To see the full code for the mixins see css/root/mixins.scss
.center-element {
  @include center;//mixin
  background: #E03D44;
  @include size(80%, 60px);
  }
  
  
  
  @mixin hidden {
  display: none !important;
  visibility: hidden;
  }
  
  .hidden-box {
   @include size(300px, 70px);
   @include center;
   padding: 7px;
   font-size: .9rem;
   color: orange;
   border: 1px solid blue;
  
    &:hover span {
     @include hidden;//mixin
   }
  }
  
  Base styles are phone-first
.media-points p {
   color: red;
  }
  
  @include media(600) {
   .media-points p {
    color: blue;
   }
  }
  
  @include media(700) {
   .media-points p {
    color: rgb(153, 71, 236);
   }
  }
  
  @include media(934) {
   .media-points p {
    color: rgb(34, 224, 126);
   }
  }
  
   @include media(93rem) {
   .media-points p {
    color: rgb(235, 220, 85);
   }
  }
  
  
    At base level this text is red
    At 600px this text is blue
    At 700px this text is purple
    At 934px this text is green
    At 93rem this text is yellow
   
@include border-top-radius(15px);
  @include border-bottom-radius(10px);
  
  
  
  @include border-left-radius(10px);
  @include border-right-radius(5px);
  
  
  
  @include ellipsis;
  .hide-text {
  @include size(220px, 120px);
  @include center;
  padding: 7px;
  border: 1px solid blue;
  
   &:hover {
    @include hide-text;//mixin
    background: url(../test-images/taj-mahal.jpg);
    background-repeat: no-repeat;
    background-size: cover;
   }
  }
  
  
  
  .hide-visually {
  @include size(220px, 120px);
  @include center;
  font-size: .9rem;
  padding: 7px;
  border: 1px solid blue;
  
   span {
    font-size: 1.3rem;
    color:#a60b55;
    @include hide-visually;//mixin
   }
  
   &:hover span {
    @include hide-visually("unhide");//alt mixin
   }
  }
  
  
  @include size(300px, 1.8em);
  
  .element {
  @include size(300px, 50px);
  @include center;
  background-color: #b25c9c;
  position: relative;
  
   &::before {
    @include triangle(up, 2rem, 1rem, #b25c9c);//mixin
    position: absolute;
    content: "";
    //position triangle on box
    top:-1rem;
    left:6rem;
   }
  }