Why can’t keep title unchaged for my theme?

I use a customized theme ,it is twentyfourteen-child.
All the title in wordpress will change into uppercase by default.
I add a css in /var/www/html/wp/wp-content/themes/twentyfourteen-child/style.css.

    h1.entry-title {
        text-transform: none !important;
    }

It take no effect at all!

cat /var/www/html/wp/wp-content/themes/twentyfourteen-child/style.css

    *{
        font-family:"DejaVu Sans Mono" !important;
    }
    .site {
        max-width: 1920px;
    }
    .site::before{
        width:400px;
    }
    .site-header {
        max-width: 1920px;
    }
    
    .site-content header .entry-meta {
        max-width: 100%;
    }
    .site-content .entry-header,
    .site-content .entry-content,
    .site-content .entry-summary,
    .site-content .entry-meta,
    .site-content .navigation,
    .comments-area,
    .page-header,
    .page-content {
        max-width: 70%;
    }
    
    article{
        margin-bottom:10px;
    }
    
    #secondary ul li{
        color:black;
        width:360px;
        font-size:16px;
    }
    
    .entry-meta  .cat-links{
        display:none;
    }
    
    pre{
        font-family:inherit;
        font-size:16px;
        border:1px solid red;
    }
  
    
    h1.entry-title {
        text-transform: none !important;
    }