/*! normalize.css v8.0.0 | MIT License | github.com/necolas/normalize.css */
/* Document
   ========================================================================== */
/**
 * 1. Correct the line height in all browsers.
 * 2. Prevent adjustments of font size after orientation changes in iOS.
 */
html {
  line-height: 1.15;
  /* 1 */
  -webkit-text-size-adjust: 100%;
  /* 2 */ }

/* Sections
   ========================================================================== */
/**
 * Remove the margin in all browsers.
 */
body {
  margin: 0; }

/**
 * Correct the font size and margin on `h1` elements within `section` and
 * `article` contexts in Chrome, Firefox, and Safari.
 */
h1 {
  font-size: 2em;
  margin: 0.67em 0; }

/* Grouping content
   ========================================================================== */
/**
 * 1. Add the correct box sizing in Firefox.
 * 2. Show the overflow in Edge and IE.
 */
hr {
  box-sizing: content-box;
  /* 1 */
  height: 0;
  /* 1 */
  overflow: visible;
  /* 2 */ }

/**
 * 1. Correct the inheritance and scaling of font size in all browsers.
 * 2. Correct the odd `em` font sizing in all browsers.
 */
pre {
  font-family: monospace, monospace;
  /* 1 */
  font-size: 1em;
  /* 2 */ }

/* Text-level semantics
   ========================================================================== */
/**
 * Remove the gray background on active links in IE 10.
 */
a {
  background-color: transparent; }

/**
 * 1. Remove the bottom border in Chrome 57-
 * 2. Add the correct text decoration in Chrome, Edge, IE, Opera, and Safari.
 */
abbr[title] {
  border-bottom: none;
  /* 1 */
  text-decoration: underline;
  /* 2 */
  text-decoration: underline dotted;
  /* 2 */ }

/**
 * Add the correct font weight in Chrome, Edge, and Safari.
 */
b,
strong {
  font-weight: bolder; }

/**
 * 1. Correct the inheritance and scaling of font size in all browsers.
 * 2. Correct the odd `em` font sizing in all browsers.
 */
code,
kbd,
samp {
  font-family: monospace, monospace;
  /* 1 */
  font-size: 1em;
  /* 2 */ }

/**
 * Add the correct font size in all browsers.
 */
small {
  font-size: 80%; }

/**
 * Prevent `sub` and `sup` elements from affecting the line height in
 * all browsers.
 */
sub,
sup {
  font-size: 75%;
  line-height: 0;
  position: relative;
  vertical-align: baseline; }

sub {
  bottom: -0.25em; }

sup {
  top: -0.5em; }

/* Embedded content
   ========================================================================== */
/**
 * Remove the border on images inside links in IE 10.
 */
img {
  border-style: none; }

/* Forms
   ========================================================================== */
/**
 * 1. Change the font styles in all browsers.
 * 2. Remove the margin in Firefox and Safari.
 */
button,
input,
optgroup,
select,
textarea {
  font-family: inherit;
  /* 1 */
  font-size: 100%;
  /* 1 */
  line-height: 1.15;
  /* 1 */
  margin: 0;
  /* 2 */ }

/**
 * Show the overflow in IE.
 * 1. Show the overflow in Edge.
 */
button,
input {
  /* 1 */
  overflow: visible; }

/**
 * Remove the inheritance of text transform in Edge, Firefox, and IE.
 * 1. Remove the inheritance of text transform in Firefox.
 */
button,
select {
  /* 1 */
  text-transform: none; }

/**
 * Correct the inability to style clickable types in iOS and Safari.
 */
button,
[type="button"],
[type="reset"],
[type="submit"] {
  -webkit-appearance: button; }

/**
 * Remove the inner border and padding in Firefox.
 */
button::-moz-focus-inner,
[type="button"]::-moz-focus-inner,
[type="reset"]::-moz-focus-inner,
[type="submit"]::-moz-focus-inner {
  border-style: none;
  padding: 0; }

/**
 * Restore the focus styles unset by the previous rule.
 */
button:-moz-focusring,
[type="button"]:-moz-focusring,
[type="reset"]:-moz-focusring,
[type="submit"]:-moz-focusring {
  outline: 1px dotted ButtonText; }

/**
 * Correct the padding in Firefox.
 */
fieldset {
  padding: 0.35em 0.75em 0.625em; }

/**
 * 1. Correct the text wrapping in Edge and IE.
 * 2. Correct the color inheritance from `fieldset` elements in IE.
 * 3. Remove the padding so developers are not caught out when they zero out
 *    `fieldset` elements in all browsers.
 */
legend {
  box-sizing: border-box;
  /* 1 */
  color: inherit;
  /* 2 */
  display: table;
  /* 1 */
  max-width: 100%;
  /* 1 */
  padding: 0;
  /* 3 */
  white-space: normal;
  /* 1 */ }

/**
 * Add the correct vertical alignment in Chrome, Firefox, and Opera.
 */
progress {
  vertical-align: baseline; }

/**
 * Remove the default vertical scrollbar in IE 10+.
 */
textarea {
  overflow: auto; }

/**
 * 1. Add the correct box sizing in IE 10.
 * 2. Remove the padding in IE 10.
 */
[type="checkbox"],
[type="radio"] {
  box-sizing: border-box;
  /* 1 */
  padding: 0;
  /* 2 */ }

/**
 * Correct the cursor style of increment and decrement buttons in Chrome.
 */
[type="number"]::-webkit-inner-spin-button,
[type="number"]::-webkit-outer-spin-button {
  height: auto; }

/**
 * 1. Correct the odd appearance in Chrome and Safari.
 * 2. Correct the outline style in Safari.
 */
[type="search"] {
  -webkit-appearance: textfield;
  /* 1 */
  outline-offset: -2px;
  /* 2 */ }

/**
 * Remove the inner padding in Chrome and Safari on macOS.
 */
[type="search"]::-webkit-search-decoration {
  -webkit-appearance: none; }

/**
 * 1. Correct the inability to style clickable types in iOS and Safari.
 * 2. Change font properties to `inherit` in Safari.
 */
::-webkit-file-upload-button {
  -webkit-appearance: button;
  /* 1 */
  font: inherit;
  /* 2 */ }

/* Interactive
   ========================================================================== */
/*
 * Add the correct display in Edge, IE 10+, and Firefox.
 */
details {
  display: block; }

/*
 * Add the correct display in all browsers.
 */
summary {
  display: list-item; }

/* Misc
   ========================================================================== */
/**
 * Add the correct display in IE 10+.
 */
template {
  display: none; }

/**
 * Add the correct display in IE 10.
 */
[hidden] {
  display: none; }

*, *:before, *:after {
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box; }

.-screenReader {
  clip: rect(1px, 1px, 1px, 1px);
  position: absolute !important;
  left: -2000px; }
  .-screenReader:focus {
    background-color: #fff;
    box-shadow: 0 0 2px 2px rgba(0, 0, 0, 0.6);
    -webkit-box-shadow: 0 0 2px 2px rgba(0, 0, 0, 0.6);
    clip: auto !important;
    color: #000;
    display: block;
    font-size: 1rem;
    height: auto;
    line-height: normal;
    padding: 1rem;
    position: absolute;
    left: 1rem;
    top: 1rem;
    text-decoration: none;
    width: auto;
    z-index: 100000; }

html,
body {
  margin: 0;
  background: #fff;
  font-family: Roboto, sans-serif;
  font-size: 14px;
  line-height: 1.8em;
  font-weight: 400;
  color: #002c40; }

a {
  color: #007ab2;
  font-weight: 500;
  text-decoration: none; }
  a:hover, a:focus {
    color: #009de5; }

.site-row {
  max-width: 900px;
  margin-left: auto;
  margin-right: auto;
  padding-left: 1rem;
  padding-right: 1rem; }
  @media (min-width: 768px) {
    .site-row {
      padding-left: 2rem;
      padding-right: 2rem; } }
  @media (min-width: 1400px) {
    .site-row {
      max-width: 1200px; } }

.bookHeader {
  max-width: 900px;
  margin-left: auto;
  margin-right: auto;
  padding-left: 1rem;
  padding-right: 1rem;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 60px;
  background: #fff;
  border-bottom: 1px solid #eee;
  z-index: 999; }
  @media (min-width: 768px) {
    .bookHeader {
      padding-left: 2rem;
      padding-right: 2rem; } }
  @media (min-width: 1400px) {
    .bookHeader {
      max-width: 1200px; } }

.bookHeader__logo {
  display: inline-block;
  padding-top: 1rem;
  padding-bottom: 1rem;
  font-size: 1.5rem;
  font-weight: 300;
  line-height: 1.2em;
  color: #002c40;
  text-decoration: none; }

.bookHeader__logoImage {
  max-height: 32px;
  width: auto;
  display: block; }

.bookHeader__sidebarControl {
  position: absolute;
  display: block;
  top: 0;
  left: 0;
  width: 60px;
  height: 60px;
  line-height: 60px;
  padding: 1rem;
  border: none;
  border-right: 1px solid #eee;
  background: transparent;
  font-size: 1.5rem;
  line-height: 1.2em;
  color: #002c40;
  cursor: pointer; }
  .bookHeader__sidebarControl:hover, .bookHeader__sidebarControl:focus {
    box-shadow: inset 4px 0 0 #007ab2;
    outline: 0; }
  .bookHeader__sidebarControl .fa-bars,
  .bookHeader__sidebarControl .fa-times {
    min-width: 2rem;
    text-align: center; }
  .bookHeader__sidebarControl .fa-times {
    display: none; }
  .bookHeader__sidebarControl + .bookHeader__logo {
    margin-left: 60px; }

.-sidebarIsOpen .bookHeader__sidebarControl .fa-bars {
  display: none; }
.-sidebarIsOpen .bookHeader__sidebarControl .fa-times {
  display: inline-block; }

.bookHeader .versions {
  display: inline-block;
  float: right;
  margin-top: 12px; }

@media (min-width: 992px) {
  .bookHeader {
    position: relative;
    min-height: 6rem;
    padding-top: 1rem;
    padding-bottom: 1rem; }

  .bookHeader__sidebarControl {
    display: none; }
    .bookHeader__sidebarControl + .bookHeader__logo {
      margin-left: 0; } }
.version {
  display: inline-block;
  padding: 0 1em;
  border: 1px solid transparent;
  border-radius: 15px;
  font-weight: 700;
  line-height: 30px; }
  .version:hover, .version:focus {
    border-color: #007ab2; }

.version--current {
  border-color: #007ab2;
  background: #007ab2;
  color: #fff; }

.book {
  max-width: 900px;
  margin-left: auto;
  margin-right: auto;
  padding-left: 1rem;
  padding-right: 1rem;
  margin-top: 4rem;
  padding-top: 3rem; }
  @media (min-width: 768px) {
    .book {
      padding-left: 2rem;
      padding-right: 2rem; } }
  @media (min-width: 1400px) {
    .book {
      max-width: 1200px; } }
  .book hr {
    margin-top: 2rem;
    margin-bottom: 2rem;
    border: none;
    border-bottom: 1px solid #eee; }
  .book img {
    max-width: 100%;
    padding: 0.5em;
    background: #eee;
    border: 1px solid #ddd;
    border-radius: 3px; }
  .book table {
    border: 1px solid #eee;
    border-collapse: collapse; }
    .book table thead {
      background: #eee; }
    .book table tfooter {
      background: #eee; }
    .book table th,
    .book table td {
      padding: 0.25em 0.5em;
      vertical-align: top; }
    .book table th {
      font-weight: 700; }
  .book > .alert:first-child {
    margin-top: 0; }

.book__content h1 {
  margin-top: 0;
  margin-bottom: 1.5rem;
  font-size: 2.2rem;
  line-height: 1.1em; }

.book__improve {
  display: inline-block;
  margin-bottom: 2em; }

.book__footer .book__improve {
  margin-top: 3rem; }

.book__sidebar {
  position: fixed;
  top: 60px;
  left: 0;
  height: 100%;
  padding: 1rem;
  background: #fff;
  transform: translateX(-100%);
  transition: transform 0.3s;
  overflow-y: scroll;
  z-index: 999; }

.book__spacer {
  padding-bottom: 5rem; }

.book__sidebarScreen {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 998;
  background: #000;
  opacity: 0;
  transition: opacity 0.3s; }

.-sidebarIsOpen .book__sidebar {
  transform: translateX(0); }
.-sidebarIsOpen .book__sidebarScreen {
  display: block;
  opacity: 0.2; }

.book__summary h1,
.book__summary h2 {
  position: absolute;
  top: 0;
  left: -9999px; }
.book__summary ul {
  margin-top: 0;
  margin-bottom: 0.5rem;
  padding: 0;
  list-style: none; }
  .book__summary ul ul {
    margin-top: -0.25rem;
    padding-left: 1.5rem; }
.book__summary li {
  list-style: none;
  font-weight: 500; }
  .book__summary li a {
    display: inline-block;
    padding: 0.55em 0;
    line-height: 1.4em;
    color: #002c40; }
    .book__summary li a:hover, .book__summary li a:focus {
      color: #007ab2; }
  .book__summary li li a {
    padding: 0.15em 0;
    font-weight: 400;
    color: rgba(0, 44, 64, 0.7);
    font-size: 0.9rem; }

.book__backToHub {
  display: inline-block;
  margin-top: 1.5rem;
  padding-top: 0.75rem;
  border-top: 1px solid #eee; }
  .book__backToHub .fa-long-arrow-alt-left {
    color: rgba(0, 44, 64, 0.7); }
  .book__backToHub p {
    display: inline-block;
    margin: 0;
    margin-left: 0.75em; }

@media (min-width: 480px) {
  .book__content p,
  .book__content blockquote {
    margin-top: 2em;
    margin-bottom: 2em;
    font-size: 1.15rem;
    line-height: 2.2em; }

  .book__improve {
    float: right;
    margin-left: 2em; }

  .book__footer .book__improve {
    float: none;
    margin-left: 0; } }
@media (min-width: 992px) {
  .book {
    padding-top: 0; }

  .body--withSidebar .book {
    position: relative; }
    .body--withSidebar .book:before, .body--withSidebar .book:after {
      content: " ";
      display: table; }
    .body--withSidebar .book:after {
      clear: both; }
  .body--withSidebar .book__sidebar {
    position: relative;
    top: auto;
    left: auto;
    overflow: hidden;
    transform: none;
    float: left;
    width: 40%;
    margin-top: 0;
    padding: 0 2rem 0 0; }
  .body--withSidebar .book__sidebarScreen {
    display: none !important; }
  .body--withSidebar .book__page {
    float: right;
    width: 60%; }

  .book__content {
    max-width: 700px;
    margin-left: auto;
    margin-right: auto; } }
@media (min-width: 1200px) {
  .body--withSidebar .book__sidebar {
    width: 25%; }
  .body--withSidebar .book__page {
    width: 75%; } }
.alert {
  margin: 4rem 0;
  padding: 1rem;
  background: #eee;
  border-left: 0.5rem solid #002c40; }

.alert__heading {
  margin-bottom: 1rem;
  font-weight: 700; }

.alert--warning {
  background: #f8dce2;
  border-left-color: #e0143f; }

.alert + .alert {
  margin: 2rem 0; }

.highlight .hll {
  background-color: #ffffcc; }

.highlight {
  background: #f0f0f0; }

.highlight .c {
  color: #60a0b0;
  font-style: italic; }

/* Comment */
.highlight .err {
  border: 1px solid #FF0000; }

/* Error */
.highlight .k {
  color: #007020;
  font-weight: bold; }

/* Keyword */
.highlight .o {
  color: #666666; }

/* Operator */
.highlight .ch {
  color: #60a0b0;
  font-style: italic; }

/* Comment.Hashbang */
.highlight .cm {
  color: #60a0b0;
  font-style: italic; }

/* Comment.Multiline */
.highlight .cp {
  color: #007020; }

/* Comment.Preproc */
.highlight .cpf {
  color: #60a0b0;
  font-style: italic; }

/* Comment.PreprocFile */
.highlight .c1 {
  color: #60a0b0;
  font-style: italic; }

/* Comment.Single */
.highlight .cs {
  color: #60a0b0;
  background-color: #fff0f0; }

/* Comment.Special */
.highlight .gd {
  color: #A00000; }

/* Generic.Deleted */
.highlight .ge {
  font-style: italic; }

/* Generic.Emph */
.highlight .gr {
  color: #FF0000; }

/* Generic.Error */
.highlight .gh {
  color: #000080;
  font-weight: bold; }

/* Generic.Heading */
.highlight .gi {
  color: #00A000; }

/* Generic.Inserted */
.highlight .go {
  color: #888888; }

/* Generic.Output */
.highlight .gp {
  color: #c65d09;
  font-weight: bold; }

/* Generic.Prompt */
.highlight .gs {
  font-weight: bold; }

/* Generic.Strong */
.highlight .gu {
  color: #800080;
  font-weight: bold; }

/* Generic.Subheading */
.highlight .gt {
  color: #0044DD; }

/* Generic.Traceback */
.highlight .kc {
  color: #007020;
  font-weight: bold; }

/* Keyword.Constant */
.highlight .kd {
  color: #007020;
  font-weight: bold; }

/* Keyword.Declaration */
.highlight .kn {
  color: #007020;
  font-weight: bold; }

/* Keyword.Namespace */
.highlight .kp {
  color: #007020; }

/* Keyword.Pseudo */
.highlight .kr {
  color: #007020;
  font-weight: bold; }

/* Keyword.Reserved */
.highlight .kt {
  color: #902000; }

/* Keyword.Type */
.highlight .m {
  color: #40a070; }

/* Literal.Number */
.highlight .s {
  color: #4070a0; }

/* Literal.String */
.highlight .na {
  color: #4070a0; }

/* Name.Attribute */
.highlight .nb {
  color: #007020; }

/* Name.Builtin */
.highlight .nc {
  color: #0e84b5;
  font-weight: bold; }

/* Name.Class */
.highlight .no {
  color: #60add5; }

/* Name.Constant */
.highlight .nd {
  color: #555555;
  font-weight: bold; }

/* Name.Decorator */
.highlight .ni {
  color: #d55537;
  font-weight: bold; }

/* Name.Entity */
.highlight .ne {
  color: #007020; }

/* Name.Exception */
.highlight .nf {
  color: #06287e; }

/* Name.Function */
.highlight .nl {
  color: #002070;
  font-weight: bold; }

/* Name.Label */
.highlight .nn {
  color: #0e84b5;
  font-weight: bold; }

/* Name.Namespace */
.highlight .nt {
  color: #062873;
  font-weight: bold; }

/* Name.Tag */
.highlight .nv {
  color: #bb60d5; }

/* Name.Variable */
.highlight .ow {
  color: #007020;
  font-weight: bold; }

/* Operator.Word */
.highlight .w {
  color: #bbbbbb; }

/* Text.Whitespace */
.highlight .mb {
  color: #40a070; }

/* Literal.Number.Bin */
.highlight .mf {
  color: #40a070; }

/* Literal.Number.Float */
.highlight .mh {
  color: #40a070; }

/* Literal.Number.Hex */
.highlight .mi {
  color: #40a070; }

/* Literal.Number.Integer */
.highlight .mo {
  color: #40a070; }

/* Literal.Number.Oct */
.highlight .sa {
  color: #4070a0; }

/* Literal.String.Affix */
.highlight .sb {
  color: #4070a0; }

/* Literal.String.Backtick */
.highlight .sc {
  color: #4070a0; }

/* Literal.String.Char */
.highlight .dl {
  color: #4070a0; }

/* Literal.String.Delimiter */
.highlight .sd {
  color: #4070a0;
  font-style: italic; }

/* Literal.String.Doc */
.highlight .s2 {
  color: #4070a0; }

/* Literal.String.Double */
.highlight .se {
  color: #4070a0;
  font-weight: bold; }

/* Literal.String.Escape */
.highlight .sh {
  color: #4070a0; }

/* Literal.String.Heredoc */
.highlight .si {
  color: #70a0d0;
  font-style: italic; }

/* Literal.String.Interpol */
.highlight .sx {
  color: #c65d09; }

/* Literal.String.Other */
.highlight .sr {
  color: #235388; }

/* Literal.String.Regex */
.highlight .s1 {
  color: #4070a0; }

/* Literal.String.Single */
.highlight .ss {
  color: #517918; }

/* Literal.String.Symbol */
.highlight .bp {
  color: #007020; }

/* Name.Builtin.Pseudo */
.highlight .fm {
  color: #06287e; }

/* Name.Function.Magic */
.highlight .vc {
  color: #bb60d5; }

/* Name.Variable.Class */
.highlight .vg {
  color: #bb60d5; }

/* Name.Variable.Global */
.highlight .vi {
  color: #bb60d5; }

/* Name.Variable.Instance */
.highlight .vm {
  color: #bb60d5; }

/* Name.Variable.Magic */
.highlight .il {
  color: #40a070; }

/* Literal.Number.Integer.Long */
pre,
pre.highlight {
  background: #eee;
  margin: 2rem 0;
  padding: 2rem;
  overflow-x: scroll;
  line-height: 1.3em;
  tab-size: 2;
  -moz-tab-size: 2;
  -o-tab-size: 2; }

code {
  padding: 0.25em;
  background: #eee;
  border-radius: 3px;
  font-family: 'Source Code Pro', monospace;
  font-size: 13px;
  font-style: normal; }

.siteFooter {
  padding-top: 2rem;
  padding-bottom: 2rem; }

.siteFooter__container {
  max-width: 900px;
  margin-left: auto;
  margin-right: auto;
  padding-left: 1rem;
  padding-right: 1rem; }
  @media (min-width: 768px) {
    .siteFooter__container {
      padding-left: 2rem;
      padding-right: 2rem; } }
  @media (min-width: 1400px) {
    .siteFooter__container {
      max-width: 1200px; } }

.siteFooter__logo {
  display: block; }
  .siteFooter__logo img {
    display: block;
    width: 140px;
    max-width: 100%;
    height: auto; }

.siteFooter__nav {
  margin-top: 2rem; }
  .siteFooter__nav p {
    margin: 0.25em 0; }

.siteFooter__navHeader {
  font-weight: 700; }

.book + .siteFooter .siteFooter__container {
  border-top: 1px solid #eee;
  margin-top: 8rem;
  padding-top: 4rem; }

@media (min-width: 767px) {
  .siteFooter {
    padding-top: 4rem;
    padding-bottom: 4rem; }

  .siteFooter__container {
    display: flex;
    justify-content: flex-start; }

  .siteFooter__logo {
    padding-right: 8rem; }

  .siteFooter__nav {
    margin-top: 0;
    padding-right: 4rem; } }
@media (min-width: 1200px) {
  .siteFooter {
    padding-top: 6rem;
    padding-bottom: 6rem; } }