<div class="form">

<div class="form__row">
<div class="form__caption"><label class="form__label form__label--important">Ваше имя:</label></div>
<div class="form__content"><input class="form__input" type="text" maxlength="35" name="f4" placeholder="Ваше имя" /></div>
</div>

<div class="form__row">
<div class="form__caption"><label class="form__label form__label--important">Ваш E-Mail:</label></div>
<div class="form__content"><input class="form__input" type="text" maxlength="35" name="f1" placeholder="Ваш E-Mail" /></div>
</div>

<div class="form__row">
<div class="form__caption"><label class="form__label form__label--important">Тема сообщения:</label></div>
<div class="form__content"><input class="form__input" type="text" maxlength="45" name="f2" placeholder="Тема сообщения" /></div>
</div>

<div class="form__row">
<div class="form__caption form__caption--above"><label class="form__label form__label--important">Ваше письмо:</label></div>
<div class="form__content"><textarea class="form__textarea" name="f3" style="height: 160px" ></textarea></div>
</div>

<div class="form__row form__row--protect">
<div class="form__caption"><label class="form__label form__label--important" for="">Защита от спама</label></div>
<div class="form__content form__content--sec-code">$SECURITY_CODE$</div>
</div>

<div class="form__row form__row--submit d-flex"><button class="form__btn" name="send_btn" type="submit">Отправить</button></div>

</div>