Редактор кода W3Schools - Tryit

<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<style>
* {
  box-sizing: border-box;
}

.row::after {
  content: "";
  clear: both;
  display: table;
}

[class*="col-"] {
  float: left;
  padding: 15px;
}

html {
  font-family: "Lucida Sans", sans-serif;
}

.header {
  background-color: #9933cc;
  color: #ffffff;
  padding: 15px;
}

.menu ul {
  list-style-type: none;
  margin: 0;
  padding: 0;
}

.menu li {
  padding: 8px;
  margin-bottom: 7px;
  background-color: #33b5e5;
  color: #ffffff;
  box-shadow: 0 1px 3px rgba(0,0,0,0.12), 0 1px 2px rgba(0,0,0,0.24);
}

.menu li:hover {
  background-color: #0099cc;
}

.aside {
  background-color: #33b5e5;
  padding: 15px;
  color: #ffffff;
  text-align: center;
  font-size: 14px;
  box-shadow: 0 1px 3px rgba(0,0,0,0.12), 0 1px 2px rgba(0,0,0,0.24);
}

.footer {
  background-color: #0099cc;
  color: #ffffff;
  text-align: center;
  font-size: 12px;
  padding: 15px;
}

/* For mobile phones: */
[class*="col-"] {
  width: 100%;
}

@media only screen and (min-width: 600px) {
  /* For tablets: */
  .col-s-1 {width: 8.33%;}
  .col-s-2 {width: 16.66%;}
  .col-s-3 {width: 25%;}
  .col-s-4 {width: 33.33%;}
  .col-s-5 {width: 41.66%;}
  .col-s-6 {width: 50%;}
  .col-s-7 {width: 58.33%;}
  .col-s-8 {width: 66.66%;}
  .col-s-9 {width: 75%;}
  .col-s-10 {width: 83.33%;}
  .col-s-11 {width: 91.66%;}
  .col-s-12 {width: 100%;}
}
@media only screen and (min-width: 768px) {
  /* For desktop: */
  .col-1 {width: 8.33%;}
  .col-2 {width: 16.66%;}
  .col-3 {width: 25%;}
  .col-4 {width: 33.33%;}
  .col-5 {width: 41.66%;}
  .col-6 {width: 50%;}
  .col-7 {width: 58.33%;}
  .col-8 {width: 66.66%;}
  .col-9 {width: 75%;}
  .col-10 {width: 83.33%;}
  .col-11 {width: 91.66%;}
  .col-12 {width: 100%;}
}
</style>
</head>
<body>

<div class="header">
  <h1>Chania</h1>
</div>

<div class="row">
  <div class="col-3 col-s-3 menu">
    <ul>
      <li>The Flight</li>
      <li>The City</li>
      <li>The Island</li>
      <li>The Food</li>
    </ul>
  </div>

<div class="col-6 col-s-9">
    <h1>The City</h1>
    <p>Chania is the capital of the Chania region on the island of Crete. The city can be divided in two parts, the old town and the modern city.</p>
  </div>

<div class="col-3 col-s-12">
    <div class="aside">
      <h2>What?</h2>
      <p>Chania is a city on the island of Crete.</p>
      <h2>Where?</h2>
      <p>Crete is a Greek island in the Mediterranean Sea.</p>
      <h2>How?</h2>
      <p>You can reach Chania airport from all over Europe.</p>
    </div>
  </div>
</div>

<div class="footer">
  <p>Измените размер окна браузера, чтобы увидеть, как контент реагирует на изменение размера.</p>
</div>

</body>
</html>

​x
 
<!DOCTYPE html><html><head><meta name="viewport" content="width=device-width, initial-scale=1.0"><style>* {  box-sizing: border-box;}​.row::after {  content: "";  clear: both;  display: table;}​[class*="col-"] {  float: left;  padding: 15px;}​html {  font-family: "Lucida Sans", sans-serif;}​.header {  background-color: #9933cc;  color: #ffffff;  padding: 15px;}​.menu ul {  list-style-type: none;  margin: 0;  padding: 0;}​.menu li {  padding: 8px;  margin-bottom: 7px;  background-color: #33b5e5;  color: #ffffff;  box-shadow: 0 1px 3px rgba(0,0,0,0.12), 0 1px 2px rgba(0,0,0,0.24);}​.menu li:hover {  background-color: #0099cc;}​.aside {  background-color: #33b5e5;  padding: 15px;  color: #ffffff;  text-align: center;  font-size: 14px;  box-shadow: 0 1px 3px rgba(0,0,0,0.12), 0 1px 2px rgba(0,0,0,0.24);}​.footer {  background-color: #0099cc;  color: #ffffff;  text-align: center;  font-size: 12px;  padding: 15px;}​/* For mobile phones: */[class*="col-"] {  width: 100%;}​@media only screen and (min-width: 600px) {  /* For tablets: */  .col-s-1 {width: 8.33%;}  .col-s-2 {width: 16.66%;}  .col-s-3 {width: 25%;}  .col-s-4 {width: 33.33%;}  .col-s-5 {width: 41.66%;}  .col-s-6 {width: 50%;}  .col-s-7 {width: 58.33%;}  .col-s-8 {width: 66.66%;}  .col-s-9 {width: 75%;}  .col-s-10 {width: 83.33%;}  .col-s-11 {width: 91.66%;}  .col-s-12 {width: 100%;}}@media only screen and (min-width: 768px) {  /* For desktop: */  .col-1 {width: 8.33%;}  .col-2 {width: 16.66%;}  .col-3 {width: 25%;}  .col-4 {width: 33.33%;}  .col-5 {width: 41.66%;}  .col-6 {width: 50%;}  .col-7 {width: 58.33%;}  .col-8 {width: 66.66%;}  .col-9 {width: 75%;}  .col-10 {width: 83.33%;}  .col-11 {width: 91.66%;}  .col-12 {width: 100%;}}</style></head><body>​<div class="header">  <h1>Chania</h1></div>​<div class="row">  <div class="col-3 col-s-3 menu">    <ul>      <li>The Flight</li>      <li>The City</li>      <li>The Island</li>      <li>The Food</li>    </ul>  </div>​  <div class="col-6 col-s-9">    <h1>The City</h1>    <p>Chania is the capital of the Chania region on the island of Crete. The city can be divided in two parts, the old town and the modern city.</p>  </div>​  <div class="col-3 col-s-12">    <div class="aside">      <h2>What?</h2>      <p>Chania is a city on the island of Crete.</p>      <h2>Where?</h2>      <p>Crete is a Greek island in the Mediterranean Sea.</p>      <h2>How?</h2>      <p>You can reach Chania airport from all over Europe.</p>    </div>  </div></div>​<div class="footer">  <p>Измените размер окна браузера, чтобы увидеть, как контент реагирует на изменение размера.</p></div>​</body></html>                