/*  JavaScript 7th Edition
    Chapter 8
    Hands-on Project 8-2

    Filename: styles.css
*/

/* apply a natural box layout model to all elements */
* {
  -moz-box-sizing: border-box;
  -webkit-box-sizing: border-box;
  box-sizing: border-box;
}

/* reset rules */
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;
  width: 960px;
  background: white;
  margin: 0 auto;
  font-family: Verdana, Geneva, sans-serif;
}

ol,
ul {
  list-style: none;
}

/* page header */
header {
  background: #5472b2;
  width: 100%;
  color: #ffffff;
  font-size: 48px;
  text-align: center;
  line-height: 1.5em;
  margin-bottom: 0;
}

/*-------------------- Project Styles ------------------*/

section {
  background-color: #ffdb70;
  margin-top: 0;
  padding-bottom: 20px;
  user-select: none;
  height: 570px;
  position: relative;
}

section h1 {
  font-size: 2.8em;
  text-align: center;
  margin: 0;
  padding: 20px 0;
}

div#box {
  width: 800px;
  height: 400px;
  border: 0px solid rgba(120, 120, 120, 0.5);
  background-color: ivory;
  position: relative;
  margin: 10px auto;
  top: 0px;
  left: 0px;
  box-shadow: 5px 5px 10px gray;
}

div.ball {
  position: absolute;
  background: radial-gradient(
    closest-corner at 25% 25%,
    rgba(92, 151, 170, 0.1) 0,
    rgba(92, 151, 170, 0.5) 100%
  );
  border: 1px solid transparent;
  width: 60px;
  height: 60px;
  border-radius: 50%;
  cursor: pointer;
}

input#addBall {
  display: block;
  width: 120px;
  height: 30px;
  margin: 25px auto;
  font-size: 1.2em;
  cursor: pointer;
}