html, body {
    margin: 0px;
    height: 100%;
    font-family: sans-serif;
}

.box {
    display: flex;
    flex-flow: column;
    height: 100%;
}

.box .header {
    flex: 0 1 auto;
    background: #222;
    color: #fff;
    font-size: 18px;
    padding: 0.5em 1em;
}

.box .main {
    flex: 1 1 auto;
    background: #0f0;
}

.box .footer {
    flex: 0 1 auto;
    background: #222;
    color: #fff;
    font-size: 16px;
    padding: 0.5em 1em;
}

.box .footer a {
    text-decoration: none;
    color: #fff;
}
.box .footer a:hover {
    text-decoration: none;
    color: #ccc;
}

#dol_area {
    padding: 1em;
}

#tip {
    visibility: hidden;
    background-color: #333;
    color: #fff;
    text-align: center;
    padding: 1px 0.5em;
    position: absolute;
    display: block;
    z-index: 1;
}

/* Dropdown **************************************************************************************/

 /* Dropdown Button */
 .dropbtn {
    background-color: #666;
    color: white;
    padding: 0.4em 0.5em;
    font-family: sans-serif;
    font-size: 16px;
    border: none;
    cursor: pointer;
    min-width: 10em;
}

/* Dropdown button on hover & focus */
.dropbtn:hover, .dropbtn:focus {
    background-color: #666;
}

/* The container <div> - needed to position the dropdown content */
.dropdown {
    position: relative;
    display: inline-block;
}

/* Dropdown Content (Hidden by Default) */
.dropdown-content {
    display: none;
    position: absolute;
    background-color: #f1f1f1;
    font-size: 16px;
    opacity: 0.92;
    min-width: 10em;
    box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
    z-index: 1;
}

/* Links inside the dropdown */
.dropdown-content a {
    color: black;
    padding: 0.4em 0.5em;
    text-decoration: none;
    display: block;
}

/* Change color of dropdown links on hover */
.dropdown-content a:hover {background-color: #ddd}

/* Show the dropdown menu (use JS to add this class to the .dropdown-content container when the user clicks on the dropdown button) */
.show {display:block;}