/* ── Reset & variables ─────────────────────────────────────────────────────── */

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

:root {
  --bg:          #f5f5f5;
  --surface:     #ffffff;
  --surface-2:   #f0f0f0;
  --border:      #d8d8d8;
  --text:        #1a1a1a;
  --text-muted:  #6b7280;
  --accent:      #6366f1;
  --accent-h:    #4f46e5;
  --error:       #dc2626;
  --error-bg:    #fef2f2;
  --error-bdr:   #fecaca;
  --radius:      12px;
  --radius-sm:   8px;
  --shadow:      0 2px 8px rgba(0,0,0,.08);
  --shadow-lg:   0 8px 24px rgba(0,0,0,.12);
  --transition:  .18s ease;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg:          #111111;
    --surface:     #1e1e1e;
    --surface-2:   #2a2a2a;
    --border:      #383838;
    --text:        #f0f0f0;
    --text-muted:  #9ca3af;
    --error-bg:    #1f1515;
    --error-bdr:   #7f1d1d;
    --shadow:      0 2px 8px rgba(0,0,0,.4);
    --shadow-lg:   0 8px 24px rgba(0,0,0,.5);
  }
}

/* ── Base ──────────────────────────────────────────────────────────────────── */

html { font-size: 16px; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* ── Header ────────────────────────────────────────────────────────────────── */

.site-header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 14px 24px;
}

.header-inner {
  max-width: 960px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}

.logo {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 700;
  font-size: 1.15rem;
  color: var(--accent);
}

.tagline {
  color: var(--text-muted);
  font-size: .85rem;
}

/* ── Main layout ───────────────────────────────────────────────────────────── */

.main {
  max-width: 960px;
  margin: 0 auto;
  padding: 32px 20px 64px;
  width: 100%;
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

/* ── Upload zone ───────────────────────────────────────────────────────────── */

.upload-section { width: 100%; }

.drop-zone {
  background: var(--surface);
  border: 2px dashed var(--border);
  border-radius: var(--radius);
  padding: 56px 24px;
  text-align: center;
  cursor: pointer;
  transition: border-color var(--transition), background var(--transition);
  outline: none;
}

.drop-zone:hover,
.drop-zone:focus-visible,
.drop-zone.drag-over {
  border-color: var(--accent);
  background: color-mix(in srgb, var(--accent) 5%, var(--surface));
}

.drop-zone input[type="file"] {
  position: absolute;
  width: 1px; height: 1px;
  opacity: 0; pointer-events: none;
}

.drop-icon {
  color: var(--text-muted);
  margin-bottom: 12px;
}

.drop-primary {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 4px;
}

.drop-secondary {
  color: var(--text-muted);
  font-size: .9rem;
  margin-bottom: 8px;
}

.link-text {
  color: var(--accent);
  text-decoration: underline;
  cursor: pointer;
}

.drop-hint {
  font-size: .8rem;
  color: var(--text-muted);
}

/* ── Error banner ──────────────────────────────────────────────────────────── */

.error-banner {
  background: var(--error-bg);
  border: 1px solid var(--error-bdr);
  color: var(--error);
  border-radius: var(--radius-sm);
  padding: 12px 16px;
  font-size: .9rem;
  line-height: 1.5;
  display: none;
}

.error-banner:not(:empty) { display: block; }

/* ── Viewer ────────────────────────────────────────────────────────────────── */

.viewer {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  width: 100%;
}

@media (max-width: 600px) {
  .viewer { grid-template-columns: 1fr; }
}

.panel {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  box-shadow: var(--shadow);
}

.panel-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 14px;
  border-bottom: 1px solid var(--border);
  background: var(--surface-2);
}

.panel-label {
  font-size: .8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: .06em;
  color: var(--text-muted);
}

.link-btn {
  background: none;
  border: none;
  color: var(--accent);
  font-size: .8rem;
  cursor: pointer;
  padding: 2px 4px;
  border-radius: 4px;
  text-decoration: underline;
}

.link-btn:hover { opacity: .75; }

.panel-body {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 220px;
  position: relative;
}

.panel-img {
  display: block;
  max-width: 100%;
  max-height: 420px;
  object-fit: contain;
  border-radius: 2px;
}

/* ── Result panel states ───────────────────────────────────────────────────── */

.result-placeholder {
  color: var(--text-muted);
  font-size: .9rem;
  text-align: center;
  padding: 24px;
}

/* ── Spinner ───────────────────────────────────────────────────────────────── */

.spinner-wrap {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  padding: 24px;
}

.spinner {
  width: 40px; height: 40px;
  border: 3px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin .75s linear infinite;
}

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

.spinner-label {
  font-size: .95rem;
  font-weight: 500;
  color: var(--text);
}

.spinner-note {
  font-size: .8rem;
  color: var(--text-muted);
  text-align: center;
}

/* ── Checkerboard for transparent result ───────────────────────────────────── */

.checkerboard {
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 8px;
  background-image:
    linear-gradient(45deg, #a0a0a0 25%, transparent 25%),
    linear-gradient(-45deg, #a0a0a0 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, #a0a0a0 75%),
    linear-gradient(-45deg, transparent 75%, #a0a0a0 75%);
  background-size: 16px 16px;
  background-position: 0 0, 0 8px, 8px -8px, -8px 0px;
  background-color: #c8c8c8;
  border-radius: 2px;
}

@media (prefers-color-scheme: dark) {
  .checkerboard {
    background-image:
      linear-gradient(45deg, #333 25%, transparent 25%),
      linear-gradient(-45deg, #333 25%, transparent 25%),
      linear-gradient(45deg, transparent 75%, #333 75%),
      linear-gradient(-45deg, transparent 75%, #333 75%);
    background-color: #444;
  }
}

/* ── Buttons ───────────────────────────────────────────────────────────────── */

.btn-primary, .btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 10px 20px;
  border-radius: var(--radius-sm);
  font-size: .9rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: opacity var(--transition), transform var(--transition);
  white-space: nowrap;
}

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

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

.btn-secondary {
  background: var(--surface-2);
  color: var(--text);
  border: 1px solid var(--border);
}

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

.btn-primary:disabled, .btn-secondary:disabled {
  opacity: .5;
  cursor: not-allowed;
}

/* ── Controls panel ────────────────────────────────────────────────────────── */

.action-bar {
  display: flex;
  flex-direction: column;
  gap: 16px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  box-shadow: var(--shadow);
}

.controls-panel {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.btn-row {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  align-items: center;
  padding-top: 4px;
  border-top: 1px solid var(--border);
}

.control-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.control-label {
  font-size: .8rem;
  font-weight: 600;
  color: var(--text-muted);
  user-select: none;
}

.control-label output {
  color: var(--accent);
  font-variant-numeric: tabular-nums;
}

.control-hint {
  font-size: .75rem;
  color: var(--text-muted);
  line-height: 1.4;
}

/* ── Model select ───────────────────────────────────────────────────────────── */

.model-select {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text);
  font-size: .875rem;
  padding: 7px 10px;
  cursor: pointer;
  outline: none;
  max-width: 420px;
}

.model-select:focus { border-color: var(--accent); }

/* ── Checkbox + badge ───────────────────────────────────────────────────────── */

.checkbox-label {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  cursor: pointer;
  font-size: .875rem;
  font-weight: 600;
  user-select: none;
}

.checkbox-label input[type="checkbox"] {
  width: 15px; height: 15px;
  accent-color: var(--accent);
  cursor: pointer;
}

.badge {
  background: color-mix(in srgb, var(--accent) 15%, transparent);
  color: var(--accent);
  font-size: .7rem;
  font-weight: 700;
  padding: 2px 6px;
  border-radius: 99px;
  text-transform: uppercase;
  letter-spacing: .04em;
}

/* ── Alpha matting sub-panel ───────────────────────────────────────────────── */

.matting-params {
  display: none;
  flex-direction: column;
  gap: 12px;
  padding: 12px;
  margin-top: 4px;
  background: var(--surface-2);
  border-left: 3px solid var(--accent);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}

.matting-params.open { display: flex; }

/* ── Tolerance slider ──────────────────────────────────────────────────────── */

.tolerance-wrap {
  display: flex;
  flex-direction: column;
  gap: 4px;
  min-width: 200px;
  max-width: 280px;
  flex: 1;
}

.tolerance-label {
  font-size: .8rem;
  font-weight: 600;
  color: var(--text-muted);
  user-select: none;
}

.tolerance-label output {
  color: var(--accent);
  font-variant-numeric: tabular-nums;
}

input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 4px;
  border-radius: 2px;
  background: var(--border);
  outline: none;
  cursor: pointer;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 16px; height: 16px;
  border-radius: 50%;
  background: var(--accent);
  border: 2px solid var(--surface);
  box-shadow: 0 0 0 1px var(--accent);
  transition: background var(--transition);
}

input[type="range"]::-moz-range-thumb {
  width: 16px; height: 16px;
  border-radius: 50%;
  background: var(--accent);
  border: 2px solid var(--surface);
  box-shadow: 0 0 0 1px var(--accent);
  cursor: pointer;
}

input[type="range"]:hover::-webkit-slider-thumb { background: var(--accent-h); }
input[type="range"]:hover::-moz-range-thumb     { background: var(--accent-h); }

.tolerance-hints {
  display: flex;
  justify-content: space-between;
  font-size: .72rem;
  color: var(--text-muted);
}

/* ── State-driven visibility ───────────────────────────────────────────────── */

/* initial: only upload zone visible */
#app[data-state="initial"] .viewer,
#app[data-state="initial"] .action-bar { display: none; }

/* selected: viewer + controls; spinner/result hidden; show remove-btn only */
#app[data-state="selected"] #upload-section { display: none; }
#app[data-state="selected"] #result-placeholder { display: flex; align-items: center; justify-content: center; }
#app[data-state="selected"] #spinner-wrap,
#app[data-state="selected"] #result-checkerboard { display: none; }
#app[data-state="selected"] #remove-btn { display: inline-flex; }
#app[data-state="selected"] #download-btn,
#app[data-state="selected"] #try-another-btn { display: none; }

/* processing: hide upload + action bar entirely; show spinner in result panel */
#app[data-state="processing"] #upload-section,
#app[data-state="processing"] .action-bar { display: none; }
#app[data-state="processing"] #result-placeholder,
#app[data-state="processing"] #result-checkerboard { display: none; }
#app[data-state="processing"] #spinner-wrap { display: flex; }
#app[data-state="processing"] #change-btn { display: none; }

/* done: show before/after + download; hide upload + remove-btn */
#app[data-state="done"] #upload-section { display: none; }
#app[data-state="done"] #result-placeholder,
#app[data-state="done"] #spinner-wrap { display: none; }
#app[data-state="done"] #result-checkerboard { display: flex; }
#app[data-state="done"] #remove-btn { display: none; }
#app[data-state="done"] #download-btn,
#app[data-state="done"] #try-another-btn { display: inline-flex; }