body {
  background-color: #1e1e2e;
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
  color: #cdd6f4;
  font-family: Arial, sans-serif;
  text-align: center;
  margin: 0;
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  transition: background-image 0.5s ease-in-out;
}

/* Dynamic Background Images */
body.env-rain {
  background-image: url('https://images.unsplash.com/photo-1519692933481-e162a57d6721?q=80&w=1600&auto=format&fit=crop');
}

body.env-cafe {
  background-image: url('https://images.unsplash.com/photo-1501339847302-ac426a4a7cbb?q=80&w=1600&auto=format&fit=crop');
}

body.env-forest {
  background-image: url('https://images.unsplash.com/photo-1448375240586-882707db888b?q=80&w=1600&auto=format&fit=crop');
}

body.env-ocean {
  background-image: url('https://images.unsplash.com/photo-1507525428034-b723cf961d3e?q=80&w=1600&auto=format&fit=crop');
}

.container {
  background: rgba(0, 0, 0, 0.65);
  backdrop-filter: blur(8px);
  padding: 30px;
  border-radius: 16px;
  box-shadow: 0 8px 32px rgba(0,0,0,0.5);
  max-width: 400px;
  width: 90%;
}

#timer {
  font-size: 64px;
  font-weight: bold;
  margin: 20px 0;
}

button {
  background-color: #89b4fa;
  border: none;
  color: #11111b;
  padding: 10px 16px;
  font-size: 14px;
  font-weight: bold;
  border-radius: 8px;
  cursor: pointer;
  margin: 4px;
}

button:hover { background-color: #b4befe; }
button.active { background-color: #a6e3a1; }

.task-box {
  margin-top: 25px;
}

#task-input {
  width: 80%;
  padding: 10px;
  border-radius: 8px;
  border: none;
  text-align: center;
}