2.编写代码实现完整的响应式基础导航栏，如图所示分别是导航栏收起、在不同宽度屏幕中的展开状态。

由于您没有提供图示，我无法准确地模拟出导航栏的样式。但是，我可以提供一些编写响应式导航栏的代码，供您参考。

HTML 代码：

<nav>
  <div class="logo">
    <a href="#">Logo</a>
  </div>
  <ul class="nav-links">
    <li><a href="#">Link 1</a></li>
    <li><a href="#">Link 2</a></li>
    <li><a href="#">Link 3</a></li>
    <li><a href="#">Link 4</a></li>
  </ul>
  <div class="burger">
    <div class="line1"></div>
    <div class="line2"></div>
    <div class="line3"></div>
  </div>
</nav>

CSS 代码：

nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 20px;
  background-color: #333;
  color: #fff;
}

.nav-links {
  display: flex;
  justify-content: space-around;
  width: 50%;
}

.nav-links li {
  list-style: none;
}

.nav-links a {
  color: #fff;
  text-decoration: none;
  font-weight: bold;
}

.burger {
  display: none;
  cursor: pointer;
}

.burger div {
  width: 25px;
  height: 3px;
  background-color: #fff;
  margin: 5px;
}

@media screen and (max-width: 1024px) {
  .nav-links {
    width: 60%;
  }
}

@media screen and (max-width: 768px) {
  body {
    overflow-x: hidden;
  }
  .nav-links {
    position: absolute;
    right: 0px;
    height: 92vh;
    top: 8vh;
    background-color: #333;
    display: flex;
    flex-direction: column;
    align-items: center;
    width: 50%;
    transform: translateX(100%);
    transition: transform 0.5s ease-in;
  }
  .nav-links li {
    opacity: 0;
  }
  .burger {
    display: block;
  }
}

.nav-active {
  transform: translateX(0%);
}

@keyframes navLinkFade {
  from {
    opacity: 0;
    transform: translateX(50px);
  }
  to {
    opacity: 1;
    transform: translateX(0px);
  }
}

.toggle .line1 {
  transform: rotate(-45deg) translate(-5px, 6px);
}

.toggle .line2 {
  opacity: 0;
}

.toggle .line3 {
  transform: rotate(45deg) translate(-5px, -6px);
}

JavaScript 代码：

const burger = document.querySelector('.burger');
const navLinks = document.querySelector('.nav-links');
const links = document.querySelectorAll('.nav-links li');

burger.addEventListener('click', () => {
  navLinks.classList.toggle('nav-active');

  links.forEach((link, index) => {
    if (link.style.animation) {
      link.style.animation = '';
    } else {
      link.style.animation = `navLinkFade 0.5s ease forwards ${index / 7 + 0.5}s`;
    }
  });

  burger.classList.toggle('toggle');
});

这个代码会在不同屏幕宽度下创建响应式导航栏，并且在点击汉堡菜单按钮时，导航栏会展开或收起。您可以根据您的需求进行修改和调整。