*{
    margin: 0;
    padding: 0;
    font-family: Arial, Helvetica, sans-serif;
    box-sizing: border-box;
    scroll-behavior: smooth;
}

header
{
    position: fixed;
    width: 100%;
    height: 80px;
    padding: 0 80px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    background:#3652a4;
    z-index: 1000;

}
header .logo
{
 color: #fff;
 font-size: 20px;
 padding-left: 0%;
 text-decoration: none;
 letter-spacing: 2px ;
 font-weight: 600;
}

header ul
{
    position: relative;
    display: flex;
    list-style: none;
}

header ul li a 
{
    position: relative;
    padding:5px 10px;
    color: #fff ;
    display: inline-block;
    text-decoration:none;
    cursor: pointer;
    font-size: larger;
    font-weight: bold;
    margin-right: 20px;

}


header ul li  :hover
{
    background-color:#404247;
    border-radius: 10px;
}


/* dropdown menu*/
.dropbtn {
    background-color:transparent ;
    color: white;
    padding-top: 5px;
    margin-right: 20px;
    font-size: 20px;
    border: none;
    font-size: larger;
    font-weight: bold;
   
  }
  
  .dropdown {
    position: relative;
    display: inline-block;
  }
  
  .dropdown-content {
    display: none;
    position: absolute;
    background-color: #3652a4;
    border-radius: 5px;
    min-width: 160px;
    z-index: 1;
  }
  
  .dropdown-content a {
    color: white;
    padding: 12px 16px;
    text-decoration: none;
    display: block;
    font-size: larger;
    font-weight: bold;
  }
  
  
  .dropdown-content a:hover {background-color:#3652a4;}
  
  .dropdown:hover .dropdown-content {display: block;}

  .dropdown-content a :hover
  {
      background-color: #3652a4;
  }

  .arrow {
    border: solid #fff;
    border-width: 0 3px 3px 0;
    display: inline-block;
    padding: 3px;
  }

  .down {
    transform: rotate(45deg);
    -webkit-transform: rotate(45deg);
  }
 /*dropdown menu*/
.toogle
{
    display: none;
}

section
{
    position: relative;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 50px;
    min-height: 70vh;

}

#home
{
    min-height: 80vh;
    padding-bottom: 0%;
    
}

#post
{
    min-height: 40vh;


}


section img
{
    max-width: 350px;
    margin-left: 30px;
}

section h2
{
    font-size: 2.5em;
    text-transform: uppercase;
    margin-bottom: 40px;
}
section p
{
    font-size: 20px;
}

section:nth-child(odd)
{
    position: relative;
    display: flex;
    justify-content: center;
    align-items: center;
    background: rgb(248, 248, 248);
    color: black;
    padding-top: 0% ;
}

@media (max-width:992px)
{
    header ul 
    {
        position: absolute;
        top: -200%;
        left: 0;
        width: 100%;
        height: 40vh;
        padding: 50px 100px;
        transition: 0.5s;
        text-align: center;
        background: #111;
        overflow: auto;
        flex-direction: column;
        transform: translateY(-100px);
        opacity: 0;
    

    }
    header.active ul 
    {
        transform: translateY(0);
        top: 65px;
        opacity: 1;

    }

    header ul li a 
    {
        margin: 5px 0;
        font-size:24px;
    }

    .toogle 
    {
        display: block;
        position: relative;
        width: 30px;
        height: 30px;
        cursor: pointer;


    }

    .toogle::before
    {
        content: '';
        position: absolute;
        top: 4px;
        width: 100% ;
        height: 2px;
        background: #fff;
        z-index: 1;
        transition: 0.5s;
        box-shadow: 0 10px 0 #fff;



    }

    .toogle::after
    {
        content: '';
        position: absolute;
        bottom: 4px;
        width: 100% ;
        height: 2px;
        background: #fff;
        z-index: 1;
        transition: 0.5s;



    }
/*
    header .active .toogle::before
    {
        top: 14px;
        transform: rotate(45deg);
        box-shadow: 0 0 0 #fff;
    }
    
    header .active .toogle::after
    {
        bottom: 14px;
        transform: rotate(-45deg);
    }
*/
    section 
    {
        padding: 60px 25px 35px ;
        flex-direction: column;
    }
    section img 
    {
        margin: 50px 0 0;
        max-width: 100;
        border-radius: 30px;

    }
    .center-it{
        width: 80%;
        margin: auto;
    }
}

/* pre test*/
.quiz {
    width: 100%;
    margin-left:0px;
    background:#d2def2;
    padding: 40px 20px;
    width:inherit;
    border-radius:20px;
    float:left;
}

.quiz input {
    margin-top: 10px;
    margin-bottom: 20px;
}
.quiz p 
{
    margin-top: 10px;
    margin-bottom: 20px;
    
}

.textbox {
    height:22px;
    width:120px;
    font-size:16px;
    border-radius:5px;
    border:none;
    padding-left:5px;
    margin-top: 30px; 
    margin-bottom: 30px;
}
.quiz .button {
    background:green;
    border:none;
    border-radius:5px;
    padding:10px;
    color:white;
    font-size:16px;
    transition-duration:.5s;
    margin-top:50px;
}


.quiz .button:hover {
    background: green;
    border:1px solid green;
    color:black;
    cursor:pointer;
   
}


.after-submit {
    visibility:hidden;
    background:#0000ff;
    padding:10px 20px 10px 20px;
    width:device-width;
    border-radius:20px;
    margin-left:20px;
    font-size:40px;
    align-content: center;
    color: green;
}
/* pre test*/


/* post test*/

#messages2
{
    color: green;
    text-align: center;

}
.correct-count
{
    color: green;
    text-align: center;
}

/* post test*/


#pre h2
{
    text-align: center;
    margin-top: 50px;
}
#quiz h2
{
    text-align: center;
    margin-top: 50px;
}


#lab h2
{
    text-align: center;
    margin-top: 50px;
}
#simulation h2
{
    text-align: center;
    margin-top: 50px;
}
#post h2
{
    text-align: center;
    margin-top: 50px;
}

#mainimg
{
    border-radius: 20px;
}

#messages
{
    color: green;
    text-align: center;

}
#number_correct
{
    color: green;
    text-align: center;
}
.center-it{
    width: 50%;
    margin: auto;
}
#quiztwo{
    width: 100%;
    margin: 1px auto;
}
@media(max-width: 768px){
    .center-it{
        width: 90%;
        margin: auto;
    }
}

@media(max-width: 375px){
    .center-it{
        width: 100%;
        margin: auto;
    }
}

#lab h3
{
    font-size: 30px;
    margin-top: 20px;
    margin-bottom: 20px;
}

#lab p
{
    font-size: 20px;
    text-align: left;
    margin-bottom: 5px;
}