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

body {
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  background: linear-gradient(135deg, #1f1f1f, #3a3a3a);
  color: #fff;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
}

.container {
  background: #2d2d2d;
  padding: 30px;
  border-radius: 15px;
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.4);
  text-align: center;
  width: 100%;
  max-width: 500px;
}

h1 {
  margin-bottom: 20px;
  font-size: 2rem;
  color: #61dafb;
}

.input-group {
  display: flex;
  gap: 10px;
  margin-bottom: 20px;
  flex-wrap: wrap;
  justify-content: center;
}

input[type="datetime-local"] {
  padding: 10px;
  border-radius: 10px;
  border: none;
  font-size: 16px;
  width: 60%;
  max-width: 250px;
}

button {
  background-color: #61dafb;
  color: #000;
  border: none;
  border-radius: 10px;
  padding: 10px 20px;
  font-size: 16px;
  cursor: pointer;
  transition: 0.3s ease;
}

button:hover {
  background-color: #21a1f1;
}

.countdown {
  display: flex;
  justify-content: center;
  gap: 15px;
  margin-top: 20px;
  flex-wrap: wrap;
}

.time-block {
  background: #444;
  border-radius: 12px;
  padding: 20px;
  min-width: 70px;
  text-align: center;
  box-shadow: 0 5px 15px rgba(0,0,0,0.2);
  transition: transform 0.3s;
}

.time-block:hover {
  transform: scale(1.05);
}

.time-block span {
  font-size: 2rem;
  display: block;
  color: #61dafb;
}

.time-block small {
  font-size: 0.9rem;
  color: #ccc;
}

#message {
  margin-top: 20px;
  font-size: 1.2rem;
  color: #f39c12;
}

/* 📱 Mobile responsiveness */
@media screen and (max-width: 480px) {
  .input-group {
    flex-direction: column;
    align-items: center;
  }

  input[type="datetime-local"] {
    width: 100%;
  }

  .countdown {
    gap: 10px;
  }

  .time-block {
    padding: 15px;
  }

  .time-block span {
    font-size: 1.5rem;
  }
}