Não carrega o style.css no wordpress

Estou estudando WordPress, mas, não consegui utilizar o functions.php para carregar o stylesheet

Estes são os arquivos

style.css

/* Theme Name: Tema Estudo Author: A Version: 1.0.0 */  body{     color:  #4d5a6c !important; } 

header.php

<!DOCTYPE html> <html lang="en"> <head>     <?php wp_head(); ?> </head> <body>  <h2>Este é o header</h2> 

index.php

<?php get_header();  while (have_posts()) {     the_post(); ?> <h2><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></h2> <?php the_content();  }  get_footer(); ?> 

footer.php

<h4>Este é o footer</h4> <?php wp_footer(); ?> </body> </html> 

functions.php

<?php  function arquivos_estilo(){     wp_enqueue_style('estilo_principal', get_stylesheet_uri()); }  add_action('wp_enqueue_scripts', 'arquivos_estilo'); 

O porquê não lê o estilo?

O que retorna é o seguinte:

<!DOCTYPE html> <html lang="en"> <head>     <meta name='robots' content='noindex,follow' /> <link rel='dns-prefetch' href='//s.w.org' />         <script type="text/javascript">             window._wpemojiSettings = {"baseUrl":"https:\/\/s.w.org\/images\/core\/emoji\/11\/72x72\/","ext":".png","svgUrl":"https:\/\/s.w.org\/images\/core\/emoji\/11\/svg\/","svgExt":".svg","source":{"concatemoji":"http:\/\/localhost\/estudo\/wp-includes\/js\/wp-emoji-release.min.js?ver=5.0.2"}};             !function(a,b,c){function d(a,b){var c=String.fromCharCode;l.clearRect(0,0,k.width,k.height),l.fillText(c.apply(this,a),0,0);var d=k.toDataURL();l.clearRect(0,0,k.width,k.height),l.fillText(c.apply(this,b),0,0);var e=k.toDataURL();return d===e}function e(a){var b;if(!l||!l.fillText)return!1;switch(l.textBaseline="top",l.font="600 32px Arial",a){case"flag":return!(b=d([55356,56826,55356,56819],[55356,56826,8203,55356,56819]))&&(b=d([55356,57332,56128,56423,56128,56418,56128,56421,56128,56430,56128,56423,56128,56447],[55356,57332,8203,56128,56423,8203,56128,56418,8203,56128,56421,8203,56128,56430,8203,56128,56423,8203,56128,56447]),!b);case"emoji":return b=d([55358,56760,9792,65039],[55358,56760,8203,9792,65039]),!b}return!1}function f(a){var c=b.createElement("script");c.src=a,c.defer=c.type="text/javascript",b.getElementsByTagName("head")[0].appendChild(c)}var g,h,i,j,k=b.createElement("canvas"),l=k.getContext&&k.getContext("2d");for(j=Array("flag","emoji"),c.supports={everything:!0,everythingExceptFlag:!0},i=0;i<j.length;i++)c.supports[j[i]]=e(j[i]),c.supports.everything=c.supports.everything&&c.supports[j[i]],"flag"!==j[i]&&(c.supports.everythingExceptFlag=c.supports.everythingExceptFlag&&c.supports[j[i]]);c.supports.everythingExceptFlag=c.supports.everythingExceptFlag&&!c.supports.flag,c.DOMReady=!1,c.readyCallback=function(){c.DOMReady=!0},c.supports.everything||(h=function(){c.readyCallback()},b.addEventListener?(b.addEventListener("DOMContentLoaded",h,!1),a.addEventListener("load",h,!1)):(a.attachEvent("onload",h),b.attachEvent("onreadystatechange",function(){"complete"===b.readyState&&c.readyCallback()})),g=c.source||{},g.concatemoji?f(g.concatemoji):g.wpemoji&&g.twemoji&&(f(g.twemoji),f(g.wpemoji)))}(window,document,window._wpemojiSettings);         </script>         <style type="text/css"> img.wp-smiley, img.emoji {     display: inline !important;     border: none !important;     box-shadow: none !important;     height: 1em !important;     width: 1em !important;     margin: 0 .07em !important;     vertical-align: -0.1em !important;     background: none !important;     padding: 0 !important; } </style> <link rel='stylesheet' id='wp-block-library-css'  href='http://localhost/estudo/wp-includes/css/dist/block-library/style.min.css?ver=5.0.2' type='text/css' media='all' /> <link rel='https://api.w.org/' href='http://localhost/estudo/wp-json/' /> <link rel="EditURI" type="application/rsd+xml" title="RSD" href="http://localhost/estudo/xmlrpc.php?rsd" /> <link rel="wlwmanifest" type="application/wlwmanifest+xml" href="http://localhost/estudo/wp-includes/wlwmanifest.xml" />  <meta name="generator" content="WordPress 5.0.2" /> </head> <body>  <h2>Este é o header</h2><h2><a href="http://localhost/estudo/2018/12/31/terceiro-post/">Terceiro post</a></h2>  <p>este é o terceiro</p> <h2><a href="http://localhost/estudo/2018/12/31/segundo-post/">Segundo post</a></h2>  <p>loremasfas ffsdfsdfsdfsd ssfsdfsdsds</p> <h2><a href="http://localhost/estudo/2018/12/31/ola-mundo/">Olá, mundo!</a></h2>  <p>Boas-vindas ao WordPress. Esse é o seu primeiro post. Edite-o ou exclua-o, e então comece a escrever!</p> <h4>Este é o footer</h4> <script type='text/javascript' src='https://localhost/estudo/wp-includes/js/wp-embed.min.js?ver=5.0.2'></script> </body> </html>