e4e4e9;
  --surface: #ffffff;
  --surface-muted: #f7f7f8;
  --border: #e1e1e6;
  --border-strong: #d4d4da;
  --text: #18181b;
  --text-muted: #71717a;
  --text-soft: #a1a1aa;
  --shadow-sm: 0 1px 2px rgba(15, 23, 42, 0.06);
  --shadow-md: 0 12px 40px rgba(15, 23, 42, 0.08), 0 2px 8px rgba(15, 23, 42, 0.04);
  --radius: 12px;
  --radius-sm: 8px;
  --font: "Inter", system-ui, -apple-system, sans-serif;
  --focus-ring: #52525b;
  /* ~80% black: neutral surround so perceived colors aren’t biased */
  --canvas-neutral-bg: #333333;
}

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

html {
  height: 100%;
}

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

body {
  height: 100%;
  overflow: hidden;
}

/* Invisible hook so Firefox exposes clipboard image data on global paste (see index paste-bridge) */
.paste-bridge {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: 0;
  padding: 0;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
  opacity: 0;
  pointer-events: none;
  z-index: -1;
}

.app {
  display: grid;
  grid-template-columns: minmax(300px, 380px) 1fr;
  grid-template-rows: 1fr;
  height: 100vh;
  max-height: 100dvh;
  min-height: 0;
  gap: 0;
  overflow: hidden;
}

@media (max-width: 840px) {
  .app {
    grid-template-columns: 1fr;
    grid-template-rows: minmax(0, min(48vh, 420px)) minmax(0, 1fr);
  }
}

.panel {
  padding: 1.35rem 1.25rem 1.5rem;
  background: var(--surface);
  border-right: 1px solid var(--border);
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  gap: 1.35rem;
  min-height: 0;
  height: 100%;
  overflow-x: hidden;
  /* Always reserve vertical scrollbar space to avoid width jump (see scrollbar-gutter). */
  overflow-y: scroll;
  scrollbar-gutter: stable;
  overscroll-behavior: contain;
  -webkit-overflow-scrolling: touch;
}

@media (max-width: 840px) {
  .panel {
    border-right: none;
    border-bottom: 1px solid var(--border);
    box-shadow: none;
    max-height: 100%;
  }
}

.panel__header {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.panel__brand {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.panel__badge {
  align-self: flex-start;
  font-size: 0.6875rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-muted);
  padding: 0.2rem 0.5rem;
  border-radius: 999px;
  background: var(--surface-muted);
  border: 1px solid var(--border);
}

.panel__header h1 {
  margin: 0;
  font-size: 1.25rem;
  font-weight: 600;
  letter-spacing: -0.03em;
  color: var(--text);
}

.panel__lede {
  margin: 0;
  font-size: 0.8125rem;
  color: var(--text-muted);
  line-height: 1.5;
}

.control-section {
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
}

.control-section__title {
  margin: 0;
  font-size: 0.6875rem;
  font-weight: 600;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  color: var(--text-soft);
}

.control-section__subtitle {
  margin: 0.35rem 0 0;
  font-size: 0.6875rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-muted);
}

.control-section--layer2 {
  padding-top: 0.35rem;
  border-top: 1px solid var(--border);
}

.layer2-enable {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--text);
  cursor: pointer;
  user-select: none;
}

.layer2-enable input {
  width: 1rem;
  height: 1rem;
  accent-color: var(--focus-ring);
}

.layer2-hint {
  margin: 0;
}

/* Author `display: flex` must not beat the `hidden` attribute (which only sets display:none in UA). */
.layer2-expanded[hidden] {
  display: none !important;
}

.layer2-expanded:not([hidden]) {
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
  margin-top: 0.35rem;
}

.grid-link-fieldset {
  border: none;
  margin: 0;
  padding: 0;
  min-width: 0;
}

.grid-link-legend {
  font-size: 0.6875rem;
  font-weight: 600;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  color: var(--text-soft);
  margin-bottom: 0.45rem;
  padding: 0;
}

.grid-link-options {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.grid-link-option {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--text);
  cursor: pointer;
  user-select: none;
}

.grid-link-option input {
  width: 1rem;
  height: 1rem;
  flex-shrink: 0;
  accent-color: var(--focus-ring);
  cursor: pointer;
}

.grid-link-option--disabled {
  opacity: 0.48;
  cursor: not-allowed;
}

.grid-link-option--disabled input {
  cursor: not-allowed;
}

.slider-field--appearance-disabled .slider-field__label {
  opacity: 0.55;
  color: var(--text-muted);
}

.slider-field--appearance-disabled .input-num,
.slider-field--appearance-disabled .range {
  opacity: 0.55;
  cursor: not-allowed;
}

.slider-field--appearance-disabled .range {
  pointer-events: none;
}

.slider-field--appearance-disabled .input-num {
  pointer-events: none;
}

.slider-field--appearance-disabled .range::-webkit-slider-thumb {
  cursor: not-allowed;
}

.slider-field--appearance-disabled .range::-moz-range-thumb {
  cursor: not-allowed;
}

.upload-zone {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.25rem;
  padding: 1rem 0.75rem;
  border: 1px dashed var(--border-strong);
  border-radius: var(--radius);
  background: var(--surface-muted);
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s;
}

.upload-zone--has-image {
  flex-direction: row;
  align-items: center;
  justify-content: flex-start;
  gap: 0.75rem;
  padding: 0.65rem 0.75rem;
  text-align: left;
}

.upload-zone__empty {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.25rem;
}

.upload-zone__loaded:not([hidden]) {
  display: flex;
  flex-direction: row;
  align-items: center;
  gap: 0.75rem;
  flex: 1;
  min-width: 0;
}

.upload-zone__thumb-shell {
  flex-shrink: 0;
  width: 48px;
  height: 48px;
  border-radius: 6px;
  overflow: hidden;
  background: var(--surface);
  border: 1px solid var(--border);
  box-shadow: 0 1px 2px rgba(15, 23, 42, 0.06);
}

.upload-zone__thumb {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.upload-zone__text {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 0.2rem;
  min-width: 0;
}

.upload-zone__dims {
  display: block;
  font-size: 0.75rem;
  line-height: 1.45;
  color: var(--text-muted);
}

.upload-zone:hover {
  border-color: var(--text-soft);
  background: #f3f3f5;
}

.upload-zone__input {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.upload-zone__label {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text);
}

.upload-zone__hint {
  font-size: 0.75rem;
  color: var(--text-muted);
}

.hint {
  margin: 0;
  font-size: 0.75rem;
  color: var(--text-muted);
}

.blend-readout {
  font-size: 0.8125rem;
  font-weight: 500;
  font-variant-numeric: tabular-nums;
  color: var(--text-muted);
  min-width: 2.75rem;
  text-align: right;
}

.slider-field {
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
}

.slider-field__row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
}

.slider-field__label {
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--text);
}

.field-label {
  display: block;
  font-size: 0.6875rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-soft);
  margin-bottom: 0.35rem;
}

.field {
  margin: 0;
}

.input-num {
  width: 4rem;
  min-width: 0;
  padding: 0.35rem 0.45rem;
  font: inherit;
  font-size: 0.8125rem;
  font-weight: 500;
  font-variant-numeric: tabular-nums;
  color: var(--text);
  text-align: right;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--surface);
}

.input-num--grow {
  flex: 1;
  width: auto;
  text-align: left;
}

.input-num:focus {
  outline: 2px solid var(--focus-ring);
  outline-offset: 1px;
}

.range {
  width: 100%;
  height: 6px;
  margin: 0;
  padding: 0;
  border-radius: 999px;
  background: linear-gradient(to right, var(--border-strong), var(--border));
  appearance: none;
  cursor: pointer;
}

.range::-webkit-slider-thumb {
  appearance: none;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--surface);
  border: 1px solid var(--border-strong);
  box-shadow: 0 1px 3px rgba(15, 23, 42, 0.12);
}

.range::-moz-range-thumb {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--surface);
  border: 1px solid var(--border-strong);
  box-shadow: 0 1px 3px rgba(15, 23, 42, 0.12);
}

.range::-moz-range-track {
  height: 6px;
  border-radius: 999px;
  background: var(--border);
}

.range:focus-visible {
  outline: 2px solid var(--focus-ring);
  outline-offset: 4px;
}

.seed-row {
  display: flex;
  gap: 0.5rem;
  align-items: stretch;
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: auto;
}

.btn {
  font: inherit;
  font-size: 0.8125rem;
  font-weight: 500;
  padding: 0.5rem 0.9rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s, color 0.15s, box-shadow 0.15s;
}

.btn:hover:not(:disabled) {
  border-color: var(--border-strong);
  background: var(--surface-muted);
}

.btn:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

.btn--primary {
  background: #3f3f46;
  border-color: #3f3f46;
  color: #fafafa;
}

.btn--primary:hover:not(:disabled) {
  background: #52525b;
  border-color: #52525b;
}

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

.btn--ghost {
  flex-shrink: 0;
  white-space: nowrap;
  background: var(--surface-muted);
}

.preview {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1.25rem;
  min-height: 0;
  height: 100%;
  overflow: hidden;
  background: var(--bg-preview);
  background-image: radial-gradient(rgba(120, 113, 139, 0.09) 1px, transparent 1px);
  background-size: 14px 14px;
}

.preview__frame {
  width: 100%;
  max-width: min(100%, calc(100vw - 2rem));
  max-height: 100%;
  min-height: 0;
  display: flex;
  align-items: center;
  justify-content: center;
}

.preview__sketch {
  width: 100%;
  max-height: 100%;
  min-height: 0;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* `[hidden]` alone loses to `.preview-empty { display: flex }` (same specificity, author wins). */
.preview-empty[hidden] {
  display: none !important;
}

.preview-empty:not([hidden]) {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.35rem;
  min-height: 180px;
  min-width: min(100%, 320px);
  max-width: 100%;
  padding: 2rem 1.5rem;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  box-shadow: var(--shadow-md);
  background: var(--surface);
  text-align: center;
  pointer-events: none;
}

.preview-empty__title {
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--text);
}

.preview-empty__hint {
  font-size: 0.8125rem;
  color: var(--text-muted);
  line-height: 1.45;
  max-width: 16rem;
}

.preview__sketch canvas {
  display: block;
  max-width: 100%;
  height: auto;
  border-radius: 0;
  border: 1px solid var(--border);
  box-shadow: var(--shadow-md);
  background: var(--canvas-neutral-bg);
}

.preview__sketch canvas.preview__canvas--idle {
  display: none !important;
}

.preview[data-drag-active="true"] {
  outline: 2px dashed var(--focus-ring);
  outline-offset: -6px;
}