login_form.php

<?php
session_start();

//セッションでのログイン
if (isset($_SESSION['id'])) {
    echo("<html><head><meta http-equiv='refresh' content='1;URL=./dash.php' /></head><body>Redirect to the dashboard.</body></html>");
    exit;
  }
?>

<html>
    <head>
        <meta charset="UTF-8">
        <title>easeLp - login</title>
        <link rel="stylesheet" href="./css/style.css">
        <link rel="stylesheet" href="./css/login.css">

        <link rel="preconnect" href="https://rsms.me/">
        <link rel="stylesheet" href="https://rsms.me/inter/inter.css">
        <link rel="preconnect" href="https://fonts.googleapis.com/">
        <link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Quicksand:300,400,500,700">

        <link rel="icon" type="image/svg+xml" href="./logo.svg" />

        <meta name="viewport" content="width=device-width,initial-scale=1">

    </head>

    <body>
        <header>
        <?php include("./header.php"); ?>
        </header>

        <div class="login_box_main">
            <div style="text-align: left;display: inline-block;">
                <div class="login_text">Login</div><br>
                <form method="POST" action="./login.php">
                    <span>user id</span><br>
                    <input type="text" name="user_id" id="user_id" class="input_box" placeholder="user id">
                    <div style="padding-top:2em;">
                        <span>password</span><br>
                        <input type="password" name="password" id="password" class="input_box" placeholder="password"></p>
                        <input type="submit" class="btn" value="login">
                    </div>
                </from>

                <div style="text-align:center;padding-top:1em;">
                    <a href="./signup_form.php" style="color:#888888;text-decoration:none;">Sign Up</a>
                </div>
            </div>
        </div>

        </div>
    </body>
</html>