html{
    scroll-behavior: smooth;
}
.menu-btn{
    display: none;
}
.menu-toggle {
  display: none;
}

@media only screen and (max-width:1199px){
body{
  background-color: #000000;
}
 .menu-btn {
  display: none;
  cursor: pointer;
  font-size: 50px;
  color: oklch(100% 0.00011 271.152);
  background: #000000;
 margin-left: 850px;
 margin-top: -70px;
 padding: 8px;

}
  .menu-toggle:checked ~ .navbar ul{
    display:contents;
  }

  .menu-btn {
    display: block;
  }
    .logo{

        margin-top: 40px;
        width: 400px;
        margin-left: -500px;
    }
 .cn{
        text-align: center;
        color:#111
    }
    .navbar{
        margin-top: -70px;
        
    }
    .navbar>ul{
    display: none;
    flex-direction: column;
    background: #000000;
    }
    .navbar>ul>li{
         margin-left: 50px;
        font-size: 50px;
        font-family:Cambria, Cochin, Georgia, Times, 'Times New Roman', serif
    }
    .navbar>ul>li>a{
        padding-top: 15px;
        margin-left: 15px;
        text-decoration: none;
        display: inline-block;
       color:rgb(0, 0, 0);
       
    }
    .navbar>ul>li.dd1{position: relative;}
  
    .navbar>ul>li.dd1 ul{
     font-size: 50px;
        list-style-type: none;
        display: none;
        background-color: rgb(0, 0, 0);
        border-radius: 3px;
    }
 
    .navbar>ul>li.dd1 ul li a{
        padding: 15px;
        display: inline-block;
        width: 100px;
        text-decoration: none;
       color: rgb(255, 255, 255);
        
    }
    
    .navbar>ul>li.dd2{position: relative;
    margin-top: -50px;}
    
   
    .navbar>ul>li.dd2 ul{
       width: auto;
        position: absolute;
        list-style-type: none;
        display: none;
        background-color: rgb(0, 0, 0);
        border-radius: 3px;
    }
    
    .navbar>ul>li.dd2 ul li a{
        padding: 10px;
        display: inline-block;
        border-bottom: 1px solid #000000;
        width: 100px;
        text-decoration: none;
       color: white;
        
    }
    .navbar>ul>li.dd3{position: relative;
    margin-top: -50px;}
  

    .navbar>ul>li.dd3 ul{
        position: absolute;
        list-style-type: none;
        width: auto;
        display: none;
        background-color: rgb(0, 0, 0);
        border-radius: 3px;
    }
  
    .navbar>ul>li.dd3 ul li a{
        padding: 10px;
        display: inline-block;
        border-bottom: 1px solid #000000;
        width: 100px;
        text-decoration: none;
        color:white;
        
    }
    .cn{  
        
        font-size: 50px;
        margin-top: 0.5%;
        font-family: 'Times New Roman', Times, serif;
        color:white;
        text-align: center;  
    }

.bokpdf{
    margin-top: 50px;
    color:rgb(0, 251, 255);
    font-size: 12px;
    text-align: center;
}
 .RocketScience{
        background-image: url(Rocket/rc.webp);
        background-size:cover; 
      margin-top: 80px;
      margin-right: -0%;
      margin-left: -0%;
      margin-bottom: -1%;
    }
    .RS{
        font-family: Arial, Helvetica, sans-serif;
        font-size: 45px;
        padding-top:180px;
        padding-bottom:170px;
        padding-right:250px;
        padding-left:65px;
        color:white;
        font-weight: bold;
    }
    .RS1{
         margin-top: -18%;
            margin-left: 0%;
            padding-left: 5%;
            color:rgb(255, 255, 255);
            font-size: 10px;
            background-color: #4c4b4b59;
    }
    .rcbd{
        margin-top: 50px;
        margin-left:15px;
    }
    .PBD{
        margin-top: 40px;
      text-align: center;
    }
    .RPB{
        font-size: 22px;
        color:rgb(0, 208, 255);
        text-decoration: none;
        line-height: 2px;
    }
    .rcbd1{
        color: white;
        font-size: 40px;
    }
    .rcbd11{
        color:white;
        margin-top: -1.5%;
        font-size: 20px;
    }
    .BasicPrinciple{
        margin-top: 50px;
        margin-left:2px;
    }
    .bp1{
        color:white;
        font-size: 30px;
    }
    .bp11{
        color:white;
        margin-top: -1%;
        font-size: 15px;
        line-height: 25px;  line-height: 20px;
    }
    .CoreComponents{
        margin-top: -1%;
        margin-left:2px;
        display: flex;
    }
    .cc1{
        color:white;
        font-size:40px;
    }
    .cc11{
        color:white;
        margin-top: -1%;
         font-size: 20px;
        line-height: 25px;  line-height: 20px;
    }
    .ccpic{
    
        display: none;
       
    }
     .ccpicagain{
        margin-top: 30px;
    border-radius: 20px;  
    margin-left: 100px; 
    margin-bottom: 30px;
    }
    .ccmarge{
        padding-right: 5%;
    }
    .KeyEquation{
        margin-top: -1%;
        margin-left:2px;
    }
    .ke1{
        color:white;
        font-size: 40px;
    }
    .ke11{
        color:white;
        margin-top: -1%;
        font-size: 20px;  line-height: 20px;
    }
    .lawpic{
        margin-left: 25%;
        width:200px;
    }
    .ke22{
        color:white;
        margin-top: -1%;
        font-size: 20px;  line-height: 20px;
    }
    .ke33{
        color:white;
        margin-top: -2.6%;
        font-size: 20px;
    }
    .Challenges{
        margin-top: .5%;
        margin-left:2px;
    }
    .ch1{
        color:white;
        font-size: 40px;
    }
    .ch11{
        color:white;
        margin-top: -1%;
        font-size: 20px;line-height: 20px;
    }
    .Applications{
        margin-top: .5%;
        margin-left:2px;
    }
    .ap1{
        color:white;
        font-size:40px;
    }
    .ap11{
        color:white;
        margin-top: -1%;
        font-size: 20px;line-height: 20px;
    }
    
    .Propulsion-Basic{
        margin-top: 2.5%;
        margin-bottom: 8.5%;
    }
    .PB{
        color: white;
        text-align: center;
        font-size: 60px;
    }
    .thrust1{
        margin-top: -5.5%;
        margin-left:1%;
    }
    .th1{
        color:white;
        font-size: 240%;
    }
    .th11{
        color:white;
        margin-top: 0%;
        font-size: 20px;
    }
    .th111{
      display: none;
    }
    .th222{
      display: none;
    }
    .Aerothermodynamics{
        margin-top: .5%;
        margin-left:1%;
    }
    .athermo1{
        color:white;
        font-size: 190%;
    }
    .athermo11{
        color:white;
        margin-top: -0%;
        font-size: 20px;
    }
    .athermo2{
       display: none;
    }
    .athermo22{
     display: none;
    }
    .RocketEngineD{
        margin-top: 12%;
        margin-left:1%;
    }
    .RE1{
        color:white;
        font-size: 220%;
    }
    .RE11{
        color:white;
        margin-top: 0%;
        font-size: 20px;
    }
    .RE2{
       display: none;
    }
    .RE22{
        display:none;
    }
    .GasTurbainRocket{
        margin-top: 1.5%;
        margin-left:1%;
    }
    .GT1{
        color:white;
        font-size: 220%;
    }
    .GT11{
        color:white;
        margin-top: 1%;
        font-size: 20px;
    }
    .GT2{
        display:none;
    }
    .GT22{
        display:none;
    }
    .EngineV{
     margin-left:30px;
     margin-top: 10px;
    }
    .engineview{
        width:900px;
        height:500px;
        border-radius: 15px;
    }
    .engineview1{
        color:white;
        font-size: 30px;
        margin-left: 17%;
        margin-top: 0%;
    }
    .FRocketEngine{
        margin-top: 3%;
        margin-left:1%;
    }
    .FRE1{
      color:white;
        font-size: 200%;
    }
    .FRE11{
        color:white;
        margin-top: 1%;
        font-size: 20px;
    }
    .FRE2{
        display:none;
    }
    .FRE22{
        display:none;
    }
    .LRP{
        margin-top: 0%;
        margin-left:1%;
    }
    .LRP1{
        color:white;
        font-size: 220%;
    }
    .LRP11{
        color:white;
        margin-top: 0%;
        font-size: 20px;
    }
    .LRP2{
        display:none;
    }
    .LRP22{
       display:none;
    }
    .RSP{
        margin-top: 0%;
        margin-left:1%;
    }
    .RSP1{
        color:white;
        font-size: 220%;
    }
    .RSP11{
        color:white;
        margin-top: 0%;
        font-size: 20px;
    }
    .RSP2{
       display:none;
    }
    .RSP22{
        display:none;
    }
    .RPE{
        margin-top: 5%;
        margin-left:1%;
    }
    .RPE1{
        color:white;
        font-size: 220%;
    }
    .RPE11{
        color:white;
        margin-top: 0%;
        font-size: 20px;
    }
    .RPE2{
      display:none;
    }
    .RPE22{
        display:none;
    }
    .RPE8{
        margin-top: 5%;
        margin-left:1%;
    }
    .RPE88{
        color:white;
        font-size: 220%;
    }
    .RPE888{
        color:white;
        margin-top: 0%;
        font-size: 20px;
    }
    .RPE28{
        display:none;
    }
    .RPE288{
    display:none;
    }
    .Hybrid-Rocket{
        margin-top: 2%;
        margin-bottom: 8.5%;
    }
    .HR{
        color: white;
        text-align: center;
        font-size: 60px;
    }
    .hr{
        margin-top: -5%;
        margin-left:1%;
    }
    .hr1{
        color:white;
        font-size: 200%;
    }
    .hr11{
        color:white;
        margin-top: 0%;
        font-size: 20px;
    }
    .hr2{
       display:none;
    }
    .hr22{
        display:none;
    }
    
    .Rss{
        margin-top: 2%;
        margin-bottom: 8.5%;
    }
    .rss{
        color: white;
        text-align: center;
        font-size: 60px;
    }
    .RSSS{
        margin-top: -5%;
        margin-left:1%;
    }
    .RSFS1{
        color:white;
        font-size: 200%;
    }
    .RSFS11{
        color:white;
        margin-top: 0%;
        font-size: 20px;
    }
    .RS111{
       display:none;
    }
    .RS1111{
        display:none;
    }
    .RSSS2{
        margin-top: -1%;
        margin-left:1%;
    }
    .RSFS2{
        color:white;
        font-size: 200%;
    }
    .RSFS22{
        color:white;
        margin-top: 0%;
        font-size: 20px;
    }
    .RSFS222{
      display:none;
    }
    .RSFS2222{
        display:none;
    }
    
    .RMA{
        margin-top: 10%;
        margin-left:1%;
    }
    .RMA1{
        color:white;
        font-size: 200%;
    }
    .RMA11{
        color:white;
        margin-top: 0%;
        font-size: 19.8px;
    }
    .RMA2{
       display:none;
    }
    .RMA22{
    display:none;
    }

  .up{ 
       left:93.5%; 
    top:92%; 
    width: 40px;
    animation-name:appear;
    animation-timeline:scroll(y);
    }
    @keyframes appear {
        0%{
            opacity: 0;
            display: none;
            position:fixed;
        }
           3%{
            opacity: 0;
            display: none;
           }  
           3.5%{
            opacity: 1;
            display: block;
           }
    
            100%{
                opacity: 1;
                display: block;
                position:fixed;
            }
    
    
    }   
 
    .footer {
      background-color: #111;
      margin-top: 5%;
      color: #ddd;
      padding: 30px 20px;
      font-family: 'Segoe UI', sans-serif;
    }
    
    .footer-content {
      display: flex;
      flex-wrap: wrap;
      justify-content: space-around;
      gap: 20px;
      margin-bottom: 15px;
    }
    
    .footer-section {
      min-width: 200px;
    }
    
    .footer-section h3 {
      color: #fff;
      margin-bottom: 10px;
    }
    
    .footer-section a {
      color: #9cf;
      text-decoration: none;
    }
    
    .footer-section a:hover {
      text-decoration: underline;
    }
    
    .social-icons img {
      font-family: Arial, Helvetica, sans-serif;
      margin-right: 10px;
      font-weight: 30;
      
    }
    
    .footer-bottom {
      text-align: center;
      border-top: 1px solid #444;
      padding-top: 10px;
      font-size: 14px;
      color: #aaa;
    }
}
@media only screen and (min-width:1200px) and (max-width:1500px){
   body{
    background-color: rgb(31, 31, 31);
}
 .logo{

         width: 500px; 
      text-align: center;
       margin-bottom: 15px;
    }
    .bokpdf{
        display: none;
    }
 .RocketScience{
        background-image: url(Rocket/rc.webp);
        background-size:cover; 
      margin-top: -3.6%;
      margin-right: -0%;
      margin-left: -0%;
      margin-bottom: -1%;
    }
    .RS{
        font-family: Arial, Helvetica, sans-serif;
        font-size: 450%;
        padding-top:180px;
        padding-bottom:170px;
        padding-right:250px;
        padding-left:65px;
        color:white;
        font-weight: bold;
    }
    .RS1{
         margin-top: -15%;
            margin-left: 5%;
            padding-bottom: 5%;
            color:rgb(255, 255, 255);
            font-size: 136%;
    }
    .rcbd{
        margin-top: 1%;
        margin-left:8%;
        display: flex;
    }
    .PBD{
        margin-top: 2%;
        margin-left:5%;
    }
    .RPB{
        font-size: 25px;
        color:white;
        text-decoration: none;
    }
    .rcbd1{
        color: white;
        font-size: 250%;
    }
    .rcbd11{
        color:white;
        margin-top: -1.5%;
        font-size: 20px;
    }
    .BasicPrinciple{
        margin-top: 2.5%;
        margin-left:2.5%;
    }
    .bp1{
        color:white;
        font-size: 220%;
    }
    .bp11{
        color:white;
        margin-top: -1%;
        font-size: 20px;
    }
    .CoreComponents{
        margin-top: -1%;
        margin-left:2.5%;
        display: flex;
    }
    .cc1{
        color:white;
        font-size: 220%;
    }
    .cc11{
        color:white;
        margin-top: -1%;
        font-size: 20px;
    }
    .ccpic{
    
        width: 350px;
        border-radius: 15px;
        margin-bottom: 10px;
        margin-top: -15%;
    }
      .ccpicagain{
    
        display: none;
       
    }
    .ccmarge{
        padding-right: 5%;
    }
    .KeyEquation{
        margin-top: -1%;
        margin-left:2.5%;
    }
    .ke1{
        color:white;
        font-size: 220%;
    }
    .ke11{
        color:white;
        margin-top: -1%;
        font-size: 20px;
    }
    .lawpic{
        margin-left: 25%;
        width:200px;
    }
    .ke22{
        color:white;
        margin-top: -1%;
        font-size: 20px;
    }
    .ke33{
        color:white;
        margin-top: -2.6%;
        font-size: 20px;
    }
    .Challenges{
        margin-top: .5%;
        margin-left:2.5%;
    }
    .ch1{
        color:white;
        font-size: 220%;
    }
    .ch11{
        color:white;
        margin-top: -1%;
        font-size: 20px;
    }
    .Applications{
        margin-top: .5%;
        margin-left:2.5%;
    }
    .ap1{
        color:white;
        font-size: 220%;
    }
    .ap11{
        color:white;
        margin-top: -1%;
        font-size: 20px;
    }
    
    .Propulsion-Basic{
        margin-top: 2.5%;
        margin-bottom: 8.5%;
    }
    .PB{
        color: white;
        text-align: center;
        font-size: 60px;
    }
    .thrust1{
        margin-top: -5.5%;
        margin-left:1%;
    }
    .th1{
        color:white;
        font-size: 240%;
    }
    .th11{
        color:white;
        margin-top: 0%;
        font-size: 20px;
    }
    .th111{
        width: 450px;
      height: 550px;
      margin-left: 65%;
      margin-bottom: 5%;
      margin-top: -38.5%;
      border-radius: 15px;
    }
    .th222{
        color:white;
        margin-top: -4.5%;
        font-size: 30px;
        margin-left: 68%;
    }
    .Aerothermodynamics{
        margin-top: .5%;
        margin-left:1%;
    }
    .athermo1{
        color:white;
        font-size: 190%;
    }
    .athermo11{
        color:white;
        margin-top: -0%;
        font-size: 20px;
    }
    .athermo2{
        width: 450px;
      height: 550px;
      margin-left: 65%;
      margin-bottom: 10%;
      margin-top: -60%;
      border-radius: 15px;
    }
    .athermo22{
        color:white;
        margin-top: -9.5%;
        font-size: 15px;
        margin-left: 67%;
    }
    .RocketEngineD{
        margin-top: 12%;
        margin-left:1%;
    }
    .RE1{
        color:white;
        font-size: 220%;
    }
    .RE11{
        color:white;
        margin-top: 0%;
        font-size: 20px;
    }
    .RE2{
        width: 450px;
      height: 550px;
      margin-left: 65%;
      margin-bottom: 5%;
      margin-top: -45.5%;
      border-radius: 15px;
    }
    .RE22{
        color:white;
        margin-top: -4.5%;

        font-size: 18px;
        margin-left: 68%;
    }
    .GasTurbainRocket{
        margin-top: 1.5%;
        margin-left:1%;
    }
    .GT1{
        color:white;
        font-size: 220%;
    }
    .GT11{
        color:white;
        margin-top: 1%;
        font-size: 20px;
    }
    .GT2{
        width: 450px;
      height: 550px;
      margin-left: 65%;
      margin-bottom: -50%;
      border-radius: 15px;
    }
    .GT22{
        color:white;
        margin-top: -.5%;
        font-size: 16px;
        margin-left: 68%;
        padding-bottom: 8%;
    }
    .EngineV{
     margin-left:25.5%;
     margin-top: -3.5%;
    }
    .engineview{
        width:600px;
        height:300px;
        border-radius: 15px;
    }
    .engineview1{
        color:white;
        font-size: 30px;
        margin-left: 17%;
        margin-top: 0%;
    }
    .FRocketEngine{
        margin-top: 3%;
        margin-left:1%;
    }
    .FRE1{
      color:white;
        font-size: 200%;
    }
    .FRE11{
        color:white;
        margin-top: 1%;
        font-size: 20px;
    }
    .FRE2{
        width: 450px;
      height: 550px;
      margin-left: 65%;
      margin-bottom: 5%;
      margin-top: -42.5%;
      border-radius: 15px;
    }
    .FRE22{
        color:white;
        margin-top: -4.5%;
        font-size: 15px;
        margin-left: 66.5%;
    }
    .LRP{
        margin-top: 0%;
        margin-left:1%;
    }
    .LRP1{
        color:white;
        font-size: 220%;
    }
    .LRP11{
        color:white;
        margin-top: 0%;
        font-size: 20px;
    }
    .LRP2{
        width: 450px;
      height: 550px;
      margin-left: 65%;
      margin-bottom: 5%;
      margin-top: -42.5%;
      border-radius: 15px;
    }
    .LRP22{
        color:white;
        margin-top: -4.5%;
        font-size: 23px;
        margin-left: 70%;
    }
    .RSP{
        margin-top: 0%;
        margin-left:1%;
    }
    .RSP1{
        color:white;
        font-size: 220%;
    }
    .RSP11{
        color:white;
        margin-top: 0%;
        font-size: 20px;
    }
    .RSP2{
        width: 450px;
      height: 550px;
      margin-left: 65%;
      margin-bottom: 5%;
      margin-top: -50%;
      border-radius: 15px;
    }
    .RSP22{
        color:white;
        margin-top: -4.5%;
        font-size: 21px;
        margin-left: 70%;
    }
    .RPE{
        margin-top: 5%;
        margin-left:1%;
    }
    .RPE1{
        color:white;
        font-size: 220%;
    }
    .RPE11{
        color:white;
        margin-top: 0%;
        font-size: 20px;
    }
    .RPE2{
        width: 450px;
      height: 550px;
      margin-left: 65%;
      margin-bottom: 5%;
      margin-top: -50%;
      border-radius: 15px;
    }
    .RPE22{
        color:white;
        margin-top: -4.5%;
        font-size: 22px;
        margin-left: 69%;
    }
    .RPE8{
        margin-top: 5%;
        margin-left:1%;
    }
    .RPE88{
        color:white;
        font-size: 220%;
    }
    .RPE888{
        color:white;
        margin-top: 0%;
        font-size: 20px;
    }
    .RPE28{
        width: 450px;
      height: 550px;
      margin-left: 65%;
      margin-bottom: 5%;
      margin-top: -50%;
      border-radius: 15px;
    }
    .RPE288{
        color:white;
        margin-top: -4.5%;
        font-size: 18px;
        margin-left: 68%;
    }
    .Hybrid-Rocket{
        margin-top: 2%;
        margin-bottom: 8.5%;
    }
    .HR{
        color: white;
        text-align: center;
        font-size: 60px;
    }
    .hr{
        margin-top: -5%;
        margin-left:1%;
    }
    .hr1{
        color:white;
        font-size: 200%;
    }
    .hr11{
        color:white;
        margin-top: 0%;
        font-size: 20px;
    }
    .hr2{
        width: 450px;
      height: 550px;
      margin-left: 65%;
      margin-bottom: 5%;
      margin-top: -50%;
      border-radius: 15px;
    }
    .hr22{
        color:white;
        margin-top: -4.5%;
        font-size: 15px;
        margin-left: 66.5%;
    }
    
    .Rss{
        margin-top: 2%;
        margin-bottom: 8.5%;
    }
    .rss{
        color: white;
        text-align: center;
        font-size: 60px;
    }
    .RSSS{
        margin-top: -5%;
        margin-left:1%;
    }
    .RSFS1{
        color:white;
        font-size: 200%;
    }
    .RSFS11{
        color:white;
        margin-top: 0%;
        font-size: 20px;
    }
    .RS111{
        width: 450px;
      height: 550px;
      margin-left: 65%;
      margin-bottom: 5%;
      margin-top: -40%;
      border-radius: 15px;
    }
    .RS1111{
        color:white;
        margin-top: -4.5%;
        font-size: 20px;
        margin-left: 67%;
    }
    .RSSS2{
        margin-top: -1%;
        margin-left:1%;
    }
    .RSFS2{
        color:white;
        font-size: 200%;
    }
    .RSFS22{
        color:white;
        margin-top: 0%;
        font-size: 20px;
    }
    .RSFS222{
        width: 450px;
      height: 550px;
      margin-left: 65%;
      margin-bottom: 10%;
      margin-top: -60%;
      border-radius: 15px;
    }
    .RSFS2222{
        color:white;
        margin-top: -9.5%;
        font-size: 20px;
        margin-left: 66.5%;
    }
    
    .RMA{
        margin-top: 10%;
        margin-left:1%;
    }
    .RMA1{
        color:white;
        font-size: 200%;
    }
    .RMA11{
        color:white;
        margin-top: 0%;
        font-size: 19.8px;
    }
    .RMA2{
        width: 450px;
      height: 550px;
      margin-left: 65%;
      margin-bottom: 5%;
      margin-top: -45%;
      border-radius: 15px;
    }
    .RMA22{
        color:white;
        margin-top: -4.5%;
        font-size: 23px;
        margin-left: 68.5%;
    }
    .up{ 
        left:98%; 
        top:90%; 
        width: 20px;
        animation-name:appear;
        animation-timeline:scroll(y);
    }
    @keyframes appear {
        0%{
            opacity: 0;
            display: none;
            position:fixed;
        }
           3%{
            opacity: 0;
            display: none;
           }  
           3.5%{
            opacity: 1;
            display: block;
           }
    
            100%{
                opacity: 1;
                display: block;
                position:fixed;
            }
        }    
    .navbar{
        margin-top: -1;
        width: 100%;
        background-color: rgba(121, 121, 119, 0.8);
    }
    .navbar>ul{
        margin:5px;
        list-style-type: none;
    }
    .navbar>ul>li{
        display: inline-block;
        font-size: 30px;
        font-family: 'Times New Roman', Times, serif;
    }
    .navbar>ul>li>a{
        text-decoration: none;
        display: inline-block;
       color:white;
        padding: 0px 20px;
    }
    .navbar>ul>li.dd1{position: relative;}
    .navbar>ul>li.dd1:hover{
        background-color: #232222;
        border-radius: 2px;
    }
    .navbar>ul>li.dd1:hover ul{
        transition:2s;
        display: block;
         background-color:rgba(83, 83, 83, 0.89);
    }
    .navbar>ul>li.dd1 ul{
       width: auto;
        position: absolute;
        list-style-type: none;
         margin-left: 35.5px;
        display: none;
        background-color: gray;
        border-radius: 3px;
    }
    .navbar>ul>li.dd1 ul li a:hover{
        background-color: #232222;
      
    }
    .navbar>ul>li.dd1 ul li a{
        margin-left: -40px;
        padding: 10px;
        display: inline-block;
        border-bottom: 1px solid #888;
        width: 100px;
        text-decoration: none;
       color: white;
        
    }
    
    .navbar>ul>li.dd2{position: relative;}
    .navbar>ul>li.dd2:hover{
        background-color: #232222;
        border-radius: 2px;
    }
    .navbar>ul>li.dd2:hover ul{
        transition:2s;
        display: block;
         background-color:rgba(83, 83, 83, 0.89);
    }
    .navbar>ul>li.dd2 ul{
       width: auto;
        position: absolute;
        list-style-type: none;
         margin-left: 25.5px;
        display: none;
        background-color: gray;
        border-radius: 3px;
    }
    .navbar>ul>li.dd2 ul li a:hover{
        background-color: #232222;
      
    }
    .navbar>ul>li.dd2 ul li a{
        margin-left: -40px;
        padding: 10px;
        display: inline-block;
        border-bottom: 1px solid #888;
        width: 100px;
        text-decoration: none;
       color: white;
        
    }
    .navbar>ul>li.dd3{position: relative;}
    .navbar>ul>li.dd3:hover{
          background-color: #232222;
        border-radius: 2px;
    }
    .navbar>ul>li.dd3:hover ul{
        transition:2s;
        display: block;
         background-color:rgba(83, 83, 83, 0.89);
    }
    .navbar>ul>li.dd3 ul{
        position: absolute;
        list-style-type: none;
        width: auto;
         margin-left: 60px;
        display: none;
        background-color: gray;
        border-radius: 3px;
    }
    .navbar>ul>li.dd3 ul li a:hover{
        background-color: #232222;
      
    }
    .navbar>ul>li.dd3 ul li a{
        margin-left: -40px;
        padding: 10px;
        display: inline-block;
        border-bottom: 1px solid #888;
        width: 100px;
        text-decoration: none;
        color:white;
        
    }
    .navbar{
      width: 100%;
     text-align: center;
      margin-top: 0%;
    }
    .cn{  
        
        font-size: 50px;
        margin-top: 0.5%;
        font-family: 'Times New Roman', Times, serif;
        color:white;
        text-align: center;
      
    }
    
    .cnt:hover{
       
    background-color: #232222;
    border-radius: 2px;
    
    }
    
    .dd11:hover{
        background-color: #232222;
        border-radius: 2px;
    }
    .footer {
      background-color: #111;
      color: #ddd;
      padding: 30px 20px;
      font-family: 'Segoe UI', sans-serif;
    }
    
    .footer-content {
      display: flex;
      flex-wrap: wrap;
      justify-content: space-around;
      gap: 20px;
      margin-bottom: 15px;
    }
    
    .footer-section {
      min-width: 200px;
    }
    
    .footer-section h3 {
      color: #fff;
      margin-bottom: 10px;
    }
    
    .footer-section a {
      color: #9cf;
      text-decoration: none;
    }
    
    .footer-section a:hover {
      text-decoration: underline;
    }
    
    .social-icons img {
      font-family: Arial, Helvetica, sans-serif;
      margin-right: 10px;
      font-weight: 30;
      
    }
    
    .footer-bottom {
      text-align: center;
      border-top: 1px solid #444;
      padding-top: 10px;
      font-size: 14px;
      color: #aaa;
}
}


@media only screen and (min-width:1501px){
body{
    background-color: rgb(31, 31, 31);
}
 .logo{
      width: 500px; 
      text-align: center;
       margin-bottom: 15px;
    }
    .bokpdf{
        display: none;
    }
.RocketScience{
    background-image: url(Rocket/rc.webp);
    background-size:cover; 
  margin-top: -3.15%;
  margin-right: -0%;
  margin-left: -0%;
  margin-bottom: -1%;
}
.RS{
    font-family: Arial, Helvetica, sans-serif;
    font-size: 500%;
    padding-top:250px;
    padding-bottom:200px;
    padding-right:250px;
    padding-left:120px;
    color:white;
    font-weight: bold;
}
.RS1{
     margin-top: -15%;
        margin-left: 7.2%;
        padding-bottom: 5%;
        color:rgb(255, 255, 255);
        font-size: 150%;
}
.rcbd{
    margin-top: 3.5%;
    margin-left:14%;
    display: flex;
}
.PBD{
    margin-top: 2.5%;
    margin-left: 10%;
}
.RPB{
    font-size: 30px;
    color:white;
    text-decoration: none;
}
.rcbd1{
    color: white;
    font-size: 250%;
}
.rcbd11{
    color:white;
    margin-top: -1.5%;
    font-size: 20px;
}
.BasicPrinciple{
    margin-top: 3.5%;
    margin-left:10%;
}
.bp1{
    color:white;
    font-size: 220%;
}
.bp11{
    color:white;
    margin-top: -1%;
    font-size: 20px;
}
.CoreComponents{
    margin-top: -1%;
    margin-left:10%;
    display: flex;
}
.cc1{
    color:white;
    font-size: 220%;
}
.cc11{
    color:white;
    margin-top: -1%;
    font-size: 20px;
}
.ccpic{

    width: 380px;
    border-radius: 15px;
    margin-bottom: 10px;
    margin-top: -15%;
}
  .ccpicagain{
    
        display: none;
       
    }
.ccmarge{
    padding-right: 9.5%;
}
.KeyEquation{
    margin-top: -1%;
    margin-left:10%;
}
.ke1{
    color:white;
    font-size: 220%;
}
.ke11{
    color:white;
    margin-top: -1%;
    font-size: 20px;
}
.lawpic{
    margin-left: 25%;
    width:200px;
}
.ke22{
    color:white;
    margin-top: -1%;
    font-size: 20px;
}
.ke33{
    color:white;
    margin-top: -2.6%;
    font-size: 20px;
}
.Challenges{
    margin-top: .5%;
    margin-left:10%;
}
.ch1{
    color:white;
    font-size: 220%;
}
.ch11{
    color:white;
    margin-top: -1%;
    font-size: 20px;
}
.Applications{
    margin-top: .5%;
    margin-left:10%;
}
.ap1{
    color:white;
    font-size: 220%;
}
.ap11{
    color:white;
    margin-top: -1%;
    font-size: 20px;
}

.Propulsion-Basic{
    margin-top: 2.5%;
    margin-bottom: 8.5%;
}
.PB{
    color: white;
    text-align: center;
    font-size: 60px;
}
.thrust1{
    margin-top: -1.5%;
    margin-left:6%;
}
.th1{
    color:white;
    font-size: 240%;
}
.th11{
    color:white;
    margin-top: 0%;
    font-size: 20px;
}
.th111{
    width: 660px;
  height: 600px;
  margin-left: 55%;
  margin-bottom: 5%;
  margin-top: -35.5%;
  border-radius: 15px;
}
.th222{
    color:white;
    margin-top: -4.5%;
    font-size: 30px;
    margin-left: 66%;
}
.Aerothermodynamics{
    margin-top: .5%;
    margin-left:6%;
}
.athermo1{
    color:white;
    font-size: 190%;
}
.athermo11{
    color:white;
    margin-top: -0%;
    font-size: 20px;
}
.athermo2{
    width: 660px;
  height: 600px;
  margin-left: 55%;
  margin-bottom: 5%;
  margin-top: -42.5%;
  border-radius: 15px;
}
.athermo22{
    color:white;
    margin-top: -4.5%;
    font-size: 23px;
    margin-left: 56%;
}
.RocketEngineD{
    margin-top: 5%;
    margin-left:6%;
}
.RE1{
    color:white;
    font-size: 220%;
}
.RE11{
    color:white;
    margin-top: 0%;
    font-size: 20px;
}
.RE2{
    width: 660px;
  height: 600px;
  margin-left: 55%;
  margin-bottom: 5%;
  margin-top: -38.5%;
  border-radius: 15px;
}
.RE22{
    color:white;
    margin-top: -4.5%;
    font-size: 23px;
    margin-left: 61%;
}
.GasTurbainRocket{
    margin-top: 1.5%;
    margin-left:6%;
}
.GT1{
    color:white;
    font-size: 220%;
}
.GT11{
    color:white;
    margin-top: 1%;
    font-size: 20px;
}
.GT2{
    width: 660px;
  height: 600px;
  margin-left: 55%;
  margin-bottom: -40%;
  border-radius: 15px;
}
.GT22{
    color:white;
    margin-top: -2.5%;
    font-size: 23px;
    margin-left: 59%;
    padding-bottom: 8%;
}
.EngineV{
 margin-left:30%;
 margin-top: -4%;
}
.engineview{
    width:600px;
    height:300px;
    border-radius: 15px;
}
.engineview1{
    color:white;
    font-size: 30px;
    margin-left: 15%;
    margin-top: 0%;
}
.FRocketEngine{
    margin-top: 5%;
    margin-left:6%;
}
.FRE1{
  color:white;
    font-size: 200%;
}
.FRE11{
    color:white;
    margin-top: 1%;
    font-size: 20px;
}
.FRE2{
    width: 660px;
  height: 600px;
  margin-left: 55%;
  margin-bottom: 5%;
  margin-top: -38.5%;
  border-radius: 15px;
}
.FRE22{
    color:white;
    margin-top: -4.5%;
    font-size: 23px;
    margin-left: 56%;
}
.LRP{
    margin-top: 0%;
    margin-left:6%;
}
.LRP1{
    color:white;
    font-size: 220%;
}
.LRP11{
    color:white;
    margin-top: 0%;
    font-size: 20px;
}
.LRP2{
    width: 660px;
  height: 600px;
  margin-left: 55%;
  margin-bottom: 5%;
  margin-top: -38.5%;
  border-radius: 15px;
}
.LRP22{
    color:white;
    margin-top: -4.5%;
    font-size: 23px;
    margin-left: 66%;
}
.RSP{
    margin-top: 0%;
    margin-left:6%;
}
.RSP1{
    color:white;
    font-size: 220%;
}
.RSP11{
    color:white;
    margin-top: 0%;
    font-size: 20px;
}
.RSP2{
    width: 660px;
  height: 600px;
  margin-left: 55%;
  margin-bottom: 5%;
  margin-top: -50%;
  border-radius: 15px;
}
.RSP22{
    color:white;
    margin-top: -4.5%;
    font-size: 23px;
    margin-left: 66%;
}
.RPE{
    margin-top: 5%;
    margin-left:6%;
}
.RPE1{
    color:white;
    font-size: 220%;
}
.RPE11{
    color:white;
    margin-top: 0%;
    font-size: 20px;
}
.RPE2{
    width: 660px;
  height: 650px;
  margin-left: 55%;
  margin-bottom: 5%;
  margin-top: -50%;
  border-radius: 15px;
}
.RPE22{
    color:white;
    margin-top: -4.5%;
    font-size: 23px;
    margin-left: 66%;
}
.RPE8{
    margin-top: 5%;
    margin-left:6%;
}
.RPE88{
    color:white;
    font-size: 220%;
}
.RPE888{
    color:white;
    margin-top: 0%;
    font-size: 20px;
}
.RPE28{
    width: 660px;
  height: 680px;
  margin-left: 55%;
  margin-bottom: 5%;
  margin-top: -50%;
  border-radius: 15px;
}
.RPE288{
    color:white;
    margin-top: -4.5%;
    font-size: 23px;
    margin-left: 62%;
}
.Hybrid-Rocket{
    margin-top: 4%;
    margin-bottom: 8.5%;
}
.HR{
    color: white;
    text-align: center;
    font-size: 60px;
}
.hr{
    margin-top: -5%;
    margin-left:6%;
}
.hr1{
    color:white;
    font-size: 200%;
}
.hr11{
    color:white;
    margin-top: 0%;
    font-size: 20px;
}
.hr2{
    width: 660px;
  height: 600px;
  margin-left: 55%;
  margin-bottom: 5%;
  margin-top: -50%;
  border-radius: 15px;
}
.hr22{
    color:white;
    margin-top: -4.5%;
    font-size: 23px;
    margin-left: 56%;
}

.Rss{
    margin-top: 2%;
    margin-bottom: 8.5%;
}
.rss{
    color: white;
    text-align: center;
    font-size: 60px;
}
.RSSS{
    margin-top: -5%;
    margin-left:6%;
}
.RSFS1{
    color:white;
    font-size: 200%;
}
.RSFS11{
    color:white;
    margin-top: 0%;
    font-size: 20px;
}
.RS111{
    width: 660px;
  height: 600px;
  margin-left: 55%;
  margin-bottom: 5%;
  margin-top: -40%;
  border-radius: 15px;
}
.RS1111{
    color:white;
    margin-top: -4.5%;
    font-size: 23px;
    margin-left: 62%;
}
.RSSS2{
    margin-top: -1%;
    margin-left:6%;
}
.RSFS2{
    color:white;
    font-size: 200%;
}
.RSFS22{
    color:white;
    margin-top: 0%;
    font-size: 20px;
}
.RSFS222{
    width: 660px;
  height: 600px;
  margin-left: 55%;
  margin-bottom: 5%;
  margin-top: -40%;
  border-radius: 15px;
}
.RSFS2222{
    color:white;
    margin-top: -4.5%;
    font-size: 23px;
    margin-left: 62%;
}
.RMA{
    margin-top: 5%;
    margin-left:6%;
}
.RMA1{
    color:white;
    font-size: 200%;
}
.RMA11{
    color:white;
    margin-top: 0%;
    font-size: 20px;
}
.RMA2{
    width: 660px;
  height: 600px;
  margin-left: 55%;
  margin-bottom: 5%;
  margin-top: -35%;
  border-radius: 15px;
}
.RMA22{
    color:white;
    margin-top: -4.5%;
    font-size: 23px;
    margin-left: 66%;
}
.up{ 
    left:98%; 
    top:90%; 
    width: 20px;
    animation-name:appear;
    animation-timeline:scroll(y);
}
@keyframes appear {
    0%{
        opacity: 0;
        display: none;
        position:fixed;
    }
       3%{
        opacity: 0;
        display: none;
       }  
       3.5%{
        opacity: 1;
        display: block;
       }

        100%{
            opacity: 1;
            display: block;
            position:fixed;
        }
    }
  
.navbar{
    margin-top: -1;
    width: 100%;
    background-color: rgba(121, 121, 119, 0.8);
}
.navbar>ul{
    margin:5px;
    list-style-type: none;
}
.navbar>ul>li{
    display: inline-block;
    font-size: 30px;
    font-family: 'Times New Roman', Times, serif;
}
.navbar>ul>li>a{
    text-decoration: none;
    display: inline-block;
   color:white;
    padding: 0px 20px;
}
.navbar>ul>li.dd1{position: relative;}
.navbar>ul>li.dd1:hover{
    background-color: #232222;
    border-radius: 2px;
}
.navbar>ul>li.dd1:hover ul{
    transition:2s;
    display: block;
     background-color:rgba(83, 83, 83, 0.89);
}
.navbar>ul>li.dd1 ul{
   width: auto;
    position: absolute;
    list-style-type: none;
     margin-left: 35.5px;
    display: none;
    background-color: gray;
    border-radius: 3px;
}
.navbar>ul>li.dd1 ul li a:hover{
    background-color: #232222;
  
}
.navbar>ul>li.dd1 ul li a{
    margin-left: -40px;
    padding: 10px;
    display: inline-block;
    border-bottom: 1px solid #888;
    width: 100px;
    text-decoration: none;
   color: white;
    
}

.navbar>ul>li.dd2{position: relative;}
.navbar>ul>li.dd2:hover{
    background-color: #232222;
    border-radius: 2px;
}
.navbar>ul>li.dd2:hover ul{
    transition:2s;
    display: block;
     background-color:rgba(83, 83, 83, 0.89);
}
.navbar>ul>li.dd2 ul{
   width: auto;
    position: absolute;
    list-style-type: none;
     margin-left: 25.5px;
    display: none;
    background-color: gray;
    border-radius: 3px;
}
.navbar>ul>li.dd2 ul li a:hover{
    background-color: #232222;
  
}
.navbar>ul>li.dd2 ul li a{
    margin-left: -40px;
    padding: 10px;
    display: inline-block;
    border-bottom: 1px solid #888;
    width: 100px;
    text-decoration: none;
   color: white;
    
}
.navbar>ul>li.dd3{position: relative;}
.navbar>ul>li.dd3:hover{
      background-color: #232222;
    border-radius: 2px;
}
.navbar>ul>li.dd3:hover ul{
    transition:2s;
    display: block;
     background-color:rgba(83, 83, 83, 0.89);
}
.navbar>ul>li.dd3 ul{
    position: absolute;
    list-style-type: none;
    width: auto;
     margin-left: 60px;
    display: none;
    background-color: gray;
    border-radius: 3px;
}
.navbar>ul>li.dd3 ul li a:hover{
    background-color: #232222;
  
}
.navbar>ul>li.dd3 ul li a{
    margin-left: -40px;
    padding: 10px;
    display: inline-block;
    border-bottom: 1px solid #888;
    width: 100px;
    text-decoration: none;
    color:white;
    
}
.navbar{
  width: 100%;
 text-align: center;
  margin-top: 0%;
}
.cn{  
    
    font-size: 50px;
    margin-top: 0.5%;
    font-family: 'Times New Roman', Times, serif;
    color:white;
    text-align: center;
  
}

.cnt:hover{
   
background-color: #232222;
border-radius: 2px;

}

.dd11:hover{
    background-color: #232222;
    border-radius: 2px;
}
.footer {
  background-color: #111;
  color: #ddd;
  padding: 30px 20px;
  font-family: 'Segoe UI', sans-serif;
}

.footer-content {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-around;
  gap: 20px;
  margin-bottom: 15px;
}

.footer-section {
  min-width: 200px;
}

.footer-section h3 {
  color: #fff;
  margin-bottom: 10px;
}

.footer-section a {
  color: #9cf;
  text-decoration: none;
}

.footer-section a:hover {
  text-decoration: underline;
}

.social-icons img {
  font-family: Arial, Helvetica, sans-serif;
  margin-right: 10px;
  font-weight: 30;
  
}

.footer-bottom {
  text-align: center;
  border-top: 1px solid #444;
  padding-top: 10px;
  font-size: 14px;
  color: #aaa;
}}