body {
  font-family: Arial, sans-serif;
  background-color: #f8f8f8;
  display: flex;
  justify-content: center;
  padding: 30px 10px;
  margin: 0;
}

.container {
  background: white;
  padding: 25px 30px;
  border-radius: 8px;
  box-shadow: 0 0 12px rgba(0,0,0,0.1);
  max-width: 360px;
  width: 100%;
}

h1 {
  text-align: center;
  margin-bottom: 20px;
  color: #222;
}

label {
  display: block;
  margin-top: 15px;
  font-weight: bold;
  color: #444;
}

select, input[type=number] {
  width: 100%;
  padding: 8px 10px;
  margin-top: 5px;
  border-radius: 5px;
  border: 1.5px solid #ccc;
  font-size: 1em;
  box-sizing: border-box;
  transition: border-color 0.3s ease;
}

select:focus, input[type=number]:focus {
  border-color: #4a90e2;
  outline: none;
}

button {
  margin-top: 25px;
  width: 100%;
  padding: 12px 0;
  font-size: 1.1em;
  background-color: #4a90e2;
  color: white;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  transition: background-color 0.25s ease;
}

button:hover {
  background-color: #357ABD;
}

.hidden {
  display: none;
}

.size-table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 15px;
}

.size-table th,
.size-table td {
  border: 1px solid #ccc;
  padding: 10px 8px;
  text-align: center;
  font-weight: 600;
  color: #333;
  background: #fafafa;
}

.size-table th {
  background: #e6e6e6;
}