:root {
  --bg: #f4f6f8;
  --panel: #ffffff;
  --panel-soft: #f8fafc;
  --border: #d9e0e6;
  --border-strong: #c3ccd4;
  --text: #1f2a33;
  --muted: #64748b;
  --accent: #1a5276;
  --accent-2: #0f766e;
  --danger: #c0392b;
  --shadow: 0 2px 10px rgba(0, 0, 0, 0.045);
  --radius: 12px;
  --viewer-bg: #e9edf1;
  --focus-ring: rgba(26, 82, 118, 0.18);
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #11161c;
    --panel: #1a222b;
    --panel-soft: #141b22;
    --border: #2d3945;
    --border-strong: #3a4753;
    --text: #e6edf3;
    --muted: #9fb0bf;
    --accent: #5fa8d3;
    --accent-2: #2dd4bf;
    --danger: #ff6b6b;
    --shadow: 0 2px 12px rgba(0, 0, 0, 0.24);
    --viewer-bg: #232b33;
    --focus-ring: rgba(95, 168, 211, 0.22);
  }
}

* { box-sizing: border-box; }
html, body { height: 100%; margin: 0; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  display: flex;
  flex-direction: column;
}

button { font: inherit; cursor: pointer; }
button:disabled { opacity: 0.45; cursor: not-allowed; }

input[type="text"], input[type="number"] {
  font: inherit;
  background: var(--panel);
  color: var(--text);
  border: 1px solid var(--border-strong);
  border-radius: 8px;
  padding: 4px 8px;
  outline: none;
}
input[type="text"]:focus, input[type="number"]:focus { border-color: var(--accent); }

.app-header {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 12px 20px;
  border-bottom: 1px solid var(--border);
  background: var(--panel);
}
.app-header h1 { font-size: 1.1rem; margin: 0; white-space: nowrap; }

.dropzone {
  flex: 1;
  border: 1.5px dashed var(--border);
  border-radius: var(--radius);
  padding: 8px 14px;
  color: var(--muted);
  font-size: 0.9rem;
  cursor: pointer;
  transition: border-color 0.15s, color 0.15s;
}
.dropzone.dragover, .dropzone:hover { border-color: var(--accent); color: var(--accent); }

.file-meta { font-size: 0.85rem; color: var(--muted); white-space: nowrap; }

.empty-state {
  margin: 60px auto;
  max-width: 480px;
  text-align: center;
  color: var(--muted);
  font-size: 0.95rem;
}

.controls-bar {
  display: none;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 18px;
  padding: 10px 20px;
  border-bottom: 1px solid var(--border);
  background: var(--panel);
}

.filter-label { font-size: 0.78rem; color: var(--muted); white-space: nowrap; }

.btn-small {
  border: 1px solid var(--border);
  background: var(--panel-soft);
  color: var(--text);
  border-radius: 8px;
  padding: 5px 10px;
  font-size: 0.8rem;
}
.btn-small:hover:not(:disabled) { border-color: var(--accent); }
.btn-small.active { background: var(--accent); border-color: var(--accent); color: #fff; }
.btn-small.danger { color: var(--danger); border-color: var(--danger); }
.btn-small.danger:hover:not(:disabled) { background: color-mix(in srgb, var(--danger) 10%, var(--panel)); }

.export-buttons { margin-left: auto; display: flex; gap: 8px; }

.step-badge {
  font-size: 0.72rem; padding: 1px 6px; border-radius: 6px;
  background: var(--panel-soft); border: 1px solid var(--border); color: var(--muted);
}

.warning-banner {
  display: none;
  padding: 6px 20px;
  background: color-mix(in srgb, var(--danger) 12%, var(--panel));
  color: var(--danger);
  font-size: 0.82rem;
  border-bottom: 1px solid var(--border);
  cursor: pointer;
}
.warning-banner:hover { background: color-mix(in srgb, var(--danger) 20%, var(--panel)); }

.app-main {
  display: none;
  flex: 1;
  gap: 14px;
  padding: 14px 20px 20px;
  min-height: 0;
  grid-template-columns: minmax(360px, 42%) 1fr;
  grid-template-rows: 1fr;
  grid-template-areas: "viewer content";
}

.panel {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  display: flex;
  flex-direction: column;
  min-height: 0;
  overflow: hidden;
}

.viewer-panel { grid-area: viewer; }
.content-panel { grid-area: content; }

.panel-toolbar {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 10px;
  border-bottom: 1px solid var(--border);
  flex-wrap: wrap;
}
.toolbar-divider { width: 1px; align-self: stretch; background: var(--border); }
.panel-title { font-size: 0.8rem; font-weight: 600; color: var(--muted); }

.chips { display: flex; gap: 6px; flex-wrap: wrap; }
.chip {
  display: inline-flex; align-items: center; gap: 4px;
  background: var(--panel-soft); border: 1px solid var(--border);
  border-radius: 999px; padding: 2px 8px 2px 10px;
  font-size: 0.78rem; color: var(--accent);
}
.chip-remove { cursor: pointer; font-size: 0.95em; line-height: 1; padding: 0 2px; }
.chip-remove:hover { color: var(--danger); }

#selection-row {
  transition: opacity 0.12s ease;
}
#selection-row.is-empty { opacity: 0; pointer-events: none; }

.viewer-3d { flex: 1; min-height: 180px; position: relative; }

.viewer-legend {
  position: absolute; left: 10px; bottom: 10px; z-index: 5;
  display: flex; flex-direction: column; gap: 3px;
  padding: 6px 10px; background: var(--panel-soft);
  border: 1px solid var(--border); border-radius: 8px; box-shadow: var(--shadow);
  pointer-events: none; max-height: calc(100% - 20px); overflow-y: auto;
}
.viewer-legend:empty { display: none; }
.viewer-legend-item { display: flex; align-items: center; gap: 6px; font-size: 0.76rem; color: var(--text); white-space: nowrap; }
.viewer-legend-swatch { width: 10px; height: 10px; border-radius: 50%; border: 1px solid var(--border-strong); flex-shrink: 0; }

.atom-list-panel {
  height: 240px; min-height: 90px; max-height: 50%;
  flex-shrink: 0; display: flex; flex-direction: column;
  border-top: 1px solid var(--border); background: var(--panel-soft);
}
.atom-list-header { display: flex; align-items: center; gap: 8px; padding: 6px 8px; border-bottom: 1px solid var(--border); flex-shrink: 0; }
.atom-list-title { font-size: 0.78rem; font-weight: 600; color: var(--muted); white-space: nowrap; }
#atom-search { flex: 1; min-width: 0; padding: 3px 8px; font-size: 0.8rem; }
.atom-list-wrap { flex: 1; min-height: 0; overflow: auto; }
.atom-list-table { width: 100%; border-collapse: collapse; font-size: 0.78rem; }
.atom-list-table th {
  position: sticky; top: 0; z-index: 1; text-align: left; padding: 4px 8px;
  background: var(--panel-soft); color: var(--muted); border-bottom: 1px solid var(--border);
  font-weight: 600; white-space: nowrap;
}
.atom-list-table td { padding: 3px 8px; border-bottom: 1px solid var(--border); font-family: ui-monospace, "SF Mono", Consolas, monospace; color: var(--muted); white-space: nowrap; }
.atom-list-table tbody tr { cursor: pointer; }
.atom-list-table tbody tr:hover td { background: var(--focus-ring); color: var(--text); }
.atom-list-table tbody tr.selected td { background: var(--accent); color: #fff; }
.atom-list-table .el-cell { font-weight: 600; color: var(--text); }
.el-swatch {
  display: inline-block; width: 9px; height: 9px; border-radius: 50%;
  margin-right: 5px; border: 1px solid var(--border-strong); vertical-align: middle;
}
.atom-list-empty { padding: 10px 8px; color: var(--muted); font-size: 0.8rem; }

.toggle-switch {
  display: flex; align-items: center; gap: 7px; flex-shrink: 0;
  font-size: 0.76rem; color: var(--muted); white-space: nowrap; cursor: pointer;
  user-select: none;
}
.toggle-switch:hover { color: var(--text); }
.toggle-switch input[type="checkbox"] {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0;
}
.toggle-track {
  position: relative; display: inline-block; flex-shrink: 0;
  width: 30px; height: 17px; border-radius: 999px;
  background: var(--border-strong); border: 1px solid var(--border-strong);
  transition: background 0.15s ease, border-color 0.15s ease;
}
.toggle-thumb {
  position: absolute; top: 1px; left: 1px; width: 13px; height: 13px;
  border-radius: 50%; background: #fff; box-shadow: 0 1px 2px rgba(0,0,0,0.35);
  transition: transform 0.15s ease;
}
.toggle-switch input:checked + .toggle-track { background: var(--accent); border-color: var(--accent); }
.toggle-switch input:checked + .toggle-track .toggle-thumb { transform: translateX(13px); }
.toggle-switch input:focus-visible + .toggle-track { outline: 2px solid var(--focus-ring); outline-offset: 1px; }

.tab-bar { gap: 4px; }
.table-scroll { overflow: auto; flex: 1; }

/* --- transform pane --- */
.xform-pane { overflow: auto; flex: 1; padding: 4px 16px 20px; }
.xform-group {
  padding: 14px 0; border-bottom: 1px solid var(--border);
}
.xform-group:last-child { border-bottom: none; }
.xform-group h3 { margin: 0 0 4px; font-size: 0.92rem; }
.xform-hint { margin: 0 0 10px; font-size: 0.8rem; color: var(--muted); line-height: 1.4; }
.xform-row { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.xform-row label { display: flex; align-items: center; gap: 5px; font-size: 0.8rem; color: var(--muted); }
.xform-row input[type="number"] { width: 80px; }
.xform-selection-note { font-size: 0.78rem; color: var(--accent); margin-top: 6px; min-height: 1.1em; }

.matrix-grid {
  display: grid; grid-template-columns: repeat(3, 68px); gap: 6px; margin-bottom: 10px;
}
.matrix-grid input { width: 100%; text-align: center; }

.group-rows { display: flex; flex-direction: column; gap: 6px; margin-top: 10px; }
.group-row { display: flex; align-items: center; gap: 8px; }
.group-label {
  flex-shrink: 0; width: 20px; height: 20px; border-radius: 6px;
  display: flex; align-items: center; justify-content: center;
  font-size: 0.72rem; font-weight: 700; color: #fff;
}
.group-label-x { background: #e6483c; }
.group-label-y { background: #2fae4e; }
.group-label-z { background: #2f8fe6; }
.group-row .chips:empty::after { content: "—"; color: var(--muted); font-size: 0.8rem; }

.log-pane { overflow: auto; flex: 1; padding: 12px 16px; }
.log-output {
  margin: 0; font-family: ui-monospace, "SF Mono", Consolas, monospace;
  font-size: 0.8rem; line-height: 1.55; white-space: pre-wrap; color: var(--text);
}
.log-empty { color: var(--muted); font-size: 0.85rem; }