*{
            box-sizing: border-box;
        }
        body,html{
            height: 100%;
            margin: 0;
            font-family: sans-serif;
            /* color: rgb(54, 58, 172); */
        }
       
        .logo{
            display: inline-block;
            max-width: 200px;
            position: relative;     
        }

        .logo:hover{
            cursor: pointer;
            opacity: 0.5;
        }

        .btn{
            display: inline-block;
            position: absolute;
            margin-left: 30%;
        }
        .bt{
            border: none;
            /* border-radius: 8%; */
            background-color: inherit;
            padding: 5px 8px;
            font-size: 16px;
            cursor: pointer;
            color: rgb(124, 92, 49);
            margin: 25px 20px;
            border-radius: 10px;
        }
        .bt:hover{
            background-color:rgb(230, 151, 61);
            color: azure;
        }
        .sidenav{
            height: 400px;
            width: 200px;
            position:absolute;
            margin-top: 100px;
            margin-left: 0px;
            background-color:white;
            /* z-index: 1;
            overflow-x: hidden; */
        }
        .sidenav a{
            padding: 8px 8px 8px 26px;
            text-decoration: none;
            font-size: 16px;
            color: rgb(124, 92, 49);
            display: block;/*a為行內元素，必須改為區塊元素才可排版*/
        }
        .sidenav a:hover{
            color:rgb(230, 151, 61);
            /* color:rgba(247, 161, 161); */
            font-size: 18px;
        }

        footer{
        
        background-color: rgb(91, 11, 11);
        color: rgb(217, 213, 213);
        text-align: center;
        padding: 8px;
        letter-spacing: 1px;
        width: 100%;
        margin-top:80px;
        
        }

        #backtotop{
            /* display: none; */
            position:fixed;
            right: 20px;
            bottom:20px;
            padding:10px 15px;
            font-size: 18px;
            border: none;
            border-radius: 50%;
            cursor: pointer;
            background-color:rgb(230, 151, 61);
            color:azure;
            opacity: 0;
            pointer-events: none;
            transition: opacity 0.3s;
        }

        #backtotop.show{
            opacity: 1;
            pointer-events: auto;
        }