body {
  margin: 0;
  padding: 0;
  color: white;
  background-color: black;
}

h1 {
  height: 5rem;
  margin: 0;
  line-height: 5rem;
  text-align: center;
  font-size: 4rem;
}

.container {
  margin-top: 5rem;
  height: 18rem;
  width: auto;
  /* margin-left: -1%; */
  display: flex;
  justify-content: center;
}

#hour,
#min,
#sec {
  width: auto;
  text-align: center;
  line-height: 18rem;
  height: 18rem;
  font-size: 14rem;
}

.dot {
  height: 17rem;
  font-size: 14rem;
}

.btns {
  text-align: center;
  height: 5rem;
  line-height: 5rem;
}

.btns button {
  height: 4.5rem;
  border: none;
  outline: none;
  width: 4.5rem;
  text-align: center;
  font-size: 1.25rem;
  border-radius: 50%;
}

#start-stop-btn {
  margin-right: 1rem;
  background-color: greenyellow;
}
#start-stop-btn:hover {
  background-color: rgba(173, 255, 47, 0.7);
}
#start-stop-btn:active {
  border: 2px solid grey;
}

#reset-btn {
  margin-left: 1rem;
  background-color: skyblue;
}
#reset-btn:hover {
  margin-left: 1rem;
  background-color: rgba(135, 206, 235, 0.7);
}
#reset-btn:active {
  border: 2px solid grey;
}

@media (max-width: 790px) {
  #hour,
  #min,
  #sec {
    font-size: 9rem;
  }

  .dot {
    line-height: 17rem;
    font-size: 7rem;
  }
}

@media (max-width: 500px) {
  #hour,
  #min,
  #sec {
    height: 9rem;
    font-size: 5rem;
  }

  .container {
    height: 15rem;
    margin-top: 0;
  }

  .dot {
    height: 8rem;
    line-height: 17rem;
    font-size: 5rem;
  }

  h1 {
    margin-top: 0.5rem;
    line-height: 2rem;
    font-size: 2rem;
  }
}