JSFiddle - React, Tailwind, and code Playground

HTML

<div class="calendar">
	<div class="day">
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour">Latino Americano</div>
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
	</div>
	<div class="day">
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour">Musica</div>
		<div class="hour"></div>
		<div class="hour"></div>
	</div>
	<div class="day">
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
	</div>
	<div class="day">
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
	</div>
	<div class="day">
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
	</div>
	<div class="day">
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
	</div>
	<div class="day">
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
		<div class="hour"></div>
	</div>
</div>

CSS

.calendar {width:700px;}
.day { float:left; width:80px;}
.hour { min-height: 50px; border:1px solid black;}

JavaScript

function cambiaSfondo(el)
{
  if (el.innerHTML=="Musica")
  {
    el.style.backgroundColor="pink"
  }
  else if (el.innerHTML=="Latino Americano")
  {
    el.style.backgroundColor="green"
  }
}

var elements = document.getElementsByClassName('hour');

for(i=0; i<elements.length; i++)
{
	cambiaSfondo(elements[i]);
}