:root {
  --bg: #F8FAFC; --card: #FFFFFF; --border: #E2E8F0; --text: #0F172A;
  --muted: #475569; --accent: #3B82F6; --danger: #DC2626; --stage: #EEF2F7;
}
.dark {
  --bg: #0F1218; --card: #1A1F29; --border: #252E3E; --text: #F3F4F6;
  --muted: #9CA3AF; --danger: #F87171; --stage: #13171F;
}
* { box-sizing: border-box; }
html, body { height: 100%; margin: 0; }
body {
  display: flex; flex-direction: column;
  background: var(--bg); color: var(--text);
  font: 14px/1.5 Inter, system-ui, -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif;
}
[hidden] { display: none !important; }

.topbar { display: flex; align-items: center; gap: 16px; flex-wrap: wrap; padding: 10px 20px; border-bottom: 1px solid var(--border); }
.topbar h1 { margin: 0; font-size: 16px; font-weight: 600; }
.home { color: var(--muted); font-size: 13px; text-decoration: none; }
.home:hover { color: var(--accent); }
.steps { display: flex; gap: 8px; margin: 0 0 0 auto; padding: 0; list-style: none; counter-reset: s; }
.steps li { counter-increment: s; padding: 3px 10px; border: 1px solid var(--border); border-radius: 999px; color: var(--muted); font-size: 12px; }
.steps li::before { content: counter(s) " · "; }
.steps li.active { background: var(--accent); border-color: var(--accent); color: #fff; }
.icon-btn { padding: 4px 9px; }

main { flex: 1; min-height: 0; display: flex; }
.step { flex: 1; min-height: 0; display: flex; flex-direction: column; padding: 20px; }
#step1 { align-items: center; justify-content: center; }

.drop {
  width: min(640px, 100%); padding: 56px 24px; text-align: center; cursor: pointer;
  background: var(--card); border: 2px dashed var(--border); border-radius: 16px;
  transition: border-color .2s;
}
.drop:hover, .drop.over, .drop:focus-visible { border-color: var(--accent); outline: none; }
.drop.loading { opacity: .6; pointer-events: none; }
.drop-title { margin: 0 0 8px; font-size: 17px; font-weight: 600; }
.hint { margin: 4px 0; color: var(--muted); font-size: 12px; }
.error { margin: 12px 0 0; color: var(--danger); font-size: 13px; }

.work { flex: 1; min-height: 0; display: flex; gap: 16px; }
.stage-wrap { position: relative; flex: 1; min-width: 0; display: flex; }
.stage {
  display: block; flex: 1; width: 100%; height: 100%; min-width: 0;
  background: var(--stage); border: 1px solid var(--border); border-radius: 12px; touch-action: none;
}
#cropCanvas { cursor: crosshair; }
#editCanvas[data-tool="view"] { cursor: grab; }
#editCanvas[data-tool="erase"], #editCanvas[data-tool="paint"] { cursor: none; }
.busy {
  position: absolute; top: 12px; left: 50%; transform: translateX(-50%);
  padding: 4px 12px; background: var(--card); border: 1px solid var(--border); border-radius: 999px;
  color: var(--muted); font-size: 12px;
}

.panel { width: 300px; flex-shrink: 0; overflow-y: auto; padding: 14px 16px; background: var(--card); border: 1px solid var(--border); border-radius: 12px; }
.panel h2 { margin: 16px 0 8px; color: var(--muted); font-size: 12px; font-weight: 600; }
.panel h2:first-child { margin-top: 0; }
.panel > label { display: block; margin: 8px 0; font-size: 13px; }
.panel label output { float: right; color: var(--muted); font: 12px "JetBrains Mono", ui-monospace, monospace; }
input[type="range"] { width: 100%; accent-color: var(--accent); }
.check { display: flex !important; align-items: center; gap: 6px; }
.select select { float: right; }

button, select {
  padding: 6px 12px; font: inherit; font-size: 13px; color: var(--text); cursor: pointer;
  background: var(--bg); border: 1px solid var(--border); border-radius: 8px;
}
select { padding: 3px 8px; }
button:hover:not(:disabled) { border-color: var(--accent); }
button:disabled { opacity: .45; cursor: not-allowed; }
button.primary { background: var(--accent); border-color: var(--accent); color: #fff; }
.row { display: flex; flex-wrap: wrap; gap: 8px; }
.nav { display: flex; gap: 8px; margin-top: 18px; }
.nav .primary { flex: 1; }

.seg { display: flex; flex-wrap: wrap; gap: 6px; }
.seg label { position: relative; display: inline-flex; align-items: center; padding: 5px 10px; border: 1px solid var(--border); border-radius: 8px; cursor: pointer; font-size: 13px; }
.seg label:has(input:checked) { border-color: var(--accent); color: var(--accent); }
.seg input { position: absolute; opacity: 0; pointer-events: none; }

.swatches { display: flex; flex-wrap: wrap; gap: 6px; }
.swatches button, .swatches .custom { display: inline-flex; align-items: center; gap: 6px; margin: 0; padding: 5px 10px; font-size: 13px; border: 1px solid var(--border); border-radius: 8px; cursor: pointer; }
.swatches .active { border-color: var(--accent); color: var(--accent); }
.dot { display: inline-block; width: 12px; height: 12px; border: 1px solid var(--border); border-radius: 50%; }
.dot-black { background: #000; }
.dot-blue { background: #1a3a8f; }
.dot-white { background: #fff; }
.dot-orig { background: linear-gradient(135deg, #c00000 50%, #1a3a8f 50%); }
.custom input[type="color"] { width: 20px; height: 20px; padding: 0; border: none; background: none; }

@media (max-width: 760px) {
  main { display: block; }
  .step { padding: 12px; }
  .work { flex-direction: column; }
  .stage-wrap { flex: none; height: 55vh; }
  .panel { width: auto; }
}