* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
.container {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
}
.heading {
  margin-bottom: 15px;
  font-size: 23px;
  font-weight: bold;
}
body.theme-1 {
    background-color: #ffcccb; /* light red */
    color: #000;
  }
  
  body.theme-2 {
    background-color: #cce7ff; /* light blue */
    color: #000;
  }
  
  body.theme-3 {
    background-color: #d4edda; /* light green */
    color: #000;
  }
  
  body.theme-4 {
    background-color: #fdfd96; /* light yellow */
    color: #000;
  }
  
  body.theme-5 {
    background-color: #2c2c2c; /* dark */
    color: #fff;
  }
  .btn button {
    font-family: 'Poppins', sans-serif;
    padding: 8px 16px;
    font-size: 16px;
    font-weight: 500;
    color: #ffffff;
    background-color: #4a90e2;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    transition: background-color 0.3s ease, transform 0.2s ease;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
  }
  
  .btn button:hover {
    background-color: #357ABD;
  }
  
  .btn button:active {
    transform: scale(0.96);
    background-color: #2d6ca2;
  }