/* toc.css — 目錄三端適配
   桌面 ≥1280px：右側固定側欄
   平板 720–1279px：浮動按鈕 + 右側抽屜
   手機 <720px：浮動按鈕 + 底部抽屜（可下滑關閉） */
@keyframes slideIn{from{opacity:0;transform:translateX(14px)}}

/* ---------- 共用：列表、進度線、滑動指示器 ---------- */
.toc-pct{font:600 13px var(--serif);letter-spacing:0;color:var(--accent);font-variant-numeric:tabular-nums}
.tc-ol{position:relative;list-style:none;margin:0;padding:0;border-left:1px solid var(--line)}
.toc-fill{position:absolute;left:-1px;top:0;height:100%;width:1px;background:var(--accent);transform-origin:top;transform:scaleY(0);transition:transform .2s linear}
.toc-ind{position:absolute;left:-2px;top:0;width:3px;height:0;border-radius:3px;background:var(--accent);box-shadow:0 0 8px var(--accent);transition:transform .5s var(--ease),height .5s var(--ease)}
.tc-ol li{animation:slideIn .55s var(--ease) backwards;animation-delay:calc(.5s + var(--i,0)*70ms)}
.tc-ol button{display:block;width:100%;text-align:left;background:none;border:0;color:var(--mute);font:inherit;font-size:13px;line-height:1.5;padding:6px 0 6px 16px;cursor:pointer;transition:color .25s,padding .35s var(--ease),transform .25s}
.tc-ol button:hover{color:var(--fg);transform:translateX(3px)}
.tc-ol button.on{color:var(--accent);padding-left:22px;transform:none}

/* ---------- 桌面側欄 ---------- */
#toc{display:none;position:fixed;top:calc(130px + env(safe-area-inset-top,0px));left:calc(50% + 390px + 40px);width:min(240px,calc(50vw - 454px));animation:fade .8s var(--ease) .4s backwards}
.toc-t{display:flex;justify-content:space-between;align-items:baseline;font:600 12px var(--sans);letter-spacing:.24em;color:var(--mute);margin-bottom:12px;text-transform:uppercase}
.toc-sc{max-height:calc(100vh - 250px);overflow:auto;padding-left:3px;margin-left:-3px;scrollbar-width:none}
.toc-sc::-webkit-scrollbar{display:none}
@media (min-width:1280px){#toc{display:block}#toc-fab,#toc-panel,#toc-mask{display:none!important}}

/* ---------- 浮動按鈕（平板／手機）：外圈是閱讀進度 ---------- */
#toc-fab{position:fixed;right:20px;bottom:calc(74px + env(safe-area-inset-bottom,0px));z-index:16;width:48px;height:48px;padding:0;border-radius:50%;border:1px solid var(--line);background:var(--card);color:var(--fg);cursor:pointer;display:grid;place-items:center;box-shadow:0 10px 24px -12px rgba(40,20,10,.55);animation:pop .55s var(--ease) backwards;transition:transform .2s var(--ease)}
#toc-fab:active{transform:scale(.9)}
#toc-fab .rg{position:absolute;inset:0;width:100%;height:100%;transform:rotate(-90deg)}
#toc-fab circle{fill:none;stroke-width:2.5}
#toc-fab .trk{stroke:var(--line)}
#toc-fab .bar{stroke:var(--accent);stroke-linecap:round;stroke-dasharray:125.66;stroke-dashoffset:125.66;transition:stroke-dashoffset .2s linear}
#toc-fab .ic{width:20px;height:20px}

/* ---------- 抽屜 ---------- */
#toc-mask{position:fixed;inset:0;z-index:30;background:rgba(20,12,8,.45);backdrop-filter:blur(2px);-webkit-backdrop-filter:blur(2px);opacity:0;pointer-events:none;transition:opacity .35s}
.toc-open #toc-mask{opacity:1;pointer-events:auto}
.toc-open{overflow:hidden}
#toc-panel{position:fixed;z-index:31;left:0;right:0;bottom:0;max-height:75vh;display:flex;flex-direction:column;background:var(--card);color:var(--fg);border-radius:22px 22px 0 0;padding-bottom:env(safe-area-inset-bottom,0px);box-shadow:0 -24px 60px -24px rgba(0,0,0,.55);transform:translateY(105%);visibility:hidden;transition:transform .45s var(--ease),visibility 0s .45s}
.toc-open #toc-panel{transform:none;visibility:visible;transition:transform .45s var(--ease),visibility 0s}
.tp-head{position:relative;display:flex;align-items:center;justify-content:space-between;padding:22px 20px 8px;touch-action:none}
.tp-grip{position:absolute;top:8px;left:50%;width:40px;height:4px;border-radius:4px;background:var(--line);transform:translateX(-50%)}
.tp-title{font:600 13px var(--sans);letter-spacing:.2em;color:var(--mute)}
.tp-title b{margin-left:8px}
.tp-x{width:44px;height:44px;margin:-8px -10px -8px 0;border:0;background:none;color:var(--mute);font-size:16px;cursor:pointer;border-radius:50%;transition:color .2s,background .2s}
.tp-x:hover{color:var(--accent);background:var(--glow)}
.tp-body{overflow:auto;overscroll-behavior:contain;-webkit-overflow-scrolling:touch;padding:6px 22px 18px 24px}
#toc-panel .tc-ol li{animation:none}
.toc-open #toc-panel .tc-ol li{animation:slideIn .5s var(--ease) backwards;animation-delay:calc(.15s + var(--i,0)*45ms)}
#toc-panel .tc-ol button{display:flex;align-items:center;min-height:44px;padding:10px 0 10px 18px;font-size:15px}
#toc-panel .tc-ol button.on{padding-left:24px}

/* 平板：右側抽屜 */
@media (min-width:720px){
  #toc-panel{left:auto;top:0;bottom:0;width:340px;max-height:none;border-radius:22px 0 0 22px;padding:env(safe-area-inset-top,0px) 0 0;box-shadow:-24px 0 60px -24px rgba(0,0,0,.55);transform:translateX(105%)}
  .tp-grip{display:none}
  .tp-head{padding-top:18px}
}
/* 手機橫屏：高度不夠時抽屜佔更多 */
@media (max-height:480px) and (max-width:719px){#toc-panel{max-height:92vh}}