CSS

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

.clearfix::after {
  content: "";
  display: block;
  clear: both;
}

header {
  position: relative;
  background-color: #29a6dc;
  height: 100vh;
  overflow: hidden;
  max-width: 1920px;
  margin: 0 auto;
}

header > * {
  position: absolute;
}

header img {
  height: 50%;
  bottom: 0;
  right: 0;
}

header div.welcome {
  z-index: 1;
  top: 7%;
  left: 5%;
  right: 5%;
  font-family: 'Saira Condensed',
  sans-serif;
  color: white;
  font-size: 40px;
  font-weight: bold;
  text-align: center;
  text-transform: uppercase;
}


header h1 {
  margin-top: 15px;
  font-size: 20px;
}

header h2 {
  font-size: 20px;
  font-weight: normal;
}

header button {
  font-family: 'Saira', sans-serif;
  font-weight: 300;
  line-height: 32px;
  padding: 0 20px;
  text-transform: uppercase;
  color: white;
  background-color: transparent;
  font-size: 12px;
  border: 2px solid white;
}

@media (orientation: portrait) and (min-width: 360px) {
  header h1 {
    font-size: 24px;
  }
  header h2 {
    font-size: 24px;
  }

  header button {
    margin-top: 24px;
    line-height: 40px;
    font-size: 16px;
  }
}

@media (orientation: portrait) and (min-width: 410px) {
  header h1 {
    font-size: 26px;
  }
  header h2 {
    font-size: 26px;
  }

  header button {
    margin-top: 40px;
    line-height: 50px;
    font-size: 20px;
  }

  header img {
    right: -20%;
  }
}

@media (orientation: portrait) and (min-width: 768px) {
  header p {
    font-size: 80px;
  }
  header h1 {
    font-size: 32px;
  }
  header h2 {
    font-size: 32px;
  }

  header button {
    margin-top: 60px;
    line-height: 60px;
    font-size: 24px;
  }

  header img {
    right: -20%;
  }
}


@media (orientation: landscape) {
  header img {
    height: 80%;
    bottom: 0;
    right: -5%;
  }
  header div.welcome {
    top: 15%;
    left: 7%;
    right: 48%;
  }
  header button {
    margin-top: 40px;
  }

}

@media (orientation: landscape) and (min-width: 640px) {
  header h1 {
    font-size: 24px;
  }
  header h2 {
    font-size: 24px;
  }
  header button {
    font-size: 16px;
    line-height: 40px;
  }
}

@media (orientation: landscape) and (min-width: 1024px) {

  header div.welcome {
    left: 3%;
  }

  header p {
    font-size: 56px;
  }
  header h1 {
    margin-top: 40px;
    font-size: 34px;
  }
  header h2 {
    font-size: 34px;
  }
  header button {
    margin-top: 80px;
    font-size: 28px;
    line-height: 70px;
  }

  header img {
    right: -22%;
    height: 85%;

  }
}

@media (orientation: landscape) and (min-width: 1280px) {

  header div.welcome {
    text-align: left;
    left: 6%;
  }
  header p {
    font-size: 100px;
  }
  header h1 {
    margin-top: 40px;
    font-size: 50px;
  }
  header h2 {
    font-size: 50px;
  }
  header button {
    margin-top: 100px;
    font-size: 30px;
    line-height: 80px;
    padding: 0 40px;
    border-width: 2px;
  }

  header img {
    right: -18%;
    height: 80%;

  }

}

@media (orientation: landscape) and (min-width: 1600px) {

  header div.welcome {
    left: 8%;
  }
  header p {
    font-size: 120px;
  }
  header h1 {
    margin-top: 40px;
    font-size: 60px;
  }
  header h2 {
    font-size: 60px;
  }
  header button {
    line-height: 90px;
  }

  header img {
    right: -8%;
    height: 90%;

  }

}

@media (min-width: 1024px) {
  header button {
    cursor: pointer;
    transition: .3s;
  }
  header button:hover {
    background-color: #fff;
    color: #111;
  }

}

section {
  min-height: 30vh;
}

/* Sekcja 1 nasze cechy*/

.features {
  max-width: 1600px;
  margin: 50px auto 0;
  padding: 5%;
  text-align: center;

}

.features h1 {
  font-family: 'Saira Condensed',
  sans-serif;
  font-size: 26px;
  text-transform: uppercase;
  margin-bottom: 15px;

}

.features h2 {
  font-family: 'Saira Condensed',
  sans-serif;
  font-size: 22px;
  text-transform: uppercase;
}

.features p {
  font-family: 'Saira',
  sans-serif;
  font-size: 12px;
  font-weight: 300;
  margin: 20px 0;
}

.features img {
  width: 100%;
  margin: 5px 0;
  max-width: 375px;
}

@media (min-width:360px) {
  .features h1 {
    font-size: 28px;
  }

  .features h2 {
    font-size: 24px;
  }
  .features p {
    font-size: 14px;
  }
}

@media (min-width:768px) {
  .features h1 {
    font-size: 36px;
  }

  .features h2 {
    font-size: 28px;
  }
  .features p {
    font-size: 18px;
  }
}

@media (min-width:1024px) {
  .features {
    margin-top: 50px;
    padding: 5% 2%;
    text-align: center;

  }
  .feature {
    float: left;
    width: 33%;
    padding: 20px;
  }
  .features h1 {
    font-size: 36px;
  }

  .features h2 {
    font-size: 22px;
  }
  .features p {
    font-size: 16px;
    line-height: 120%;
    padding: 0 10px;
  }
}

@media (min-width:1600px) {


  .feature {

    padding: 20px 50px;
  }
  .features h1 {
    font-size: 60px;
  }

  .features h2 {
    font-size: 32px;
  }
  .features p {
    font-size: 21px;
    line-height: 140%;
    padding: 0 10px;
  }
}

.portfolio {
  background-color: black;
  padding: 10px 0 30px;
}

.portfolio h1 {
  font-size: 28px;
  font-family: 'Saira Condensed',
  sans-serif;
  text-transform: uppercase;
  color: white;
  text-align: center;
  padding: 10px 20px;
  margin-bottom: 15px;
}

.portfolio .web img {
  width: 100%;
}

.portfolio .about {
  color: white;
  font-weight: normal;
  padding: 10px 20px 20px 0;
  text-align: left;
}

.portfolio .about h2 {
  font-size: 18px;
  border-bottom: 2px solid white;
  margin-bottom: 12px;
  padding-bottom: 6px;
  text-indent: 20px;
}

.portfolio .about p {
  font-size: 12px;
  padding-left: 20px;
}

.portfolio .project {
  max-width: 1400px;
  margin: 0 auto 20px;
}

.portfolio .project:nth-of-type(odd) {
  background-color: #ff4f2c;
}

.portfolio .project:nth-of-type(even) {
  background-color: #29a6dc;
}

@media (min-width:768px) {

  .portfolio h1 {
    font-size: 40px;
  }

  .portfolio .about h2 {
    font-size: 28px;
    text-indent: 40px;
  }

  .portfolio .about p {
    font-size: 18px;
    padding-left: 40px;
  }

  .portfolio .project {
    margin-bottom: 40px;
  }

}

@media (orientation: landscape){
    .web,
    .about{
        width: 50%;
        float: left;
    }
    img {
        display: block;
    }

    .portfolio .project:nth-of-type(even)
    .web{
        float:right;
    }
       
    
    
}

/* SLOGAN */

.slogan{
    background-image: url(../images/motto.jpg);
    text-align: center;
    background-size: cover;
    background-position: center;
    color:white;
    font-family: 'Saira',sans-serif;
    height: 70vh;
}
.slogan h1{    
    padding: 10px 10px;
    font-size: 15px;
    text-transform: uppercase;
    
}
.slogan h2{
    width: 75%;
    font-size: 13px;
    margin-left: auto;
    margin-right: auto;
    margin-bottom: 8px; 
}
.slogan p{
    padding: 5px;
    font-size: 19px;
}
.bg{
    background-color: rgba(0, 62, 112, 0.5);
    padding: 43px 10px;
    height: 70vh;
}

@media (orientation:landscape){
    .slogan h1{
        font-size: 18px;
    }
    .slogan h2{
        font-size: 16px;
    }
    .slogan p{
        font-size: 16px;
    }
}

/* HOBBY */

.hobby{
    height: 40vh;
}

.hobby h1{
    font-size: 21px;
     font-family: 'Saira',sans-serif;
    color: black;
    text-align: center;
    padding: 14px;
    text-transform: uppercase;
}
.hobby .item{
    height: 30vh;
    background-position: center;
    background-repeat: no-repeat;
}
    


.hobby .item:nth-of-type(1){
   background-image: url(../images/hobby1.jpg);
    
}
.hobby .item:nth-of-type(2){
   background-image: url(../images/hobby2.jpg);
    
}
.hobby .item:nth-of-type(3){
   background-image: url(../images/hobby3.jpg);
    
}
.hobby .item:nth-of-type(4){
   background-image: url(../images/hobby4.jpg);
    
    
}
.hobby .item p{
    font-family: 'Saira',sans-serif;
    font-size: 18px;
    color: white;
     font-family: 'Saira',sans-serif;
    background-color: rgba(0, 0, 0, 0.5);
    line-height: 30vh;
    text-align: center;
}
 
@media (min-width:1024px){
    .hobby h1{
        font-size: 45px;
        padding: 40px;
    }
    .hobby .item{
        float:left;
        width: 50%;
        height: 48vh;
    }
    .hobby .item p{
        line-height: 48vh;
        font-size: 30px;
        text-transform: uppercase;
        opacity: 0;
        transition: 1s;
    }
    
    .hobby .item:hover p{
       opacity: 1;
    }
    
}

HTML

<!DOCTYPE html>
<html lang="pl">

<head>
  <meta charset="UTF-8">
  <title>Adam Kowalski - Web Developer</title>
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <link href="https://fonts.googleapis.com/css?family=Saira+Condensed:400,700|Saira:300,400&amp;subset=latin-ext" rel="stylesheet">
  <link rel="stylesheet" href="css/style.css">
</head>

<body>
  <header>
    <div class="welcome">
      <p>witaj!</p>
      <h1>jestem Adam Kowalski</h1>
      <h2>web developer - freelancer</h2>
      <button>Zobacz moje portfolio</button>
    </div>
    <img src="images/photo1.png" alt="Zdjęcie Adam Kowalski">
  </header>
  <section class="features clearfix">
    <h1>Tworzę bardzo dobre strony internetowe</h1>
    <div class="feature">
      <img src="images/services1.png" alt="loga html js i css">
      <h2>Nowoczesne i zgodne z aktualnymi standardami</h2>
      <p class="description">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Cum earum maiores dolores fugit, soluta? Sed repudiandae, fugit provident suscipit cum architecto asperiores, sequi obcaecati, alias sunt ea. Soluta, rerum, perspiciatis.</p>
    </div>
    <div class="feature">
      <img src="images/services2.png" alt="loga html js i css">
      <h2>Zoptymalizowanie pod kątem wyszukiwarek internetowych</h2>
      <p class="description">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Cum earum maiores dolores fugit, soluta? Sed repudiandae, fugit provident suscipit cum architecto asperiores, sequi obcaecati, alias sunt ea. Soluta, rerum, perspiciatis.</p>
    </div>
    <div class="feature">
      <img src="images/services3.png" alt="loga html js i css">
      <h2>Świetnie wyglądające na urzedziach mobilnych</h2>
      <p class="description">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Cum earum maiores dolores fugit, soluta? Sed repudiandae, fugit provident suscipit cum architecto asperiores, sequi obcaecati, alias sunt ea. Soluta, rerum, perspiciatis.</p>
    </div>

  </section>
  <section class="portfolio">
    <h1>Projekty, z których jestem dumny</h1>
    <div class="project clearfix">
      <div class="web">
        <img src="images/portfolio1.jpg" alt="portfolio przykład 1">
      </div>
      <div class="about">
        <h2>Nazwa projektu</h2>
        <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Sed doloremque quidem illo doloribus ipsa, facere, quae eligendi debitis. A debitis totam amet aperiam enim. Qui velit corrupti consequatur nihil est.</p>
      </div>
    </div>
    <div class="project clearfix">
      <div class="web">
        <img src="images/portfolio2.jpg" alt="portfolio przykład 2">
      </div>
      <div class="about">
        <h2>Nazwa projektu</h2>
        <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Sed doloremque quidem illo doloribus ipsa, facere, quae eligendi debitis. A debitis totam amet aperiam enim. Qui velit corrupti consequatur nihil est.</p>
      </div>
    </div>
    <div class="project clearfix">
      <div class="web">
        <img src="images/portfolio3.jpg" alt="portfolio przykład 3">
      </div>
      <div class="about">
        <h2>Nazwa projektu</h2>
        <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Sed doloremque quidem illo doloribus ipsa, facere, quae eligendi debitis. A debitis totam amet aperiam enim. Qui velit corrupti consequatur nihil est.</p>
      </div>
    </div>
    <div class="project clearfix">
      <div class="web">
        <img src="images/portfolio4.jpg" alt="portfolio przykład 4">
      </div>
      <div class="about">
        <h2>Nazwa projektu</h2>
        <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Sed doloremque quidem illo doloribus ipsa, facere, quae eligendi debitis. A debitis totam amet aperiam enim. Qui velit corrupti consequatur nihil est.</p>
      </div>
    </div>
  </section>
  <section class="slogan">
    <div class="bg">
      <h1>Moje życiowe motto</h1>
      <p class="text">Lorem ipsum dolor sit amet, consectetur adipisicing elit. Fuga id architecto harum sint at alias. </p>
      <p class="author">Jan Nowak</p>
    </div>
  </section>

  <section class="hobby clearfix">
    <h1>W wolnym czasie uwielbiam</h1>
    <div class="item">
      <p>Chodzić po górach</p>
    </div>
    <div class="item">
      <p>Patrzeć wysoko</p>
    </div>
    <div class="item">
      <p>Zmieniać świat</p>
    </div>
    <div class="item">
      <p>Jeść owoce i warzywa</p>
    </div>
  </section>

<section>
    <h1></h1>
</section>
  
 
 <section class="kontakt">
     <h1>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Sed doloremque quidem illo doloribus ipsa, facere, quae eligendi debitis. A debitis totam amet aperiam enim. Qui velit corrupti consequatur nihil est.</h1>
 </section>

  <footer></footer>
</body>

</html>