.wrapper {
    width: 900px;
    max-width: 100%;
    margin: auto;
}

form.multi-form {
    padding: 20px;
}

    form.multi-form fieldset:not(.active) {
        display: none;
    }

    form.multi-form fieldset.active:first-of-type ~ .buttons .prev,
    form.multi-form fieldset.active:first-of-type ~ .buttons .submit {
        display: none;
    }

    form.multi-form fieldset.active:not(:last-of-type) ~ .buttons .submit {
        display: none;
    }

    form.multi-form fieldset.active:last-of-type ~ .buttons .next {
        display: none;
    }

.field-validation-error {
    color: #ff0000;
}


.field-validation-valid {
    display: none;
}

.input-validation-error {
    border: 1px solid #ff0000;
    background-color: #ffeeee;
}

.valid {
    border: 1px solid green;
}