Media query

body{
    background-image: url("img_tree.gif");
    background-repeat: no-repeat;
    background-attachment: fixed;
}

<style>

 .circle:before {
                    content: ' \25CF';
                    font-size: 50px;
                    color: black;
                }
</style>

<span class="circle"></span>

img {
  mask-image: url(‘mask.png’) linear-gradient(-45deg,
                        rgba(0,0,0,1) 20%, rgba(0,0,0,0) 50%);
  mask-image: url(#masking); /*referencing to the element generated and defined in SVG code*/
} 

/*EX:.container {
    padding: 0 15px;
// 576px window width and more
    @include sm {
        padding: 0 20px;
    }
// 992px window width and more
    @include lg {
        margin-left: auto;
        margin-right: auto;
        max-width: 1100px;
    } */

// Small tablets and large smartphones (landscape view)
$screen-sm-min: 576px;

// Small tablets (portrait view)
$screen-md-min: 768px;

// Tablets and small desktops
$screen-lg-min: 992px;

// Large tablets and desktops
$screen-xl-min: 1200px;


// Small devices
@mixin sm {
   @media (min-width: #{$screen-sm-min}) {
       @content;
   }
}

// Medium devices
@mixin md {
   @media (min-width: #{$screen-md-min}) {
       @content;
   }
}

// Large devices
@mixin lg {
   @media (min-width: #{$screen-lg-min}) {
       @content;
   }
}

// Extra large devices
@mixin xl {
   @media (min-width: #{$screen-xl-min}) {
       @content;
   }
}

 .rotate {

  transform: rotate(-90deg);


  /* Legacy vendor prefixes that you probably don
                                

.box-one {
	width: 100px;
	margin: 0 auto;
}

.box-two {
	width: 100px;
	margin-left: auto;
    margin-right: auto;
}

.truncate {
  width: 250px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

<h1 class="ribbon">
   <strong class="ribbon-content">Everybody loves ribbons</strong>
</h1>

.dynamic-shadow {

  position: relative;

  width: rem;

  height: 10rem;

  background: linear-gradient(5deg, #d7ff, #00ffb8);
6
  z-index: 1;
7
}
8
.dynamic-shadow::after {

  content: '';
10
  width: 100%;

  height: 100%;

  position: absolute;

  background: inherit;

  top: 0.5rem;

  filter: blur(0.4rem);

  opacity: 0.7;

  z-index: -1;

}

​

 add_filter( 'jetpack_sharing_counts', '__return_false', 99 );
add_filter( 'jetpack_implode_frontend_css', '__return_false', 99 );
                                

ol li {
	 list-style-type: none;
     }
     
// OR

li {
	list-style-type: none;
}

.gradient {
  background-image:
    linear-gradient(
      to right, 
      red, 
      blue,
      yellow, 
      green
    );
}

p {
  position: absolute;
  left: 0px;
  top: 0px;
}

.container {
 position: relative;
 left: 50px;
 top: 50px
}

* {
  outline: 1px solid red;
}