body{
    background-color:#efefef
}
 
header{
    background-color:#efefef;
    height: 140px;
    width: 100%;
    position: relative;
    z-index: 10;
   
}

header div{
    height: 0;
    width: 100%;
    position: absolute;
    display:flex;
    align-items: center;
    justify-content: center;
         
}

header nav{
    position: relative;
    top: 14vh;

}
.nav-item{
    margin: 35px;
}
.navbar-nav{
    color: #395159;
    font-weight: bold;
    font-size: 14pt;
    position: absolute;
    display:flex;
    align-items: center;
    justify-content: center;
}   


li:hover>ul.dropdown-menu{
        display:block;
}    
    
.dropdown-submenu{
    color: #395159;
    font-size: 12pt;
    font-weight: bold;
    position: relative;
}
.dropdown-submenu>.dropdown-menu{
    color: #395159;
    font-size: 12pt;
    font-weight: bold;
    top:0%;
    left: 100%;
    margin-top: -6px;
}

.dropdown-menu>li>a:hover:after{
    transform:rotate(-90deg) ;
}
li a:hover{
    text-decoration:underline;
}

header a {
    color:#efefef;
    text-decoration:none;
}
.logo{
    position: absolute;
    left: 1vh;
    top:1vh;

}

.media{
    position: absolute;
    right:2vh;
    top:2vh;
}
main{
    background-color: #efefef;
    height: 1400px;
}

.slogan{
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    align-self: flex-start;
    position: absolute;
    right: 12vh;
    top:20vh;
    text-shadow:8px 7px 10px #90a3a7;
    
}

.slogan p1{
    color:#395159;
    font-size: 26pt;
    font-family: Swiss 721 BT;
    font-weight: bold;
    
    
}
.slogan p2{
    color:#395159;
    font-size: 18pt;
    font-family: Swiss 721 BT;
    font-weight: bold;
    text-shadow: none;
    
}
section img{
    width: 90px;
}

.OPENTECH3D{
    position: absolute;
    top: 35vh;
    width: 1080px;
    height: 880PX;
    left: 50%;
    transform: translateX(-50%);
    background-image: url(images/opentech3d.jpg);
    background-repeat: no-repeat;
    background-position: center;
    background-size: cover;
    padding: 75px;
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    

}
.OPENTECH3D1{
    display: flex;
    flex-direction: column;
    align-items: center;
}

.box1 h2{
    font-weight: bold;
    text-shadow: #ffffff 0px 0px 10px;   
}
.box1 h4{
    font-weight: bold;
    text-shadow: #ffffff 0px 0px 10px;   
}

.box2{
    width: 850PX;
    height: 135px;
    background-color: rgb(239, 239, 239,0.7);
    display: flex;
    flex-direction: row;
    justify-content: space-around;
    border-radius: 15px;
    position: absolute;
    top: 35vh;
    padding: 7px 0px 0px 0px;
}
.OPENTECH3D2 img{
    width: 200px;
}
.OPENTECH3D2{
    display: flex;
    flex-direction: column;
    align-items: center;
}
.box3{
    background-color: rgb(239, 239, 239,0.7);
    border-radius: 15px;
    width: 980px;
    display: flex;
    flex-direction: row;
    justify-content: space-around;
    position: absolute;
    top: 90vh;
    left: 50%;
    transform: translateX(-50%);
    padding: 10px;

}


footer{
    background-color: #395159;
    color: #efefef;
    height: 100px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    font-size: 9pt;
    font-family:Adobe 繁黑體 Std, Arial;
    
}


@media screen and (max-width:980px){
   
    .logo{
        width: 60%;
        left: 50%;
        transform: translateX(-50%);
    }

    

    .navbar-toggler{
        position: absolute;
        top: -15px;
        left: 10px;
        border: none;
        cursor: pointer;
   
    }
    

    .navbar-nav{
        background-color: rgba(239, 239, 239, 0.8); 
        width: 200px;
        border-radius: 20px;
        position: absolute;
        top:1vh;
        display:flex;
        align-items: center;
        justify-content: center;
        font-size: 10pt;
        
    }
    header div{
        display:flex;
        align-items: center;
        justify-content: center;

    }

    .nav-item{    
        margin: 0px;
    }
    

    .media{
        position: absolute;
        right:1vh;
        top:3vh;
        display: flex;
        flex-direction: column;
        align-items: center;
        
    }
    .media img{
        width: 30px;
    }
    
    .dropdown-submenu{
        color: #395159;
        font-size: 9pt;
        font-weight: bold;
        position: relative;
    }
    .dropdown-submenu>.dropdown-menu{
        color: #395159;
        font-size: 9pt;
        font-weight: bold;
      
    }
    
    .slogan{
    display: flex;
    flex-direction: column;
    align-items: flex-end;
    align-self: flex-start;
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    top:20vh;
    text-shadow:8px 7px 10px #395159;
    width: 300px;
    
}
    .slogan p1{
        color:#395159;
        font-size: 20pt;
        font-family: Swiss 721 BT;
        font-weight: bold;
        
        
    }
    .slogan p2{
        color:#395159;
        font-size: 12pt;
        font-family: Swiss 721 BT;
        font-weight: bold;
        text-shadow: none;
        
    }
 

}