modo-correto-modificador.css

.l-card {
  width: 290px;
}

.card {
  overflow: hidden;
  border-radius: 5px;
  border: 1px solid #d4d4d5;
}

.card__img {
  display: block;
}

.card__content {
  background: #fff;
  padding: 15px;
}

.card__content--disable {
  background: #BDADA2;
}

.card__title {
  line-height: 3;
  font-size: 25px;
}

.card__text {
  color: #888
}

modo-correto-modificador.html

<div class="l-card">
  <article class="card">

      <img class="card__img" src="http://fakeimg.pl/300x250/009EEB/FFF/?text=Imagem.jpg" alt="" />

    <div class="card__content card__content--disable">
      <h1 class="card__title">Title</h1>
      <p class="card__text">Lorem ipsum dolor sit amet, consectetur adipisicing elit.</p>
    </div>

  </article>
</div>