feat(reader): immersive chrome + WeChat-Read/Mihon-style bottom sheets — tap-center toggles header/toolbar, progress & page sliders seek anywhere, WYSIWYG theme swatches, A± font size; CBZ gains 连读/整页/适高 modes, edge-tap & arrow-key paging, persisted mode (seekChapter helper + test)

frontend/src/index.css

@@ -44,6 +44,21 @@ body {
 .rd-btn-on { @apply font-semibold; background: color-mix(in oklab, currentColor 20%, transparent); }
 .rd-divider { border-color: color-mix(in oklab, currentColor 14%, transparent); }
 
+/* 进度/页码滑条:主题色轨道 + 强调色拇指,触摸友好 */
+.rd-range { @apply h-1.5 w-full cursor-pointer appearance-none rounded-full; background: color-mix(in oklab, currentColor 18%, transparent); }
+.rd-range::-webkit-slider-thumb {
+  @apply h-4 w-4 appearance-none rounded-full ring-2 ring-black/10; background: var(--rd-link, #f59e0b);
+}
+.rd-range::-moz-range-thumb { @apply h-4 w-4 rounded-full border-0; background: var(--rd-link, #f59e0b); }
+
+/* 沉浸态底部工具抽屉的滑入动效 */
+@keyframes rd-rise { from { transform: translateY(100%); opacity: 0.4; } to { transform: translateY(0); opacity: 1; } }
+.rd-sheet { animation: rd-rise 0.2s ease-out; }
+@media (prefers-reduced-motion: reduce) {
+  .rd-sheet { animation: none; }
+  .rd-rise-anim { transition: none !important; }
+}
+
 /* markdown 正文(仅 .md-body 作用域) */
 .md-body h1 { @apply mt-8 mb-3 text-2xl font-semibold; }
 .md-body h2 { @apply mt-6 mb-2 text-xl font-semibold; }