#search input:focus {
    width: 500px;
}
#search #search-hints {
    display: none;
    position: absolute;
    top: 3em;
    background: white;
    border: 1px solid #ced4da;
    border-top: none;
    width: 500px;
    box-shadow: 3px 3px 10px #ddd;
    padding: 1em;
}
#search:focus-within #search-hints {
    display: block;
}

/*
 This is taken from: https://gist.github.com/YushengLi/824d3317f36c31f3d3e9 to
 allow bootstrap dropdown menus to work without the associated javascript
 plugin.
 */
a.dropdown-toggle:focus {
    pointer-events: none;
}

a.dropdown-toggle:focus + .dropdown-menu {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
}

.dropdown-menu {
    opacity: 0;
    display: block;
    visibility: hidden;
    transition: visibility 0.5s;
}