<?php
session_start();
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    // For now, hardcoded authentication
    if ($_POST['username'] === 'user' && $_POST['password'] === 'user123') {
        $_SESSION['is_logged_in'] = true;
        header('Location: /');
        exit;
    } else {
        $error = 'Invalid credentials';
    }
}
?>
<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <title>登录 - 聊天系统</title>
    <style>
        body { font-family: sans-serif; display: flex; justify-content: center; align-items: center; height: 100vh; background: #f0f2f5; }
        .login-box { background: white; padding: 20px; border-radius: 8px; box-shadow: 0 2px 10px rgba(0,0,0,0.1); width: 300px; }
        input { width: 100%; padding: 10px; margin: 10px 0; border: 1px solid #ccc; border-radius: 4px; box-sizing: border-box;}
        button { width: 100%; padding: 10px; background: #00a884; color: white; border: none; border-radius: 4px; cursor: pointer; }
    </style>
</head>
<body>
    <div class="login-box">
        <h2>用户登录</h2>
        <?php if (isset($error)) echo "<p style='color:red'>$error</p>"; ?>
        <form method="post">
            <input type="text" name="username" placeholder="账号" required>
            <input type="password" name="password" placeholder="密码" required>
            <button type="submit">登录</button>
        </form>
    </div>
</body>
</html>
