[Bootstrap]ナビゲーションをAffixさせる際にスライドインする処理

<div class="navbar" data-spy="affix" data-offset-top="60"> Header Navigation</div><div class="empty-field"></div>.navbar { background: #000; color: #fff; padding: 15px 0; text-align: center;}.navbar.affix-top { position: static; top: -120px;}.navbar.affix { position: fixed; top: 0px; width: 100%; -webkit-transition: all 1s ease-in-out; transition: all 1s ease-in-out; opacity: 0.95;}body { /* Affixをわかりやすくするためにグラデーションつける */ background-color: #F07575; /* fallback color if gradients are not supported */ background-image: linear-gradient(to bottom, hsl(0, 80%, 70%), #bada55); /* Standard syntax; must be last */}.empty-field { height: 1000px;}