* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
  background-color: #f2f4f8;
  color: #333;
  padding: 20px;
}

.container {
  max-width: 700px;
  margin: auto;
  background-color: #fff;
  padding: 30px;
  border-radius: 15px;
  box-shadow: 0 0 15px rgba(0,0,0,0.1);
}

h1 {
  text-align: center;
  margin-bottom: 20px;
  font-size: 28px;
  color: #2c3e50;
}

.section {
  margin-bottom: 30px;
}

.section-title {
  font-size: 20px;
  margin-bottom: 10px;
  color: #34495e;
}

input[type="text"],
input[type="number"] {
  width: 100%;
  padding: 10px;
  margin: 8px 0 15px;
  border: 1px solid #ccc;
  border-radius: 8px;
  font-size: 16px;
}

button {
  width: 100%;
  padding: 12px;
  margin-top: 10px;
  background-color: #2ecc71;
  border: none;
  color: white;
  font-size: 16px;
  border-radius: 8px;
  cursor: pointer;
  transition: background-color 0.3s ease;
}

button:hover {
  background-color: #27ae60;
}

.result-box {
  margin-top: 15px;
}

.span-item {
  display: block;
  padding: 10px;
  border-radius: 6px;
  margin-top: 10px;
  font-size: 16px;
}

.success {
  background-color: #e8f5e9;
  color: #2e7d32;
  border: 1px solid #81c784;
/*   jstibebmj */
}

.err {
  background-color: #fdecea;
  color: #c62828;
  border: 1px solid #ef9a9a;
}

/* Responsive Layout */
@media screen and (max-width: 768px) {
  .container {
    padding: 20px;
  }

  h1 {
    font-size: 24px;
  }

  .section-title {
    font-size: 18px;
  }

  button {
    font-size: 15px;
  }
}