body {
    display: flex;
    max-width: 100vw;
    width: 100vw;
}
header {
    float: left;
    background-image: url(../img/layout/left.jpg);
    background-size: cover;
    height: 100vh;
    aspect-ratio: 9 / 16;
}
h1 {
    margin: 0; padding: 10px;
    text-align: right;
    font-size: 5vw;
}
nav {
    text-align: right;
}
form {
    margin-right: 10px;
}
select {
    padding: 3px;
    font-family: Georgia, 'Times New Roman', Times, serif;
    background-color: #fff;
    color: #f00;
    border: 2px solid #000;
}
audio {
    margin: 10px;
    width: 50%; 
    padding: 3px;
    background-color: #fff;
    border: 2px solid #000;
}
iframe {
flex-grow: 1;
}