Heading Sizes

Hi,
On my clients site https://www.brendaharrislac.com

I am having trouble changing the size of the headings on pages. I changed the sizes in the CSS (child theme don’t worry). Maybe someone can peek at the code and let me know what obvious thing I’m missing?

Thanks,

/* Headings */
hr {
background-color: #ccc;
border: 0;
height: 1px;
margin-bottom: 1.625em;
}

h1 {
font: Arial;
size: 55px;
}
h2 {
font: Arial;
size: 35px;
}
h3 {
font: Arial;
size: 25px;
}