Target Header Button?

Site URL: https://monicakayne.squarespace.com/?password=kozlov

I'm trying to change the buttons on my site to gold ones via CSS, but for some reason I can't target the header button?

Anyone know why? I'm sure it's my own error, but I've tried:

.header-button

.header-action .btn

.header-action-ation .btn

CSS Code is: 

// GOLD BUTTONS
.sqs-block-button-element,
.newsletter-form-button,
.header-actions-action .btn,
.form-wrapper input[type=submit],
 {
border-radius: 5px;
padding: 10px 25px;
color: #000!important;
text-transform: uppercase;
text-shadow: 0px -1px 0px rgba(0,0,0,0.4);
background-image: -webkit-repeating-linear-gradient(
		left, rgba(255, 238, 170, 0)0%,
		rgba(255, 238, 170, 0)3%,
		rgba(255, 238, 170, 0)5%),
		linear-gradient(180deg, #a95 0%,
			#fea 47%, #dc8 53%, #fea 100%);
   
}

Use this code

header#header a.btn {
    border-radius: 5px;
    padding: 10px 25px;
    color: #000!important;
    text-transform: uppercase;
    text-shadow: 0px -1px 0px rgb(0 0 0 / 40%);
    background-image: -webkit-repeating-linear-gradient( left, rgba(255, 238, 170, 0)0%, rgba(255, 238, 170, 0)3%, rgba(255, 238, 170, 0)5%), linear-gradient(180deg, #a95 0%, #fea 47%, #dc8 53%, #fea 100%) !important;
}

Thanks @tuanphan... I tried it but this error message came up... 

ah, forgot, use this code

header#header a.btn {
    border-radius: 5px;
    padding: 10px 25px;
    color: #000!important;
    text-transform: uppercase;
    text-shadow: 0px -1px 0px rgba(0,0,0,0.4);
    background-image: -webkit-repeating-linear-gradient( left, rgba(255, 238, 170, 0)0%, rgba(255, 238, 170, 0)3%, rgba(255, 238, 170, 0)5%), linear-gradient(180deg, #a95 0%, #fea 47%, #dc8 53%, #fea 100%) !important;
}