JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
        <h2>Регистрация</h2>
        <form method="post">
            <p class="email">Введите адрес электронной почты
                <input name="emailadress" type="email" placeholder="example@email.com" class="input">
            </p>
            <p class="username">Введите логин<br>
                <input name="username" type="text" placeholder="Jack" class="input">
            </p>
            <p class="password">Введите пароль<br>
                <input name="password" type="password" class="input">
            </p>
            <p class="rpassword">Повторите пароль<br>
                <input name="password" type="password" class="input">
            </p>
            <div class="submit"><input type="submit" value="Зарегистрироваться" class="input"></div>
        </form>
    </div>

CSS

*{
    margin: 0;
    padding: 0;
}
.container {
    position: fixed;
    width: 350px;
    height: 500px;
    border: 2px solid gray;
    background-color: lightgrey;
    text-align: center;
    border-radius: 10px;
    margin: auto;
    top: 0;bottom: 0;left: 0;right: 0;
    color: darkcyan;
}
h2 {
    margin-top: 16px;
}
.email {
    border: dotted 1px black; /*добавил, чтобы посмотреть ширину*/
    position: absolute;
    top:25%;
    margin-left: auto;
    font-size: 14pt;
}
.username {
    position: absolute;
    border: dotted 1px black;
    top: 40%;
    left: 50%;
    margin-left: -25%;
    font-size: 14pt;
}
.password {
    border: dotted 1px black;
    position: absolute;
    top: 55%;
    left: 50%;
    margin-left: -25%;
    font-size: 14pt;
}
.rpassword {
    border: dotted 1px black;
    position: absolute;
    top: 70%;
    left: 50%;
    margin-left: -25%;
    font-size: 14pt;
}
.submit {
    width: 180px;
    border: dotted 1px black;
    position: absolute;
    top: 90%;
    left: 50%;
    margin-left: -90px;
}
.input{
    font-size: 14pt;
}