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.p-navgroup-link--snow {
    position: relative;
    
    &:before {
        .m-faContent(@fa-var-snowflake);
        font-size: 18px;
        line-height: 1;
        display: inline-block;
        vertical-align: middle;
        opacity: .6;
        transition: opacity .15s ease, transform .15s ease;
    }
    
    &:hover:before {
        opacity: 1;
    }
}

body[data-snow="on"] .p-navgroup-link--snow:before {
    opacity: 1;
    transform: rotate(-15deg);
}

<script>
(function() {
    var searchLink = document.querySelector('.p-navgroup-link--search');
    if (!searchLink) return;

    var btn = document.createElement('a');
    btn.href = 'javascript:void(0)';
    btn.className = 'p-navgroup-link p-navgroup-link--iconic p-navgroup-link--snow';
    btn.setAttribute('role', 'button');
    btn.title = 'Toggle snow';
    searchLink.insertAdjacentElement('afterend', btn);

    var scriptId = 'snow-script';
    var key = 'snowEnabled';

    function update(on) {
        btn.classList.toggle('is-active', on);
        document.body.dataset.snow = on ? 'on' : 'off';
    }

    function enable() {
        if (!document.getElementById(scriptId)) {
            var s = document.createElement('script');
            s.src = 'https://app.embed.im/snow.js';
            s.id = scriptId;
            s.defer = true;
            document.body.appendChild(s);
        }
        localStorage.setItem(key, '1');
        update(true);
    }

    function disable() {
        var s = document.getElementById(scriptId);
        var c = document.getElementById('embedim--snow');
        if (s) s.remove();
        if (c) c.remove();
        localStorage.setItem(key, '0');
        update(false);
    }

    localStorage.getItem(key) === '1' ? enable() : update(false);

    btn.onclick = function() {
        localStorage.getItem(key) === '1' ? disable() : enable();
    };
})();
</script>
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