body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0;
  background: #1c1c1c;
  color: #f5f5f5;
}

header {
  text-align: center;
  padding: 20px;
  background: #333;
}

h1 {
  margin: 0;
  font-size: 2rem;
}

.selector {
  margin: 20px;
  text-align: center;
}

select {
  padding: 10px;
  font-size: 1rem;
  border-radius: 6px;
  border: none;
}

.tools {
  display: flex;
  justify-content: space-around;
  flex-wrap: wrap;
  padding: 20px;
}

.group {
  flex: 1;
  min-width: 220px;
  margin: 10px;
}

.group h2 {
  text-align: center;
  margin-bottom: 10px;
}

.tool {
  padding: 10px;
  margin: 5px 0;
  border-radius: 8px;
  background: #2c2c2c;
  cursor: pointer;
  text-align: center;
}

.tool.selected {
  border: 2px solid #4E61D3;
  background: #3a3a3a;
}

/* Aplica el borde izquierdo según el color */
.tool.amarilla { border-left: 6px solid #FFD700; }
.tool.azul     { border-left: 6px solid #1E90FF; }
.tool.roja     { border-left: 6px solid #FF4500; }