* {
  box-sizing: border-box;
}

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

.calculator {
  background: white;
  padding: 30px;
  border-radius: 20px;
  text-align: center;
  width: 100%;
  max-width: 380px;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
}

h1 {
  margin-bottom: 25px;
  font-size: 28px;
}

input,
select {
  width: 100%;
  padding: 14px;
  border: 2px solid #ddd;
  border-radius: 10px;
  font-size: 16px;
  outline: none;
  margin-bottom: 15px;
  background: white;
}

input:focus,
select:focus {
  border-color: #667eea;
}

button {
  width: 100%;
  padding: 14px;
  border: none;
  border-radius: 10px;
  background: #667eea;
  color: white;
  font-size: 16px;
  font-weight: bold;
  cursor: pointer;
  transition: 0.2s;
}

button:hover {
  opacity: 0.9;
}

button:active {
  transform: scale(0.97);
}

.reset {
  background: #e74c3c;
  margin-top: 10px;
}

.print-btn {
  background: #27ae60;
  margin-top: 10px;
}

.dark-btn {
  background: #333;
  margin-top: 10px;
}

.result-card {
  margin-top: 20px;
  padding: 20px;
  border-radius: 15px;
  background: #f8f9fa;
  border-left: 5px solid #667eea;
  border-top: 1px solid #ddd;
  border-right: 1px solid #ddd;
  border-bottom: 1px solid #ddd;
  text-align: left;
  font-size: 17px;
  line-height: 1.6;
}

.result-card h3 {
  text-align: center;
  margin-top: 0;
  margin-bottom: 15px;
}

.result-card p {
  margin: 8px 0;
  padding: 8px;
  border-bottom: 1px solid #ddd;
}

.result-card p:last-child {
  border-bottom: none;
}

body.dark-mode input,
body.dark-mode select {
  background: #333;
  color: white;
  border-color: #666;
}

body.dark-mode .result-card {
  background: #2b2b2b;
  color: white;
  border-color: #667eea;
}

@media print {
  body {
    background: white !important;
  }

  .calculator > input,
  .calculator > select,
  .calculator > button {
    display: none;
  }

  .result-card {
    display: block;
    box-shadow: none;
    border: 2px solid #333;
  }
}

@media (max-width: 480px) {
  .calculator {
    padding: 20px;
  }

  h1 {
    font-size: 24px;
  }

  .result-card {
    padding: 15px;
    font-size: 16px;
  }
}
.info {
  margin-top: 20px;
  font-size: 14px;
  color: #666;
  line-height: 1.5;
}
footer {
  text-align: center;
  margin-top: 15px;
  font-size: 13px;
  color: white;
}
.about {
  margin-top: 20px;
  padding: 18px;
  background: #f8f9fa;
  border-radius: 15px;
  text-align: left;
}

.about h2 {
  text-align: center;
  margin-top: 0;
}

.about p {
  margin: 8px 0;
}