/* ============================================================
   人间三卷 · 站点内「回到总览」入口
   供《生在何朝》《如果当时》共用：左侧竖排书签
   不改动各站布局，只做一层悬浮元素
   ============================================================ */

.hub-tab{
  position:fixed;
  left:0; top:50%;
  transform:translateY(-50%);
  z-index:80;

  writing-mode:vertical-rl;
  text-orientation:upright;

  font-family:"Songti SC","Source Han Serif SC","Noto Serif CJK SC","SimSun","STSong",serif;
  font-size:11.5px;
  line-height:1;
  letter-spacing:.26em;
  text-indent:.26em;
  padding:14px 5px;

  color:#57503f;
  background:rgba(250,247,238,.94);
  border:1px solid rgba(35,32,27,.16);
  border-left:0;
  border-radius:0 6px 6px 0;

  text-decoration:none;
  opacity:.62;
  box-shadow:0 1px 3px rgba(70,55,35,.07);

  transition:opacity .18s ease, color .18s ease, background .18s ease;
}
.hub-tab:hover{
  opacity:1;
  color:#9c2b1e;
  background:#faf7ee;
}
.hub-tab:focus-visible{
  outline:2px solid #9c2b1e;
  outline-offset:2px;
  opacity:1;
}

/* 《如果当时》深色界面用 */
.hub-tab--night{
  color:#E8C268;
  background:rgba(12,9,30,.88);
  border-color:rgba(232,194,104,.34);
  box-shadow:0 0 0 1px rgba(0,0,0,.25);
  opacity:.8;
}
.hub-tab--night:hover{
  color:#F5D68C;
  background:rgba(18,14,44,.96);
  opacity:1;
}

@media (max-width:560px){
  .hub-tab{
    font-size:11px;
    letter-spacing:.2em;
    text-indent:.2em;
    padding:11px 4px;
  }
}

@media (prefers-reduced-motion:reduce){
  .hub-tab{ transition:none; }
}