:root{
  --bg: #ffffff;
  --panel: #f7f7f7;
  --muted: #6b7280;
  --text: #0f1724;
  --accent: #1fb6ff;
  --accent-2: #7c3aed;
  --success: #16a34a;
  --danger: #ef4444;
  --border: #e6e9ee;
  --nav-bg: #e6f7ff;
  --nav-border: #d6eefb;
}

*{margin:0;padding:0;box-sizing:border-box}

body{font-family:Inter, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;background:var(--bg);color:var(--text)}

.container{max-width:1200px;margin:0 auto;padding:20px}

.header, header{background:var(--panel);padding:18px 0;margin-bottom:18px;border-bottom:1px solid var(--border)}
.header h1, header h1{font-weight:700;font-size:20px;padding:0 20px;color:var(--text)}

/*navbar as light blue banner*/
nav{display:flex;gap:6px;align-items:center;padding:12px 18px;margin-bottom:18px;background:var(--nav-bg);border-bottom:1px solid var(--nav-border)}
nav a{color:var(--text);text-decoration:none;padding:8px 12px;border-radius:6px;transition:all .12s ease;font-weight:600}
nav a:hover{background:rgba(31,182,255,0.08);color:var(--text)}
/*primary link style inside nav for actions*/
nav a.btn-nav{background:transparent;border:1px solid transparent}
nav a.btn-primary-nav{background:var(--accent);color:#fff;border-color:var(--accent)}

.btn{display:inline-block;padding:8px 12px;border-radius:6px;border:1px solid var(--border);font-weight:600;cursor:pointer;background:transparent;color:var(--text)}
.btn-primary{background:var(--accent);color:#ffffff;border-color:var(--accent)}
.btn-primary:hover{opacity:.95}
.btn-success{background:var(--success);color:#fff;border-color:var(--success)}
.btn-danger{background:var(--danger);color:#fff;border-color:var(--danger)}
.btn-secondary{background:transparent;color:var(--muted);border:1px solid var(--border)}

.form-group {
  margin-bottom: 20px;
}

label{display:block;margin-bottom:6px;color:var(--muted);font-weight:600}
input[type="text"],input[type="email"],input[type="password"],input[type="number"],textarea,select{width:100%;padding:10px;border-radius:6px;border:1px solid var(--border);background:var(--panel);color:var(--text)}
input:focus,textarea:focus,select:focus{outline:none;box-shadow:0 6px 18px rgba(31,182,255,0.08);border-color:var(--accent)}

textarea {
  resize: vertical;
  min-height: 100px;
}

.alert{padding:10px;margin-bottom:12px;border-radius:6px;display:none}
.alert.show{display:block}
.alert-error{background:#fff5f5;color:var(--danger);border:1px solid rgba(239,68,68,0.08)}
.alert-success{background:#f6fffa;color:var(--success);border:1px solid rgba(16,185,129,0.06)}
.alert-info{background:#f0f9ff;color:var(--accent);border:1px solid rgba(31,182,255,0.08)}

.card{background:var(--panel);border:1px solid var(--border);border-radius:8px;padding:18px;margin-bottom:18px}
.card-header{padding-bottom:10px;margin-bottom:12px}
.card-header h2{margin:0;font-size:18px;color:var(--text)}
.text-muted{color:var(--muted)}
.automata-grid{grid-template-columns:repeat(auto-fill,minmax(280px,1fr))}
.automata-card{display:flex;flex-direction:column;gap:12px}
.automata-card-header{display:flex;justify-content:space-between;align-items:flex-start;gap:12px;margin-bottom:0;padding-bottom:0}
.automata-card-header h3{font-size:17px;margin-bottom:4px}
.automata-card-header p{margin:0;font-size:14px;line-height:1.4}
.automata-meta{display:flex;flex-direction:column;gap:6px;color:var(--muted);font-size:14px}
.action-row{display:flex;flex-wrap:wrap;gap:8px;margin-top:auto}

table {
  width: 100%;
  border-collapse: collapse;
  background-color: white;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.table thead{background:transparent;color:var(--muted)}

table th {
  padding: 12px;
  text-align: left;
  font-weight: 600;
}

table td {
  padding: 12px;
  border-bottom: 1px solid #ddd;
}

table tbody tr:hover {
  background-color: #f9f9f9;
}

.badge {
  display: inline-block;
  padding: 5px 10px;
  border-radius: 3px;
  font-size: 12px;
  font-weight: 600;
  margin-right: 5px;
}

.badge-primary{background:var(--accent);color:#fff}
.badge-success{background:var(--success);color:#fff}
.badge-danger{background:var(--danger);color:#fff}

.list-group {
  list-style: none;
  padding: 0;
}

.list-group-item {
  padding: 10px;
  border-bottom: 1px solid #ddd;
  background-color: white;
}

.list-group-item:last-child {
  border-bottom: none;
}

.list-group-item:hover {
  background-color: #f9f9f9;
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 20px;
}

.result {
  padding: 20px;
  border-radius: 4px;
  margin-top: 20px;
  text-align: center;
  font-size: 18px;
  font-weight: bold;
}

.result.success {
  background-color: #d4edda;
  color: #155724;
  border: 2px solid #27ae60;
}

.result.danger {
  background-color: #f8d7da;
  color: #721c24;
  border: 2px solid #e74c3c;
}

.loading{text-align:center;padding:28px;font-size:15px;color:var(--muted)}

.graph-container{width:100%;height:440px;border-radius:8px;background:var(--panel);border:1px solid var(--border)}

.graph-legend {
  margin-top: 10px;
  display: flex;
  gap: 16px;
  align-items: center;
}

.legend-item {
  display: flex;
  align-items: center;
  gap: 8px;
  color: #333;
}

.legend-dot {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  display: inline-block;
  border: 2px solid #2c3e50;
}

.legend-dot.accept{background:var(--success);border-color:var(--success)}
.legend-dot.initial{background:var(--accent-2);border-color:var(--accent-2)}
.legend-dot.regular{background:var(--accent);border-color:var(--accent)}
.legend-dot.current{background:#ffd27a;border-color:#f59e0b}

.animation-controls {
  display: flex;
  gap: 10px;
  align-items: center;
  flex-wrap: wrap;
  margin-top: 10px;
}

.animation-controls .btn {
  flex: 0 1 auto;
}

.step-indicator {
  color: #7f8c8d;
  font-weight: 600;
  white-space: nowrap;
}

table tbody tr.highlight {
  background-color: #ffeaa7 !important;
  font-weight: bold;
}

.graph-editor-container{width:100%;aspect-ratio:1/1;height:auto;min-height:480px;border-radius:8px;background:var(--panel);border:1px solid var(--border);margin:12px 0;position:relative}
.graph-editor-container canvas{width:100%!important;height:100%!important;display:block}

.graph-editor-canvas{position:absolute;inset:0}
.graph-editor-toolbar{position:absolute;top:10px;right:10px;z-index:20;display:flex;gap:8px}
.graph-editor-reset{box-shadow:0 2px 8px rgba(15,23,36,0.08)}

#automataEditor {
  width: 100%;
  height: 100%;
}

.editor-instructions{background:var(--panel);border-left:4px solid var(--accent);padding:12px;margin:12px 0;border-radius:6px}
.editor-instructions p{margin:0 0 8px 0;color:var(--muted)}
.editor-instructions ul{margin:0;padding-left:18px;color:var(--muted)}

.editor-instructions li {
  margin: 5px 0;
}

.empty-state {
  text-align: center;
  padding: 40px;
  color: #7f8c8d;
}

.empty-state h3 {
  margin-bottom: 10px;
}

/* Responsive */
@media (max-width: 768px) {
  .grid {
    grid-template-columns: 1fr;
  }

  table {
    font-size: 12px;
  }

  table th,
  table td {
    padding: 8px;
  }

  .btn {
    padding: 8px 12px;
    font-size: 12px;
  }
}