:root {
  --bg: #f3f4f6;
  --panel: #ffffff;
  --ink: #111827;
  --muted: #6b7280;
  --line: #d1d5db;
  --accent: #0f766e;
  --accent-soft: #ccfbf1;
  --box: #d97706;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
  background: radial-gradient(circle at 10% 0%, #ffffff 0%, #eef2f7 38%, #e7ebf2 100%);
  color: var(--ink);
  font-family: "Manrope", sans-serif;
}

.app-shell {
  max-width: 1520px;
  margin: 0 auto;
  min-height: 100vh;
  padding: 16px;
  display: grid;
  grid-template-rows: auto 1fr;
  gap: 12px;
}

.control-strip {
  display: grid;
  grid-template-columns: 220px 280px 1fr;
  gap: 10px;
  align-items: start;
}

.control-group,
.settings-panel {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 10px;
}

.control-group label,
.panel-header label {
  display: block;
  font-size: 12px;
  color: var(--muted);
  margin-bottom: 6px;
  font-weight: 600;
  letter-spacing: 0.02em;
}

select,
input[type="number"] {
  width: 100%;
  padding: 9px 10px;
  border-radius: 8px;
  border: 1px solid var(--line);
  background: #fff;
  color: var(--ink);
  font-size: 14px;
}

.settings-panel summary {
  cursor: pointer;
  font-size: 13px;
  color: var(--muted);
  font-weight: 700;
  list-style: none;
}

.settings-panel summary::-webkit-details-marker {
  display: none;
}

.settings-grid {
  margin-top: 8px;
  display: grid;
  grid-template-columns: repeat(4, minmax(140px, 1fr));
  gap: 8px;
}

.settings-grid label {
  font-size: 12px;
  color: var(--muted);
  display: grid;
  gap: 6px;
}

.viewer-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
  min-height: 0;
}

.panel {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 12px;
  display: grid;
  grid-template-rows: auto 1fr;
  overflow: hidden;
}

.panel-header {
  padding: 10px;
  border-bottom: 1px solid var(--line);
}

.stage {
  position: relative;
  min-height: 300px;
  background: #dbe2ea;
  display: grid;
  place-items: center;
  overflow: hidden;
}

.layer {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
}

.layer.base {
  object-fit: contain;
  background: #edf2f7;
  z-index: 1;
}

.layer.mask {
  object-fit: contain;
  mix-blend-mode: multiply;
  pointer-events: none;
  z-index: 2;
}

.layer.reveal {
  object-fit: contain;
  pointer-events: none;
  display: none;
  z-index: 4;
}

.layer.boxes {
  pointer-events: auto;
  cursor: crosshair;
  z-index: 3;
}

@media (max-width: 1200px) {
  .control-strip {
    grid-template-columns: 1fr 1fr;
  }

  .settings-panel {
    grid-column: 1 / -1;
  }

  .settings-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 860px) {
  .viewer-grid {
    grid-template-columns: 1fr;
  }

  .app-shell {
    min-height: auto;
  }
}