body {
  font-family: Arial, sans-serif;
  background-color: #f0f0f0;
  color: #222;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  margin: 0;
  padding: 0;
  overflow: hidden;
  transition: background-color 0.3s ease, color 0.3s ease;
}

body.dark {
  background-color: #121212;
  color: #fff;
}

.card {
  background: white;
  padding: 15px;
  border-radius: 8px;
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
  width: 100%;
  max-width: 380px;
  margin-top: 10px;
}

body.dark .card {
  background: #1e1e1e;
}

button {
  background-color: #28a745;
  color: white;
  padding: 8px 16px;
  border: none;
  border-radius: 5px;
  margin-top: 5px;
  cursor: pointer;
  font-size: 14px;
}

button:hover {
  background-color: #218838;
}

.alert {
  padding: 8px;
  background-color: #f44336;
  color: white;
  border-radius: 5px;
  margin-top: 10px;
}

.alert.success {
  background-color: #4CAF50;
}

.alert.hidden {
  display: none;
}

#strength {
  height: 8px;
  background-color: lightgray;
  margin-top: 5px;
  width: 100%;
}

#strength-bar {
  height: 100%;
  width: 0;
  background-color: green;
}

#dashboard {
  display: none;
  width: 100%;
  max-width: 750px;
  padding: 15px;
}

canvas {
  margin-top: 15px;
  width: 100%;
  height: 200px;
}

.transaction {
  margin: 5px 0;
  display: flex;
  justify-content: space-between;
  gap: 10px;
}

@media (max-width: 600px) {
  .card {
    max-width: 330px;
  }

  #dashboard {
    padding: 10px;
  }

  button {
    padding: 6px 12px;
    font-size: 13px;
  }
}