body {
  background-color: rgb(0, 0, 0);
  color: white;
  height: 100vh;
  margin: 0;
  cursor: default;
}

h1,
p {
  margin: 0;
}

#donthide {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}

.calculator {
  background-color: #222;
  border-radius: 10px;
  padding: 20px;
  box-shadow: 0 0 20px rgba(0, 0, 0, 0.5);
}

#display {
  width: 100%;
  height: 40px;
  font-size: 24px;
  text-align: right;
  margin-bottom: 10px;
  border: 1px solid #555;
  border-radius: 5px;
  padding: 5px;
  background-color: #333;
  color: white;
}

.buttons {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
}

button {
  padding: 20px;
  font-size: 18px;
  border: none;
  border-radius: 5px;
  background-color: #007bff;
  color: white;
  cursor: pointer;
  transition: background-color 0.3s, transform 0.1s;
}

button:hover {
  background-color: #0056b3;
}

button:active {
  transform: scale(0.95);
}

button:focus {
  outline: 2px solid #fff;
}

.double {
  grid-column: span 2;
}

.topbar {
  z-index: 2;
  display: flex;
  justify-content: center;
  align-items: center;
  position: fixed;
  background-color: rgb(30, 30, 30);
  width: 100%;
  height: calc(10vh + 2vw);
  max-height: 19vh;
  top: 2vh;
  left: 0;
  right: 0;
  border-radius: 15px;
  padding: 0 2vw;
  box-sizing: border-box;
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.3);
}

.us {
  z-index: 7;
  font-size: 5vw;
  font-family: Arial, Helvetica, sans-serif;
  text-align: center;
  max-height: 20vh;
  overflow: hidden;
  min-height: 10vh;
  cursor: pointer;
  padding: 0;
  margin: 0;
  flex: 1;
  opacity: 1;
}

.us a {
  color: rgb(255, 255, 255);
  text-decoration: none;
  transition: color 0.5s ease;
}

.us a:hover {
  color: rgb(60, 60, 60);
  text-decoration: underline;
}

body {
  opacity: 0;
  transition: opacity 1.5s ease-in;
}

body.visible {
  opacity: 1;
}