/*! normalize.css v8.0.1 | 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;
}

/**
	* Render the `main` element consistently in IE.
	*/

main {
	display: block;
}

/**
	* 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;
}

.display_none {
	display: none;
}
/* http://meyerweb.com/eric/tools/css/reset/ 
   v2.0 | 20110126
   License: none (public domain)
*/

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;
}
/* HTML5 display-role reset for older browsers */
article, aside, details, figcaption, figure, 
footer, header, hgroup, menu, nav, section {
	display: block;
}
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;
}

img {
	vertical-align: top;
}
html{
  overscroll-behavior: none;
  font-family: 'Noto Sans', sans-serif;
} 

body {
  /* display: flex;
  flex-direction: column;
  justify-content: center; */
  background: radial-gradient(circle, rgba(0,117,255,1) 0%, rgba(9,9,121,1) 75%, rgba(2,0,36,1) 100%) no-repeat center center/cover;
  /* height: calc(var(--vh, 1vh) * 100); */
  /* height: 100%; */
  min-height: 100vh;
}

h1 {
  font-size: 35px;
  font-weight: 700;
  text-shadow: 1px 1px 2px #020024, 0 0 1em #090979, 0 0 0.2em #fff;
  color: white;
  text-align: center;
}


/* /////////// index.html ////////////*/
#intro {
  display: flex;
  flex-direction: column;
  justify-content: center;
  min-height: 100vh;
}

#intro form {
  text-align: center;
  padding: 25px 0 0;
  display: flex;
  flex-direction: column;
  gap: 25px;
  align-items: center;
}

.option_wrap {
  /* display: flex;
  flex-direction: column;
  align-items: center; */
}

.option_wrap h2 {
  white-space: nowrap;
  color: #fff;
  padding-bottom: 10px;
}

.option {
  cursor: default;
  display: flex;
  gap: 10px;
}

#intro form button {
  border: none;
  border-radius: 10px;
  padding: 10px 50px;
  background-color: #fff;
  font-size: 20px;
  font-weight: 800;
  cursor: pointer;
  transition: all 0.5s;
  box-shadow: 0px 8px 15px rgba(0, 0, 0, 0.25);
  text-transform: capitalize;
}

#intro form button:hover {
  background-color:lightsteelblue;
}

label, input[type="radio"] {
  cursor: pointer;
}

/* The switch - the box around the slider */
/* .switch {
  position: relative;
  display: inline-block;
  width: 50px;
  height: 30px;
} */

/* Hide default HTML checkbox */
/* .switch input {
  opacity: 0;
  width: 0;
  height: 0;
} */

/* The slider */
/* .slider {
  position: absolute;
  cursor: pointer;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: #ccc;
  -webkit-transition: .4s;
  transition: .4s;
}

.slider:before {
  position: absolute;
  content: "";
  height: 23px;
  width: 23px;
  left: 4px;
  bottom: 3.5px;
  background-color: white;
  -webkit-transition: .4s;
  transition: .4s;
}

input:checked + .slider {
  background-color: #2196F3;
}

input:focus + .slider {
  box-shadow: 0 0 1px #2196F3;
}

input:checked + .slider:before {
  -webkit-transform: translateX(19px);
  -ms-transform: translateX(19px);
  transform: translateX(19px);
} */

/* Customize the label (the container) */
.container {
  cursor: pointer;
  font-size: 17px;
  color:aliceblue;
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 5px;
}

/* Hide the browser's default radio button */
.container input {
  position: absolute;
  opacity: 0;
  cursor: pointer;
  height: 0;
  width: 0;
}

/* Create a custom radio button */
.checkmark {
  line-height: 30px;
  padding: 3px 8px;
  border: 2px solid #eee;
  border-radius: 15px;
}

/* On mouse-over, add a grey background color */
.container:hover input ~ .checkmark {
  background-color: #ccc; 
}

/* When the radio button is checked, add a blue background */
.container input:checked ~ .checkmark {
  background-color: darkred;
}

/* Create the indicator (the dot/circle - hidden when not checked) */
.checkmark:after {
  /* content: "";
  position: absolute;
  display: none; */
}

/* Show the indicator (dot/circle) when checked */
.container input:checked ~ .checkmark:after {
  /* display: block; */
}

/* Style the indicator (dot/circle) */
.container .checkmark:after {
  /* top: 6px;
  left: 6px;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: white; */
}

/* /////////// game_board.html ////////////*/
nav ul {
  display: flex;
  gap: 20px;
  padding: 25px 10px;
  color: #eee;
}
nav ul a {
  color: #eee;
  text-decoration: none;
}

#game_board {
  padding: 0 10px;
}

#board {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
}

/* #game_board section > div {
  height: 100%;
  display: flex;
  align-items: center; 
  justify-content: center;
  flex-wrap: wrap;
  max-width: 90%;
  margin: 0 auto;
  padding: 20px;
} */

/* #game_board nav {
  padding: 8px 15px;
  color: #fff;
  display: flex;
  gap: 20px
} */

/* #game_board nav a {
  color: #fff;
  text-decoration: none;
} */

/* The flip card container */
.flip-card {
  background-color: transparent;
  width: 150px;
  height: 225px;
  perspective: 1000px; /* Remove this if you don't want the 3D effect */
}
          
/* This container is needed to position the front and back side */
.flip-card-inner {
  position: relative;
  width: 100%;
  height: 100%;
  text-align: center;
  transition: transform 0.5s;
  transform-style: preserve-3d;
}

.flip-card.flipped .flip-card-inner {
  transform: rotateY(180deg);
}

.flip-card.flipped.incorrect {
  animation: shake 0.5s;
  animation-delay: .3s;
  animation-iteration-count: forward;
}

/* Position the front and back side */
.flip-card-front, .flip-card-back {
  position: absolute;
  width: 100%;
  height: 100%;
  -webkit-backface-visibility: hidden; /* Safari */
  backface-visibility: hidden;
}

/* Style the front side */
.flip-card-front {
  background-color: #bbb;
  color: black;
}

.flip-card-front img{
  width: 100%;
}

/* Style the back side */
.flip-card-back {
  background-color: #000;
  color: white;
  transform: rotateY(180deg);
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.flip-card-back > div {
  position: absolute;
  left: 0;
  bottom: 0;
  text-align: left;
  word-break: break-all;
  background-color: #222;
  padding: 5px;
  font-size: 8px;
}


.cards_img {
  width: 300px;
  position: fixed;
}
.cards_img img {
  aspect-ratio: 1/1.2;
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.cards_img.img_bottom {
  left: -25px;
  bottom: 0;
  transform: translateY(25%);
}
.cards_img.img_top {
  top: 0;
  right: -35px;
  transform: translateY(-10%);
}

@keyframes shake {
  0% { transform: translate(1px, 1px) rotate(0deg); }
  10% { transform: translate(-1px, -2px) rotate(-1deg); }
  20% { transform: translate(-3px, 0px) rotate(1deg); }
  30% { transform: translate(3px, 2px) rotate(0deg); }
  40% { transform: translate(1px, -1px) rotate(1deg); }
  50% { transform: translate(-1px, 2px) rotate(-1deg); }
  60% { transform: translate(-3px, 1px) rotate(0deg); }
  70% { transform: translate(3px, 1px) rotate(-1deg); }
  80% { transform: translate(-1px, -1px) rotate(1deg); }
  90% { transform: translate(1px, 2px) rotate(0deg); }
  100% { transform: translate(1px, -2px) rotate(-1deg); }
 }

/*1024 아이패드 프로*/
/*768 아이패드 */
/*480 모바일 */

/*1024이하 */
@media(max-width:1024px) { 
  /* #game_board section > div > div {
    width: 100%;
  } */
  #game_board section > div{
    /* width: 100%; */
    /* padding: 20px; */
  }
  .flip-card {
    width: 16.666%;
    height: auto;
    position: relative;
  }
  .flip-card::before {
    content: '';
    display: block;
    padding-top: 150%;
  }
  .flip-card .flip-card-inner {
    position: absolute;
    left: 0;
    right: 0;
    top:0;
    bottom: 0;
  }
}
/*768이하 */
@media(max-width:768px){
  .cards_img {
    width: 200px;
  }
}
/*480이하 */
@media(max-width:480px) { 
  .flip-card {
    width: 25%;
  }
  .beginner#game_board {
    /* padding: 0 20px; */
  }
  .intermediate .flip-card {
    width: 22%;
  }
  .advanced .flip-card {
    width: 18%;
  }
  .flip-card-back > div {
    padding: 2px;
    font-size: 5px;
  }
}

#no-results {
  text-align: center;
  color: #fff;
  font-size: 20px;
  line-height: 27px;
}
#no-results strong {
  font-size: 24px;
  font-weight: bold;
  background-color: #222;
}