html {
    font-family: Verdana, Geneva, Tahoma, sans-serif;
    transition-duration: 100ms;
    height: 100vh;
    overflow: hidden;
}

body {
    padding: 0;
    margin: 0;
    overflow: hidden;
}

#topnav {
    width: 100%;
    height: max-content;
    background-color: black;
    margin: 0;
    padding: 0;
    margin-bottom: 10px;
}

button {
    background-color: black;
    color: white;
    border: none;
    padding: 15px;
    font-size: larger;
    transition-duration: 100ms;
}

.mobile button {
    background-color: black;
    color: white;
    border: none;
    padding: 15px;
    font-size: larger;
    transition-duration: 100ms;
    font-size: xx-large;
}

.mobile #plcaeholder_stundenplan {
    width: 100vw;
}

button:hover {
    background-color: white;
    color: black;
    cursor: pointer;
    transition-duration: 100ms;
}

#topnav .backbutton {
    float: right;
}

#topnav select,
#topnav input {
    background-color: black;
    color: white;
    border: none;
    padding: 15px;
    font-size: larger;
    text-decoration: none;
}

.tab {
    opacity: 0;
    z-index: -1;
    transition-duration: 400ms;
    position: absolute;
    height: 99vh;
    overflow: scroll;
}

.visibleTab {
    opacity: 1;
    z-index: 0;
    transition-duration: 400ms;
}

.refresh_button {
    font-size: small;
    padding: 5px;
    margin: 5px;
    vertical-align: middle;
}