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: inherit;
  font-size: 100%;
  vertical-align: baseline;
}

html {
  line-height: 1;
}

ol, ul {
  list-style: none;
}

table {
  border-collapse: collapse;
  border-spacing: 0;
}

caption, th, td {
  text-align: left;
  font-weight: normal;
  vertical-align: middle;
}

q, blockquote {
  quotes: none;
}
q:before, q:after, blockquote:before, blockquote:after {
  content: "";
  content: none;
}

a img {
  border: none;
}

article, aside, details, figcaption, figure, footer, header, hgroup, main, menu, nav, section, summary {
  display: block;
}

body {
  background: #ECEFF1;
}

h1 {
  font-family: 'Open Sans',sans-serif;
  padding: 20px 100px;
  margin-top: 30vh;
  text-align: center;
  font-size: 24px;
  font-weight: 700;
  color: #607D8B;
}

.holder {
  max-width: 728px;
  width: 100%;
  margin: 20px auto 0 auto;
  position: relative;
}

.hamburger-menu {
  left: 50%;
  margin-left: -24px;
}

.menu-holder {
  display: none;
  position: absolute;
  top: 0;
  left: 0;
  height: 100%;
  border-top: 48px solid transparent;
  width: 100%;
  text-align: center;
  padding: 10px;
  box-sizing: border-box;
}
.menu-holder li {
  display: block;
  margin: 0 0 10px 0;
}
.menu-holder a {
  font-size: 14px;
  font-family: 'Arial',sans-serif;
  font-weight: 700;
  background: #607D8B;
  padding: 10px;
  display: inline-block;
  color: #fff;
  text-decoration: none;
}

.hamburger-menu {
  position: relative;
  height: 48px;
  width: 48px;
  overflow: hidden;
  text-indent: -9999px;
  border: 0;
  background: #607D8B;
  padding: 0;
  outline: 0;
  cursor: pointer;
}
.hamburger-menu span {
  top: 50%;
  margin-top: -2.5px;
  left: 10px;
  right: 10px;
  position: absolute;
  height: 5px;
  background: #fff;
  display: block;
  transition: background .3s linear;
  -moz-transition: background .3s linear;
  -webkit-transition: background .3s linear;
  -webkit-backface-visibility: hidden;
}
.hamburger-menu span:before, .hamburger-menu span:after {
  content: '';
  display: block;
  width: 100%;
  height: 5px;
  background: #fff;
  position: absolute;
}
.hamburger-menu span:before {
  transition: top .3s .3s, -webkit-transform .3s 0s;
  -moz-transition: top .3s .3s, -webkit-transform .3s 0s;
  -webkit-transition: top .3s .3s, -webkit-transform .3s 0s;
  top: -10px;
  -webkit-transform: rotate(0);
}
.hamburger-menu span:after {
  transition: bottom .2s .3s, -webkit-transform .3s 0s;
  -moz-transition: bottom .2s .3s, -webkit-transform .3s 0s;
  -webkit-transition: bottom .2s .3s, -webkit-transform .3s 0s;
  bottom: -10px;
  -webkit-transform: rotate(0);
}
.hamburger-menu:focus span {
  background: transparent;
}
.hamburger-menu:focus span:before {
  transition: top .3s 0s, transform .3s .3s;
  top: 0;
  transform: rotate(45deg);
}
.hamburger-menu:focus span:after {
  transition: bottom .3s 0s, transform .3s .3s;
  bottom: 0;
  transform: rotate(-45deg);
}
.hamburger-menu:focus + .menu-holder {
  display: block;
}
.hamburger-menu.is-active span {
  background: transparent;
}
.hamburger-menu.is-active span:before {
  transition: top .3s 0s, transform .3s .3s;
  top: 0;
  transform: rotate(45deg);
}
.hamburger-menu.is-active span:after {
  transition: bottom .3s 0s, transform .3s .3s;
  bottom: 0;
  transform: rotate(-45deg);
}