body {
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
}

.calculator-container {
  position: relative;
  max-width: 500px; 
  margin: auto;
  padding-top: 40px; /* Make space for the theme selector */
}

.theme-selector-container {
  position: absolute; /* Absolute positioning */
  right: 0; /* Stick to the right */
  top: 0; /* Place it at the top of the .calculator-container */
  border-radius: 5px;
  padding: 5px;
  z-index: 10;
}

.theme-selector-container select {
  border: none;
  background-color: transparent;
}

.theme-default {
  background-color: #fff; /* Changing the background color of entire page */
  color: #000;
}

.theme-default .calculator {
  background-color: #fff; /* Very dark grey for calculator background */
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.15);
}

.theme-default button, .theme-default #result {
  box-shadow: 0 0 5px rgba(0, 0, 0, 0.15);
  background-color: #fff; /* Dark grey for buttons and result screen */
  color: #000;
}

.theme-default .theme-selector-container {
  background-color: #fff; /* Dark grey background for theme selector */
  color: #010101; /* White text color */
}

.theme-default .theme-selector-container select {
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.25);
  background-color: #fff; /* Dark grey background for select dropdown */
  color: #010101; /* White text color */
}

.theme-dark {
  background-color: #000; /* Changing the background color of entire page */
  color: #fff;
}

.theme-dark .calculator {
  background-color: #000;
  box-shadow: 0 0 10px rgba(255, 255, 255, 0.25);
}

.theme-dark button, .theme-dark #result {
  background-color: #010101; /* Dark grey for buttons and result screen */
  box-shadow: 0 0 5px rgba(255, 255, 255, 0.25);
  color: #fff;
}

.theme-dark .theme-selector-container {
  background-color: #010101; /* Dark grey background for theme selector */
  color: #fff; /* White text color */
}

.theme-dark .theme-selector-container select {
  box-shadow: 0 0 10px rgba(255, 255, 255, 0.35);
  background-color: #010101; /* Dark grey background for select dropdown */
  color: #fff; /* White text color */
}


.theme-dark button:hover {
  background-color: #222;
}

.theme-light {
  background-color: #eee; /* Changing the background color of entire page */
  color: #000;
}

.theme-light .calculator {
  background-color: #eee; /* Very dark grey for calculator background */
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.2);
}

.theme-light button, .theme-light #result {
  box-shadow: 0 0 5px rgba(0, 0, 0, 0.2);
  background-color: #eee; /* Dark grey for buttons and result screen */
  color: #000;
}

.theme-light .theme-selector-container {
  background-color: #eee; /* Dark grey background for theme selector */
  color: #010101; /* White text color */
}

.theme-light button:hover {
  background-color: #ddd;
}


.theme-light .theme-selector-container select {
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.2);
  background-color: #eee; /* Dark grey background for select dropdown */
  color: #010101; /* White text color */
}

.calculator {
  display: flex;
  flex-direction: column;
  align-items: center;
  border-radius: 10px;
  font-size: 2em;
  width: 100%;
  max-width: 500px;
  padding: 20px;
}

#result {
  font-size: 1.5em;
  text-align: right;
  padding: 10px;
  border: none;
  border-radius: 5px;
  margin-bottom: 10px;
  width: 100%;
}

.row {
  display: flex;
  justify-content: space-between;
  width: 100%;
}

button {
  font-size: 1em;
  padding: 10px;
  margin: 10px;
  border: none;
  border-radius: 5px;
  cursor: pointer;
  width: 23%;
}

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