Snowbird Theme WP : Change sidebar background

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<pre class="xdebug-var-dump" dir="ltr">
<small>
    C:\wamp\www\wordpress\test\wp-content\themes\snowbird-child\sidebar.php:24:
</small>
<b>array</b>
<i>(size=4)</i>
  0
<font color="#888a85">=></font>
<small>string</small>
<font color="#cc0000">'http://test/wp-content/uploads/2017/07/cropped-16683843_1247769308646829_3029531631477004492_n-400x360.jpg'</font>
<i>(length=117)</i>
1 <font color="#888a85">=></font>
<small>int</small>
<font color="#4e9a06">400</font>
2 <font color="#888a85">=></font>
<small>int</small>
<font color="#4e9a06">360</font>
3 <font color="#888a85">=></font>
<small>boolean</small>
<font color="#75507b">true</font>
</pre>
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