* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
}

.container {
  background: white;
  border-radius: 20px;
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
  padding: 40px;
  max-width: 500px;
  width: 100%;
}

h1 {
  color: #333;
  text-align: center;
  margin-bottom: 20px;
  font-size: 2rem;
  font-weight: 600;
}

.calculator {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.input-group {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

label {
  color: #555;
  font-weight: 600;
  font-size: 1.1rem;
}

input {
  padding: 15px;
  border: 2px solid #e1e5e9;
  border-radius: 10px;
  font-size: 1rem;
  transition: all 0.3s ease;
  outline: none;
}

input:focus {
  border-color: #667eea;
  box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

input::placeholder {
  color: #999;
}

button {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
  border: none;
  padding: 15px 30px;
  border-radius: 10px;
  font-size: 1.1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  margin-top: 10px;
}

button:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 20px rgba(102, 126, 234, 0.3);
}

button:active {
  transform: translateY(0);
}

.result {
  background: #f8f9fa;
  border-radius: 10px;
  padding: 20px;
  margin-top: 10px;
}

.result h3 {
  color: #333;
  margin-bottom: 10px;
  font-size: 1.2rem;
}

.result p {
  color: #666;
  font-size: 1rem;
  line-height: 1.5;
}

.open {
  color: #28a745 !important;
  font-weight: 600;
}

.not-open {
  color: #dc3545 !important;
  font-weight: 600;
}

/* Tablet Responsive */
@media (max-width: 768px) {
  .container {
    padding: 30px;
    max-width: 450px;
  }

  h1 {
    font-size: 1.8rem;
  }

  input {
    padding: 12px;
    font-size: 0.95rem;
  }

  button {
    padding: 14px 28px;
    font-size: 1rem;
  }

  .result {
    padding: 18px;
  }
}

/* Mobile Responsive */
@media (max-width: 480px) {
  body {
    padding: 15px;
  }

  .container {
    padding: 20px;
    border-radius: 15px;
  }

  h1 {
    font-size: 1.5rem;
    margin-bottom: 15px;
  }

  .input-group {
    gap: 6px;
  }

  label {
    font-size: 1rem;
  }

  input {
    padding: 12px;
    font-size: 0.9rem;
    border-radius: 8px;
  }

  button {
    padding: 12px 24px;
    font-size: 0.95rem;
  }

  .result {
    padding: 15px;
  }

  .result h3 {
    font-size: 1.1rem;
  }

  .result p {
    font-size: 0.9rem;
  }
}

/* Small Mobile Responsive */
@media (max-width: 360px) {
  body {
    padding: 10px;
  }

  .container {
    padding: 15px;
  }

  h1 {
    font-size: 1.3rem;
    margin-bottom: 12px;
  }

  .calculator {
    gap: 15px;
  }

  input {
    padding: 10px;
    font-size: 0.85rem;
  }

  button {
    padding: 10px 20px;
    font-size: 0.9rem;
  }

  .result {
    padding: 12px;
  }

  .result h3 {
    font-size: 1rem;
  }

  .result p {
    font-size: 0.85rem;
  }
}

/* Landscape Mobile */
@media (max-height: 500px) and (orientation: landscape) {
  body {
    padding: 10px;
  }

  .container {
    padding: 15px;
    max-width: 400px;
  }

  h1 {
    font-size: 1.2rem;
    margin-bottom: 10px;
  }

  .calculator {
    gap: 12px;
  }

  .input-group {
    gap: 5px;
  }

  input {
    padding: 8px;
    font-size: 0.85rem;
  }

  button {
    padding: 8px 20px;
    font-size: 0.9rem;
    margin-top: 5px;
  }

  .result {
    padding: 10px;
    margin-top: 5px;
  }
}

/* High DPI Displays */
@media (-webkit-min-device-pixel-ratio: 2), (min-resolution: 192dpi) {
  .container {
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15);
  }

  button:hover {
    box-shadow: 0 10px 20px rgba(102, 126, 234, 0.4);
  }
}