section.theme h1 {
    font-size: 1.8em
}

section.theme h2 {
    font-size: 1.7em
}

section.theme h3 {
    font-size: 1.6em
}

section.theme h4 {
    font-size: 1.5em
}

section.theme h5 {
    font-size: 1.4em
}

section.theme h6 {
    font-size: 1.3em
}