Instagram.com CSS Base Styles (Flex Box)

base.css

html, body, div, span, applet, object, iframe, h1, h2, h3, h4, h5, h6, p, blockquote, pre, a, abbr, acronym,
address, big, cite, code, del, dfn, em, img, ins, kbd, q, s, samp, small, strike, strong, sub, sup, tt, var, b, u, i,
center, dl, dt, dd, ol, ul, li, fieldset, form, label, legend, table, caption, tbody, tfoot, thead, tr,
th, td, article, aside, canvas, details, embed, figure, figcaption, footer, header, hgroup, menu, nav,
output, ruby, section, summary, time, mark, audio, video {
    margin: 0;
    padding: 0;
    border: 0;
    font-size: 100%;
    font: inherit;
    vertical-align: baseline
}
body {
    line-height: 1
}
ol, ul {
    list-style: none
}
blockquote, q {
    quotes: none
}
blockquote:before, blockquote:after, q:before, q:after {
    content: '';
    content: none
}
table {
    border-collapse: collapse;
    border-spacing: 0
}
article, div, footer, header, main, nav, section, #react-root {
    align-items: stretch;
    border: 0 solid #000;
    box-sizing: border-box;
    display: flex;
    flex-direction: column;
    flex-shrink: 0;
    margin: 0;
    padding: 0;
    position: relative
}
body {
    overflow-y: scroll
}
html, body {
    height: 100%
}
#react-root {
    height: 100%;
    z-index: 0
}
body, button, input, textarea {
    font-family: 'proxima-nova', 'Helvetica Neue', Arial, Helvetica, sans-serif
}
a, a:visited {
    color: #003569;
    text-decoration: none
}
a:active {
    opacity: .5
}