html,
body {
  margin: 0;
  padding: 0;
  background-color: #1b1d28;
  width: 100%;
}

.container {
  max-width: 800px;
  margin: 0 auto;
  padding: 20px;
  text-align: center;
  color: white;
}

.header {
  background: #1b1d28;
  position: fixed;
  width: 100%;
  top: 0;
  z-index: 100;
}

.top-buttons {
  padding: 12px 20px;
  display: flex;
  justify-content: flex-end;
  gap: 10px;
  position: absolute;
  top: 0;
  right: 0;
}

.top-buttons button {
  padding: 12px 24px;
  font-size: 16px;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  transition: all 0.2s ease;
  background: rgba(134, 239, 172, 0.9);
  color: #000;
  width: 120px;
}

.top-buttons button:hover {
  background: rgba(108, 213, 146, 0.9);
  transform: translateY(-2px);
}

/* Mobile-specific styles */
@media screen and (max-width: 767px) {
  .header {
    background: rgba(27, 29, 40, 0.95);
    position: relative;
  }

  .top-buttons {
    position: relative;
    justify-content: center;
    padding: 12px 8px;
  }

  .container {
    padding-top: 20px;
  }

  .top-buttons button {
    width: 45%;
    max-width: 140px;
  }
}

*,
*:before,
*:after {
  box-sizing: border-box;
}

.explanation {
  margin: 20px 0;
  text-align: center;
  line-height: 1.6;
}

.numpad {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
  max-width: 300px;
  margin: 20px auto;
}

.numpad button {
  padding: 20px;
  font-size: 20px;
  border: 1px solid rgb(134, 239, 172);
  background: rgb(134, 239, 172);
  color: #000;
  cursor: pointer;
  transition: background-color 0.2s ease;
  border-radius: 4px;
}

.numpad button:hover {
  background: rgb(108, 213, 146);
  border-color: rgb(108, 213, 146);
}

#display {
  width: 100%;
  max-width: 280px;
  padding: 10px;
  margin: 10px auto;
  font-size: 24px;
  text-align: center;
  border: 1px solid #ccc;
  border-radius: 4px;
}

.faq {
  text-align: left;
  margin-top: 40px;
  max-width: 300px;
  margin-left: auto;
  margin-right: auto;
}

.faq h2 {
  margin-bottom: 30px;
}

.faq h3 {
  margin-top: 20px;
}

.faq p {
  margin-bottom: 20px;
}

.signup-form {
  display: none;
  margin-top: 20px;
}

.signup-form input {
  display: block;
  width: 100%;
  max-width: 280px;
  margin: 10px auto;
  padding: 10px;
  border: 1px solid #ccc;
  border-radius: 4px;
}

.signup-form button {
  padding: 10px 20px;
  background: #007bff;
  color: white;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  transition: background-color 0.2s ease;
}

.signup-form button:hover {
  background: #0056b3;
}

.black-text-button {
  color: black !important;
}