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<title>Constants: Switch</title>
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<h2>Switch</h2>
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<h2>Constants: <code>@constant</code></h2>
<p>Allows authors to define a one or more values that cannot be changed while the stylesheet is parsed. Unlike variables, constants do not have to begin with a dollar-sign ($). Also unlike variables, constants have no scope, they are considered global and can be used anywhere.</p>
<div class="example">
<pre class="input"><code>@constant BODY_BACKGROUND_COLOR: #fff;
.container {
background-color: BODY_BACKGROUND_COLOR;
}
</code></pre>
<pre class="output"><code>.container {
background-color: #fff;
}</code></pre>
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<p>For clarity, authors should define constants with names in all-caps. While constants do not have to begin with $, authors may wish to do so as some constant names can cause unexpected results!</p>
<div class="example">
<pre class="input"><code>@constant 1px: 10em;
.unexpected {
border: 1px solid #f00;
}
</code></pre>
<pre class="output"><code>.unexpected {
border: 10em solid #f00;
}</code></pre>
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<p>If a constant is declared again or an attempt is made to give it a different value, the parser will ignore the request and continue processing the stylesheet. However, a parser may add a comment to the stylesheet or provide another indication that a invalid request was made.</p>
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