* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}
html {
    font-size: 62.5%;
}
header {
    display: flex;
    flex-wrap: wrap;
    background-color: #000000;
    padding: 2rem;
    font-family: 'Trebuchet MS', 'Lucida Sans Unicode', 'Lucida Grande', 'Lucida Sans', Arial, sans-serif;
    color: #fff;
    justify-content: space-evenly;
}
body{
    background-color: #000000;
}
h1 {
    display: inline-block;
    font-size: 4.8rem;
}

nav ul li {
    padding-top: 1.5rem;
    font-size: 2rem;
    font-family: 'Gill Sans', 'Gill Sans MT', Calibri, 'Trebuchet MS', sans-serif;
    display: inline-block;
    justify-content:flex-end;
    margin-left: 2.5rem;
}

main {
    display: flex;
    flex-wrap: wrap;
    flex-direction: row;
    justify-content: space-around;
}

div {
    background-color: rgb(255, 255, 255);
    height: 15rem;
    width: 30rem;
    padding: 2rem;
    border: 1px solid  rgb(255, 255, 255);
    border-radius: 2rem;
    margin: 2rem;
    opacity: 0.6;
    text-align: center;
    line-height: 0.1rem;
    font-size: 2.5rem;
    font-weight: bold;
    box-shadow: 10px 10px 10px #aaa;
}

div:hover {
    opacity: 1.0;
    transform: rotate(-1deg) scale(1.1);
}

.InsConstructors{
    background-image: url(./assets/01-Ins-Constructors.PNG);
    background-size:200px 80px;;
    background-repeat: no-repeat;
    background-position:bottom;
}

.StuConstructors{
    background-image: url(./assets/02-Stu-Constructors.PNG);
    background-size:200px 80px;;
    background-repeat: no-repeat;
    background-position:bottom;
}

.InsPrototypes{
    background-image: url(./assets/03-Ins-Prototypes.PNG);
    background-size:200px 80px;;
    background-repeat: no-repeat;
    background-position:bottom;
}

.StuPrototypes{
    background-image: url(./assets/04-Stu-Prototypes.PNG);
    background-size:200px 80px;;
    background-repeat: no-repeat;
    background-position:bottom;
}

.InsPolymorphism{
    background-image: url(./assets/05-Ins-Polymorphism.PNG);
    background-size:200px 80px;;
    background-repeat: no-repeat;
    background-position:bottom;
}

.StuPolymorphism{
    background-image: url(./assets/06-Stu-Polymorphism.PNG);
    background-size:200px 80px;;
    background-repeat: no-repeat;
    background-position:bottom;
}

.InsPromises{
    background-image: url(./assets/07-Ins-Promises.PNG);
    background-size:200px 80px;;
    background-repeat: no-repeat;
    background-position:bottom;
}

.StuPromises{
    background-image: url(./assets/08-Stu-Promises.PNG);
    background-size:200px 80px;;
    background-repeat: no-repeat;
    background-position:bottom;
}

.InsPromiseAll{
    background-image: url(./assets/09-Ins-Promise-All.PNG);
    background-size:200px 80px;;
    background-repeat: no-repeat;
    background-position:bottom;
}

.StuPromiseAll{
    background-image: url(./assets/10-Stu-Promise-All.PNG);
    background-size:200px 80px;;
    background-repeat: no-repeat;
    background-position:bottom;
}

.InsTDD{
    background-image: url(./assets/11-Ins-TDD.PNG);
    background-size:200px 80px;;
    background-repeat: no-repeat;
    background-position:bottom;
}

.StuTDD{
    background-image: url(./assets/12-Stu-TDD.PNG);
    background-size:200px 80px;;
    background-repeat: no-repeat;
    background-position:bottom;
}

.InsPassTests{
    background-image: url(./assets/13-Ins-Pass-Tests.PNG);
    background-size:200px 80px;;
    background-repeat: no-repeat;
    background-position:bottom; 
}

.StuPassTests{
    background-image: url(./assets/14-Stu-Pass-Tests.PNG);
    background-size:200px 80px;;
    background-repeat: no-repeat;
    background-position:bottom; 
}

.InsOrganizingTests{
    background-image: url(./assets/15-Ins-Organizing-Tests.PNG);
    background-size:200px 80px;;
    background-repeat: no-repeat;
    background-position:bottom; 
}

.StuOrganizingTests{
    background-image: url(./assets/16-Stu-Organizing-Tests.PNG);
    background-size:200px 80px;;
    background-repeat: no-repeat;
    background-position:bottom; 
}

.InsIntroduceMocks{
    background-image: url(./assets/17-Ins-Introduce-Mocks.PNG);
    background-size:200px 80px;;
    background-repeat: no-repeat;
    background-position:bottom; 
}

.StuFirstMock{
    background-image: url(./assets/18-Stu-First-Mock.PNG);
    background-size:200px 80px;;
    background-repeat: no-repeat;
    background-position:bottom; 
}

.InsModuleMockDemo{
    background-image: url(./assets/19-Ins-Module-Mock-Demo.PNG);
    background-size:200px 80px;;
    background-repeat: no-repeat;
    background-position:bottom; 
}

.StuMockFs{
    background-image: url(./assets/20-Stu-Mock-Fs.PNG);
    background-size:200px 80px;;
    background-repeat: no-repeat;
    background-position:bottom; 
}

.InsClasses{
    background-image: url(./assets/21-Ins-Classes.PNG);
    background-size:200px 80px;;
    background-repeat: no-repeat;
    background-position:bottom; 
}

.StuClasses{
    background-image: url(./assets/22-Stu-Classes.PNG);
    background-size:200px 80px;;
    background-repeat: no-repeat;
    background-position:bottom; 
}

.InsSubclasses{
    background-image: url(./assets/23-Ins-Subclasses.PNG);
    background-size:200px 80px;;
    background-repeat: no-repeat;
    background-position:bottom; 
}

.StuSubclasses{
    background-image: url(./assets/24-Stu-Subclasses.PNG);
    background-size:200px 80px;;
    background-repeat: no-repeat;
    background-position:bottom; 
}

.InsMultipleClasses{
    background-image: url(./assets/25-Ins-Multiple-Classes.PNG);
    background-size:200px 80px;;
    background-repeat: no-repeat;
    background-position:bottom;
    }

.StuMultipleClasses{
    background-image: url(./assets/26-Stu-Multiple-Classes.PNG);
    background-size:200px 80px;;
    background-repeat: no-repeat;
    background-position:bottom;
    }

.StuMiniProject{
    background-image: url(./assets/28-Stu-Mini-Project.PNG);
    background-size:200px 80px;;
    background-repeat: no-repeat;
    background-position:bottom;
}

/* Dark mide Switch */
.switch {
    position: relative;
    display: inline-block;
    width: 60px;
    height: 34px;
  }
  
  /* Hide default HTML checkbox */
  .switch input {
    opacity: 0;
    width: 0;
    height: 0;
  }
  
  /* The slider */
  .slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: #ff0000;
    -webkit-transition: .4s;
    transition: .4s;
  }
  
  .slider:before {
    position: absolute;
    content: "";
    height: 26px;
    width: 26px;
    left: 4px;
    bottom: 4px;
    background-color: rgb(255, 255, 255);
    -webkit-transition: .4s;
    transition: .4s;
  }
  
  input:checked + .slider {
    background-color: rgb(0, 255, 0);
  }
  
  input:focus + .slider {
    box-shadow: 0 0 1px rgb(29, 128, 210);
  }
  
  input:checked + .slider:before {
    -webkit-transform: translateX(26px);
    -ms-transform: translateX(26px);
    transform: translateX(26px);
  }
  
  /* Rounded sliders */
  .slider.round {
    border-radius: 34px;
  }
  
  .slider.round:before {
    border-radius: 50%;
  }
  
  .row {
    margin: 20px;
    display: flex;
  }
  .col {
    margin: 20px;
  }
  /* Dark mide Switch */