:root {
  --bg: #f6f8fb;
  --card: #ffffff;
  --border: #d9e0ea;
  --text: #17212b;
  --muted: #5b6777;
  --primary: #0d6efd;
  --primary-dark: #084db3;
  --success: #1f9d55;
  --danger: #dc3545;
  --warn: #d97706;
  --highlight: #ffb020;
}

* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: Arial, Helvetica, sans-serif;
  background: var(--bg);
  color: var(--text);
}

.container {
  max-width: 1400px;
  margin: 24px auto;
  padding: 0 18px 30px;
}

h1 {
  margin: 0 0 14px;
  font-size: 2.1rem;
  color: #0b4d9b;
}

.intro {
  font-size: 1rem;
  color: var(--muted);
  margin: 0 0 18px;
  line-height: 1.45;
}

.panel,
.canvas-wrap {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 14px;
  box-shadow: 0 8px 24px rgba(16, 24, 40, 0.06);
}

.panel {
  padding: 16px;
}

.row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 12px;
}

input {
  flex: 1 1 420px;
  min-width: 240px;
  padding: 12px 14px;
  font-size: 1rem;
  border: 1px solid #c9d3e0;
  border-radius: 10px;
  outline: none;
}

input:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(13, 110, 253, 0.12);
}

button {
  padding: 12px 16px;
  border: none;
  border-radius: 10px;
  background: var(--primary);
  color: white;
  font-size: 1rem;
  cursor: pointer;
  transition: 0.18s ease;
}

button:hover:not(:disabled) {
  background: var(--primary-dark);
}

button:disabled {
  cursor: not-allowed;
  opacity: 0.5;
}

.meta-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 10px;
  margin: 12px 0;
  font-size: 0.98rem;
}

.label {
  font-weight: 700;
}

.step-description {
  margin-top: 8px;
  padding: 12px 14px;
  border-radius: 10px;
  background: #f3f7ff;
  border: 1px solid #d8e5ff;
  font-weight: 700;
}

.legend {
  display: flex;
  flex-wrap: wrap;
  gap: 18px;
  margin: 14px 4px;
  font-size: 0.95rem;
  color: var(--muted);
}

.dot {
  display: inline-block;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  margin-right: 6px;
  vertical-align: middle;
}
.dot.start { background: var(--success); }
.dot.accept { background: var(--danger); }
.dot.normal { background: var(--primary); }
.dot.highlight { background: var(--highlight); }

.canvas-wrap {
  padding: 10px;
  min-height: 720px;
}

#graphSvg {
  width: 100%;
  height: 700px;
  display: block;
  background: linear-gradient(180deg, #ffffff 0%, #fbfcff 100%);
  border-radius: 12px;
}

.state-label {
  font-size: 18px;
  fill: white;
  text-anchor: middle;
  dominant-baseline: middle;
  font-weight: 700;
}

.edge-label {
  font-size: 15px;
  fill: #1f2937;
  font-weight: 700;
}

.small-muted {
  color: var(--muted);
}

.result-accepted { color: var(--success); font-weight: 800; }
.result-rejected { color: var(--danger); font-weight: 800; }
.result-info { color: var(--warn); font-weight: 800; }

@media (max-width: 768px) {
  h1 { font-size: 1.7rem; }
  button { width: 100%; }
  input { flex-basis: 100%; }
  #graphSvg { height: 620px; }
  .canvas-wrap { min-height: 640px; }
}

.guide {
  margin: 18px 0;
  padding: 16px;
  background: #f4f7fb;
  border: 1px solid #dbe4f0;
  border-radius: 10px;
}

.guide h3 {
  margin: 0 0 10px 0;
  color: #0d4d92;
}

.guide ul {
  margin: 0 0 14px 18px;
}

.examples {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.ex-btn {
  padding: 8px 12px;
  border: none;
  border-radius: 6px;
  background: #198754;
  color: white;
  cursor: pointer;
  font-size: 14px;
}

.ex-btn:hover {
  background: #157347;
}