微博首頁是一個非常重要的平臺，它為廣大用戶提供了一個分享和交流的空間。為了讓用戶能夠更加愉悅地使用微博，我們不僅需要優化用戶體驗，還需要對網頁進行一些優化。下面是微博首頁的CSS代碼：

/* reset */
*,
*::before,
*::after {
box-sizing: border-box;
margin: 0;
padding: 0;
}
html {
font-size: 62.5%;
}
body {
font-family: "Microsoft Yahei", sans-serif;
font-size: 1.4rem;
color: #333;
background-color: #f2f2f2;
line-height: 1.5;
}
/* header */
.header {
height: 5rem;
background-color: #fff;
display: flex;
justify-content: space-between;
align-items: center;
padding: 0 3rem;
}
.header__logo {
height: 3rem;
}
.header__nav {
display: flex;
align-items: center;
}
.header__nav-item {
margin-left: 2rem;
font-size: 1.6rem;
color: #666;
}
/* main */
.main {
width: 100%;
max-width: 120rem;
margin: 0 auto;
padding: 3rem;
background-color: #fff;
box-shadow: 0 0.2rem 0.6rem rgba(0, 0, 0, 0.15);
}
.main__user-card {
display: flex;
align-items: center;
margin-bottom: 2rem;
}
.main__user-card-avatar {
width: 5rem;
height: 5rem;
border-radius: 50%;
margin-right: 1.5rem;
}
.main__user-card-name {
font-size: 2rem;
color: #666;
}
.main__post {
border-top: 1px solid #f2f2f2;
padding-top: 3rem;
}
.main__post-content {
font-size: 1.8rem;
color: #333;
line-height: 1.8;
margin-bottom: 2rem;
}
.main__post-img {
width: 100%;
height: auto;
margin-top: 2rem;
}
.main__post-actions {
display: flex;
justify-content: space-between;
align-items: center;
margin-top: 3rem;
}
.main__post-action {
font-size: 1.6rem;
color: #666;
display: flex;
align-items: center;
}
.main__post-action--like {
margin-right: 2rem;
}
.main__post-action-icon {
margin-right: 1rem;
}
.main__post-action--comment .main__post-action-icon {
margin-left: -1rem;
margin-right: 0.5rem;
}

這些代碼構成了微博首頁的頁面樣式，通過這些樣式，我們可以讓用戶更加方便地使用微博。