E para colocar, você vai no painel do seu Blog, na Opção Layout >> e clique em Adicionar um Gadget >> e depois em HTML/JavaScripts
E no HTML/JavaScripts você vai adicionar o código que está aí logo a baixo e depois salvar
<div style="text-align:center;">Troque a cor do blog</div><br /><center>
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</center>
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