CSS Code, How can I modify the font in header

Site URL: https://www.narabura.co/

I want to change my website's header (in the red circle)

I've already done with the code with h1 h2 h3 , but the header still not change.

Now my css code is like this

I'd like to change to font 'BogueMed' according to my recent css code.

Thank you so much and appreciate your help in advance.

:))

Quote

@font-face {
 font-family: 'ThaiHelvetica';
 src: url(https://static1.squarespace.com/static/5f1a5f45ca5a6f1c30bd3aac/t/5f201ea6d5f9b4137eaaae69/1595940519387/DB+Helvethaica+X+Li+v3.2.ttf),
}
@font-face {
 font-family: 'BogueReg';
 src: url(https://static1.squarespace.com/static/6009520ef925b727b5e3cca7/t/600c33d97ee73853feb3169e/1611412444078/Bogue+Regular.ttf)
}
@font-face {
 font-family: 'BogueSemibold';
 src: url(https://static1.squarespace.com/static/6009520ef925b727b5e3cca7/t/600c3436399aeb619ee6fee1/1611412538442/Bogue+Semibold.ttf)
}
@font-face {
 font-family: 'BogueLight';
 src: url(https://static1.squarespace.com/static/6009520ef925b727b5e3cca7/t/600c3e7c8c87b41f3010d819/1611415167664/Bogue+Light.ttf)
}
@font-face {
 font-family: 'BogueThin';
 src: url(https://static1.squarespace.com/static/6009520ef925b727b5e3cca7/t/600c3f084955200b5b09bee3/1611415307889/Bogue+Thin.ttf)
}
@font-face {
 font-family: 'BogueMed';
 src: url(https://static1.squarespace.com/static/6009520ef925b727b5e3cca7/t/600c3e0d20c2137a1c1170f3/1611415056348/Bogue+Medium.ttf)
}

h2{
 font-family:'BogueThin';
   font-size:40px;
}

h3{
 font-family:'BogueThin';
   font-size:30px;
}

h4{
 font-family:'BogueMed';
   font-size:20px;
}

 p {
 font-family:'ThaiHelvetica';
 font-size:24px;
 line-height:1;
   }

/* title in blog detail */
h1.entry-title {
    font-family: 'ThaiHelveticaMed' !important;
   font-size:80px!important;
   line-height:0.8!important;
}

/* blog title */
h1.blog-title {
    font-family: 'ThaiHelvetica' !important;
   font-size:22px!important;
   line-height:0!important;
}

/* summary title */
a.summary-title-link {
    font-family: 'ThaiHelvetica';
    line-height: 0.0em;
    font-size: 22px;
}

/* Summary category */
.summary-metadata-item--cats * {
    font-family: 'ThaiHelvetica';
    line-height: 0.0em;
   font-size: 16px;
}

/* space between title - excerpt */
.summary-title {
    margin-bottom: 0 !important;
}

use this CSS

a#site-title {
    font-family: 'ThaiHelvetica';
}