src/css/docsearch.css

.navbar .DocSearch-Button {
    height: 30px;
}

.navbar .DocSearch-Button-Placeholder {
    font-size: 1.1rem;
    font-family: 'IBM Plex Mono';
    color: #999
}

body .navbar .DocSearch-Search-Icon {
    width: 15px;
    height: 15px;
    color:#999
}

.navbar .DocSearch-Button-Key {
    width: 18px;
    height: 16px;
    top: 0px;
}