JSFiddle - React, Tailwind, and code Playground

HTML

<main>
            <div class="login_form">
                <form action="?" method="POST">
                   
                    <div class="form_field">
                        <label for="login_name">yyy</label>
                        <input id="login_name" type="text" name="username" placeholder="Username" required>
                    </div>
                   
                    <div class="form_field">
                        <label for="login_password">xxx</label>
                        <input id="login_password" type="password" name="password" placeholder="Password" required>
                    </div>
                   
                    <div class="form_field">
                        <input type="submit" value="Login">
                    </div>
                </form>
            </div>
        </main>

CSS

html,body {
    background-color: #2c3338;
    font-family: Open Sans;
    font-size: 9pt;
    height: 100%;
    margin:0; /* weitere Ergänzung */
    padding:0; /* damit keine Scrollbalken erscheinen */
}
 
h1, h2, h3, h4, h5, p {
    color: rgba(255, 255, 255, 0.15);
    font-weight: 100;
}
 
body {
    display: flex;
    align-items: center;
    justify-content: center;
}
 
main {
    width: 90%;
    max-width: 30rem;
   
    margin-left: auto;
    margin-right: auto;
}
 
input {
    background-image: none;
    border: 0;
    color: inherit;
    font: inherit;
    margin: 0;
    outline: 0;
    padding: 0;
    transition: background-color 0.3s;
}
 
.login_form form input[type='text'], form input[type='password'], form input[type='submit'], form label {
    padding: 1rem;
}
 
.login_form form input[type='text'], form input[type='password'] {
    border-radius: 0px 5px 5px 0px;
    background-color: rgba(255, 255, 255, 0.1);
    border: none;
   
    width: 100%;
}
 
.login_form form input[type='text']:hover, form input[type='password']:hover {
    background-color: rgba(255, 255, 255, 0.2);
}
 
.login_form form input[type='submit'] {
    width: 100%;
    border-radius: 5px;
    text-transform: uppercase;
    font-weight: 700;
    color: rgba(255, 255, 255, 1);
    background-color: rgba(0, 0, 0, 0.5);
    cursor: pointer;
}
 
.login_form form input[type='submit']:hover {
    background-color: rgba(0, 0, 0, 0.2);
}
 
 
.login_form form label {
    background-color: #363b41;
    border-radius: 5px 0px 0px 5px;
    padding-left: 1.25rem;
    padding-right: 1.25rem;
   
}
 
.form_field {
    display: flex;
    margin: 1rem;
}