body {
    font-family: Arial, sans-serif;
    overflow: hidden;
  
  }
  .app {
    position: relative;
    z-index: 1;
    min-height: 100vh;
    padding: 2rem;
    display: flex;
    justify-content: center;
    align-items: end;
    height: 80vh;
    margin: 0;
  }

  /* Background container pinned to viewport */
.bg-illustration {
  position: fixed;
  inset: 0;            /* top:0 right:0 bottom:0 left:0 */
  z-index: 0;
  pointer-events: none; /* clicks go through */
  overflow: hidden;
}

/* Make the SVG cover the screen nicely */
.bg-illustration svg {
  width: 100vw;
  height: 100vh;
  display: block;
  object-fit: cover;    /* preserve viewBox nicely */
}
.calculator {
  background: #fff; /* solid white background */
  width: 70%;
  padding: 3.5rem 20px;
  border-radius: 8px;
  text-align: center;
  margin-bottom: 2rem;
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
  transition: all 0.5s ease-in-out;

  /* Transparent border so gradient shows */
  border: 4px solid transparent;

  /* Layer 1 = white content background, Layer 2 = gradient border */
  background-image:
    linear-gradient(#fff, #fff),
    linear-gradient(90deg, red, blue, green, red);
  background-origin: padding-box, border-box;
  background-clip: padding-box, border-box;

  /* Animate the gradient movement */
  animation: move-border 4s linear infinite;
}

/* Keyframes to slide the colors */
@keyframes move-border {
  0% {
    background-image:
      linear-gradient(#fff, #fff),
      linear-gradient(90deg, red, blue, green, red);
  }
  100% {
    background-image:
      linear-gradient(#fff, #fff),
      linear-gradient(450deg, rgb(111, 246, 111), blue, green, teal);
  }
}



  .calculator h2 {
    font-size: 24px;
    margin-bottom: 20px;
    font-weight: bold;
    color: rgb(103, 102, 102);
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  }
  input, select, button {
    margin: 10px;
    padding: 12px;
    font-size: 16px;
    border-radius: 6px;
    border: 1px solid rgb(190, 186, 186);
    cursor: pointer;
    outline: none;
    font-weight: bold;
    color: rgb(103, 102, 102);
  }
  button {
    background-color: #70E697;
    color: white;
    border: none;
    cursor: pointer;
    border-radius: 6px;
    padding: 12px;
    font-size: 16px;
  }
  button:hover {
    background-color: #60f968;
  }
  #result {
    font-weight: 900;
    font-size: 24px;
    margin-top: 3rem;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    color: rgb(103, 102, 102);
  }
  #result span {
    color: #70E697;
  }