:root {
    --theme-background-color: white;
    --theme-button-background-color: #d9001d;
    --theme-font-color: #ffffff;
    --theme-body-title-font: plex-sans,sans-serif;
    --theme-body-font: "plex-sans","Helvetica Neue",Helvetica,Arial,"Microsoft YaHei","?????","Hiragino Sans GB","????",sans-serif;
    --theme-body-color: #2e3333;
    --theme-input-title-color: #000000;
    --theme-form-container-color: #495057;
    --theme-form-container-background-color: #fff;
    --theme-form-container-border-color: #ced4da;
}
#btn-submit {
    background-color: var(--theme-button-background-color);
    color: var(--theme-font-color);
}