nextcloud-server/apps/theming/css/settings-admin.css

#theming input {
    width: 17em;
}

#theming .upload-logo-field {
    display: none;
}

#theming .theme-undo {
    cursor: pointer;
}

#theming .icon {
    display: inline-block;
}

#theming .theming-label {
    min-width: 6em;
    display: inline-block;
}

#theming .icon-upload {
    display: inline-flex;
}

div#theming_settings_msg {
    margin-left: 10px;
}