, because the article lives inside a React-hydrated tree and extra nodes there get removed when React recovers from a hydration mismatch. Why each piece exists (these are behavioural, not decorative): PROGRESS BAR Visible progress toward a goal measurably increases completion (goal-gradient effect). It also reduces *perceived* length, which is what actually drives people to abandon long reads. CONTENTS RAIL Chunking a wall of text into named sections lowers cognitive load, and a scroll-spy marker answers "where am I / how much is left" without the reader having to scrub the scrollbar. READING TIME Setting an explicit expectation up front reduces bounce: people abandon when length is unknown, not when it is long. BACK TO TOP Removes the friction of a long scroll-back, and only appears once it is actually needed so it never competes for attention. SHARE Sharing is an impulse. If it needs more than one tap the impulse is gone. ========================================================================== */ :root { --rp-rail-w: 232px; --rp-z: 90; } /* ========================================================================== 1. READING PROGRESS ========================================================================== */ .rp-progress { position: fixed; top: 0; left: 0; right: 0; height: 3px; z-index: calc(var(--rp-z) + 20); background: transparent; pointer-events: none; } .rp-progress__bar { height: 100%; width: 0; border-radius: 0 2px 2px 0; background: linear-gradient( 90deg, var(--color-primary-500, #4f3ff0), var(--color-primary-300, #9a8cff) ); /* transform is compositor-only; animating width would trigger layout on every scroll frame. */ transform-origin: 0 50%; transition: opacity .25s ease; } @media (prefers-reduced-motion: reduce) { .rp-progress__bar { transition: none; } } /* ========================================================================== 2. CONTENTS RAIL (>= 1280px) -------------------------------------------------------------------------- The article is max-w-3xl (768px) and centred, so at 1280px there is exactly 256px of clear space either side. A 232px rail at right:24px fits without ever overlapping the text. ========================================================================== */ .rp-toc { position: fixed; top: 50%; right: 24px; translate: 0 -50%; width: var(--rp-rail-w); max-height: 70vh; z-index: var(--rp-z); display: none; /* enabled by the media query below */ flex-direction: column; gap: 10px; padding: 18px; border: 1px solid var(--border-subtle, rgba(255, 255, 255, .09)); border-radius: var(--radius-lg, 18px); background: color-mix(in srgb, var(--surface-1, #0c0e1a) 88%, transparent); backdrop-filter: blur(18px) saturate(140%); -webkit-backdrop-filter: blur(18px) saturate(140%); font-family: var(--font-body, inherit); } @supports not ((backdrop-filter: blur(1px)) or (-webkit-backdrop-filter: blur(1px))) { .rp-toc { background: var(--surface-1, #0c0e1a); } } .rp-toc__head { display: flex; align-items: baseline; justify-content: space-between; gap: 8px; padding-bottom: 10px; border-bottom: 1px solid var(--border-subtle, rgba(255, 255, 255, .09)); } .rp-toc__title { font-size: .625rem; font-weight: 600; letter-spacing: .14em; text-transform: uppercase; color: var(--fg-faint, #8d93b0); } .rp-toc__meta { font-size: .625rem; color: var(--fg-faint, #8d93b0); white-space: nowrap; } .rp-toc__list { list-style: none; margin: 0; padding: 0; overflow-y: auto; overscroll-behavior: contain; scrollbar-width: thin; display: flex; flex-direction: column; gap: 2px; } .rp-toc__list::-webkit-scrollbar { width: 6px; } .rp-toc__list::-webkit-scrollbar-thumb { background: var(--border-strong, rgba(255, 255, 255, .17)); border-radius: 99px; } .rp-toc__link { display: block; padding: 6px 10px; border-left: 2px solid transparent; border-radius: 0 6px 6px 0; color: var(--fg-muted, #8f94b5); font-size: .8125rem; line-height: 1.4; text-decoration: none; transition: color .15s ease, background .15s ease, border-color .15s ease; /* Long headings truncate to two lines rather than pushing the rail wide. */ display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; } .rp-toc__link:hover { color: var(--fg-primary, #f6f7fd); background: color-mix(in srgb, var(--fg-primary, #fff) 5%, transparent); } /* Two cues for the active section, not just colour: a filled rail marker plus weight. Colour alone is not an accessible signal. */ .rp-toc__link[aria-current="true"] { color: var(--fg-primary, #f6f7fd); border-left-color: var(--color-primary-400, #7a64fb); background: color-mix(in srgb, var(--color-primary-500, #4f3ff0) 12%, transparent); font-weight: 500; } @media (min-width: 1280px) { .rp-toc { display: flex; } } /* ========================================================================== 3. FLOATING ACTIONS (contents / share / top) ========================================================================== */ .rp-fab-stack { position: fixed; right: 16px; bottom: calc(16px + env(safe-area-inset-bottom, 0px)); z-index: calc(var(--rp-z) + 10); display: flex; flex-direction: column; gap: 10px; align-items: flex-end; } .rp-fab { display: inline-flex; align-items: center; justify-content: center; gap: 8px; height: 44px; /* 44px: comfortable touch target */ min-width: 44px; padding: 0 14px; border: 1px solid var(--border-subtle, rgba(255, 255, 255, .09)); border-radius: 999px; background: color-mix(in srgb, var(--surface-2, #12142a) 92%, transparent); backdrop-filter: blur(14px); -webkit-backdrop-filter: blur(14px); color: var(--fg-secondary, #c6cae2); font-family: var(--font-body, inherit); font-size: .8125rem; font-weight: 500; cursor: pointer; box-shadow: 0 6px 20px rgba(0, 0, 0, .28); transition: opacity .2s ease, transform .2s ease, color .15s ease, border-color .15s ease; -webkit-tap-highlight-color: transparent; } .rp-fab:hover { color: var(--fg-primary, #f6f7fd); border-color: var(--color-primary-400, #7a64fb); } .rp-fab:active { transform: scale(.95); } .rp-fab svg { width: 16px; height: 16px; flex: none; } /* Hidden until useful, so it never competes with the content for attention. */ .rp-fab.is-hidden { opacity: 0; transform: translateY(8px) scale(.9); pointer-events: none; } /* The contents button is only an alternative to the rail, so hide it once the rail is visible. */ @media (min-width: 1280px) { .rp-fab[data-rp="contents"] { display: none; } } /* ========================================================================== 4. CONTENTS SHEET (< 1280px) ========================================================================== */ .rp-sheet { position: fixed; inset: 0; z-index: calc(var(--rp-z) + 30); display: flex; align-items: flex-end; background: rgba(4, 5, 12, .55); backdrop-filter: blur(3px); -webkit-backdrop-filter: blur(3px); opacity: 0; pointer-events: none; transition: opacity .22s ease; } .rp-sheet.is-open { opacity: 1; pointer-events: auto; } .rp-sheet__panel { width: 100%; max-height: 78dvh; display: flex; flex-direction: column; padding: 14px 18px calc(24px + env(safe-area-inset-bottom, 0px)); border-radius: 22px 22px 0 0; background: var(--surface-1, #0c0e1a); border: 1px solid var(--border-subtle, rgba(255, 255, 255, .09)); border-bottom: 0; translate: 0 100%; transition: translate .28s cubic-bezier(.2, 0, 0, 1); } .rp-sheet.is-open .rp-sheet__panel { translate: 0 0; } /* Grab handle: signals the sheet is dismissable. */ .rp-sheet__panel::before { content: ""; width: 38px; height: 4px; margin: 0 auto 14px; border-radius: 99px; background: var(--border-strong, rgba(255, 255, 255, .17)); flex: none; } .rp-sheet .rp-toc__list { max-height: 60dvh; } .rp-sheet .rp-toc__link { font-size: .9375rem; padding: 10px 12px; } @media (min-width: 1280px) { .rp-sheet { display: none; } } @media (prefers-reduced-motion: reduce) { .rp-sheet, .rp-sheet__panel, .rp-fab { transition: none; } } /* ========================================================================== 5. ARTICLE IMAGE STABILITY -------------------------------------------------------------------------- The exported article images carry no width/height attributes, so the browser cannot reserve space and the text jumps when they decode. A default aspect-ratio removes that shift; any image that does declare dimensions overrides it naturally. ========================================================================== */ article img:not([width]):not([height]) { aspect-ratio: 16 / 9; width: 100%; height: auto; object-fit: cover; background: var(--surface-2, #12142a); } /* ========================================================================== 6. PRINT ========================================================================== */ @media print { .rp-progress, .rp-toc, .rp-fab-stack, .rp-sheet { display: none !important; } }