Generated by SassMeister.com.

SassMeister-input-HTML.html

<div class="promo-app">
  <p class="promo-app__p">
      <strong>¡Pagá y enviá dinero desde tu celular!</strong>  
      Descargá gratis la aplicación de MercadoPago
  </p>
  <a href="" class="promo-app__logo">PlayStore</a>
</div>

SassMeister-input.sass

// ----
// Sass (v3.4.4)
// Compass (v1.0.1)
// ----

@import url(http://fonts.googleapis.com/css?family=Lato:100,300,400,700,900)

@font-face
  font-family: 'Lato', sans-serif
  

%overflow_zoom 
  overflow: hidden
  zoom: 1
  
=hide-text()  
  text-indent: 100%
  white-space: nowrap
  overflow: hidden

=vertical_align()
  position: relative
  top: 50%
  transform: translateY(50%)
  -webkit-transform: translateY(50%)
  -ms-transform: translateY(50%)
  
.promo-app 
  @extend %overflow_zoom
  background-color: rgba(0, 0, 0, 0.3)
  filter: alpha(opacity=60) //backgroun alpha For IE8 and earlier
  border: 1px solid #333
  border-radius: 10px
  padding: 10px
  position: relative
  width: auto
  
  font-family: 'Lato'
  
  &__p
    @extend %overflow_zoom
    color: #fff
    display: block
    font-size: 14px
    font-weight: 100
    letter-spacing: 2px
    float: left

    strong
      display: block
      font-weight: 700
      font-size: 16px
  &__logo
    background-image: url("http://placehold.it/112x36")
    float: right
    height: 36px
    width: 112px
    
    +hide-text
    +vertical_align

SassMeister-output.css

@import url(http://fonts.googleapis.com/css?family=Lato:100,300,400,700,900);
@font-face {
  font-family: "Lato", sans-serif;
}
.promo-app, .promo-app__p {
  overflow: hidden;
  zoom: 1;
}

.promo-app {
  background-color: rgba(0, 0, 0, 0.3);
  filter: alpha(opacity=60);
  border: 1px solid #333;
  border-radius: 10px;
  padding: 10px;
  position: relative;
  width: auto;
  font-family: "Lato";
}
.promo-app__p {
  color: #fff;
  display: block;
  font-size: 14px;
  font-weight: 100;
  letter-spacing: 2px;
  float: left;
}
.promo-app__p strong {
  display: block;
  font-weight: 700;
  font-size: 16px;
}
.promo-app__logo {
  background-image: url("http://placehold.it/112x36");
  float: right;
  height: 36px;
  width: 112px;
  text-indent: 100%;
  white-space: nowrap;
  overflow: hidden;
  position: relative;
  top: 50%;
  transform: translateY(50%);
  -webkit-transform: translateY(50%);
  -ms-transform: translateY(50%);
}

SassMeister-rendered.html

<div class="promo-app">
  <p class="promo-app__p">
      <strong>¡Pagá y enviá dinero desde tu celular!</strong>  
      Descargá gratis la aplicación de MercadoPago
  </p>
  <a href="" class="promo-app__logo">PlayStore</a>
</div>