@import url
('https://fonts.googleapis.com/css?family=PT+Sans');
@import url
('https://fonts.googleapis.com/css?family=PT+Serif');

@media only screen and (min-width: 620px) 

body {
  max-width: 95%;
  margin: 0 auto;
  padding: 0;
  font-size: 16px;
  font-family: "PT Sans", sans-serif;  
  }

/*Scroll To Top Button*/
#myBtn {
  display: none;
  position: fixed;
  bottom: 40px;
  right: 30px;  
  font-size: 30px;
  border: none;
  outline: none;
  background-color: #50b9e1;
  color: white;
  cursor: pointer;
  padding: 15px;
  border-radius: 4px;
}

#myBtn:hover {
  background-color: #555;
}



/*for all page*/
ul {
  padding: 0;
}

ul li {
  display: inline-block;
}
a {
  text-decoration: none;
  
}

span {
  color: #50b9e1;
}

h2 {
  font-family: "PT Serif", serif;
  font-size: 32px;
  letter-spacing: 2px;
   margin: 20px 0px;
  padding: 25px 0px;
}
p{
  font-size: 18px;
}
/*navigation*/

.navigation {
  padding: 10px;
  text-align: center;
}

.site-title {
  font-size: 36px;
  display: inline-block;
  width: 22%;
}

nav {
  display: inline-block;  
}
nav ul li:not(:last-child) {
  padding-right: 50px;  
}

nav ul li a {
  color: #474747;
  font-size: 20px; 
  padding-left: 5px;
  font-weight: bold;
}
nav ul li a:hover {
  color: #50b9e1;
}

.navigation > nav > ul >
li:nth-child(6) > ul {
  padding-left: 15px;
}

.navigation > nav > ul >
li:nth-child(6) > ul li:not(:last-child) {
  padding-right: 5px;
}

.navigation > nav > ul >
li:nth-child(6) > ul li a i {
  border: 1px solid black;
  border-radius: 50%;
  padding: 5px;
} 

/*site-header*/
.site-header {
  background: 
  linear-gradient(rgba(0,0,0,0.3),
  rgba(0,0,0,0.6)),
  url("Images/cover.jpg") no-repeat center;    
  background-size: cover;
  width: 95%;
  margin: auto;
  
}

.site-header h1 {
  margin: 0;
  color: white;
  font-size: 8vw;
  padding: 200px 0 50px 100px;
  width: 60%;
  letter-spacing: 2px;
}
.site-header button {
  margin: 0 0 200px 100px;
  padding: 10px 15px;
  font-size: 26px;
  color: white;
  opacity: 0.3;
  border: 2px solid white;
  border-radius: 5px;
}

.site-header button:hover {
  background: #50b9e1;
  color: white;
  border-color: #50b9e1;
  border-radius: 5px;
}
main{
  width: 100%;
  margin: auto;
}
/*main .video-math */
.mathematics{
 width: 70%;
  margin: auto;
}

.video-math {
  color: #5a7c8a;
  text-align:center;
  width: 95%;
  margin: 0 auto;
  padding: 20px 0;
  border: rgba(200,200,200,0.6);
  border-radius: 5px;
  
}
.video-math p{
  font-size: 20px;
  font-family: "PT Sans", sans-serif;
  margin: auto;
  padding-top: 50px;
  width: 95%;
}
.iframe-cont{
  overflow:hidden;
    padding-bottom:56.25%;
    position:relative;
    height:0;
  
}
.iframe-cont iframe{
  left:0;
  top:0;
  height:100%;
  width:100%;
  position:absolute;
}

/*main lessons*/
.lessons{
  margin:auto;
  padding: 50px 0;
  background: #43bae3;
  color: white;
  text-align: center;
  width: 95%;
}
.video-lessons h3{
text-align: center;
font-size: double;
font-style: italic;
margin: 0px;
}
.video-lessons img {
  width: 70px;
}

.video-lessons li {
  width: 75px;
  padding: 25px 50px;
}

.video-lessons li a {
  color: white; 
}  
.video-lessons img:hover {
  opacity: 0.4;
}




/*main welcome*/
.welcome{
  width: 95%;
  margin: auto;
  background: rgba(200,200,200,0.6); 

}
.welcome p{
    color: #5a7c8a;
    text-align: center;
    width: 60%;
    margin: 0 auto;
    padding: 20px 0;
    font-size: 20px;
    font-style: italic;
    font-family: "PT Sans", sans-serif;
}
/*main welcome*/
.welcome h2{
  text-align: center;
  color:#5a7c8a;
}



/*main math*/
.math {
  text-align: center;
  padding: 50px 0;
  color: #5a7c8a;
}

body > main > section.math > p {
  width: 50%;
  margin: 0 auto;
  padding-bottom: 30px;
}

.math li {
  width: 400px;
}
.math li:not(:last-child) {
  padding-right: 45px;
}
.math h3{
  text-align: center;
}

.math img {
  width: 200px;
  height: auto;
}
.math img :hover{
  opacity: 0.1;
}

.info-1 {
  padding-bottom: 10px;
  border-bottom: 2px solid #5a7c8a;
}
.info-1 div:nth-child(1) {
  display: inline-block;
  width: 329px;
  text-align: left;
}

.info-1 div:nth-child(2) {
  display: inline-block;
  width: 20px;
  text-align: right;  
  font-size: 16px;
  background: #43bae3;
  color: white;
  padding: 0px;
}


.info-1 p, .info-1 h3 {
  margin: 2px 0;
  
}

.geogebra{
  width: 100%;
  background: red;
}
.geogebra iframe{
  width: 80%;
}

#read-button{
  color: white;
  text-align: center;
  width: 95%;
  margin: 30px auto;
  padding: 50px 0;
  font-size: 20px;
  font-style: italic;
  font-family: "PT Sans", sans-serif;
  background: rgba(18,62,104,0.6); 
}




/*before*/
.before-first{
  text-align: center;
  padding: 50px 0;
  color: #5a7c8a;
}
.before { 
  width: 95%;
  height: 400px;
  margin:20px auto;

}
.before li{
  width:400px;
}

 .before ul{
    text-align: center;
  }
  .game {
    width: 100%;
    height: auto;
    border: 5px solid #50b9e1;
    border-radius: 4px;
    opacity: 0.9;
    margin-top: 30px;
  } 
  .before h3{
    text-align: center;
    font-size: 40px;
  }
    
  .before p{
    text-align: center;
    font-size: 20px;
    padding-left: 40px;
    padding-bottom: 100px;
  }

/*conection*/
.conection-project{ 
  width: 95%;
  text-align: center;
  margin: 20px auto;
}
.conection-project ul li a{
  width:95%;
  text-align: center;
  margin: 20px;
  font-size: 40px;
  color: #123e68;

}
.conection-project ul{
  text-align: center;
}

.conection-project h2{
  text-align: center;
  font-size: 30px;
  color:#5a7c8a;
  padding:10px;
}
.conection-project p{
  text-align: center;
  font-size: 20px;
  color:#5a7c8a;
  padding-left: 40px;
}
.conection-project hr{
  height: 5px;
  color:#5a7c8a;
}
/*conection-us*/
.conection-us {
  text-align: center;
  padding: 10px 0;
  color: #5a7c8a;
  
}

body > main > section.conection-us > p {
  width: 50%;
  margin: 0 auto;
  padding-bottom: 30px;
}

.conection-us li {
  width: 400px;
}
.conection-us li:not(:last-child) {
  padding-right: 45px;
}
.conection-us h3{
  text-align: center;
  font-size: 20px;
}

.conection-us img {
  width: 350px;
  height: auto;
}
.conection-us img :hover{
  opacity: 0.1;
}

.conection-more {
  padding-bottom: 10px;
  border-bottom: 2px solid #5a7c8a;
}
.conection-more div:nth-child(1) {
  display: inline-block;
  width: 329px;
  text-align: left;
}

.conection-more div:nth-child(2) {
  display: inline-block;
  width: 20px;
  text-align: right;  
  font-size: 16px;
  background: #43bae3;
  color: white;
  padding: 0px;
}


.conection-more p, .conection-more h3 {
  margin: 2px 0;
  
}

   /*footer*/
footer{
  background: #123e68;
  width: 95%;
  margin: auto;
  
}

footer p {
display: inline-block;
width: 30%;
text-align: right;
color: #43bae3;
}

footer ul {
display: inline-block;
width: 60%;
text-align: center;
}
footer ul li{
  text-align: right;
  color: #50b9e1;
}
footer ul li a {
  color: #50b9e1;
  font-size: 20px;
  padding: 0px 20px;
 

 
}
footer ul li a:hover {
  color: white;
}