一个简单的页面布局：导航+主体，包括自动主题切换、滚动隐藏导航栏

<template>
  <nav class="navbar" :class="{ 'navbar-hidden': !isShowNav }">
    <div class="nav-container">
      <div class="nav-brand">Logo</div>
      <ul class="nav-menu">
        <li><a href="#home">Home</a></li>
        <li><a href="#posts">Posts</a></li>
        <li><a href="#download">Download</a></li>
        <li><a href="#about">About</a></li>
      </ul>
      <div class="nav-actions">
        <button class="nav-toggle">☰</button>
      </div>
    </div>
  </nav>
  <main class="main-container">
    <p style="height:100px;">Content1</p>
    <p style="height:100px;">Content2</p>
    <p style="height:100px;">Content3</p>
    <p style="height:100px;">Content4</p>
    <p style="height:100px;">Content5</p>
    <p style="height:100px;">Content6</p>
    <p style="height:100px;">Content7</p>
    <p style="height:100px;">Content8</p>
    <p style="height:100px;">Content9</p>
    <p style="height:100px;">Content10</p>
    <p style="height:100px;">Content11</p>
    <p style="height:100px;">Content12</p>
  </main>
</template>

<script setup lang="ts">
import { onMounted, onUnmounted, ref } from "vue";

const isShowNav = ref(true);
let scrollTimer: number | null = null;

const handleScrollWithDebounce = () => {
  if (scrollTimer) {
    clearTimeout(scrollTimer);
  }
  scrollTimer = window.setTimeout(() => {
    const scrollTop = window.scrollY || document.documentElement.scrollTop;
    if (scrollTop > 50) {
      isShowNav.value = false;
    } else {
      isShowNav.value = true;
    }
  }, 50);
};

onMounted(() => {
  window.addEventListener('scroll', handleScrollWithDebounce);
});

onUnmounted(() => {
  window.removeEventListener('scroll', handleScrollWithDebounce);
  if (scrollTimer) {
    clearTimeout(scrollTimer);
  }
});
</script>

<style scoped>
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  padding: 0 20px;
  background: rgba(29, 29, 29, 0.95);
  backdrop-filter: blur(10px);
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
  transition: transform 0.3s ease-in-out;
  height: 64px;
  display: flex;
  align-items: center;
}

.navbar-hidden {
  transform: translateY(-100%);
}

.nav-container {
  max-width: 1200px;
  width: 100%;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.nav-brand {
  font-size: 20px;
  font-weight: 700;
  color: #ffffff;
  letter-spacing: 1px;
  cursor: pointer;
}

.nav-menu {
  display: flex;
  list-style: none;
  gap: 32px;
  margin: 0;
  padding: 0;
  align-items: center;
}

.nav-menu li a {
  color: rgba(255, 255, 255, 0.8);
  text-decoration: none;
  font-size: 15px;
  font-weight: 500;
  padding: 8px 12px;
  border-radius: 6px;
  transition: all 0.2s ease;
  position: relative;
}

.nav-menu li a:hover {
  color: #ffffff;
  background: rgba(255, 255, 255, 0.1);
}

.nav-menu li a::after {
  content: '';
  position: absolute;
  bottom: 4px;
  left: 50%;
  width: 0;
  height: 2px;
  background: #4a9eff;
  transition: all 0.3s ease;
  transform: translateX(-50%);
}

.nav-menu li a:hover::after {
  width: 60%;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

.nav-toggle {
  display: none;
  background: none;
  border: none;
  color: #ffffff;
  font-size: 24px;
  cursor: pointer;
  padding: 4px 8px;
  border-radius: 4px;
  transition: background 0.2s ease;
}

.nav-toggle:hover {
  background: rgba(255, 255, 255, 0.1);
}

/* 响应式设计 */
@media (max-width: 768px) {
  .nav-toggle {
    display: block;
  }

  .nav-menu {
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    flex-direction: column;
    background: rgba(29, 29, 29, 0.98);
    backdrop-filter: blur(10px);
    padding: 20px;
    gap: 12px;
    transform: scaleY(0);
    transform-origin: top;
    transition: transform 0.3s ease;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
  }

  .nav-menu.active {
    transform: scaleY(1);
  }

  .nav-menu li {
    width: 100%;
  }

  .nav-menu li a {
    display: block;
    text-align: center;
    padding: 12px;
    font-size: 16px;
  }

  .nav-menu li a::after {
    display: none;
  }
}

/* 滚动条样式优化 */
::-webkit-scrollbar {
  width: 6px;
}

::-webkit-scrollbar-track {
  background: #1d1d1d;
}

::-webkit-scrollbar-thumb {
  background: #4a9eff;
  border-radius: 3px;
}

::-webkit-scrollbar-thumb:hover {
  background: #3a8aef;
}

/* 自动主题切换：亮色模式 */
@media (prefers-color-scheme: light) {
  .navbar {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
  }

  .nav-brand {
    color: #1d1d1d;
  }

  .nav-menu li a {
    color: rgba(0, 0, 0, 0.7);
  }

  .nav-menu li a:hover {
    color: #000000;
    background: rgba(0, 0, 0, 0.05);
  }

  .nav-toggle {
    color: #1d1d1d;
  }

  .nav-toggle:hover {
    background: rgba(0, 0, 0, 0.05);
  }

  @media (max-width: 768px) {
    .nav-menu {
      background: rgba(255, 255, 255, 0.98);
      border-top: 1px solid rgba(0, 0, 0, 0.1);
    }
  }
}

.main-container {
  max-width: 1200px;
  margin: 0 auto;
  padding-top: 100px;
}
</style>