纯 CSS Parallax + Navigation Reveal on Scroll

Question

所以我遇到了一个问题，涉及纯 CSS 视差与固定导航栏相结合，当页面开始滚动或返回顶部时，该导航栏会改变大小。这两个部分中的每一个都独立工作，但是当我将它们结合起来时，视差效果仍然有效，而导航栏不会从其初始状态改变。

这是视差的代码：

main {
  perspective: 1px;
  transform-style: preserve-3d;
  height: 100vh;
  overflow-x: hidden;
  overflow-y: scroll;
}

header {
  display: flex;
  flex: 1 0 auto;
  position: relative;
  z-index: -1;
  height: 100vh;
  justify-content: center;
  align-items: center;
  transform: translateZ(-1px) scale(2.25);
  background: url('https://faith.prismapixel.studio/assets/img/hero-desktop.jpg') top center / cover;
}

section {
  position: relative;
  display: block;
  background: #FFFFFF;
  z-index: 1;
}

section article {
  max-width: 75rem;
  margin: 0 auto;
  padding: 7.5rem 0;
}

p {
  margin: 7.5rem 0;
}

<main>
  <header class="section parallax">
    <h1>HEADLINE HERE</h1>
  </header>
  <section class="section static">
    <article>
      <p>ʻO Lorem Ipsum kahi haʻahaʻa wale nō o ka paʻi a me keʻano o nāʻoihana. ʻO Lorem Ipsum ka 'ōlelo papahana maʻamau o kaʻoihana o ka makahiki 1500, i ka wā i lawe ai kekahi mea paʻi kiʻiʻole i keʻano o ka type a scrambled iā ia e hana i kahi puke
        kiko'ī. ʻAʻole i ola wale i kaʻelima mau kenekulia, akā,ʻo ka leleʻana hoʻi i nāʻano o ka lolouila, e hoʻololiʻoleʻia ana. Ua hoʻolahaʻia i nā makahiki 1960 me ka hoʻokuʻuʻana i nā pepa Letraset i loko o nā moʻolelo Lorem Ipsum, a me nā mea hou
        aku me ka polokalamu hoʻopuka pākī e like me Aldus PageMaker me nā papa o Lorem Ipsum.
      </p>
      <p>ʻO Lorem Ipsum kahi haʻahaʻa wale nō o ka paʻi a me keʻano o nāʻoihana. ʻO Lorem Ipsum ka 'ōlelo papahana maʻamau o kaʻoihana o ka makahiki 1500, i ka wā i lawe ai kekahi mea paʻi kiʻiʻole i keʻano o ka type a scrambled iā ia e hana i kahi puke
        kiko'ī. ʻAʻole i ola wale i kaʻelima mau kenekulia, akā,ʻo ka leleʻana hoʻi i nāʻano o ka lolouila, e hoʻololiʻoleʻia ana. Ua hoʻolahaʻia i nā makahiki 1960 me ka hoʻokuʻuʻana i nā pepa Letraset i loko o nā moʻolelo Lorem Ipsum, a me nā mea hou
        aku me ka polokalamu hoʻopuka pākī e like me Aldus PageMaker me nā papa o Lorem Ipsum.
      </p>
      <p>ʻO Lorem Ipsum kahi haʻahaʻa wale nō o ka paʻi a me keʻano o nāʻoihana. ʻO Lorem Ipsum ka 'ōlelo papahana maʻamau o kaʻoihana o ka makahiki 1500, i ka wā i lawe ai kekahi mea paʻi kiʻiʻole i keʻano o ka type a scrambled iā ia e hana i kahi puke
        kiko'ī. ʻAʻole i ola wale i kaʻelima mau kenekulia, akā,ʻo ka leleʻana hoʻi i nāʻano o ka lolouila, e hoʻololiʻoleʻia ana. Ua hoʻolahaʻia i nā makahiki 1960 me ka hoʻokuʻuʻana i nā pepa Letraset i loko o nā moʻolelo Lorem Ipsum, a me nā mea hou
        aku me ka polokalamu hoʻopuka pākī e like me Aldus PageMaker me nā papa o Lorem Ipsum.
      </p>
      <p>ʻO Lorem Ipsum kahi haʻahaʻa wale nō o ka paʻi a me keʻano o nāʻoihana. ʻO Lorem Ipsum ka 'ōlelo papahana maʻamau o kaʻoihana o ka makahiki 1500, i ka wā i lawe ai kekahi mea paʻi kiʻiʻole i keʻano o ka type a scrambled iā ia e hana i kahi puke
        kiko'ī. ʻAʻole i ola wale i kaʻelima mau kenekulia, akā,ʻo ka leleʻana hoʻi i nāʻano o ka lolouila, e hoʻololiʻoleʻia ana. Ua hoʻolahaʻia i nā makahiki 1960 me ka hoʻokuʻuʻana i nā pepa Letraset i loko o nā moʻolelo Lorem Ipsum, a me nā mea hou
        aku me ka polokalamu hoʻopuka pākī e like me Aldus PageMaker me nā papa o Lorem Ipsum.
      </p>
      <p>ʻO Lorem Ipsum kahi haʻahaʻa wale nō o ka paʻi a me keʻano o nāʻoihana. ʻO Lorem Ipsum ka 'ōlelo papahana maʻamau o kaʻoihana o ka makahiki 1500, i ka wā i lawe ai kekahi mea paʻi kiʻiʻole i keʻano o ka type a scrambled iā ia e hana i kahi puke
        kiko'ī. ʻAʻole i ola wale i kaʻelima mau kenekulia, akā,ʻo ka leleʻana hoʻi i nāʻano o ka lolouila, e hoʻololiʻoleʻia ana. Ua hoʻolahaʻia i nā makahiki 1960 me ka hoʻokuʻuʻana i nā pepa Letraset i loko o nā moʻolelo Lorem Ipsum, a me nā mea hou
        aku me ka polokalamu hoʻopuka pākī e like me Aldus PageMaker me nā papa o Lorem Ipsum.
      </p>
    </article>
  </section>
</main>

这里是导航栏的代码：

window.onscroll = function() {
  yScroll()
};

function yScroll() {
  if (document.body.scrollTop > 10 || document.documentElement.scrollTop > 10) {
    document.getElementsByTagName('nav')[0].className = "mini";
  } else {
    document.getElementsByTagName('nav')[0].className = "";
  }
}
window.addEventListener("scroll", yScroll);

nav {
  position: fixed;
  z-index: 9;
  top: 0;
  left: 0;
  width: 100%;
  height: 0rem;
  background: #FFFFFF;
  opacity: 0;
  color: #FFF;
  font-size: 23px;
  transition: height 0.3s ease 0s, opacity 0.3s ease 0s;
  overflow: hidden;
}

nav.mini {
  opacity: 1;
  height: 3rem;
}

header {
  display: flex;
  flex: 1 0 auto;
  position: relative;
  z-index: -1;
  height: 100vh;
  justify-content: center;
  align-items: center;
  transform: translateZ(-1px) scale(2.25);
  background: url('https://faith.prismapixel.studio/assets/img/hero-desktop.jpg') top center / cover;
}

section {
  position: relative;
  display: block;
  background: #FFFFFF;
  z-index: 1;
}

section article {
  max-width: 75rem;
  margin: 0 auto;
  padding: 7.5rem 0;
}

p {
  margin: 7.5rem 0;
}

<nav class="">

</nav>
<main>
  <header class="section parallax">
    <h1>HEADLINE HERE</h1>
  </header>
  <section class="section static">
    <article>
      <p>ʻO Lorem Ipsum kahi haʻahaʻa wale nō o ka paʻi a me keʻano o nāʻoihana. ʻO Lorem Ipsum ka 'ōlelo papahana maʻamau o kaʻoihana o ka makahiki 1500, i ka wā i lawe ai kekahi mea paʻi kiʻiʻole i keʻano o ka type a scrambled iā ia e hana i kahi puke
        kiko'ī. ʻAʻole i ola wale i kaʻelima mau kenekulia, akā,ʻo ka leleʻana hoʻi i nāʻano o ka lolouila, e hoʻololiʻoleʻia ana. Ua hoʻolahaʻia i nā makahiki 1960 me ka hoʻokuʻuʻana i nā pepa Letraset i loko o nā moʻolelo Lorem Ipsum, a me nā mea hou
        aku me ka polokalamu hoʻopuka pākī e like me Aldus PageMaker me nā papa o Lorem Ipsum.
      </p>
      <p>ʻO Lorem Ipsum kahi haʻahaʻa wale nō o ka paʻi a me keʻano o nāʻoihana. ʻO Lorem Ipsum ka 'ōlelo papahana maʻamau o kaʻoihana o ka makahiki 1500, i ka wā i lawe ai kekahi mea paʻi kiʻiʻole i keʻano o ka type a scrambled iā ia e hana i kahi puke
        kiko'ī. ʻAʻole i ola wale i kaʻelima mau kenekulia, akā,ʻo ka leleʻana hoʻi i nāʻano o ka lolouila, e hoʻololiʻoleʻia ana. Ua hoʻolahaʻia i nā makahiki 1960 me ka hoʻokuʻuʻana i nā pepa Letraset i loko o nā moʻolelo Lorem Ipsum, a me nā mea hou
        aku me ka polokalamu hoʻopuka pākī e like me Aldus PageMaker me nā papa o Lorem Ipsum.
      </p>
      <p>ʻO Lorem Ipsum kahi haʻahaʻa wale nō o ka paʻi a me keʻano o nāʻoihana. ʻO Lorem Ipsum ka 'ōlelo papahana maʻamau o kaʻoihana o ka makahiki 1500, i ka wā i lawe ai kekahi mea paʻi kiʻiʻole i keʻano o ka type a scrambled iā ia e hana i kahi puke
        kiko'ī. ʻAʻole i ola wale i kaʻelima mau kenekulia, akā,ʻo ka leleʻana hoʻi i nāʻano o ka lolouila, e hoʻololiʻoleʻia ana. Ua hoʻolahaʻia i nā makahiki 1960 me ka hoʻokuʻuʻana i nā pepa Letraset i loko o nā moʻolelo Lorem Ipsum, a me nā mea hou
        aku me ka polokalamu hoʻopuka pākī e like me Aldus PageMaker me nā papa o Lorem Ipsum.
      </p>
      <p>ʻO Lorem Ipsum kahi haʻahaʻa wale nō o ka paʻi a me keʻano o nāʻoihana. ʻO Lorem Ipsum ka 'ōlelo papahana maʻamau o kaʻoihana o ka makahiki 1500, i ka wā i lawe ai kekahi mea paʻi kiʻiʻole i keʻano o ka type a scrambled iā ia e hana i kahi puke
        kiko'ī. ʻAʻole i ola wale i kaʻelima mau kenekulia, akā,ʻo ka leleʻana hoʻi i nāʻano o ka lolouila, e hoʻololiʻoleʻia ana. Ua hoʻolahaʻia i nā makahiki 1960 me ka hoʻokuʻuʻana i nā pepa Letraset i loko o nā moʻolelo Lorem Ipsum, a me nā mea hou
        aku me ka polokalamu hoʻopuka pākī e like me Aldus PageMaker me nā papa o Lorem Ipsum.
      </p>
      <p>ʻO Lorem Ipsum kahi haʻahaʻa wale nō o ka paʻi a me keʻano o nāʻoihana. ʻO Lorem Ipsum ka 'ōlelo papahana maʻamau o kaʻoihana o ka makahiki 1500, i ka wā i lawe ai kekahi mea paʻi kiʻiʻole i keʻano o ka type a scrambled iā ia e hana i kahi puke
        kiko'ī. ʻAʻole i ola wale i kaʻelima mau kenekulia, akā,ʻo ka leleʻana hoʻi i nāʻano o ka lolouila, e hoʻololiʻoleʻia ana. Ua hoʻolahaʻia i nā makahiki 1960 me ka hoʻokuʻuʻana i nā pepa Letraset i loko o nā moʻolelo Lorem Ipsum, a me nā mea hou
        aku me ka polokalamu hoʻopuka pākī e like me Aldus PageMaker me nā papa o Lorem Ipsum.
      </p>
    </article>
  </section>
</main>

如您所见，它们都可以单独工作。如果我删除 <main> 标签的样式，那么导航栏会起作用，但视差效果不会。

我做错了什么？

Answer 1

在网上搜索并自学更多关于 javascript 的知识后，我解决了我的困境。

function yScroll() {
  var el = document.getElementById("main");
  var nav = document.getElementById("navBar");
  var y = el.scrollTop;
  if (y >= 50) {
    nav.className = "mini";
  } else {
    nav.className = "";
  }
}

html {
  font-size: 10px;
  scroll-behavior: smooth;
  color: #212121;
  box-sizing: border-box;
  line-height: 1.4;
  margin: 0;
  padding: 0;
  min-width: 32rem;
}

body {
  font: normal 400 1.5rem 'Montserrat Alternates';
  background: #ffffff;
  margin: 0;
  padding: 0;
  height: 100%;
  width: 100%;
  position: absolute;
  top: 0;
  left: 0;
  overscroll-behavior-y: none;
}

nav {
  width: calc(100% - 1rem);
  height: 0rem;
  position: fixed;
  top: 0;
  left: 0;
  z-index: 9000;
  text-transform: uppercase;
  transition: all 150ms ease 0s;
}

nav.mini {
  background: #FFFFFF;
  height: 5rem;
  box-shadow: 0 0 .5rem 0 rgba(0, 0, 0, .15);
}

#main {
  perspective: 1px;
  transform-style: preserve-3d;
  height: 100vh;
  overflow-x: hidden;
  overflow-y: scroll;
}

#main::-webkit-scrollbar {
  width: 1rem;
}

#main::-webkit-scrollbar-track {
  -webkit-box-shadow: inset 0 0 .5rem rgba(#212121, .5);
}

#main::-webkit-scrollbar-thumb {
  background-color: darkgrey;
  outline: 1px solid slategrey;
}

header {
  background: url('https://faith.prismapixel.studio/assets/img/hero-desktop.jpg') top center / cover;
  display: flex;
  flex: 1 0 auto;
  position: relative;
  z-index: -1;
  height: 100vh;
  justify-content: center;
  align-items: center;
  transform: translateZ(-1px) scale(2.25);
}

section {
  position: relative;
  display: block;
  background: #FFFFFF;
  z-index: 1;
}

section article {
  max-width: 75rem;
  margin: 0 auto;
  padding: 7.5rem 0;
}

p {
  margin: 7.5rem 0;
}

</style>

<nav id="navBar" class="">
</nav>
<main id="main" onscroll="yScroll()">
  <header>
    <h1 id="print">Headline Here</h1>
  </header>
  <section>
    <article>
      <p>ʻO Lorem Ipsum kahi haʻahaʻa wale nō o ka paʻi a me keʻano o nāʻoihana. ʻO Lorem Ipsum ka 'ōlelo papahana maʻamau o kaʻoihana o ka makahiki 1500, i ka wā i lawe ai kekahi mea paʻi kiʻiʻole i keʻano o ka type a scrambled iā ia e hana i kahi puke
        kiko'ī. ʻAʻole i ola wale i kaʻelima mau kenekulia, akā,ʻo ka leleʻana hoʻi i nāʻano o ka lolouila, e hoʻololiʻoleʻia ana. Ua hoʻolahaʻia i nā makahiki 1960 me ka hoʻokuʻuʻana i nā pepa Letraset i loko o nā moʻolelo Lorem Ipsum, a me nā mea hou
        aku me ka polokalamu hoʻopuka pākī e like me Aldus PageMaker me nā papa o Lorem Ipsum.
      </p>
      <p>ʻO Lorem Ipsum kahi haʻahaʻa wale nō o ka paʻi a me keʻano o nāʻoihana. ʻO Lorem Ipsum ka 'ōlelo papahana maʻamau o kaʻoihana o ka makahiki 1500, i ka wā i lawe ai kekahi mea paʻi kiʻiʻole i keʻano o ka type a scrambled iā ia e hana i kahi puke
        kiko'ī. ʻAʻole i ola wale i kaʻelima mau kenekulia, akā,ʻo ka leleʻana hoʻi i nāʻano o ka lolouila, e hoʻololiʻoleʻia ana. Ua hoʻolahaʻia i nā makahiki 1960 me ka hoʻokuʻuʻana i nā pepa Letraset i loko o nā moʻolelo Lorem Ipsum, a me nā mea hou
        aku me ka polokalamu hoʻopuka pākī e like me Aldus PageMaker me nā papa o Lorem Ipsum.
      </p>
      <p>ʻO Lorem Ipsum kahi haʻahaʻa wale nō o ka paʻi a me keʻano o nāʻoihana. ʻO Lorem Ipsum ka 'ōlelo papahana maʻamau o kaʻoihana o ka makahiki 1500, i ka wā i lawe ai kekahi mea paʻi kiʻiʻole i keʻano o ka type a scrambled iā ia e hana i kahi puke
        kiko'ī. ʻAʻole i ola wale i kaʻelima mau kenekulia, akā,ʻo ka leleʻana hoʻi i nāʻano o ka lolouila, e hoʻololiʻoleʻia ana. Ua hoʻolahaʻia i nā makahiki 1960 me ka hoʻokuʻuʻana i nā pepa Letraset i loko o nā moʻolelo Lorem Ipsum, a me nā mea hou
        aku me ka polokalamu hoʻopuka pākī e like me Aldus PageMaker me nā papa o Lorem Ipsum.
      </p>
    </article>
  </section>
</main>

由于滚动条实际上​​位于<main> 元素而不是<body> 上，因此在解决了我的困境后我不得不修改导航栏的宽度以适应滚动条的宽度。但这很容易做到。

我希望这可以帮助其他尝试将滚动导航栏上的固定显示添加到纯 CSS 网站的人。