main.css

body {
  font-family: Arial, sans-serif;
  background-color: #f2f2f2;
  margin: 0;
  padding: 20px;
}

h1 {
  color: #333333;
  text-align: center;
}

.tab {
  display: none;
}

.tab.active {
  display: block;
}

.tab-links {
  margin-bottom: 20px;
}

.tab-links a {
  display: inline-block;
  padding: 10px 20px;
  background-color: #ffffff;
  border-radius: 5px 5px 0 0;
  border: 1px solid #cccccc;
  cursor: pointer;
  font-size: 16px;
  color: #333333;
  text-decoration: none;
}

.tab-links a.active {
  background-color: #cccccc;
}

.form-container {
  margin-bottom: 20px;
}

.form-container label {
  display: block;
  margin-bottom: 5px;
  color: #333333;
}

.form-container input[type="text"],
.form-container input[type="password"],
.form-container textarea {
  width: 100%;
  padding: 5px;
  border: 1px solid #cccccc;
  border-radius: 5px;
}

.form-container input[type="submit"] {
  padding: 10px 20px;
  background-color: #333333;
  color: #ffffff;
  border: none;
  border-radius: 5px;
  cursor: pointer;
}

.message-container {
  margin-top: 20px;
}

.message-container h2 {
  margin-bottom: 10px;
  color: #333333;
}

.error-message {
  color: red;
  margin-top: 10px;
}