styles.css

* {
    padding: 0;
    margin: 0;
    box-sizing: border-box;
    scroll-behavior: smooth;
  }
  
  body {

    font-family: Arial, Helvetica, sans-serif;
    font-style: normal;
    font-weight: normal;
    font-size: medium;
    font-display: auto;
    overflow: hidden;
  }
  
  nav {
    background: #0082e6;
    height: 80px;
    width: 100%;
  }
  label.logo {
    color: white;
    font-size: 35px;
    line-height: 80px;
    padding: 0 100px;
    font-weight: bold;
  }
  nav ul {
    float: right;
    margin-right: 20px;
  }
  nav ul li {
    display: inline-block;
    line-height: 80px;
    margin: 0 5px;
  }
  nav ul li a {
    color: white;
    font-size: 17px;
    padding: 7px 13px;
    border-radius: 3px;
    text-transform: uppercase;
  }
  a.active,
  a:hover {
    background: #1b9bff;
    transition: 0.5s;
  }
  .checkbtn {
    font-size: 30px;
    color: white;
    float: right;
    line-height: 80px;
    margin-right: 40px;
    cursor: pointer;
    display: none;
  }
  #check {
    display: none;
  }
  @media (max-width: 952px) {
    label.logo {
      font-size: 30px;
      padding-left: 50px;
    }
    nav ul li a {
      font-size: 16px;
    }
  }
  @media (max-width: 858px) {
    .checkbtn {
      display: block;
      margin-top: 5px;
    }
    ul {
      position: fixed;
      width: 100%;
      height: 100vh;
      background: #2c3e50;
      top: 80px;
      left: -100%;
      text-align: center;
      transition: all 0.5s;
    }
    nav ul li {
      display: block;
      margin: 50px 0;
      line-height: 30px;
    }
    nav ul li a {
      font-size: 20px;
    }
    a:hover,
    a.active {
      background: none;
      color: #0082e6;
    }
    #check:checked ~ ul {
      left: 0;
    }
  }
  section {
    background-size: cover;
    height: calc(100vh - 80px);
  }