calendar.css

.content {
    flex: 1 0 auto;
    font-size: 1.2em;
    padding: 1em;
}

#start-date, #end-date {
    appearance: none;
    border: none;
    outline: none;
    background: none;
    padding: 0px;
    color-scheme: light dark;

    width: 10ch;
    font-size: 1em;
    color: var(--text-color);
    border-bottom: 0.1em solid var(--text-color);
    font-family: monospace;
}


#file1, #file2 {
    white-space: nowrap;
}

#google-cal, #yandex-cal {
    white-space: nowrap;
}

#first-week {
    color-scheme: light dark;
    vertical-align: bottom;
    cursor: pointer;
    width: 1rem;
    height: 1rem;
}

#google-cal::before {
    content: "\200b";
    display: inline-block;
    background-image: url(https://calendar.google.com/googlecalendar/images/favicons_2020q4/calendar_1.ico);
    background-size: 1em 1em;
    width: 1em;
    height: 1em;
    margin-right: 0.1em;
}

#yandex-cal::before {
    content: "\200b";
    display: inline-block;
    background-image: url(https://calendar.yandex.ru/favicon/png/32/1.png);
    background-size: 1em 1em;
    width: 1em;
    height: 1em;
    margin-right: 0.1em;
}