.center {
  display: block;
  margin-left: auto;
  margin-right: auto;
}
  
.p {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    border-color: black;
    border-style: solid;
    background-color: lightgreen;
}

.g {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    border-color: black;
    border-style: solid;
    background-color: green;
}

.r {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    border-color: black;
    border-style: solid;
    background-color: red;
}

.on {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    border-color: black;
    border-style: solid;
    background-color: yellow;
}

.off {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    border-color: black;
    border-style: solid;
    background-color: lightslategray;
}

.c {
  width: 20px;
  height: 20px;
  border-radius: 50%;
  border-color: black;
  border-style: solid;
  background-color: yellow;
  display: inline-block;
  margin: 0 5px;
}

.c1 {
  animation: blink 3s infinite;
}

.c2 {
  animation: blink 3s infinite 1s;
}

.c3 {
  animation: blink 3s infinite 2s;
}

.c4 {
  animation: blink 1s infinite ;
}

@keyframes blink {
  0%, 33% {
    opacity: 1;
  }
  34%, 100% {
    opacity: 0;
  }
}

.container {
  display: flex;  /* Usamos flexbox para alinear los círculos horizontalmente */
  gap: 20px;  /* Espacio entre los círculos */
}

.circle{
  width: 20px;
  height: 20px;
  border-radius: 50%;
  border-color: black;
  border-style: solid;
  background-color:  #444;
  animation: lightUp 4s infinite;
}

/* Delay específico para coordinar los pares */
.circle:nth-child(1) {
  animation-delay: 0s;
}

.circle:nth-child(2) {
  animation-delay: 1s;
}

.circle:nth-child(3) {
  animation-delay: 2s;
}

.circle:nth-child(4) {
  animation-delay: 3s;
}

/* Keyframes para encender los círculos */
@keyframes lightUp {
  0%, 25% {
    background-color: yellow; /* #00ff00; /* Encendido */
  }
  26%, 50% {
    background-color: yellow; /* #00ff00; /* Encendido (superposición con el siguiente círculo) */
  }
  51%, 100% {
    background-color: #444; /* Apagado */
  }
}

/* Center header menu (Material tabs) */
.md-tabs__list {
  justify-content: center;
}
.md-tabs__item {
  flex: 0 0 auto; /* avoid stretching items */
}