Generated by SassMeister.com.

SassMeister-input-HTML.html

<input type="text" placeholder="Super Platzhalter">

SassMeister-input.scss

// ----
// Sass (v3.3.8)
// Compass (v1.0.0.alpha.19)
// ----

@mixin input-placeholder() {
	&::-webkit-input-placeholder { // WebKit browsers
		@content;
	}
	&:-moz-placeholder  { // Mozilla Firefox 4 to 18
		@content;
		opacity: 1;
	}
	&::-moz-placeholder { // Mozilla Firefox 19+
		@content;
//		opacity: 1;
	}
	&:-ms-input-placeholder { // Internet Explorer 10+
		@content;
	}
	&:placeholder {
		@content;
	}
}

input {
  @include input-placeholder(){
    color: #a20000;
  }
  font-size: 20px;
  border: 2px solid #a20000;
  padding: 10px;
}

SassMeister-output.css

input {
  font-size: 20px;
  border: 2px solid #a20000;
  padding: 10px;
}
input::-webkit-input-placeholder {
  color: #a20000;
}
input:-moz-placeholder {
  color: #a20000;
  opacity: 1;
}
input::-moz-placeholder {
  color: #a20000;
}
input:-ms-input-placeholder {
  color: #a20000;
}
input:placeholder {
  color: #a20000;
}

SassMeister-rendered.html

<input type="text" placeholder="Super Platzhalter">