If you want to do this design on all pages then you go to all edit page and copy to paste this code.
Inline :
.t-Header-branding{
background: rgb(200,86,98)!important;
background: radial-gradient(circle, rgba(200,86,98,1) 0%, rgba(130,20,32,1) 45%, rgba(102,9,19,1) 61%, rgba(84,7,16,1) 77%, rgba(51,2,7,1) 90%) !important;
}
.t-TreeNav {
background: rgb(204, 198, 15)!important;
background: radial-gradient(circle, rgb(194, 153, 157) 0%, rgb(192, 161, 164) 45%, rgb(184, 154, 157) 61%, rgb(168, 136, 140) 77%, rgb(197, 124, 131) 90%) !important;
}
.t-TreeNav .a-TreeView-node--topLevel .a-TreeView-row.is-current, .t-TreeNav .a-TreeView-node--topLevel .a-TreeView-row.is-current--top.is-selected, .t-TreeNav .a-TreeView-node--topLevel .a-TreeView-row.is-selected {
background-color: #d8243c !important;
}
.t-TreeNav .a-TreeView-node--topLevel .a-TreeView-row.is-hover{
background-color: #49b464 !important;
}