* { box-sizing: border-box; }

html, body {
  padding: 0;
  margin: 0;
  background: #FAFAFA;
  font-family: Arial, sans-serif;
}

.header {
  width: 100%;
  height: 56px;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.4);
  background: #333;
  color: #FFF;
  display: flex;
  flex-direction: row;
  align-items: center;
  padding: 0 16px;
}

.header__menu-toggle {
  background: none;
  border: none;
  width: 24px;
  height: 24px;
  padding: 0;
  margin: 0;
  color: #FFF;
}

.side-nav {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  overflow: hidden;
  pointer-events: none;
}

.side-nav--visible { pointer-events: auto; }

.side-nav::before {
  content: '';
  display: block;
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.4);
  opacity: 0;
  transition: opacity 0.3s cubic-bezier(0, 0, 0.3, 1);
}

.side-nav__container {
  position: relative;
  width: 90%;
  max-width: 400px;
  background: #FFF;
  height: 100%;
  box-shadow: 2px 0 12px rgba(0, 0, 0, 0.4);
  transform: translateX(-102%);
  display: flex;
  flex-direction: column;
}

.side-nav--visible .side-nav__container { transition: transform 0.13s cubic-bezier(0, 0, 0.3, 1); }

.side-nav--visible .side-nav--animatable .side-nav__container { transition: transform 0.33s cubic-bezier(0, 0, 0.3, 1); }

.side-nav--visible::before { opacity: 1; }

.side-nav--visible .side-nav__container { transform: none; }

.side-nav__hide {
  position: absolute;
  left: 16px;
  top: 16px;
  background: none;
  border: none;
  color: #FFF;
}

.side-nav__header {
  height: 200px;
  background: #330099;
  color: #FFF;
  display: flex;
  padding: 16px;
  align-items: flex-end;
}

.side-nav__content {
  flex: 1;
  list-style: none;
  padding: 0;
  margin: 0;
  overflow-x: hidden;
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
}

.side-nav__content li {
  height: 32px;
  line-height: 32px;
  padding: 0 16px;
}

.side-nav__content li:hover { background: #CCC; }