:root {
  --bg: #f9fafb;
  --panel: #ffffff;
  --border: #d0d7de;
  --text: #0f172a;
  --muted: #475569;
  --accent: #2563eb;
  --shadow: 0 8px 24px rgba(0, 0, 0, 0.06);
  --radius: 10px;
  --spacing: 14px;
  --code: #0b1120;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: "Segoe UI", system-ui, -apple-system, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
}
header {
  padding: 18px 22px;
  background: #0f172a;
  color: #e2e8f0;
  box-shadow: var(--shadow);
  position: sticky;
  top: 0;
  z-index: 10;
}
header h1 {
  margin: 0;
  font-size: 20px;
  letter-spacing: 0.4px;
}
main {
  padding: 18px 22px;
  display: grid;
  grid-template-columns: 1.15fr 1fr;
  gap: 16px;
}
section {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: var(--spacing);
}
h2 {
  margin: 0 0 8px 0;
  font-size: 17px;
}
.subtext { color: var(--muted); font-size: 13px; margin-bottom: 8px; }
textarea {
  width: 100%;
  min-height: 240px;
  padding: 10px;
  border-radius: 8px;
  border: 1px solid var(--border);
  font-family: "SFMono-Regular", Menlo, Consolas, monospace;
  font-size: 14px;
  background: #f8fafc;
  color: var(--code);
  resize: vertical;
}
#preview {
  min-height: 320px;
  background: #f8fafc;
  border: 1px dashed var(--border);
  border-radius: 8px;
  padding: 10px;
  overflow: auto;
}
.preview-section #preview { margin-bottom: 12px; }
.preview-wrapper { position: relative; }
.preview-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 8px;
}
.sim-overlay {
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 8px 10px;
  box-shadow: var(--shadow);
  max-width: 360px;
}
.sim-controls {
  display: flex;
  gap: 6px;
  align-items: center;
  flex-wrap: wrap;
  margin-bottom: 4px;
}
.sim-controls button {
  padding: 6px 10px;
  font-size: 13px;
}
.sim-step {
  font-size: 13px;
  color: var(--text);
  line-height: 1.4;
}
.sim-meta {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  align-items: center;
}
.CodeMirror .sim-line-highlight {
  background: #e5e7eb;
}
.CodeMirror-gutters {
  background: #f8fafc;
}
.CodeMirror-gutter.drag-gutter {
  width: 18px;
}
.drag-handle {
  cursor: grab;
  color: #94a3b8;
  font-size: 12px;
  line-height: 1;
  padding-left: 2px;
  user-select: none;
}
.drag-handle:hover {
  color: #2563eb;
}
.sim-highlight path,
.sim-highlight line {
  stroke: #f97316 !important;
  stroke-width: 2.5 !important;
}
.sim-highlight text {
  fill: #f97316 !important;
  font-weight: 700;
}
.controls {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-top: 10px;
  flex-wrap: wrap;
  justify-content: space-between;
}
.selector {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}
.selector label {
  font-size: 13px;
  color: var(--muted);
}
.selector select {
  appearance: none;
  padding: 9px 36px 9px 12px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: linear-gradient(180deg, #fff 0%, #f8fafc 100%);
  color: var(--text);
  font-size: 14px;
  box-shadow: var(--shadow);
  min-width: 240px;
  background-image: linear-gradient(45deg, transparent 50%, #475569 50%), linear-gradient(135deg, #475569 50%, transparent 50%);
  background-position: calc(100% - 16px) calc(50% - 3px), calc(100% - 12px) calc(50% - 3px);
  background-size: 6px 6px, 6px 6px;
  background-repeat: no-repeat;
}
.selector select:focus {
  outline: 2px solid #dbeafe;
  border-color: #93c5fd;
}
.control-right { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
button {
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 8px;
  padding: 9px 14px;
  font-size: 14px;
  cursor: pointer;
  box-shadow: 0 6px 18px rgba(37, 99, 235, 0.25);
}
button.secondary {
  background: #e2e8f0;
  color: #0f172a;
  box-shadow: none;
}
.status {
  font-size: 13px;
  color: var(--muted);
}
.error { color: #b91c1c; }
.panel-muted {
  background: #f8fafc;
  border-radius: 10px;
  border: 1px dashed var(--border);
  padding: 10px;
  margin-top: 12px;
}
.form-row {
  display: flex;
  gap: 8px;
  margin-bottom: 8px;
  flex-wrap: wrap;
}
.form-row input, .form-row select {
  padding: 8px 10px;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: #fff;
  font-size: 13px;
}
.builder-placeholder button[disabled],
.builder-placeholder input[disabled],
.builder-placeholder select[disabled] {
  opacity: 0.6;
  cursor: not-allowed;
}
.comment-block {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-top: 10px;
}
.comment-block label { font-size: 13px; color: var(--muted); }
.comment-area {
  min-height: 120px;
  background: #ffffff;
  font-family: "Segoe UI", system-ui, -apple-system, sans-serif;
  font-size: 14px;
  color: var(--text);
}
.cm-critical-word { color: #b91c1c; font-weight: 700; }
.cm-callout-word { color: #2563eb; font-weight: 600; }
.inline-badge {
  display: inline-block;
  padding: 2px 6px;
  border-radius: 6px;
  background: #e0f2fe;
  color: #075985;
  font-size: 12px;
  margin-left: 6px;
}
footer {
  padding: 10px 22px 22px 22px;
  color: var(--muted);
  font-size: 13px;
}
@media (max-width: 1024px) {
  main { grid-template-columns: 1fr; }
}