结构 · 11 LINES
<div class="fixed-banner"><span>FIXED TOP BAR</span><span>滚动时保持可见</span></div>
<button class="fixed-fab">↑</button>
<div class="scroll-body">
<div class="fake-text w80"></div><div class="fake-text"></div><div class="fake-text w60"></div>
<div class="fake-text w80"></div><div class="fake-text"></div><div class="fake-text w40"></div>
<div class="fake-text w80"></div><div class="fake-text"></div><div class="fake-text w60"></div>
<div class="fake-text w80"></div><div class="fake-text"></div><div class="fake-text w40"></div>
<div class="fake-text w80"></div><div class="fake-text"></div><div class="fake-text w60"></div>
<div class="fake-text w80"></div><div class="fake-text"></div><div class="fake-text w40"></div>
<div class="fake-text w80"></div><div class="fake-text"></div>
</div>
样式 · 本 demo 自定义 13 LINES + 共享令牌类
/* ═══ 本 demo 自定义样式 ═══ */
.fixed-banner {
position: fixed; top: 0; left: 0; right: 0; z-index: 9;
background: var(--ink); color: var(--paper);
font-family: var(--mono); font-size: 10.5px; letter-spacing: .12em;
padding: 8px 16px; display: flex; justify-content: space-between;
}
.fixed-fab {
position: fixed; right: 18px; bottom: 18px; z-index: 9;
width: 44px; height: 44px; border-radius: 50%;
background: var(--accent); color: var(--paper); border: none;
display: grid; place-items: center; font-size: 18px;
}
.scroll-body { padding-top: 40px; }
/* ═══ 共享令牌类 · demo 外壳已内置 ═══ */
.blk {
background: color-mix(in srgb, var(--ink) 4%, transparent);
border: 1px solid var(--line); border-radius: 2px;
display: grid; place-items: center;
font-family: var(--mono); font-size: 10.5px; letter-spacing: .08em; color: var(--ink-2);
padding: 10px; min-height: 34px;
}
.blk.acc {
background: color-mix(in srgb, var(--accent) 12%, transparent);
border-color: color-mix(in srgb, var(--accent) 45%, transparent); color: var(--accent);
}
.blk.ink { background: var(--ink); color: var(--paper); border-color: var(--ink); }
.tag {
display: inline-block; font-family: var(--mono); font-size: 10px; letter-spacing: .08em;
border: 1px solid var(--line); color: var(--ink-2); padding: 2px 8px;
border-radius: 2px; background: var(--paper-2);
}
.card { background: var(--paper-2); border: 1px solid var(--line); border-radius: 3px; overflow: hidden; }
.card .cv { aspect-ratio: 16/10; background: color-mix(in srgb, var(--accent) 10%, var(--paper-2)); border-bottom: 1px solid var(--line); }
.card .bd { padding: 9px 10px; }
.card .bd .t { font-weight: 600; font-size: 12.5px; }
.card .bd .m { font-family: var(--mono); font-size: 10px; color: var(--ink-3); margin-top: 2px; }
.avatar {
width: 34px; height: 34px; border-radius: 50%; flex: none;
background: color-mix(in srgb, var(--accent) 22%, var(--paper-2)); border: 1px solid var(--line);
}
.fake-text { height: 8px; background: color-mix(in srgb, var(--ink) 10%, transparent); border-radius: 1px; }
.fake-text.w60 { width: 60%; } .fake-text.w80 { width: 80%; } .fake-text.w40 { width: 40%; }
.fake-text + .fake-text { margin-top: 6px; }