path: root/files/es/conflicting/learn/css/building_blocks/selectors/index.html

---
title: Selectores
slug: conflicting/Learn/CSS/Building_blocks/Selectors
translation_of: Learn/CSS/Building_blocks/Selectors
translation_of_original: Web/Guide/CSS/Getting_started/Selectors
original_slug: Web/CSS/Introducción/Selectors
---
<p>{{ CSSTutorialTOC() }}</p>

<p>{{ previousPage("/en-US/docs/Web/Guide/CSS/Getting_Started/Cascading_and_inheritance", "Cascading &amp; inheritance")}}<span id="result_box" lang="es"><span class="hps">Esta</span> <span class="hps">es</span> <span class="hps">la sección</span> <span class="hps">quinta</span> <span class="hps">del</span> </span><span id="result_box" lang="es"><span class="hps">tutoria</span></span><span class="seoSummary"><a href="/en-US/docs/Web/Guide/CSS/Getting_Started" title="en-US/docs/Web/Guide/CSS/Getting Started">CSS Getting Started</a> ;</span><span id="result_box" lang="es"><span class="hps">En él se explica</span> <span class="hps">cómo se puede aplicar</span> <span class="hps">estilos</span> <span class="hps">de forma selectiva</span><span>,</span> <span class="hps">y cómo</span> <span class="hps">los diferentes tipos de</span> <span class="hps">selectores</span> <span class="hps">tener diferentes</span> <span class="hps">prioridades.</span> <span class="hps">Agregar algunos</span> <span class="hps">atributos a</span> <span class="hps">las</span> <span class="hps">etiquetas</span> <span class="hps">en su</span> <span class="hps">documento de muestra</span><span>,</span> <span class="hps">y</span> <span class="hps">utiliza estos</span> <span class="hps">atributos en</span> <span class="hps">su hoja de estilos</span> <span class="hps">de muestra.</span></span></p>

<h2 class="clearLeft" id="Información_Selectores"><span id="result_box" lang="es"><span class="hps">Información:</span> <span class="hps">Selectores</span></span></h2>

<p><br>
 <span id="result_box" lang="es"><span class="hps">CSS</span> <span class="hps">tiene su propia terminología</span> <span class="hps">para describir el</span> <span class="hps">lenguaje CSS</span><span>.</span> <span class="hps">Anteriormente</span> <span class="hps">en este tutorial,</span> <span class="hps">que ha creado</span> <span class="hps">una línea en</span> <span class="hps">su hoja de estilos</span> <span class="hps alt-edited">como esta:</span></span></p>

<pre class="brush: css">strong {
  color: red;
}
</pre>

<p><span id="result_box" lang="es"><span class="hps">En la terminología de</span> <span class="hps">CSS</span><span>,</span> <span class="hps">toda</span> <span class="hps">esta línea</span> <span class="hps">es una </span></span><em><code><strong>rule </strong></code>(</em><span id="result_box" lang="es"><span class="hps">regla).</span> <span class="hps">Esta regla</span> <span class="hps">comienza con</span> </span><strong><em><code>strong</code></em></strong><span lang="es"><span>, que es un</span> <span class="hps">selector.</span> <span class="hps alt-edited">Permite seleccionar</span> <span class="hps">qué elementos</span> <span class="hps">en el DOM</span> <span class="hps">se aplica la regla</span><span>.</span></span></p>

<div class="tuto_details">
<div class="tuto_type"><span id="result_box" lang="es"><span class="hps alt-edited">Más</span> <span class="hps">detalles</span></span></div>

<p><span id="result_box" lang="es"><span class="hps">La parte</span> <span class="hps">interior de las</span> <span class="hps">llaves</span> <span class="hps">es la declaración</span><span>.</span></span></p>

<p><span id="result_box" lang="es"><span class="hps"> L</span><span class="hps alt-edited">a palabra clave es </span></span><span id="result_box" lang="es"><code><em><span class="hps">color</span></em></code>, que </span><span id="result_box" lang="es"><span class="hps alt-edited">es</span> <span class="hps">una propiedad,</span> <span class="hps">y el <code><em>rojo </em></code>es</span> <span class="hps">el valor.</span></span></p>

<p><span id="result_box" lang="es"><span class="hps">El punto y coma</span> <span class="hps">después de el</span> <span class="hps">par</span> <span class="hps">propiedad</span><span class="atn">-</span><span>valor</span> <span class="hps">separa los posibles </span><span class="hps">otros pares de </span> <span class="hps">propiedad</span><span>-valor en</span> una <span class="hps">misma declaración.</span></span></p>

<p> <span id="result_box" lang="es"><span class="hps">Este tutorial</span> <span class="hps">se refiere a</span> <span class="hps">un selector</span> <span class="hps">como</span> </span><em><strong><code>strong</code> </strong></em><span lang="es"><span class="hps">como un</span> <span class="hps">selector de etiquetas</span><span>.</span> <span class="hps">La</span> <span class="hps">especificación</span> <span class="hps">CSS</span> <span class="hps">se refiere a él como</span> <span class="hps">un selector de</span> <span class="hps">tipo <code><strong>(</strong></code></span></span><code><strong> type selector)</strong></code><span lang="es"><span>.</span></span></p>
</div>

<p><span id="result_box" lang="es"><span class="hps alt-edited">En esta página</span> <span class="hps">del tutorial</span> <span class="hps alt-edited">se explica</span> <span class="hps">más acerca de los</span> <span class="hps">selectores</span> <span class="hps">que se pueden utilizar</span> <span class="hps">en</span> <span class="hps">las reglas CSS</span><span>.</span></span></p>

<p><span id="result_box" lang="es"><span class="hps">Además de añadir </span></span><span id="result_box" lang="es"><span class="hps">nombres a las e</span></span><span id="result_box" lang="es"><span class="hps">tiquetas</span> <span>, puede usar </span><span class="hps alt-edited">valores en los atributos</span> de <span class="hps">los selectores</span><span>.</span> <span class="hps">Esto permite que sus</span> <span class="hps">reglas sean</span> <span class="hps">más específicas.</span></span></p>

<p><span id="result_box" lang="es"><span class="hps">Dos</span> <span class="hps">atributos tienen</span> <span class="hps">un estatus especial</span> <span class="hps">para</span> <span class="hps">CSS</span><span>.</span> <span class="hps">Son</span></span> <a href="/en-US/docs/Web/HTML/Global_attributes#attr-class" title="en-US/docs/Web/HTML/Global_attributes#attr-class"><code>class</code></a> <code>e </code><a href="/en-US/docs/Web/HTML/Global_attributes#id" title="en-US/docs/Web/HTML/Global_attributes#id"><code>id</code></a>.</p>

<h3 id="Class_Selectores_de_clase">Class: <span id="result_box" lang="es"><span class="hps">Selectores de clase</span></span></h3>

<p><span id="result_box" lang="es"><span class="hps">Utilice el</span> <span class="hps">atributo</span></span> <a href="/en-US/docs/Web/HTML/Global_attributes#attr-class" title="en-US/docs/Web/HTML/Global_attributes#attr-class"><code>class</code></a> para <span id="result_box" lang="es"><span class="hps">asignarle  a </span></span><span id="result_box" lang="es"><span class="hps">un elemento</span> un nombre de clase<code><strong><em> (class)</em></strong></code></span>. <span id="result_box" lang="es"><span class="hps">Depende de</span><span class="hps">l</span><span class="hps"> nombre que elijas</span> como <span class="hps"><code><strong><em>class</em></strong></code>.</span></span> <span id="result_box" lang="es"><span class="hps">Múltiples</span> <span class="hps">elementos en un documento</span> <span class="hps">pueden tener el mismo</span> <span class="hps">valor de la clase</span><span>.</span></span></p>

<p><span id="result_box" lang="es"><span class="hps">En</span> <span class="hps">su hoja de estilo</span><span>, escriba</span> <span class="hps atn">un punto (.</span><span>)</span> <span class="hps">antes del </span><span class="hps">nombre de la clase</span>,<span class="hps"> cuando</span> <span class="hps">se utiliza como </span><span class="hps">un selector.</span></span></p>

<h3 id="Selectores_ID"><span id="result_box" lang="es"><span class="hps alt-edited">Selectores ID</span></span></h3>

<p><span id="result_box" lang="es"><span class="hps">Utilice el atributo</span> <span class="hps">id en</span> <span class="hps">un elemento</span> <span class="hps">para asignar un</span> <span class="hps alt-edited">identificación para</span> ese <span class="hps">elemento</span><span>.</span> <span class="hps">Depende de</span> usted el <span class="hps">nombre que elija</span> <span class="hps">para el ID</span><span>.</span> <span class="hps">El nombre de</span> <span class="hps">ID</span> <span class="hps">debe ser único</span> <span class="hps">en el documento.</span></span><br>
  </p>

<p><span id="result_box" lang="es"><span class="hps">En</span> <span class="hps">su hoja de estilo</span><span>, escriba un</span> <span class="hps alt-edited">símbolo de almohadilla</span> <span class="hps atn">(</span><span class="alt-edited">#)</span> <span class="hps alt-edited">ante el</span> <span class="hps alt-edited">ID cuando</span> <span class="hps alt-edited">se utiliza esto en</span> <span class="hps">un selector.</span></span></p>

<div class="tuto_example">
<div class="tuto_type">Ejemplo</div>

<p><span id="result_box" lang="es"><span class="hps">Esta etiqueta</span> <span class="hps">HTML</span> <span class="hps">tiene un</span> <span class="hps alt-edited">atributo <code>class</code></span><code> </code><span class="hps">y un atributo</span> <span class="hps"><code>id</code>:</span></span></p>

<pre class="brush: html">&lt;p class="key" id="principal"&gt;
</pre>

<p><span id="result_box" lang="es"><span class="hps">El</span> <span class="hps alt-edited">valor de <code><em><strong>id </strong></em></code>es</span><span class="alt-edited">, <strong>principal</strong>,</span> <span class="hps">debe ser único</span> <span class="hps">en el documento;</span> <span class="hps">pero</span> <span class="hps">otras</span> <span class="hps">etiquetas del documento</span> <span class="hps">puede tener el mismo</span> <span class="hps alt-edited">nombre de la <strong><em><code>class</code></em></strong></span><span>,</span> <span class="hps alt-edited">Key.</span></span></p>

<p><span id="result_box" lang="es"><span class="hps">En</span> <span class="hps">una hoja de estilo</span> <span class="hps">CSS</span><span>,</span> <span class="hps">esta regla</span> <span class="hps">hace que todos</span> <span class="hps">los elementos con la <code><em>class</em></code></span><code><em> </em></code><span class="hps"><code><em><strong>key </strong></em></code>sean verdes</span> <span>.</span> <span class="hps atn">(</span><span>Puede ser que no</span> <span class="hps">todos los sean</span> <span class="hps atn">{</span><span class="atn">{</span><span>HTMLElement</span> <span class="hps">()</span><span>}</span> <span class="hps">"p"</span><span>}</span> <span class="hps">elementos.</span><span>)</span></span></p>

<pre class="brush: css">.key {
  color: green;
}
</pre>

<p><span id="result_box" lang="es"><span class="hps">Esta regla</span> <span class="hps">hace que</span> <span class="hps">el </span></span><span id="result_box" lang="es"><span class="hps">único </span></span><span id="result_box" lang="es"><span class="hps"> </span></span><span id="result_box" lang="es"><span class="hps">elemento</span> </span><span id="result_box" lang="es"> <span class="hps alt-edited">de id </span></span><span id="result_box" lang="es"><code><strong><em><span class="hps alt-edited">principal</span></em></strong></code> este en <span class="hps">negrita:</span></span></p>

<pre class="brush: css">#principal {
  font-weight: bolder;
}
</pre>
</div>

<p><span id="result_box" lang="es"><span class="hps">Si más de una</span> <span class="hps">regla se aplica a</span> <span class="hps">un elemento</span> <span class="hps">y especifica</span> <span class="hps">la misma propiedad,</span> <span class="hps alt-edited">entonces</span> <span class="hps alt-edited">el CSS</span> <span class="hps">da prioridad</span> <span class="hps">a la regla que</span> <span class="hps">tiene el</span> <span class="hps">selector más específico</span><span>.</span> <span class="hps">Un selector</span> <code><em><strong><span class="hps">ID</span> </strong></em></code><span class="hps">es más específico que</span> <span class="hps">un</span> <span class="hps alt-edited">selector de <em><strong><code>class</code></strong></em></span><span>,</span> <span class="hps">que a su vez</span> <span class="hps">es más específico que</span> <span class="hps">un</span> <span class="hps alt-edited">selector (<strong>tag</strong>) de etiquetas</span><span>.</span></span></p>

<div class="tuto_details">
<div class="tuto_type"><span id="result_box" lang="es"><span class="hps alt-edited">Más</span> <span class="hps">detalles</span></span></div>

<p><span id="result_box" lang="es"><span class="hps">También se pueden combinar</span> <span class="hps">selectores</span><span>, haciendo un</span> <span class="hps">selector más específico</span><span>.</span></span><br>
 <br>
 Por ejemplo, el selector <strong><em><code>.key</code></em></strong> selecciona <span id="result_box" lang="es"><span class="hps">todos los</span> <span class="hps">elementos que tienen</span> <code><em><strong><span class="hps">key</span> </strong></em></code>como <span class="hps alt-edited">nombre de clase (<strong><em><code>class</code></em></strong></span></span>). El selector <code><em><strong>p</strong></em>.key</code> <span id="result_box" lang="es"><span class="hps">selecciona</span> <span class="hps">sólo el elemento</span></span> {{ HTMLElement("p") }} que tiene de nombre <em><strong><code>key</code></strong></em>.</p>

<p><span id="result_box" lang="es"><span class="hps">Usted no esta </span><span class="hps">limitado a los dos</span> <span class="hps">atributos especiales</span><span>, </span></span><em><strong><code>class</code> </strong></em><span lang="es"><span class="hps">e <em><code><strong>id</strong></code></em></span><span>.</span>  Se p<span class="hps">uede especificar</span> <span class="hps">otros atributos</span> <span class="hps">mediante corchetes</span><span>.</span> <span class="hps">Por ejemplo</span><span>, el selector</span> <span class="hps atn">[</span></span><strong><em><code>type='button'</code></em></strong><span lang="es"><span>] selecciona</span> <span class="hps">todos los</span> <span class="hps">elementos que tienen</span> <span class="hps">un atributo de tipo</span> <span class="hps">con el </span> <span class="hps">valor </span></span><strong><em><code>button</code></em></strong><span lang="es"><span>.</span></span></p>
</div>

<p><span id="result_box" lang="es"><span class="hps">Si</span> <span class="hps">la hoja de estilo</span> <span class="hps">tiene reglas</span> <span class="hps">en conflicto</span> <span class="hps">y son</span> <span class="hps">igualmente específicas</span><span>, entonces</span> <span class="hps alt-edited">el CSS</span> <span class="hps">da</span> <span class="hps">prioridad a</span> <span class="hps alt-edited">la regla que</span> <span class="hps alt-edited">está</span> <span class="hps alt-edited">después en</span> <span class="hps">la hoja de estilos</span><span>.</span></span></p>

<p><span id="result_box" lang="es"><span class="hps">Cuando</span> <span class="hps">usted tiene un problema</span> <span class="hps alt-edited">con las reglas</span> <span class="hps">en conflicto,</span> <span class="hps alt-edited">trate de resolverlo</span> <span class="hps">haciendo</span> <span class="hps">una de las</span> <span class="hps">normas más específicas</span><span>, para que</span> <span class="hps alt-edited">tenga </span><span class="hps">prioridad.</span> <span class="hps">Si usted no puede</span> <span class="hps">hacer esto</span><span>, trate de mover</span> <span class="hps">una de las reglas</span> mas <span class="hps alt-edited">cerca del</span> <span class="hps">final de</span> <span class="hps">la hoja de estilos</span> <span class="hps">para que tenga</span> la <span class="hps">prioridad.</span></span></p>

<h3 id="Las_pseudo-clases_de_los_selectores"><span class="short_text" id="result_box" lang="es"><span class="hps atn">Las pseudo-</span><span>clases de</span> los <span class="hps">selectores </span></span></h3>

<p><span id="result_box" lang="es"><span class="hps">Una</span> <span class="hps">pseudo-clase </span></span> <a href="/en-US/docs/Web/CSS/Pseudo-classes" title="en-US/docs/Web/Guide/CSS/Pseudo-classes">pseudo-class</a><span lang="es"> <span class="hps alt-edited">es en  CSS</span> <span class="hps">una palabra clave</span> <span class="hps">añadida a</span> <span class="hps">los selectores,</span> <span class="hps">que especifica</span> <span class="hps">un estado especial</span> <span class="hps">del elemento</span> <span class="hps">a seleccionar.</span> <span class="hps">Por ejemplo</span> <span class="hps atn">{</span><span class="atn">{</span><span>Css</span> <span class="hps">Href</span> <span class="hps atn">(</span><span class="hps atn">"</span><span>: hover</span><span>")}</span><span>}</span> <span class="hps">aplicará</span> <span class="hps">un estilo</span> <span class="hps">cuando el</span> <span class="hps">usuario se desplaza sobre</span> <span class="hps">el elemento especificado</span> <span class="hps alt-edited">mediante el selector</span></span>.</p>

<p><span id="result_box" lang="es"><span class="hps">Las </span></span><code>Pseudo-classes</code><span lang="es"><span>,</span> <span class="hps">junto con</span> <span class="hps">los <code>pseudo-elements</code></span><span>,</span> <span class="hps">permiten aplicar</span> <span class="hps">un estilo</span> <span class="hps">a un elemento</span> <span class="hps">no sólo</span> <span class="hps">en relación con</span> <span class="hps">el contenido</span> <span class="hps">de</span> <span class="hps">la estructura del documento</span><span>,</span> <span class="hps">sino también en relación</span> <span class="hps">a los factores externos</span><span>, como</span> <span class="hps">la historia del</span> <span class="hps atn">navegador </span><span>por ejemplo:</span><span class="hps atn"> (</span><span class="atn">{</span><span class="atn">{</span><span>href</span> <span class="hps">css</span> <span class="hps atn">(</span><span class="hps atn">"</span><span class="hps">: visited</span> <span class="hps">")}</span><span>}</span><span>, )</span><span>,</span> <span class="hps">el estado de</span> <span class="hps">su contenido</span> <span class="hps">(como</span> <span class="hps atn">{</span><span class="atn">{</span><span>ref</span> <span class="hps">css</span> <span class="hps atn">(</span><span>"</span><span>: </span></span>:checked"<span lang="es"><span class="hps">)}</span><span>} en</span> <span class="hps">algunos</span> <span class="hps">elementos de formulario</span><span>)</span><span>,</span> <span class="hps">o</span> <span class="hps">la posición del</span> <span class="hps">ratón</span> <span class="hps">(como</span> <span class="hps atn">{</span><span class="atn">{</span><span>cssxref</span> <span class="hps">("</span></span>:hover<span lang="es"> <span class="hps">")}</span><span>}</span> <span class="hps">que le permite saber</span> <span class="hps">si</span> <span class="hps">el ratón está sobre</span> <span class="hps">un elemento o</span> <span class="hps">no).</span> <span class="hps">Para ver</span> <span class="hps">una lista completa de</span> <span class="hps">selectores</span><span>,</span> <span class="hps">visite</span> <span class="hps">especificación</span> <span class="hps">CSS3</span> <span class="hps">Selectores</span> <span class="hps">de trabajo </span></span> <a class="external" href="http://www.w3.org/TR/selectors/#selectors" rel="external nofollow" title="CSS3 Selectors working spec">CSS3 Selectors working spec</a>.</p>

<div class="tuto_example">
<div class="tuto_type"><span class="short_text" id="result_box" lang="es"><span class="hps">Sintaxis</span></span></div>

<pre class="brush:css">selector:pseudo-class {
  property: value;
}
</pre>
</div>

<h4 id="Listado_de_pseudo-classes">Listado de pseudo-classes:</h4>

<ul>
 <li>{{ Cssxref(":link") }}</li>
 <li>{{ Cssxref(":visited") }}</li>
 <li>{{ Cssxref(":active") }}</li>
 <li>{{ Cssxref(":hover") }}</li>
 <li>{{ Cssxref(":focus") }}</li>
 <li>{{ Cssxref(":first-child") }}</li>
 <li>{{ Cssxref(":last-child") }}</li>
 <li>{{ Cssxref(":nth-child") }}</li>
 <li>{{ Cssxref(":nth-last-child") }}</li>
 <li>{{ Cssxref(":nth-of-type") }}</li>
 <li>{{ Cssxref(":first-of-type") }}</li>
 <li>{{ Cssxref(":last-of-type") }}</li>
 <li>{{ Cssxref(":empty") }}</li>
 <li>{{ Cssxref(":target") }}</li>
 <li>{{ Cssxref(":checked") }}</li>
 <li>{{ Cssxref(":enabled") }}</li>
 <li>{{ Cssxref(":disabled") }}</li>
</ul>

<h2 id="Información_Los_selectores_basados_en_relaciones_(relationships)"><span id="result_box" lang="es"><span class="hps">Información:</span> <span class="hps">Los selectores</span> <span class="hps">basados en relaciones </span></span>(relationships)</h2>

<p><span id="result_box" lang="es"><span class="hps alt-edited">El CSS</span> <span class="hps">tiene algunas</span> <span class="hps">formas de seleccionar</span> <span class="hps">elementos en función de</span> <span class="hps">las</span> <span class="hps">relaciones entre los elementos</span><span>.</span> <span class="hps">Usted</span> <span class="hps">puede utilizar estas para</span> <span class="hps">hacer</span> <span class="hps">selectores</span> <span class="hps alt-edited">que sean más específicos</span><span>.</span></span></p>

<table id="relselectors">
 <caption><span class="short_text" id="result_box" lang="es"><span class="hps">Selectores</span> <span class="hps">comunes</span> <span class="hps alt-edited">basados en relaciones</span></span></caption>
 <tbody>
  <tr>
   <td style="width: 10em;"><strong>Selector</strong></td>
   <td><strong>Selects</strong></td>
  </tr>
  <tr>
   <td><code>A E</code></td>
   <td><span id="result_box" lang="es"><span class="hps">Cualquier</span> <span class="hps">elemento E</span> <span class="hps">que</span> <span class="hps">es un descendiente de</span> <span class="hps">un elemento</span> <span class="hps atn">A (</span><span>que</span> <span class="hps">es:</span> <span class="hps alt-edited">un hijo o</span> <span class="hps alt-edited">un hijo</span> <span class="hps alt-edited">de un hijo</span> <span class="hps">etc.</span><span>)</span></span></td>
  </tr>
  <tr>
   <td><code>A &gt; E</code></td>
   <td><span id="result_box" lang="es"><span class="hps">Cualquier</span> <span class="hps">elemento E</span> <span class="hps">que</span> <span class="hps">es un hijo de</span> <span class="hps">un elemento A</span></span></td>
  </tr>
  <tr>
   <td><code>E:first-child</code></td>
   <td><span id="result_box" lang="es"><span class="hps">Cualquier</span> <span class="hps">elemento E</span> <span class="hps">que</span> <span class="hps">es el primer</span> <span class="hps">hijo de su padre</span></span></td>
  </tr>
  <tr>
   <td><code>B + E</code></td>
   <td><span id="result_box" lang="es"><span class="hps">Cualquier</span> <span class="hps">elemento E</span> <span class="hps">que</span> <span class="hps">es</span> <span class="hps">el siguiente hermano</span> <span class="hps">de un elemento</span> <span class="hps">B</span> <span class="hps">(es decir</span><span>:</span> <span class="hps">el</span> <span class="hps">próximo hijo</span> <span class="hps">del mismo</span> <span class="hps">padre)</span></span></td>
  </tr>
 </tbody>
</table>

<p><span id="result_box" lang="es"><span class="hps">Usted</span> <span class="hps">puede combinarlas para</span> <span class="hps">expresar relaciones</span> <span class="hps">complejas</span><span>.</span><br>
 <br>
 <span class="hps">También puede utilizar</span> <span class="hps">el símbolo</span> <span class="hps">asterisco </span></span><span lang="es"> <span class="hps">(*</span><span>)</span> <span class="hps alt-edited">para significar</span> <span class="hps atn">"</span><span>cualquier elemento</span><span>"</span><span>.</span></span></p>

<div class="tuto_example">
<div class="tuto_type">Ejemplo</div>

<p><span id="result_box" lang="es"><span class="hps">Una tabla HTML</span> <span class="hps">tiene</span> <span class="hps">un atributo <strong><em><code>id</code></em></strong></span><span>,</span> <span class="hps">pero sus</span> <span class="hps">filas y</span> <span class="hps alt-edited">las celdas</span> <span class="hps">no tienen</span> <span class="hps">identificadores individuales</span><span>:</span></span></p>

<pre class="brush: html">&lt;table id="data-table-1"&gt;
...
&lt;tr&gt;
&lt;td&gt;Prefix&lt;/td&gt;
&lt;td&gt;0001&lt;/td&gt;
&lt;td&gt;default&lt;/td&gt;
&lt;/tr&gt;
...
</pre>

<p><span id="result_box" lang="es"><span class="hps">Estas</span> <span class="hps">reglas hacen</span> <span class="hps">que la primera celda de</span> <span class="hps">cada fila</span> sea en <span class="hps">negrita,</span> <span class="hps">y</span> <span class="hps">la segunda celda</span> de <span class="hps">cada fila</span> en  la familia de fuente <span class="hps"> monoespaciado</span><span>.</span> <span class="hps alt-edited">Esto</span> <span class="hps alt-edited">sólo afecta a</span> <span class="hps">una</span> <span class="hps alt-edited">tabla concreta</span> <span class="hps alt-edited">del documento:</span></span></p>

<pre class="brush:css">    #data-table-1 td:first-child {font-weight: bolder;}
    #data-table-1 td:first-child + td {font-family: monospace;}
</pre>

<p><span class="short_text" id="result_box" lang="es"><span class="hps">El resultado</span> <span class="hps">se ve así:</span></span></p>

<table style="border: 2px outset #36b; padding: 1em; background-color: white;">
 <tbody>
  <tr>
   <td>
    <table style="width: 18em; margin-right: 2em;">
     <tbody>
      <tr>
       <td><strong>Prefix</strong></td>
       <td><code>0001</code></td>
       <td>default</td>
      </tr>
     </tbody>
    </table>
   </td>
  </tr>
 </tbody>
</table>
</div>

<div class="tuto_details">
<div class="tuto_type"><span id="result_box" lang="es"><span class="hps alt-edited">Más</span> <span class="hps">detalles</span></span></div>

<p><span id="result_box" lang="es"><span class="hps">La manera mas </span><span class="hps">habitual es hacer</span><span class="hps alt-edited"> que un</span> <span class="hps alt-edited">selector sea más específico</span><span>, entonces</span> aumentara <span class="hps">su prioridad.</span></span></p>

<p><span id="result_box" lang="es"><span class="hps">Si utiliza</span> <span class="hps">estas técnicas</span><span>, se evita</span> <span class="hps">la necesidad de especificar</span> <span class="hps">la</span></span> <strong><em><code>class</code> </em></strong><span id="result_box" lang="es"><span class="hps">o</span> <span class="hps">atributos <strong><em><code>ID</code></em></strong></span></span><strong><em><code> </code></em></strong><span id="result_box" lang="es"><span class="hps alt-edited">en muchas</span> <span class="hps">etiquetas</span> <span class="hps alt-edited">del documento.</span> <span class="hps">En su lugar</span><span>, CSS</span> <span class="hps">hace este trabajo.</span></span></p>

<p><span id="result_box" lang="es"><span class="hps">En grandes</span> <span class="hps">diseños</span> <span class="hps">donde la velocidad es</span> <span class="hps">importante</span><span>,</span> <span class="hps">usted puede hacer sus</span> <span class="hps">hojas de estilo</span> <span class="hps">más eficiente</span> <span class="hps">evitando</span> <span class="hps">reglas complejas</span> <span class="hps">que dependen de</span> <span class="hps">relaciones entre los elementos</span><span>.</span></span></p>

<p><span id="result_box" lang="es"><span class="hps">Para más ejemplos</span> <span class="hps">sobre</span> <span class="hps">las tablas</span><span>,</span> <span class="hps">ver</span></span> <a href="/en-US/docs/Web/Guide/CSS/Getting_Started/Tables" title="en-US/docs/Web/Guide/CSS/Getting_Started/Tables">Tables</a> <span id="result_box" lang="es"><span class="hps">en</span> <span class="hps">la página</span> <span class="hps">CSS Reference</span><span>.</span></span></p>
</div>

<h2 id="Action_Using_class_and_ID_selectors">Action: Using class and ID selectors</h2>

<ol>
 <li><span id="result_box" lang="es"><span class="hps">Edite su archivo</span> <span class="hps">HTML</span><span>,</span> <span class="hps">y duplicar</span> <span class="hps">el</span> <span class="hps">párrafo</span> <span class="hps">copiando y</span> <span class="hps">pegando</span><span>.</span></span></li>
 <li><span id="result_box" lang="es"><span class="hps">A continuación, agregue los atibutos </span></span> <strong>id</strong> y <strong>class</strong> <span id="result_box" lang="es"><span class="hps">a</span> <span class="hps">la primera copia</span><span>,</span> <span class="hps">y</span> <span class="hps">un atributopara</span> <span class="hps">la segunda copia</span> <span class="hps">como se muestra</span> <span class="hps">a continuación.</span> <span class="hps">Alternativamente</span><span>, copie</span> <span class="hps">y pegue el</span> <span class="hps">archivo entero</span> <span class="hps">de nuevo</span><span>:</span></span>
  <pre class="brush: html">&lt;!doctype html&gt;
&lt;html&gt;
  &lt;head&gt;
  &lt;meta charset="UTF-8"&gt;
  &lt;title&gt;Sample document&lt;/title&gt;
  &lt;link rel="stylesheet" href="style1.css"&gt;
  &lt;/head&gt;
  &lt;body&gt;
    &lt;p id="first"&gt;
      &lt;strong class="carrot"&gt;C&lt;/strong&gt;ascading
      &lt;strong class="spinach"&gt;S&lt;/strong&gt;tyle
      &lt;strong class="spinach"&gt;S&lt;/strong&gt;heets
    &lt;/p&gt;
    &lt;p id="second"&gt;
      &lt;strong&gt;C&lt;/strong&gt;ascading
      &lt;strong&gt;S&lt;/strong&gt;tyle
      &lt;strong&gt;S&lt;/strong&gt;heets
    &lt;/p&gt;
  &lt;/body&gt;
&lt;/html&gt;
</pre>
 </li>
 <li><span id="result_box" lang="es"><span class="hps">Ahora edite</span> <span class="hps">su archivo</span> <span class="hps">CSS</span><span>.</span> <span class="hps alt-edited">Reemplazar todo el contenido</span> <span class="hps">con</span><span>:</span></span>
  <pre class="brush:css">strong { color: red; }
.carrot { color: orange; }
.spinach { color: green; }
#first { font-style: italic; }
</pre>
 </li>
 <li><span id="result_box" lang="es"><span class="hps">Guarde los archivos</span> <span class="hps">y</span> <span class="hps">actualizar el navegador</span> <span class="hps">para ver el resultado</span><span>:</span></span>
  <table style="border: 2px outset #36b; padding: 1em;">
   <tbody>
    <tr>
     <td style="font-style: italic;"><strong style="color: orange;">C</strong>ascading <strong style="color: green;">S</strong>tyle <strong style="color: green;">S</strong>heets</td>
    </tr>
    <tr>
     <td><strong style="color: red;">C</strong>ascading <strong style="color: red;">S</strong>tyle <strong style="color: red;">S</strong>heets</td>
    </tr>
   </tbody>
  </table>

  <p><span id="result_box" lang="es"><span class="hps alt-edited">Puede intentar</span> <span class="hps">reordenar las</span> <span class="hps">líneas</span> <span class="hps">en el archivo</span> <span class="hps">CSS</span> <span class="hps alt-edited">de mostrar</span> <span class="hps alt-edited">de que el orden</span> <span class="hps alt-edited">no efecta.</span></span></p>

  <p><span id="result_box" lang="es"><span class="hps">Los</span> <span class="hps">selectores de <code>class</code></span></span><strong><em><code>.carrot</code></em></strong> and <em><strong><code>.spinach</code></strong></em> <span id="result_box" lang="es"><span class="hps">tienen prioridad sobre</span> <span class="hps">el selector de etiquetas</span></span> <em><strong><code>strong</code></strong></em>.</p>

  <p>El <strong><code><em>ID </em></code></strong>selector<code> #<em>first</em></code><em> </em><span id="result_box" lang="es"><span class="hps">tiene prioridad sobre</span> <span class="hps">los</span> <span class="hps">selectores de clase</span> <span class="hps">y</span> <span class="hps">etiqueta</span><span>.</span></span></p>
 </li>
</ol>

<div class="tuto_example">
<div class="tuto_type"><span class="short_text" id="result_box" lang="es"><span class="hps">Desafíos</span></span></div>

<ol>
 <li><span id="result_box" lang="es"><span class="hps">Sin cambiar</span> <span class="hps">su archivo</span> <span class="hps">HTML</span><span>,</span> <span class="hps alt-edited">agregue una sola</span> <span class="hps">regla para</span> <span class="hps">su archivo</span> <span class="hps">CSS</span> <span class="hps alt-edited">que mantenga</span> <span class="hps">todas las letras</span> <span class="hps">iniciales que</span> <span class="hps">mismo color que</span> <span class="hps">están ahora,</span> <span class="hps">pero</span> <span class="hps alt-edited">hace que</span> <span class="hps">todo el</span> <span class="hps">otro texto</span> <span class="hps">en el segundo párrafo</span> <span class="hps alt-edited">sea azul</span><span>:</span></span>

  <table style="border: 2px outset #36b; padding: 1em; background-color: white;">
   <tbody>
    <tr>
     <td style="font-style: italic;"><strong style="color: orange;">C</strong>ascading <strong style="color: green;">S</strong>tyle <strong style="color: green;">S</strong>heets</td>
    </tr>
    <tr>
     <td style="color: blue;"><strong style="color: red;">C</strong>ascading <strong style="color: red;">S</strong>tyle <strong style="color: red;">S</strong>heets</td>
    </tr>
   </tbody>
  </table>
 </li>
 <li><span id="result_box" lang="es"><span class="hps alt-edited">Ahora cambie</span> <span class="hps">la regla</span> <span class="hps">que acaba de agregar</span> <span class="hps atn">(</span><span>sin cambiar nada más</span><span>)</span><span>,</span> <span class="hps">para hacer</span> <span class="hps alt-edited">que el primer párrafo</span> <span class="hps alt-edited">sea azul</span> <span class="hps">también</span><span>:</span></span>
  <table style="border: 2px outset #36b; padding: 1em; background-color: white;">
   <tbody>
    <tr>
     <td style="font-style: italic; color: blue;"><strong style="color: orange;">C</strong>ascading <strong style="color: green;">S</strong>tyle <strong style="color: green;">S</strong>heets</td>
    </tr>
    <tr>
     <td style="color: blue;"><strong style="color: red;">C</strong>ascading <strong style="color: red;">S</strong>tyle <strong style="color: red;">S</strong>heets</td>
    </tr>
   </tbody>
  </table>
 </li>
</ol>

<div class="tuto_details" id="tutochallenge">
<div class="tuto_type">Possible solution</div>

<ol>
 <li>Add a rule with an ID selector of <code>#second</code> and a declaration <code>color: blue;</code>, as shown below:

  <pre class="brush: css">#second { color: blue; }
</pre>
  A more specific selector, <code>p#second</code> also works.</li>
 <li>Change the selector of the new rule to be a tag selector using <code>p</code>:
  <pre class="brush: css">p { color: blue; }
</pre>
 </li>
</ol>
<a class="hideAnswer" href="#challenge">Hide solution</a></div>
<a href="#tutochallenge" title="Display a possible solution for the challenge">See a solution for the challenge.</a></div>

<h2 id="Action_Using_pseudo-classes_selectors">Action: Using pseudo-classes selectors</h2>

<ol>
 <li><span class="short_text" id="result_box" lang="es"><span class="hps alt-edited">Cree un</span> <span class="hps alt-edited">HTML como el siguiente</span><span>:</span></span>

  <pre class="brush: html">&lt;!doctype html&gt;
&lt;html&gt;
  &lt;head&gt;
  &lt;meta charset="UTF-8"&gt;
  &lt;title&gt;Sample document&lt;/title&gt;
  &lt;link rel="stylesheet" href="style1.css"&gt;
  &lt;/head&gt;
  &lt;body&gt;
    &lt;p&gt;Go to our &lt;a class="homepage" href="http://www.example.com/" title="Home page"&gt;Home page&lt;/a&gt;.&lt;/p&gt;
  &lt;/body&gt;
&lt;/html&gt;
</pre>
 </li>
 <li><span id="result_box" lang="es"><span class="hps">Ahora edite</span> <span class="hps">su archivo</span> <span class="hps">CSS</span><span>.</span> <span class="hps alt-edited">Reemplace todo el contenido</span> <span class="hps">con</span><span>:</span></span>
  <pre class="brush: css">a.homepage:link, a.homepage:visited {
  padding: 1px 10px 1px 10px;
  color: #fff;
  background: #555;
  border-radius: 3px;
  border: 1px outset rgba(50,50,50,.5);
  font-family: georgia, serif;
  font-size: 14px;
  font-style: italic;
  text-decoration: none;
}

a.homepage:hover, a.homepage:focus, a.homepage:active {
  background-color: #666;
}
</pre>
 </li>
 <li><span id="result_box" lang="es"><span class="hps">Guarde los archivos</span> <span class="hps">y</span> <span class="hps alt-edited">actualice el explorador</span> <span class="hps">para ver el resultado</span> <span class="hps atn">(</span><span>poner</span> <span class="hps">el ratón sobre el</span> <span class="hps">siguiente enlace para ver</span> <span class="hps">el efecto</span><span>)</span><span>:</span></span>
  <table style="border: 2px outset #36b; padding: 1em;">
   <tbody>
    <tr>
     <td>Go to our <a class="tutospecial" href="#" title="Home page">Home page</a><span style="display: none;"> </span><span style="display: none;"> </span></td>
    </tr>
   </tbody>
  </table>
 </li>
</ol>

<h2 id="Acción_Uso_de_selectores_basados_en_las_relaciones_y_pseudo-clases"><span id="result_box" lang="es"><span class="hps">Acción</span><span>: Uso de</span> <span class="hps">selectores</span> <span class="hps">basados</span> <span class="hps">en las relaciones y</span> <span class="hps">pseudo-clases</span></span></h2>

<p><span id="result_box" lang="es"><span class="hps">Con</span> <span class="hps">selectores</span> <span class="hps">basados</span> <span class="hps">en las relaciones y</span> <span class="hps">pseudo-clases</span> <span class="hps">puede crear</span> <span class="hps">algoritmos </span></span><span id="result_box" lang="es"><span class="hps">complejos</span></span><span id="result_box" lang="es"> en <span class="hps alt-edited">cascada</span> <span class="hps">.</span> <span class="hps">Esto es una técnica</span> <span class="hps">común que se utiliza</span><span>, por ejemplo,</span> <span class="hps">con el fin de</span> <span class="hps">crear menús</span> <span class="hps">desplegables</span> <span class="hps">en </span></span><span id="result_box" lang="es"><span class="hps">puro</span> </span><span id="result_box" lang="es"><span class="hps">CSS</span> <span class="hps">(es decir</span> <span class="hps">sólo</span> <span class="hps">CSS,</span> <span class="hps">sin necesidad de utilizar</span></span> <a href="/en-US/docs/Web/JavaScript" title="en-US/docs/Web/JavaScript">JavaScript</a>). <span id="result_box" lang="es"><span class="hps">La esencia</span> <span class="hps">de esta técnica es</span> <span class="hps">la creación de</span> <span class="hps">una regla como</span> <span class="hps">la siguiente</span><span>:</span></span></p>

<pre class="brush: css">div.menu-bar ul ul {
  display: none;
}

div.menu-bar li:hover &gt; ul {
  display: block;
}</pre>

<p><span id="result_box" lang="es"><span class="hps alt-edited">Aplicararemos a</span> <span class="hps">una estructura de</span> <span class="hps alt-edited">HTML como el siguiente</span><span>:</span></span></p>

<pre class="brush: html">&lt;div class="menu-bar"&gt;
  &lt;ul&gt;
    &lt;li&gt;
      &lt;a href="example.html"&gt;Menu&lt;/a&gt;
      &lt;ul&gt;
        &lt;li&gt;
          &lt;a href="example.html"&gt;Link&lt;/a&gt;
        &lt;/li&gt;
        &lt;li&gt;
          &lt;a class="menu-nav" href="example.html"&gt;Submenu&lt;/a&gt;
          &lt;ul&gt;
            &lt;li&gt;
              &lt;a class="menu-nav" href="example.html"&gt;Submenu&lt;/a&gt;
              &lt;ul&gt;
                &lt;li&gt;&lt;a href="example.html"&gt;Link&lt;/a&gt;&lt;/li&gt;
                &lt;li&gt;&lt;a href="example.html"&gt;Link&lt;/a&gt;&lt;/li&gt;
                &lt;li&gt;&lt;a href="example.html"&gt;Link&lt;/a&gt;&lt;/li&gt;
                &lt;li&gt;&lt;a href="example.html"&gt;Link&lt;/a&gt;&lt;/li&gt;
              &lt;/ul&gt;
            &lt;/li&gt;
            &lt;li&gt;&lt;a href="example.html"&gt;Link&lt;/a&gt;&lt;/li&gt;
          &lt;/ul&gt;
        &lt;/li&gt;
      &lt;/ul&gt;
    &lt;/li&gt;
  &lt;/ul&gt;
&lt;/div&gt;
</pre>

<p><span id="result_box" lang="es"><span class="hps">Vea nuestro</span> <span class="hps">ejemplo completo</span></span><a class="internal" href="https://mdn.mozillademos.org/files/3700/css_dropdown_menu.html" title="css_dropdown_menu.html">CSS-based dropdown menu example</a> <span id="result_box" lang="es"><span class="hps">para una posible</span> referencia<span>.</span></span></p>

<h2 id="¿Y_ahora_qué"><span id="result_box" lang="es"><span class="hps">¿Y ahora qué</span><span>?</span></span></h2>

<p><span id="result_box" lang="es"><span class="hps">Su</span> <span class="hps alt-edited">hoja de estilos</span> <span class="hps alt-edited">de muestra</span> <span class="hps">está empezando a parecer</span> <span class="hps alt-edited">densa</span> <span class="hps alt-edited">y complicada.</span> <span class="hps">La</span> <span class="hps">siguiente sección</span> <span class="hps">describe</span> <span class="hps">maneras de hacer</span> <span class="hps">CSS</span> <span class="hps">más fácil de leer</span><span>.</span> </span> <a href="/en-US/docs/Web/Guide/CSS/Getting_Started/Readable_CSS" title="/en-US/docs/Web/Guide/CSS/Getting_Started/Readable_CSS">easier to read</a>.{{nextPage("/en-US/docs/Web/Guide/CSS/Getting_Started/Readable_CSS", "Readable CSS")}}</p>