/* Book Publishing Systems — the public site. One stylesheet, no scripts.
 *
 * THE LOOK (2026-10-07, evening): a sheet coming off a press.
 *   - Paper with a grain, one black, and the three process inks: cyan, magenta
 *     and yellow. Where the inks overlap they overprint, as on a real sheet.
 *   - Halftone: the big discs of dots, and the bands of dots where paper turns
 *     to ink, are gradients pushed through a contrast filter. No pictures.
 *   - Register: headings arrive with their three plates out of line and settle
 *     into register. Buttons do the same on the way up.
 *   - The systems are SOFTWARE, and are shown as what they are: app windows
 *     with their real pictures in them, standing in the air at an angle.
 *   - Going from page to page turns the leaf, and a system's window is carried
 *     across to its own page, where it grows into the big picture of the app
 *     (browsers that can; the rest just change page).
 *   - As you scroll: a ribbon bookmark comes down the side, pictures of the
 *     apps settle flat onto the sheet, and the parts of a page rise into place.
 * Everything that moves is switched off for anyone who has asked their
 * computer for less motion, and nothing here is needed to read the page.
 *
 * THE RULE: the site's page rule (_headers) allows no script, no inline style
 * and nothing from another site. So: no style="" in build.js, no data: URLs
 * here, and the only picture this file asks for is our own grain.svg.
 *
 * SPEED (measured with tools/measure-speed.js; keep it at these):
 *   - A page that is standing still does no work. Anything that moves on its
 *     own must only slide, turn, scale or fade (translate / rotate / scale /
 *     transform / opacity): the graphics card does those without the page
 *     redrawing. Never animate a background, a shadow, a size or a colour on
 *     a loop: the page then redraws 60 to 120 times a second for ever.
 *   - Nothing waits on a picture: the stylesheet is the only thing a page
 *     needs before it can be drawn, so nothing in build.js may be marked as
 *     more urgent than it (no fetchpriority="high" on a picture that is not
 *     the main thing on its page).
 *   - content-visibility: auto was tried on the top of each page (to stop the
 *     inks when scrolled away) and taken out again: it made the page jump as
 *     it loaded, and movement that only slides costs nothing out of sight. */

:root {
  --paper: #f5f0e6; --band: #ebe4d3; --card: #fffdf8;
  --ink: #14120e; --ink-2: #4a473e; --ink-3: #69655a; --rule: #d6cebb;
  --night: #100f0c; --on-night: #f5f0e6; --on-night-2: #b8b2a3; --night-rule: #37342c;
  --c: #00a7e6; --m: #ee1b8c; --y: #ffe600;                      /* the process inks */
  --green: #1d5a48; --green-deep: #154536; --on-green: #fffdf7; --green-wash: #dfe9e2;
  --ochre: #6f4b00; --ochre-wash: #fff5a8; --ochre-line: #e0b400;   /* "not yet": legal.css uses these names */
  --serif: "Iowan Old Style", "Palatino Linotype", Palatino, "Book Antiqua", Georgia, serif;
  --sans: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", sans-serif;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  --wide: 1160px;
  --ease: cubic-bezier(0.2, 0.8, 0.2, 1);
  --dots: radial-gradient(closest-side, #7d7d7d, #fff);          /* one halftone dot, before the contrast filter */
  interpolate-size: allow-keywords;
}

*, ::before, ::after { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; scroll-padding-top: 90px; }
body { margin: 0; background: var(--paper) url(grain.89904f664e.svg); color: var(--ink); font: 17px/1.6 var(--sans); -webkit-font-smoothing: antialiased; }
img { max-width: 100%; height: auto; display: block; }
picture { display: block; }
h1, h2, h3, p, ul, ol, figure { margin: 0; }
a { color: inherit; text-decoration-color: var(--m); text-decoration-thickness: 2px; text-underline-offset: 3px; }
a:hover { text-decoration-color: currentColor; }
:focus-visible { outline: 3px solid var(--m); outline-offset: 3px; border-radius: 4px; }
::selection { background: var(--y); color: var(--ink); }
.wrap { position: relative; max-width: var(--wide); margin: 0 auto; padding: 0 24px; }
.skip { position: absolute; left: -999px; top: 8px; background: var(--ink); color: var(--paper); padding: 8px 14px; border-radius: 8px; z-index: 40; }
.skip:focus { left: 12px; }

.label { font: 600 12px/1.4 var(--mono); letter-spacing: 0.14em; text-transform: uppercase; color: var(--ink-3); }
.serif { font-family: var(--serif); }

/* --------------------------------------------------------------- draft -- */
.draft { position: relative; z-index: 1; background: var(--y); border-bottom: 1.5px solid var(--ink); color: var(--ink); font-size: 14px; padding: 9px 0; }
.draft .wrap { padding-right: 40px; }
.draft b { font-weight: 700; }
.draft a, .fine a { color: inherit; font-weight: 650; text-decoration-thickness: 1.5px; text-underline-offset: 2px; }
.draft summary { cursor: pointer; }
.draft ul { margin: 8px 0 4px; padding-left: 20px; }

/* -------------------------------------------------------------- header -- */
.mast { position: sticky; top: 0; z-index: 20; background: rgba(245, 240, 230, 0.8); -webkit-backdrop-filter: blur(10px) saturate(1.5); backdrop-filter: blur(10px) saturate(1.5); border-bottom: 1px solid var(--rule); }
.top { display: flex; align-items: center; justify-content: space-between; gap: 20px; padding-top: 14px; padding-bottom: 14px; }
.brand { display: inline-flex; align-items: center; gap: 11px; color: var(--ink); text-decoration: none; font: 600 19px/1 var(--serif); letter-spacing: 0.005em; }
.brand svg { width: 30px; height: 30px; flex: none; transition: rotate 0.5s var(--ease); }
.brand:hover svg { rotate: -8deg; }
.top nav { display: flex; align-items: center; gap: 6px 26px; font-size: 15px; }
.top nav a:not(.btn) { color: var(--ink-2); text-decoration: none; padding: 6px 0; background: linear-gradient(var(--y), var(--y)) no-repeat 0 78% / 0% 38%; transition: background-size 0.3s var(--ease), color 0.2s; }
.top nav a:not(.btn):hover { color: var(--ink); background-size: 100% 38%; }
.top nav a[aria-current="page"] { color: var(--ink); font-weight: 650; background-size: 100% 38%; }

.btn { display: inline-block; background: var(--ink); color: var(--paper); text-decoration: none; font: 650 16px/1 var(--sans); padding: 15px 22px; border-radius: 12px; border: 1.5px solid var(--ink); box-shadow: 0 0 0 var(--m), 0 0 0 var(--c); transition: transform 0.2s var(--ease), box-shadow 0.2s var(--ease), background-color 0.2s; }
.btn:hover { transform: translate(-3px, -3px); box-shadow: 3px 3px 0 var(--m), 6px 6px 0 var(--c); }   /* out of register on the way up */
.btn:active { transform: none; box-shadow: 0 0 0 var(--m), 0 0 0 var(--c); }
.btn.line { background: var(--card); color: var(--ink); }
.btn.line:hover { background: var(--y); box-shadow: 3px 3px 0 var(--ink), 3px 3px 0 var(--ink); }
.btn.small { padding: 10px 16px; font-size: 15px; border-radius: 10px; }

/* ---------------------------------------------------------- the inks -- */
/* Three discs of halftone dots. Under each lies a sheet of grey dots multiplied
 * by a soft round shadow, and the contrast filter turns that into black dots
 * that shrink toward the rim. Over it lies the ink's colour, "screened" so it
 * shows only where the dots are, and the whole disc is then "multiplied" onto
 * whatever is beneath: it prints. Each plate is turned to its own screen
 * angle, as a printer turns them, so the overlaps make rosettes. */
.inks { position: absolute; inset: 0; pointer-events: none; }
.ink { position: absolute; width: 68%; aspect-ratio: 1; mix-blend-mode: multiply; }
.ink::before { content: ""; position: absolute; inset: -21%; background: var(--dots) 0 0 / var(--dot, 11px) var(--dot, 11px), radial-gradient(closest-side, #5a5a5a 0%, #8c8c8c 36%, #fff 70%); background-blend-mode: multiply; filter: contrast(15); }
.ink::after { content: ""; position: absolute; inset: -1px; border-radius: 50%; background: var(--ink-colour); mix-blend-mode: screen; }
.ink.c { --ink-colour: var(--c); left: 0; top: 0; } .ink.c::before { rotate: 15deg; }
.ink.m { --ink-colour: var(--m); right: 0; top: 4%; } .ink.m::before { rotate: 75deg; }
.ink.y { --ink-colour: var(--y); left: 17%; top: 27%; }

/* on a dark ground the same plates are lights: they add up instead of overprinting */
.night .inks { overflow: hidden; }
.night .ink { mix-blend-mode: screen; width: 36%; opacity: 0.85; }   /* never opacity on .inks: that would cut the plates off from what they print on */
.night .ink::before { filter: contrast(15) invert(1); }
.night .ink::after { mix-blend-mode: multiply; }
.night .ink.c { left: -8%; top: -34%; } .night .ink.m { right: -9%; top: 8%; } .night .ink.y { left: 30%; top: auto; bottom: -78%; }

/* the band of dots where paper turns to ink, above and below a dark part */
.edge { position: absolute; left: 0; right: 0; height: clamp(54px, 7.2vw, 96px); background: var(--night); mix-blend-mode: multiply; pointer-events: none; overflow: hidden; }
.edge.top { bottom: 100%; } .edge.bot { top: 100%; }
.edge i { position: absolute; inset: 0; background: var(--dots) 50% 0 / 12px 12px, linear-gradient(#fff 4%, #6c6c6c 100%); background-blend-mode: multiply; filter: contrast(15); mix-blend-mode: screen; }
.edge.bot i { background-image: var(--dots), linear-gradient(#6c6c6c 0%, #fff 96%); }
/* no band between two dark parts (the footer is always dark) */
.night + .night > .edge.top, .night:has(+ .night) > .edge.bot, main > .night:first-child > .edge.top, main > .night:last-child > .edge.bot, main:has(> .night:last-child) + footer > .edge.top { display: none; }

/* ---------------------------------------------------------------- hero -- */
.hero { position: relative; overflow: clip; padding: clamp(26px, 4.4vw, 60px) 0 clamp(84px, 10vw, 140px); }
.hero-grid { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1.14fr); gap: clamp(20px, 3.4vw, 50px); align-items: center; }
.hero-say { position: relative; z-index: 2; }
.hero .label::before, .page-hero .ph-say > .label::before { content: ""; display: inline-block; width: 31px; height: 11px; margin-right: 10px; vertical-align: -1px; background: radial-gradient(circle at 5.5px 50%, var(--c) 5px, transparent 5.5px), radial-gradient(circle at 15.5px 50%, var(--m) 5px, transparent 5.5px), radial-gradient(circle at 25.5px 50%, var(--y) 5px, transparent 5.5px); }
.hero h1 { font: 500 clamp(44px, 5.9vw, 84px)/0.98 var(--serif); letter-spacing: -0.03em; margin-top: 18px; text-wrap: balance; }
.hero h1 em { font-style: italic; white-space: nowrap; padding: 0 0.07em; margin: 0 -0.07em; background: linear-gradient(transparent 60%, var(--y) 60% 93%, transparent 93%) no-repeat 0 0 / 100% 100%; }
.hero .lede { margin-top: 24px; font-size: 19.5px; line-height: 1.55; color: var(--ink-2); max-width: 35em; text-wrap: pretty; }
.hero .cta { margin-top: 30px; display: flex; flex-wrap: wrap; gap: 12px; align-items: center; }
.hero .fine { margin-top: 16px; font-size: 14.5px; color: var(--ink-3); }

.stage { position: relative; display: grid; align-items: center; }
@media (min-width: 1300px) { .stage { margin-right: -56px; } }   /* runs a little past the column, where the window has a margin to take it */
.stage .inks { inset: -12% -14% -10% -8%; }
.stage .ink { width: 60%; }
.stage .ink.c { left: 0; top: 0; } .stage .ink.m { right: 0; top: 24%; } .stage .ink.y { left: 14%; top: 42%; }

.state { display: inline-block; font: 700 11px/1 var(--mono); letter-spacing: 0.08em; text-transform: uppercase; padding: 6px 9px 5px; border-radius: 999px; white-space: nowrap; }
.state.live { background: var(--green); color: var(--on-green); }
.state.soon { background: var(--y); color: var(--ink); box-shadow: inset 0 0 0 1.5px var(--ink); }
.state.later { color: var(--ink-3); box-shadow: inset 0 0 0 1px var(--ink-3); }

/* ------------------------------------------ the systems as app windows -- */
/* Each system is a window with its real picture in it, standing in the air
 * at an angle. The link (.win) stays flat and only holds the perspective;
 * the window inside it (.pane) is what turns. Hovering, or tabbing to one,
 * turns it to face you. */
.deck { list-style: none; margin: 0; padding: 0; position: relative; z-index: 1; width: 100%; aspect-ratio: 1.12; }
.deck li { position: absolute; }
.deck li:nth-child(1) { left: 0; bottom: 2%; width: 88%; z-index: 3; }
.deck li:nth-child(2) { right: 0; top: 0; width: 72%; z-index: 2; }
.deck li:nth-child(3) { left: -3%; top: 4%; width: 46%; z-index: 1; }
.deck li:hover, .deck li:focus-within { z-index: 4; }
.win { display: block; perspective: 1300px; color: inherit; text-decoration: none; -webkit-tap-highlight-color: transparent; }
.win:focus-visible { outline-offset: 10px; }
.pane { display: block; overflow: hidden; border-radius: 12px; border: 1.5px solid var(--ink); background: var(--card); transform: rotateY(-12deg) rotateX(5deg) rotateZ(1deg); transition: transform 0.6s var(--ease), box-shadow 0.6s var(--ease);
  box-shadow: 0 1px 0 rgba(20, 18, 14, 0.3), 14px 26px 44px -18px rgba(20, 18, 14, 0.5), 30px 60px 80px -40px rgba(20, 18, 14, 0.45); }
.deck li:nth-child(2) .pane { transform: rotateY(-12deg) rotateX(5deg) rotateZ(1deg) translateZ(-60px); }
a.win:hover .pane, a.win:focus-visible .pane { transform: rotateY(-5deg) rotateX(2deg) translateZ(46px); box-shadow: 0 1px 0 rgba(20, 18, 14, 0.3), 7px 9px 0 var(--m), 14px 18px 0 var(--c); }
/* the window's bar: three lights in the press's own inks, the system's number and name, and how far along it is */
.bar { display: flex; align-items: center; gap: 9px; padding: 9px 12px 8px; border-bottom: 1.5px solid var(--ink); background: var(--paper); white-space: nowrap; }
.bar::before { content: ""; flex: none; width: 38px; height: 10px; background: radial-gradient(circle at 5px 50%, var(--c) 4.5px, transparent 5px), radial-gradient(circle at 19px 50%, var(--m) 4.5px, transparent 5px), radial-gradient(circle at 33px 50%, var(--y) 4.5px, transparent 5px); }
.bar .n { font: 600 11px/1 var(--mono); letter-spacing: 0.1em; color: var(--ink-3); }
.bar b { font: 650 13.5px/1.1 var(--sans); overflow: hidden; text-overflow: ellipsis; }
.bar .state { margin-left: auto; font-size: 9.5px; padding: 5px 7px 4px; }
.pane img { width: 100%; background: var(--ink); }
.foot { display: block; padding: 8px 12px 9px; border-top: 1.5px solid var(--ink); font: 500 12.5px/1.35 var(--sans); color: var(--ink-2); }
/* the system that is not built yet: only the outline of a window, furthest back */
.win.ghost .pane { background: rgba(245, 240, 230, 0.6); border: 1.5px dashed var(--ink-3); box-shadow: none; transform: rotateY(-12deg) rotateX(5deg) rotateZ(1deg) translateZ(-130px); }
.win.ghost .bar { background: none; border-bottom: 1.5px dashed var(--ink-3); }
.win.ghost .bar::before { background: radial-gradient(circle at 5px 50%, transparent 3.2px, var(--ink-3) 3.5px 4.5px, transparent 5px), radial-gradient(circle at 19px 50%, transparent 3.2px, var(--ink-3) 3.5px 4.5px, transparent 5px), radial-gradient(circle at 33px 50%, transparent 3.2px, var(--ink-3) 3.5px 4.5px, transparent 5px); }
/* its words sit at the left of the empty window, the part the other windows leave in view */
.blank { display: grid; align-content: start; justify-items: start; gap: 9px; aspect-ratio: 1.55; padding: 12px 12px 0; background: repeating-linear-gradient(135deg, rgba(105, 101, 90, 0) 0 9px, rgba(105, 101, 90, 0.16) 9px 10px); }
.blank b { max-width: 6.2em; font: 500 17px/1.12 var(--serif); letter-spacing: -0.01em; color: var(--ink-2); }
.blank .state { font-size: 9.5px; padding: 5px 7px 4px; background: var(--paper); }

/* ------------------------------------------- a picture, as a press sheet -- */
/* crop marks at the corners, a colour bar and a register mark in the margin */
.proof { --pm: 30px; --pt: 18px; position: relative; padding: var(--pm); margin: 46px calc(var(--pm) * -1) 0; perspective: 1900px;
  background:
    linear-gradient(var(--ink), var(--ink)) left var(--pm) top 0 / 1px var(--pt) no-repeat,
    linear-gradient(var(--ink), var(--ink)) left 0 top var(--pm) / var(--pt) 1px no-repeat,
    linear-gradient(var(--ink), var(--ink)) right var(--pm) top 0 / 1px var(--pt) no-repeat,
    linear-gradient(var(--ink), var(--ink)) right 0 top var(--pm) / var(--pt) 1px no-repeat,
    linear-gradient(var(--ink), var(--ink)) left var(--pm) bottom 0 / 1px var(--pt) no-repeat,
    linear-gradient(var(--ink), var(--ink)) left 0 bottom var(--pm) / var(--pt) 1px no-repeat,
    linear-gradient(var(--ink), var(--ink)) right var(--pm) bottom 0 / 1px var(--pt) no-repeat,
    linear-gradient(var(--ink), var(--ink)) right 0 bottom var(--pm) / var(--pt) 1px no-repeat; }
.proof::before { content: ""; position: absolute; left: calc(var(--pm) + var(--pt) + 12px); top: 8px; width: 168px; height: 12px;
  background: linear-gradient(90deg, var(--c) 0 12.5%, var(--m) 12.5% 25%, var(--y) 25% 37.5%, var(--ink) 37.5% 50%, #7fd3f2 50% 62.5%, #f68dc5 62.5% 75%, #fff27f 75% 87.5%, #8a8986 87.5% 100%); }
.proof::after { content: ""; position: absolute; right: calc(var(--pm) + var(--pt) + 12px); top: 4px; width: 19px; height: 19px;
  background: linear-gradient(var(--ink), var(--ink)) 50% 0 / 1px 100% no-repeat, linear-gradient(var(--ink), var(--ink)) 0 50% / 100% 1px no-repeat, radial-gradient(circle, transparent 5px, var(--ink) 5px 6px, transparent 6.5px); }
.sheet { position: relative; border-radius: 10px; overflow: hidden; background: var(--ink); transform-origin: 50% 100%;
  box-shadow: 0 1px 0 rgba(20, 18, 14, 0.3), 0 34px 60px -30px rgba(20, 18, 14, 0.6), 0 70px 120px -60px rgba(20, 18, 14, 0.45); }
.sheet img { width: 100%; }
.sheet::after { content: ""; position: absolute; top: 0; bottom: 0; left: 0; width: 45%; pointer-events: none; translate: -110% 0; background: linear-gradient(105deg, rgba(255, 255, 255, 0) 20%, rgba(255, 255, 255, 0.28) 50%, rgba(255, 255, 255, 0) 80%); }   /* a gleam, waiting off the left edge */
.proof figcaption { position: absolute; left: calc(var(--pm) + var(--pt) + 12px); bottom: 7px; font: 500 11.5px/1 var(--mono); letter-spacing: 0.06em; color: var(--ink-3); }

/* ------------------------------------------------------------ sections -- */
section { position: relative; padding: clamp(64px, 8.6vw, 112px) 0; }
section.band { background: var(--band); border-top: 1px solid var(--rule); border-bottom: 1px solid var(--rule); }
.night, section.band.night { position: relative; background: var(--night); color: var(--on-night); border: 0; }
.night .label { color: var(--on-night-2); }
.head { display: grid; gap: 12px; max-width: 48em; margin-bottom: 44px; }
.head h2 { font: 500 clamp(32px, 4.5vw, 60px)/1.03 var(--serif); letter-spacing: -0.025em; text-wrap: balance; }
.head p:not(.label) { color: var(--ink-2); font-size: 18.5px; max-width: 38em; text-wrap: pretty; }
.night .head p:not(.label) { color: var(--on-night-2); }
.mark { display: inline-block; width: 18px; height: 18px; vertical-align: -3px; margin-right: 8px; color: var(--m); }

/* -------------------------------------------------------------- systems -- */
/* a system is a card with two more sheets under it, and its number standing on top */
.system { position: relative; display: grid; grid-template-columns: minmax(0, 1fr); margin-top: clamp(86px, 11.5vw, 168px); background: var(--card); color: var(--ink); border-radius: 22px; box-shadow: 0 9px 0 -4px #e7e0cf, 0 18px 0 -9px #cfc7b3; }
.head + .system { margin-top: clamp(70px, 9vw, 130px); }
.system .numeral { position: absolute; right: 30px; bottom: 100%; margin-bottom: 0.004em; font: 500 clamp(92px, 13vw, 196px)/0.74 var(--serif); letter-spacing: -0.045em; pointer-events: none;
  color: transparent; -webkit-text-stroke: 1.5px var(--on-night); background: radial-gradient(circle, var(--y) 38%, rgba(255, 230, 0, 0) 42%) 0 0 / 5px 5px; -webkit-background-clip: text; background-clip: text; }
.sys-head { display: flex; flex-wrap: wrap; align-items: center; gap: 10px 18px; padding: 22px 30px; border-bottom: 1.5px solid var(--ink); }
.sys-head .n { font: 600 12px/1 var(--mono); letter-spacing: 0.14em; color: var(--ink-3); }
.sys-head h3 { font: 600 clamp(28px, 3vw, 38px)/1.05 var(--serif); letter-spacing: -0.02em; }
.sys-head .state { margin-left: auto; }
.sys-body { display: grid; grid-template-columns: minmax(0, 0.92fr) minmax(0, 1.08fr); gap: 0; }
.sys-say { padding: 30px 30px 34px; border-right: 1px solid var(--rule); }
.sys-say .tagline { font: 500 clamp(24px, 2.5vw, 30px)/1.18 var(--serif); letter-spacing: -0.015em; text-wrap: balance; }   /* not "line": that is the outlined button */
.sys-say .body { margin-top: 14px; color: var(--ink-2); text-wrap: pretty; }
.sys-note { margin-top: 20px; padding: 12px 14px; background: var(--ochre-wash); border-left: 4px solid var(--ink); font-size: 15px; color: var(--ink); border-radius: 0 8px 8px 0; }
.sys-cta { margin-top: 26px; display: flex; flex-wrap: wrap; gap: 10px; }
.points { list-style: none; padding: 14px 30px 18px; display: grid; gap: 0; align-content: start; }
.points li { padding: 15px 0 15px 38px; position: relative; border-bottom: 1px solid var(--rule); }
.points li:last-child { border-bottom: 0; }
.points li::before { content: ""; position: absolute; left: 0; top: 17px; width: 23px; height: 23px; border-radius: 50%; background: var(--y); }
.points li::after { content: ""; position: absolute; left: 6.5px; top: 23.5px; width: 10px; height: 5.5px; border-left: 2.3px solid var(--ink); border-bottom: 2.3px solid var(--ink); transform: rotate(-45deg); }
.points b { display: block; font-weight: 650; }
.points span { color: var(--ink-2); font-size: 16px; }
.sys-shot { border-top: 1.5px solid var(--ink); padding: 30px 30px 38px; background: var(--paper) url(grain.89904f664e.svg); border-radius: 0 0 22px 22px; }
.sys-shot .proof { margin: 0; }

/* chapter by chapter: what "saved as it goes" looks like */
.chapters { margin-top: 28px; }
.chapters ol { list-style: none; padding: 0; display: flex; gap: 6px; }
.chapters li { flex: 1; min-width: 0; height: 50px; border-radius: 8px; display: grid; place-items: center; font: 600 11px/1 var(--mono); letter-spacing: 0.04em; }
.chapters li.done { background: var(--ink); color: var(--paper); }
.chapters li.now { position: relative; overflow: hidden; isolation: isolate; color: var(--ink); border: 1.5px solid var(--ink); background: var(--card); }
.chapters li.now::before { content: ""; position: absolute; inset: 0; z-index: -1; background: var(--y); transform-origin: 0 50%; scale: 0.34 1; }
.chapters li.next { border: 1.5px dashed var(--ink-3); color: var(--ink-3); }
.chapters p { margin-top: 11px; font-size: 14px; color: var(--ink-3); }
.chapters .key { display: inline-block; width: 11px; height: 11px; border-radius: 3px; margin: 0 5px 0 12px; vertical-align: -1px; }
.chapters .key:first-child { margin-left: 0; }
.chapters .key.done { background: var(--ink); } .chapters .key.now { background: var(--y); border: 1.5px solid var(--ink); } .chapters .key.next { border: 1.5px dashed var(--ink-3); }

/* the files a finished book downloads as */
.outs { margin-top: 24px; }
.outs ul { list-style: none; padding: 0; margin-top: 9px; display: flex; gap: 10px; }
.outs li { flex: 1; background: var(--card); border: 1.5px solid var(--ink); border-radius: 4px; padding: 13px 12px 10px; font-size: 13.5px; color: var(--ink-2); position: relative; clip-path: polygon(0 0, calc(100% - 17px) 0, 100% 17px, 100% 100%, 0 100%); transition: translate 0.3s var(--ease); }
.outs li::after { content: ""; position: absolute; right: -1.5px; top: -1.5px; width: 17px; height: 17px; background: linear-gradient(225deg, transparent 50%, var(--ink) 50%, var(--ink) calc(50% + 1.5px), var(--band) calc(50% + 1.5px)); border-bottom: 1.5px solid var(--ink); border-left: 1.5px solid var(--ink); }
.outs li:hover { translate: 0 -5px; }
.outs b { display: block; font: 600 17px/1.2 var(--mono); color: var(--ink); }

/* how many kinds of puzzle, for whom */
.kinds { margin-top: 28px; }
.kinds svg { display: block; border-radius: 6px; }
.kinds rect.k1 { fill: var(--ink); } .kinds rect.k2 { fill: var(--c); } .kinds rect.k3 { fill: var(--m); }
.kinds rect.k4 { fill: var(--y); } .kinds rect.k5 { fill: var(--green); }
.kinds ul { list-style: none; padding: 0; margin-top: 11px; display: flex; flex-wrap: wrap; gap: 4px 18px; font-size: 14px; color: var(--ink-2); }
.kinds li b { font: 600 14px/1 var(--mono); color: var(--ink); margin-right: 5px; }
.kinds li::before { content: ""; display: inline-block; width: 11px; height: 11px; border-radius: 50%; margin-right: 6px; background: var(--ink); vertical-align: -1px; }
.kinds li:nth-child(2)::before { background: var(--c); } .kinds li:nth-child(3)::before { background: var(--m); }
.kinds li:nth-child(4)::before { background: var(--y); box-shadow: inset 0 0 0 1px var(--ink-3); } .kinds li:nth-child(5)::before { background: var(--green); }

.more { margin-top: 46px; border: 1.5px dashed var(--ink-3); border-radius: 22px; padding: 26px 30px; display: grid; grid-template-columns: auto 1fr; gap: 6px 18px; align-items: baseline; }
.more .n { font: 600 12px/1 var(--mono); letter-spacing: 0.14em; color: var(--ink-3); }
.more h3 { font: 600 24px/1.2 var(--serif); }
.more p { grid-column: 2; color: var(--ink-2); max-width: 44em; }
.night .more { border-color: var(--on-night-2); } .night .more .n, .night .more p { color: var(--on-night-2); }

/* ---------------------------------------------------------------- steps -- */
.steps { list-style: none; padding: 0; display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 22px; }
.steps li { position: relative; padding: 28px 26px 30px; background: var(--card); border: 1.5px solid var(--ink); border-radius: 20px; }
.steps li:not(:last-child)::after { content: ""; position: absolute; left: 100%; top: 50px; width: 22px; border-top: 2px dotted var(--ink); }   /* the dotted line to the next step */
.steps svg { width: 26px; height: 26px; padding: 11px; box-sizing: content-box; border-radius: 50%; color: var(--ink); background: var(--y); }
.steps .n { position: absolute; right: 22px; top: 14px; font: 500 68px/1 var(--serif); color: transparent; -webkit-text-stroke: 1.5px var(--ink-3); }
.steps h3 { font: 600 22px/1.2 var(--serif); margin-top: 16px; }
.steps p { margin-top: 8px; color: var(--ink-2); font-size: 16px; }
.needs { margin-top: 36px; display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 22px; }
.need { border-top: 3px solid var(--ink); padding-top: 16px; }
.need h3 { font: 600 21px/1.25 var(--serif); margin-top: 4px; }
.need p { margin-top: 6px; color: var(--ink-2); font-size: 16px; }

/* ---------------------------------------------------------------- facts -- */
.facts { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 0; border-top: 2px solid var(--ink); border-left: 1px solid var(--rule); }
.fact { padding: 26px 24px 28px; border-right: 1px solid var(--rule); border-bottom: 1px solid var(--rule); transition: background-color 0.3s; }
.fact:hover { background: rgba(255, 253, 248, 0.7); }
.fact h3 { font: 600 21px/1.22 var(--serif); display: flex; gap: 9px; align-items: flex-start; }
.fact h3 svg { width: 17px; height: 17px; flex: none; margin-top: 4px; color: var(--m); transition: rotate 0.6s var(--ease); }
.fact:hover h3 svg { rotate: 90deg; }
.fact p { margin-top: 9px; color: var(--ink-2); font-size: 16px; }

/* ------------------------------------------------------------ questions -- */
.qa { border-top: 2px solid var(--ink); max-width: 860px; }
.qa details { border-bottom: 1px solid var(--rule); }
.qa summary { cursor: pointer; list-style: none; padding: 20px 54px 20px 0; position: relative; font: 600 21px/1.3 var(--serif); transition: padding-left 0.3s var(--ease); }
.qa summary:hover { padding-left: 8px; }
.qa summary::-webkit-details-marker { display: none; }
.qa summary::after { content: ""; position: absolute; right: 4px; top: 50%; width: 32px; height: 32px; margin-top: -16px; border-radius: 50%; background: linear-gradient(var(--ink), var(--ink)) 50% 50% / 13px 2px no-repeat, linear-gradient(var(--ink), var(--ink)) 50% 50% / 2px 13px no-repeat, var(--y); transition: rotate 0.4s var(--ease); }
.qa details[open] summary::after { rotate: 135deg; }
.qa p { padding: 0 54px 22px 0; color: var(--ink-2); }
.qa details::details-content { block-size: 0; overflow: clip; transition: block-size 0.45s var(--ease), content-visibility 0.45s allow-discrete; }
.qa details[open]::details-content { block-size: auto; }

/* ---------------------------------------------------------------- close -- */
.close { text-align: center; padding: clamp(96px, 13vw, 176px) 0 clamp(70px, 9vw, 120px); }
.close .wrap { z-index: 1; }
.close h2 { font: 500 clamp(34px, 5.4vw, 76px)/1.02 var(--serif); letter-spacing: -0.028em; text-wrap: balance; }
.close p { margin: 18px auto 0; color: var(--on-night-2); max-width: 34em; font-size: 18.5px; }
.close p.label { margin-top: 0; margin-bottom: 14px; font-size: 12px; }
.close .cta { margin-top: 30px; display: flex; flex-wrap: wrap; gap: 12px; justify-content: center; }
.close p.fine { margin-top: 26px; font-size: 15.5px; }   /* the line for a visitor with no key, under the buttons */
.close .huge { margin: 0 auto 6px; max-width: none; font: 500 clamp(120px, 26vw, 330px)/0.8 var(--serif); letter-spacing: -0.05em; color: transparent; -webkit-text-stroke: 2px var(--on-night); background: radial-gradient(circle, var(--y) 31%, rgba(255, 230, 0, 0) 34%) 0 0 / 11px 11px; -webkit-background-clip: text; background-clip: text; }
.night .btn { background: var(--paper); color: var(--ink); border-color: var(--paper); }
.night .btn.line { background: transparent; color: var(--paper); }
.night .btn.line:hover { background: var(--y); color: var(--ink); border-color: var(--y); box-shadow: 3px 3px 0 var(--m), 6px 6px 0 var(--c); }
.night .system .btn { background: var(--ink); color: var(--paper); border-color: var(--ink); }
.night .system .btn.line { background: var(--card); color: var(--ink); }
.night .system .btn.line:hover { background: var(--y); border-color: var(--ink); box-shadow: 3px 3px 0 var(--ink), 3px 3px 0 var(--ink); }
.night .system .label { color: var(--ink-3); }

footer { padding: 34px 0 50px; font-size: 14px; color: var(--on-night-2); }
.colophon { margin-bottom: 34px; padding-bottom: 0.14em; border-bottom: 1px solid var(--night-rule); font: 500 clamp(44px, 8vw, 126px)/0.98 var(--serif); letter-spacing: -0.035em; text-wrap: balance;
  color: transparent; background: linear-gradient(90deg, var(--c), var(--m) 45%, var(--y)); -webkit-background-clip: text; background-clip: text; }
footer .row { display: flex; flex-wrap: wrap; gap: 12px 28px; align-items: center; justify-content: space-between; }
footer .brand { color: var(--on-night); }
.night .brand svg .k { fill: var(--on-night); }
footer .legal { margin-top: 18px; max-width: 70em; line-height: 1.55; }
footer a { color: var(--on-night); }
footer nav { display: flex; flex-wrap: wrap; gap: 6px 20px; }
footer nav a { text-decoration: none; } footer nav a:hover { text-decoration: underline; text-decoration-color: var(--y); }

/* ------------------------------------------------------ the pages inside -- */
.page-hero { position: relative; overflow: clip; padding: clamp(30px, 5vw, 66px) 0 10px; }
.page-hero .inks { left: auto; right: -30px; top: -44%; bottom: auto; width: min(44%, 480px); aspect-ratio: 1.08; }
.ph-say { position: relative; z-index: 1; }
.page-hero .label { display: flex; align-items: center; gap: 10px; }
.page-hero .label::before { flex: none; margin-right: 0; }
.page-hero h1 { font: 500 clamp(44px, 7vw, 100px)/0.98 var(--serif); letter-spacing: -0.03em; margin-top: 16px; text-wrap: balance; max-width: 13em; }
.page-hero .lede { margin-top: 20px; font-size: 19.5px; line-height: 1.55; color: var(--ink-2); max-width: 37em; text-wrap: pretty; }
.page-hero .cta { margin-top: 28px; display: flex; flex-wrap: wrap; gap: 12px; }
.page-hero .fine { margin-top: 14px; font-size: 14.5px; color: var(--ink-3); }
.page-hero .sys-note { max-width: 40em; }
section.tight { padding-top: 44px; }
.morelink { margin-top: 26px; font-weight: 650; }
.morelink a { text-decoration: none; border-bottom: 2px solid var(--m); padding-bottom: 2px; }
.morelink a span { display: inline-block; transition: translate 0.3s var(--ease); }
.morelink a:hover span { translate: 6px 0; }
.card { background: var(--card); border: 1.5px solid var(--ink); border-radius: 22px; }
.card .points { grid-template-columns: repeat(2, minmax(0, 1fr)); column-gap: 44px; padding-top: 10px; padding-bottom: 10px; }
.card .points li:nth-last-child(2):nth-child(odd) { border-bottom: 0; }
.card.spaced { margin-top: 30px; }
.two { margin-top: 34px; display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 44px; align-items: start; }
.two .chapters, .two .outs { margin-top: 0; }

/* numbered parts in a row: an app's own steps */
.flow { list-style: none; padding: 0; display: grid; gap: 18px; }
.flow.n3 { grid-template-columns: repeat(3, minmax(0, 1fr)); } .flow.n4 { grid-template-columns: repeat(4, minmax(0, 1fr)); } .flow.n5 { grid-template-columns: repeat(5, minmax(0, 1fr)); }
.flow li { position: relative; padding: 24px 20px 26px; background: var(--card); border: 1.5px solid var(--ink); border-radius: 18px; }
.flow li:not(:last-child)::after { content: ""; position: absolute; left: 100%; top: 43px; width: 18px; border-top: 2px dotted var(--ink); }
.flow .n { display: grid; place-items: center; width: 40px; height: 40px; border-radius: 50%; background: var(--ink); color: var(--paper); font: 600 18px/1 var(--serif); box-shadow: 3px 3px 0 var(--y); }
.flow h3 { font: 600 21px/1.2 var(--serif); margin-top: 16px; }
.flow p { margin-top: 6px; color: var(--ink-2); font-size: 15.5px; }

/* real pages, fanned out as sheets of paper */
/* A look inside: more real pictures of a system, two to a row. Each is a link to the picture itself at full size.
   It lifts out of register under the pointer, as a button does. */
section.inside { padding-top: clamp(26px, 3.4vw, 48px); }
.looks { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 42px 30px; }
.looks figure { min-width: 0; }
.looks a { display: block; border: 1.5px solid var(--ink); border-radius: 12px; overflow: hidden; background: var(--ink); box-shadow: 0 0 0 var(--m), 0 0 0 var(--c); transition: transform 0.25s var(--ease), box-shadow 0.25s var(--ease); }
.looks a:hover, .looks a:focus-visible { transform: translate(-4px, -4px); box-shadow: 4px 4px 0 var(--m), 8px 8px 0 var(--c); }
.looks img { width: 100%; }
.looks figcaption { display: grid; gap: 4px; margin-top: 14px; font-size: 15.5px; line-height: 1.45; color: var(--ink-2); }
.looks figcaption b { font: 600 12px/1.3 var(--mono); letter-spacing: 0.12em; text-transform: uppercase; color: var(--ink); }
.sheets { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 30px; padding: 10px 3% 0; }
.sheets figure { position: relative; transition: transform 0.5s var(--ease); }
.sheets figure:nth-child(1) { rotate: -3.5deg; translate: 5% 2%; }
.sheets figure:nth-child(2) { translate: 0 -3%; z-index: 1; }
.sheets figure:nth-child(3) { rotate: 3.5deg; translate: -5% 2%; }
.sheets figure:hover { transform: translateY(-14px) scale(1.035); z-index: 2; }
.sheets img { width: 100%; background: #fff; border: 1px solid var(--rule); box-shadow: 0 1px 0 rgba(20, 18, 14, 0.2), 0 24px 40px -22px rgba(20, 18, 14, 0.6); }
.sheets figcaption { margin-top: 14px; font: 600 12px/1 var(--mono); letter-spacing: 0.12em; text-transform: uppercase; color: var(--ink-3); text-align: center; }

/* a moving line of the kinds of puzzle (they are all listed, standing still, further down) */
.ticker { overflow: hidden; margin-top: clamp(50px, 7vw, 90px); padding: 20px 0 22px; display: grid; gap: 8px; background: var(--y); border-top: 1.5px solid var(--ink); border-bottom: 1.5px solid var(--ink); }
.ticker .track { display: flex; width: max-content; }
.ticker span { display: inline-flex; align-items: center; white-space: nowrap; font: italic 500 clamp(24px, 3.2vw, 42px)/1.15 var(--serif); letter-spacing: -0.015em; }
.ticker span::after { content: ""; width: 0.36em; height: 0.36em; margin: 0 0.62em; border-radius: 50%; border: 2px solid var(--ink); }
.ticker .track:nth-child(2) span { font-style: normal; color: transparent; -webkit-text-stroke: 1.3px var(--ink); }
.ticker .track:nth-child(2) span::after { background: var(--ink); }

h3.who { font: 600 26px/1.2 var(--serif); margin: 38px 0 16px; padding-top: 18px; border-top: 2px solid var(--ink); }
.kindlist { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 26px 30px; }
.kindlist ul { list-style: none; padding: 0; margin-top: 9px; font-size: 15.5px; color: var(--ink-2); }
.kindlist li { padding: 4px 0; border-bottom: 1px dotted var(--rule); }
.aside { margin-top: 24px; color: var(--ink-2); max-width: 46em; }
.getone { margin-top: 44px; padding: 28px 30px; background: var(--card); border: 1.5px solid var(--ink); border-radius: 22px; max-width: 660px; box-shadow: 7px 7px 0 var(--y); }
.getone h2 { font: 600 28px/1.2 var(--serif); }
.getone p { margin-top: 10px; color: var(--ink-2); }
.plainlist { list-style: none; padding: 0; border-top: 2px solid var(--ink); max-width: 860px; }
.plainlist li { padding: 17px 0 17px 40px; border-bottom: 1px solid var(--rule); position: relative; font-size: 18px; }
.plainlist li::before { content: ""; position: absolute; left: 2px; top: 19px; width: 23px; height: 23px; border-radius: 50%; background: linear-gradient(var(--paper), var(--paper)) 50% 50% / 11px 2px no-repeat, linear-gradient(var(--paper), var(--paper)) 50% 50% / 2px 11px no-repeat, var(--ink); rotate: 45deg; }
h2.qgroup { font: 600 13px/1.4 var(--mono); letter-spacing: 0.14em; text-transform: uppercase; color: var(--ink-3); margin: 38px 0 10px; }
h2.qgroup:first-child { margin-top: 0; }

/* --------------------------------------------------------------- narrow -- */
@media (max-width: 1240px) { .proof { margin-left: -24px; margin-right: -24px; } .sys-shot .proof { margin: 0; } }   /* no wider than the page's own gutter, or it spills */
@media (max-width: 900px) {
  body { font-size: 16.5px; }
  .mast { position: static; }
  .top { flex-wrap: wrap; row-gap: 6px; }
  .top nav { gap: 4px 20px; flex-wrap: wrap; }
  .hero-grid { grid-template-columns: minmax(0, 1fr); gap: 16px; }
  .stage { padding-top: 34px; }
  .stage .inks { inset: 0 -4% -8% -4%; }
  .deck { aspect-ratio: 1.02; }
  .deck li:nth-child(1) { width: 90%; } .deck li:nth-child(2) { width: 76%; } .deck li:nth-child(3) { width: 50%; top: 4%; }
  .pane, .deck li:nth-child(2) .pane, .win.ghost .pane { transform: rotateY(-12deg) rotateX(5deg) rotateZ(1deg); }
  .ink { --dot: 9px; }
  .sys-body { grid-template-columns: minmax(0, 1fr); }
  .sys-say { border-right: 0; border-bottom: 1px solid var(--rule); }
  .steps { grid-template-columns: minmax(0, 1fr); gap: 16px; }
  .steps li:not(:last-child)::after, .flow li:not(:last-child)::after { left: 46px; top: 100%; width: 0; height: 16px; border-top: 0; border-left: 2px dotted var(--ink); }
  .facts { grid-template-columns: minmax(0, 1fr); }
  .needs { grid-template-columns: minmax(0, 1fr); }
  .proof { --pm: 14px; --pt: 10px; margin-left: 0; margin-right: 0; margin-top: 34px; }
  .proof::before, .proof::after, .proof figcaption { display: none; }
  .sheet { border-radius: 6px; }
  .sys-head, .sys-say, .points, .sys-shot { padding-left: 20px; padding-right: 20px; }
  .system .numeral { right: 20px; }
  .more { grid-template-columns: minmax(0, 1fr); padding: 22px 20px; } .more p { grid-column: 1; }
  .flow.n3, .flow.n4, .flow.n5 { grid-template-columns: minmax(0, 1fr); gap: 16px; }
  .flow li { display: grid; grid-template-columns: 40px 1fr; column-gap: 16px; padding: 18px 18px 20px; }
  .flow h3 { margin-top: 7px; } .flow p { grid-column: 2; }
  .card .points { grid-template-columns: minmax(0, 1fr); }
  .card .points li:nth-last-child(2):nth-child(odd) { border-bottom: 1px solid var(--rule); }
  .two { grid-template-columns: minmax(0, 1fr); gap: 26px; }
  .looks { grid-template-columns: minmax(0, 1fr); gap: 30px; }
  .sheets { grid-template-columns: minmax(0, 1fr); max-width: 400px; margin: 0 auto; gap: 34px; padding: 0 6%; }
  .sheets figure:nth-child(1) { rotate: -2deg; translate: 0 0; } .sheets figure:nth-child(2) { rotate: 1.5deg; translate: 0 0; } .sheets figure:nth-child(3) { rotate: -1.5deg; translate: 0 0; }
  .page-hero .inks { right: -18%; top: -8%; width: 74%; }
  .page-hero .ink { opacity: 0.6; }
  .night .ink { width: 62%; }
}
@media (max-width: 520px) {
  .bar { gap: 7px; padding-left: 10px; padding-right: 10px; } .bar .n { display: none; } .bar .state { font-size: 8.5px; }
  .foot { font-size: 11.5px; padding-left: 10px; padding-right: 10px; }
  .blank { padding: 9px 9px 0; gap: 7px; } .blank b { font-size: 14px; max-width: 5.4em; } .blank .state { font-size: 8.5px; }
  .chapters li { font-size: 0; }   /* the tiles stay; their tiny words would not fit */
  .brand { font-size: 17px; }
  .hero h1 { font-size: clamp(40px, 12.4vw, 56px); }
  .page-hero h1 { font-size: clamp(42px, 13vw, 60px); }
  .outs ul { gap: 7px; } .outs li { padding-left: 9px; padding-right: 8px; }
}

/* ------------------------------------------------------------- movement -- */
/* Only for people who have not asked for less of it. */
@media (prefers-reduced-motion: no-preference) {
  /* arriving: the plates come into register, the inks settle, the windows fly in and then hang in the air */
  @keyframes register { from { text-shadow: -0.055em 0.03em 0 var(--c), 0.05em -0.034em 0 var(--m), 0.014em 0.056em 0 var(--y); } to { text-shadow: 0 0 0 rgba(0, 167, 230, 0), 0 0 0 rgba(238, 27, 140, 0), 0 0 0 rgba(255, 230, 0, 0); } }
  @keyframes arrive { from { opacity: 0; translate: 0 26px; } }
  @keyframes swipe { from { background-size: 0% 100%; } }
  @keyframes fly-in { from { opacity: 0; translate: 70px 34px; } }
  @keyframes hang { from { translate: 0 -5px; } to { translate: 0 6px; } }
  @keyframes drift-c { from { translate: -16% 10%; } to { translate: 5% -3%; } }
  @keyframes drift-m { from { translate: 15% -9%; } to { translate: -6% 5%; } }
  @keyframes drift-y { from { translate: -4% 17%; } to { translate: 4% -7%; } }
  @keyframes writing { from { scale: 0 1; } to { scale: 1 1; } }
  @keyframes tick { to { translate: -50% 0; } }

  .hero h1, .page-hero h1 { animation: register 1.2s var(--ease) 0.1s both; }
  .hero h1 em { animation: swipe 0.9s var(--ease) 0.75s both; }
  .hero .label, .page-hero .ph-say > .label { animation: arrive 0.8s var(--ease) both; }
  .hero .lede, .page-hero .lede { animation: arrive 0.9s var(--ease) 0.25s both; }
  .hero .cta, .hero .fine, .page-hero .cta, .page-hero .fine, .page-hero .sys-note { animation: arrive 0.9s var(--ease) 0.4s both; }
  .deck .win { animation: fly-in 0.9s var(--ease) both; }
  .deck li:nth-child(1) .win { animation-delay: 0.45s; } .deck li:nth-child(2) .win { animation-delay: 0.3s; } .deck li:nth-child(3) .win { animation-delay: 0.15s; }
  .deck li { animation: hang 6s ease-in-out infinite alternate; }
  .deck li:nth-child(2) { animation-duration: 7.5s; animation-delay: -3s; } .deck li:nth-child(3) { animation-duration: 9s; animation-delay: -5s; }
  .ink.c { animation: drift-c 15s ease-in-out infinite alternate; } .ink.m { animation: drift-m 19s ease-in-out infinite alternate; } .ink.y { animation: drift-y 23s ease-in-out infinite alternate; }
  .chapters li.now::before { animation: writing 2.6s linear infinite; }
  .ticker .track { animation: tick 95s linear infinite; }
  .ticker .track:nth-child(2) { animation-duration: 125s; animation-direction: reverse; }
  .ticker:hover .track { animation-play-state: paused; }

  /* scrolling: tied to how far the page has moved, not to a clock */
  @supports (animation-timeline: view()) {
    @keyframes rise { from { opacity: 0; translate: 0 54px; } }
    @keyframes settle { from { transform: rotateX(17deg) scale(0.92); } to { transform: none; } }
    @keyframes sheen { to { translate: 250% 0; } }
    @keyframes ribbon { from { translate: 0 -100%; } to { translate: 0 -34%; } }
    @keyframes numeral { from { translate: 0 0.5em; opacity: 0; } }
    @keyframes fan-l { from { rotate: 0deg; translate: 96% 3%; } }
    @keyframes fan-r { from { rotate: 0deg; translate: -96% 3%; } }

    /* a ribbon bookmark that comes down the side as the page is read */
    body::after { content: ""; position: fixed; z-index: 19; top: 0; right: calc(50vw - var(--wide) / 2 - 44px); width: 12px; height: 100vh; background: var(--m); clip-path: polygon(0 0, 100% 0, 100% 100%, 50% calc(100% - 9px), 0 100%); pointer-events: none; animation: ribbon linear both; animation-timeline: scroll(root block); }

    .head h2, .close h2 { animation: register linear both; animation-timeline: view(); animation-range: entry 10% cover 34%; }
    .head, .system, .more, .steps li, .flow li, .need, .fact, .qa details, .card, .getone, .kindlist > div, .plainlist li, h3.who, .two > div, .legal article { animation: rise linear both; animation-timeline: view(); animation-range: cover 0% cover 20%; }
    .steps li:nth-child(2), .flow li:nth-child(2), .fact:nth-child(3n + 2), .need:nth-child(2) { animation-range: cover 3% cover 23%; }
    .steps li:nth-child(3), .flow li:nth-child(3), .fact:nth-child(3n) { animation-range: cover 6% cover 26%; }
    .flow li:nth-child(4) { animation-range: cover 9% cover 29%; } .flow li:nth-child(5) { animation-range: cover 12% cover 32%; }
    .system .numeral { animation: numeral linear both; animation-timeline: view(); animation-range: cover 0% cover 26%; }
    .proof .sheet { animation: settle linear both; animation-timeline: view(); animation-range: entry 0% cover 40%; }
    .sheet::after { animation: sheen linear both; animation-timeline: view(); animation-range: entry 30% cover 62%; }
    .sheets figure:nth-child(1) { animation: fan-l linear both; animation-timeline: view(); animation-range: entry 0% cover 36%; }
    .sheets figure:nth-child(3) { animation: fan-r linear both; animation-timeline: view(); animation-range: entry 0% cover 36%; }
    /* where there is no margin to hang it in, it would lie over the words: no ribbon there */
    @media (max-width: 1280px) { body::after { display: none; } }
  }
}
@media (prefers-reduced-motion: no-preference) and (max-width: 900px) {
  @supports (animation-timeline: view()) { .sheets figure:nth-child(1), .sheets figure:nth-child(3) { animation: none; } }
}
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }

/* ----------------------------------------------------- from page to page -- */
/* A browser that can keeps the old page as a picture for a moment, so it can
 * be turned like a leaf while the new one waits under it; and it carries a
 * system's window from the front page into the big picture on its own page
 * (and back). One that cannot just changes page. Nothing is sent or kept. */
@view-transition { navigation: auto; }
.win.ai-writer, .sheet.shot-ai-writer { view-transition-name: shot-ai-writer; }
.win.puzzle-press, .sheet.shot-puzzle-press { view-transition-name: shot-puzzle-press; }
/* leaving the front page: only the window whose page is being opened travels. The link just pressed has the focus,
 * so any other window gives up its name and stays on the leaf, turning with it. */
body:has(a:focus:not([href^="ai-writer"])) .win.ai-writer, body:has(a:focus:not([href^="puzzle-press"])) .win.puzzle-press { view-transition-name: none; }
@media (prefers-reduced-motion: no-preference) {
  @keyframes leaf-out { to { transform: perspective(3000px) rotateY(-97deg); filter: brightness(0.5); } }
  @keyframes leaf-under { from { filter: brightness(0.62); } }
  @keyframes put-away { to { opacity: 0; } }
  ::view-transition-old(root), ::view-transition-new(root) { mix-blend-mode: normal; }
  ::view-transition-old(root) { z-index: 1; transform-origin: 0 50%; animation: 0.66s cubic-bezier(0.6, 0.04, 0.3, 1) both leaf-out; }
  ::view-transition-new(root) { animation: 0.66s ease-out both leaf-under; }
  ::view-transition-group(shot-ai-writer), ::view-transition-group(shot-puzzle-press) { animation-duration: 0.66s; animation-timing-function: cubic-bezier(0.3, 0.9, 0.3, 1); }
  /* a picture with nowhere to go on the next page is put away at once, not left hanging over the turning leaf */
  ::view-transition-old(shot-ai-writer):only-child, ::view-transition-old(shot-puzzle-press):only-child { animation: 0.1s linear both put-away; }
}
@media (prefers-reduced-motion: reduce) { ::view-transition-group(*), ::view-transition-old(*), ::view-transition-new(*) { animation: none !important; } }

/* ------------------------------------------------------------ the rainbow -- */
/* The front page (featured.html, since 2026-10-13) has a look of its own: src/featured.css, the rainbow. The
 * other pages keep the press sheet, and wear the rainbow as one fine line under the bar at the top, so that a
 * visitor who comes across from the front page is still on the same site. Drawn once; it never moves. */
.mast::after { content: ""; position: absolute; left: 0; right: 0; top: 100%; height: 4px; background: linear-gradient(90deg, #ff5a4f, #ff9838, #ffd83d, #4fcf86, #33c6dd, #5b8dff, #a47bff, #ff7ac3); }
/* a page whose top is followed at once by a dark part (software.html): room for the band of dots between them */
.page-hero:has(+ .night) { padding-bottom: clamp(84px, 10vw, 140px); }

/* Book Publishing Systems — ONE LOOK (2026-10-13). build.js puts this file after style.css, in the same
 * stylesheet, so every page that is not the front page wears the front page's look.
 *
 * WHY: the front page (featured.html, src/featured.css) became a rainbow on 2026-10-13, and the pages behind it
 * were still the press sheet: another typeface, another bar at the top, other buttons, other colours. A visitor
 * who pressed "Other software" seemed to have left the site. Found when the whole site was audited that day.
 *
 * WHAT IT CHANGES, and nothing else: the typefaces (Bricolage Grotesque, our own files, the same three the front
 * page asks for, so a visitor who came by the front page already has them), the paper and the inks, the bar at
 * the top, the buttons, the glow in place of the three discs of halftone dots, a rainbow line in place of the
 * bands of dots, and the foot of the page. What a page SAYS and what it is made of (the cards, the app's
 * pictures on their sheet, the steps) is style.css's, untouched.
 *
 * TO GO BACK to the press sheet on these pages: set ONE_LOOK to false in build.js. This file is then left out,
 * and build.js puts the discs, the bands of dots and the big name over the foot back.
 *
 * THE RULES are style.css's own: no data: address, nothing from another site, and a page standing still does no
 * work (what moves on a loop only turns, scales, slides or fades). Measured with tools/measure-speed.js. */

@font-face { font-family: "Bricolage Grotesque"; font-weight: 400; font-display: swap; src: url(fonts/BricolageGrotesque-Regular.0b5a929eac.ttf) format("truetype"); }
@font-face { font-family: "Bricolage Grotesque"; font-weight: 600; font-display: swap; src: url(fonts/BricolageGrotesque-SemiBold.e9bcaab249.ttf) format("truetype"); }
@font-face { font-family: "Bricolage Head"; font-weight: 800; font-display: swap; src: url(fonts/BricolageGrotesque-CondensedExtraBold.6be56005b9.ttf) format("truetype"); }
/* while a typeface is on its way: the computer's own Arial, scaled to take the same room (featured.css says how
 * these were measured), so nothing moves when it arrives */
@font-face { font-family: "Bricolage Stand-in"; font-weight: 400; src: local("Arial"), local("ArialMT"); size-adjust: 104.3%; }
@font-face { font-family: "Bricolage Stand-in"; font-weight: 600; src: local("Arial Bold"), local("Arial-BoldMT"); size-adjust: 100.1%; }
@font-face { font-family: "Bricolage Head Stand-in"; font-weight: 800; src: local("Arial Bold"), local("Arial-BoldMT"); size-adjust: 75%; }

:root {
  --paper: #f4f0e8; --band: #ebe6db; --card: #fffdf8; --sheet: #fffefb;
  --ink: #1c1a17; --ink-2: #4d483f; --ink-3: #625b51;
  --night: #15130f; --on-night: #f4f0e8; --on-night-2: #b9b2a4;
  /* the front page's eight inks. The three names the press sheet used now mean three of them. */
  --r: #ff5a4f; --o: #ff9838; --y: #ffd83d; --g: #4fcf86; --t: #33c6dd; --b: #5b8dff; --v: #a47bff; --p: #ff7ac3;
  --c: var(--b); --m: var(--p);
  --bow: linear-gradient(90deg, var(--r), var(--o), var(--y), var(--g), var(--t), var(--b), var(--v), var(--p));
  --sans: "Bricolage Grotesque", "Bricolage Stand-in", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --head: "Bricolage Head", "Bricolage Head Stand-in", "Bricolage Grotesque", "Arial Narrow", system-ui, sans-serif;
  --serif: var(--head);   /* every heading style.css sets in its serif is set in the front page's heading face */
  --wide: 1220px;
  color-scheme: light;
}
html { scroll-padding-top: 86px; }
@supports not (overflow: clip) { body { overflow-x: hidden; } }
body { background: var(--paper); font: 400 17.5px/1.55 var(--sans); }   /* plain paper, as the front page's is */
a { text-decoration-color: currentColor; text-decoration-thickness: 1.5px; }
:focus-visible { outline-color: var(--b); border-radius: 6px; }
.label { font-size: 13px; letter-spacing: 0.12em; }

/* the bar across the very top: the rainbow, filled as far as the page has been read */
.read { position: fixed; inset: 0 0 auto 0; height: 5px; z-index: 50; background: var(--bow); transform-origin: 0 50%; pointer-events: none; }
@keyframes read { from { transform: scaleX(0); } to { transform: scaleX(1); } }

/* ---------------------------------------------------------------- the top -- */
.mast { background: var(--paper); -webkit-backdrop-filter: none; backdrop-filter: none; border-bottom: 1.5px solid var(--ink); }
.mast::after { content: none; }
.top { gap: 16px; padding-top: 10px; padding-bottom: 10px; }
.brand { gap: 10px; padding: 7px 0; font: 800 22px/1 var(--head); letter-spacing: 0.005em; white-space: nowrap; }
.brand svg { width: 28px; height: 28px; transition: none; }
.brand:hover svg { rotate: none; }
.top nav { gap: 2px; font-size: 16.5px; font-weight: 600; }
.top nav a:not(.btn) { color: var(--ink); padding: 9px 12px; border-radius: 8px; white-space: nowrap; background: none; transition: none; }
.top nav a:not(.btn):hover { background: var(--y); }
/* the page you are on: a short rainbow under its name */
.top nav a[aria-current="page"], .top nav a[aria-current="page"]:hover { font-weight: 600; background: var(--bow) no-repeat 12px calc(100% - 3px) / calc(100% - 24px) 4px; }

/* Puzzle Press's own black button. The one a page most wants pressed stands on a rainbow that slides along under it
 * (not the one in the bar at the top: see src/featured.css). */
.btn { position: relative; display: inline-flex; align-items: center; gap: 9px; white-space: nowrap; font: 600 18px/1 var(--sans); padding: 17px 24px; border-radius: 10px; box-shadow: none; transition: translate 0.2s var(--ease), background-color 0.2s; }
.btn:hover, .btn.line:hover, .night .btn.line:hover, .night .system .btn.line:hover { transform: none; box-shadow: none; translate: 0 -3px; }
.btn:active { translate: 0 0; }
.btn.small { padding: 13px 17px; font-size: 16.5px; border-radius: 10px; }
.mast .btn.small { margin-left: 10px; }
/* The rainbow: a block the button's own size and shape, 5px down and 5px to the right, like a hard shadow (it was a
 * strip under the button, a little to one side, and looked as if it had slipped). It lies over the button and is cut
 * away where the button is, so nothing has to be put behind anything: what shows is the bottom edge, the right edge
 * and the corner between them. (3.5 and -6.5: measured from inside the button's 1.5px border.) A browser that cannot
 * cut it gets a line the button's own width under it instead, and the words are never covered. */
.bow { position: absolute; left: 0; right: 0; top: calc(100% + 4px); height: 6px; overflow: hidden; border-radius: 99px; pointer-events: none; }
@supports (mask: linear-gradient(#000 0 0) right / 5px 100% no-repeat) or (-webkit-mask: linear-gradient(#000 0 0) right / 5px 100% no-repeat) {
  .bow { inset: 3.5px -6.5px -6.5px 3.5px; height: auto; border-radius: 10px;
    --cut: linear-gradient(#000 0 0) right / 5px 100% no-repeat, linear-gradient(#000 0 0) bottom / 100% 5px no-repeat, radial-gradient(circle at 0 0, transparent 9.5px, #000 10px) calc(100% - 5px) calc(100% - 5px) / 10px 10px no-repeat;
    -webkit-mask: var(--cut); mask: var(--cut); }
}
.bow::before { content: ""; position: absolute; inset: 0 auto 0 0; width: 200%;
  background: linear-gradient(90deg, var(--r) 0, var(--o) 6.25%, var(--y) 12.5%, var(--g) 18.75%, var(--t) 25%, var(--b) 31.25%, var(--v) 37.5%, var(--p) 43.75%, var(--r) 50%, var(--o) 56.25%, var(--y) 62.5%, var(--g) 68.75%, var(--t) 75%, var(--b) 81.25%, var(--v) 87.5%, var(--p) 93.75%, var(--r) 100%); }
@keyframes slide { to { transform: translateX(-50%); } }
.cta { padding-bottom: 10px; }   /* room for the rainbow under a button */

/* --------------------------------------------------------------- the glow -- */
/* The front page's glow, in place of the three discs of dots: two wheels of the eight inks, blurred, turning
 * opposite ways. ONE animation to a disc and none on what holds them (featured.css says what it cost when the
 * holder moved too). At the top of a page it sits in the corner, clear of the words; in a dark closing part it
 * lies along the foot, as it does at the end of the front page.
 * It stands in a box of its own (.aura) that is the size of the part it belongs to, and is cut off at that box's
 * edge. At the top of a page the box runs out to the side of the window, and the paper comes back up over the
 * foot of it, so the glow fades away before the part ends and never lies under what the page says next. */
.aura { position: absolute; inset: 0; overflow: hidden; pointer-events: none; }
.glow { position: absolute; left: 50%; top: 50%; width: 172%; aspect-ratio: 1; translate: -50% -50%; pointer-events: none; }
.glow::before, .glow::after { content: ""; position: absolute; border-radius: 50%; filter: blur(46px);
  -webkit-mask-image: radial-gradient(closest-side, #000 46%, transparent 97%); mask-image: radial-gradient(closest-side, #000 46%, transparent 97%); }
.glow::before { inset: 0; opacity: 0.9; background: conic-gradient(var(--r), var(--o), var(--y), var(--g), var(--t), var(--b), var(--v), var(--p), var(--r)); }
.glow::after { inset: 17%; opacity: 0.8; background: conic-gradient(from 200deg, var(--b), var(--p), var(--y), var(--t), var(--r), var(--v), var(--g), var(--o), var(--b)); }
@keyframes turn-a { 0% { transform: rotate(0deg) scale(1); opacity: 0.9; } 50% { transform: rotate(180deg) scale(1.1); opacity: 0.74; } 100% { transform: rotate(360deg) scale(1); opacity: 0.9; } }
@keyframes turn-b { 0% { transform: rotate(0deg) scale(1.08); opacity: 0.66; } 50% { transform: rotate(-180deg) scale(1); opacity: 0.82; } 100% { transform: rotate(-360deg) scale(1.08); opacity: 0.66; } }

.page-hero { overflow: visible; overflow-x: clip; padding: clamp(30px, 5vw, 62px) 0 14px; }
.page-hero .aura { top: calc(-1 * clamp(30px, 5vw, 62px)); bottom: -14px; right: calc(50% - 50vw); }   /* the whole part, and out to the window's right-hand side */
.page-hero .aura::after { content: ""; position: absolute; inset: 38% 0 0 0; background: linear-gradient(rgba(244, 240, 232, 0), var(--paper) 94%); }
.page-hero .glow { left: min(50vw, 610px); top: 0; width: min(54vw, 656px); translate: 0 -28%; }
.page-hero:has(+ .night) { padding-bottom: clamp(44px, 6vw, 84px); }
.page-hero:has(+ .night) .aura { bottom: calc(-1 * clamp(44px, 6vw, 84px)); }
.close { overflow: clip; padding-bottom: clamp(230px, 27vw, 340px); }
.close .glow { top: auto; bottom: 0; width: min(1240px, 150%); translate: -50% 50%; }

/* ------------------------------------------------------------ the headings -- */
.hero .label::before, .page-hero .ph-say > .label::before, .head .label::before { content: ""; display: inline-block; flex: none; width: 46px; height: 10px; margin-right: 11px; vertical-align: 0; border-radius: 99px; background: var(--bow); }
.page-hero .ph-say > .label::before { margin-right: 1px; }
.head .label .mark { display: none; }   /* the register mark belonged to the press sheet */
.page-hero h1 { margin-top: 16px; font: 800 clamp(48px, 7.4vw, 108px)/0.9 var(--head); letter-spacing: -0.012em; }
.page-hero .lede { margin-top: 24px; font-size: clamp(18px, 1.55vw, 20.5px); line-height: 1.5; }
.head h2 { font: 800 clamp(40px, 5.5vw, 78px)/0.94 var(--head); letter-spacing: -0.01em; }
.head p:not(.label) { font-size: 19px; }
.close h2 { font: 800 clamp(40px, 6vw, 86px)/0.94 var(--head); letter-spacing: -0.01em; }
.close p { font-size: 19px; }
.close p.label { font-size: 13px; }
.sys-head h3 { font: 800 clamp(32px, 3.5vw, 46px)/1 var(--head); letter-spacing: 0; }
.sys-say .tagline { font: 800 clamp(27px, 2.9vw, 36px)/1.04 var(--head); letter-spacing: 0; }
.more h3 { font: 800 28px/1.1 var(--head); }
.steps h3, .flow h3 { font: 800 27px/1.08 var(--head); }
.need h3, .fact h3 { font: 800 25px/1.12 var(--head); }
.qa summary { font: 800 25px/1.15 var(--head); }
h3.who, .getone h2 { font: 800 30px/1.1 var(--head); }
.legal h2 { font: 800 28px/1.1 var(--head); letter-spacing: 0; }
.flow .n { font: 600 18px/1 var(--sans); }
.blank b { font: 800 19px/1.05 var(--head); letter-spacing: 0; }
.system .numeral, .steps .n, .close .huge { letter-spacing: -0.01em; }

/* --------------------------------------------------- where paper turns dark -- */
/* a rainbow line, as on the front page, where the press sheet had a band of dots */
section.night::before, footer::before { content: ""; position: absolute; inset: 0 0 auto 0; height: 8px; background: var(--bow); }
.night + .night::before, main > .night:first-child::before { content: none; }
.sys-shot { background: var(--paper); }

/* ------------------------------------------------------------- the foot -- */
footer { position: relative; padding: 50px 0 40px; font-size: inherit; }
footer .row { gap: 18px 24px; }
footer nav { gap: 0 6px; margin: 0 -8px; font-size: 16px; }
footer nav a { padding: 10px 8px; color: var(--on-night-2); }   /* room for a finger */
footer nav a:hover { color: var(--on-night); text-decoration: underline; text-decoration-color: currentColor; }
footer .legal { max-width: 72em; margin-top: 26px; font-size: 13.5px; line-height: 1.5; color: var(--on-night-2); }
footer .legal a { display: inline-block; padding: 8px 0; }

/* two buttons side by side in a system's card, as they were */
.sys-cta .btn { padding: 15px 17px; font-size: 16.5px; }

/* -------------------------------------------------------------- what moves -- */
/* A heading no longer arrives with its three plates out of line (that was the press sheet's, and at the foot of a
 * tall window a heading could be left standing with its colours still apart). */
.page-hero h1, .head h2, .close h2 { animation: none; }
@media (prefers-reduced-motion: no-preference) {
  .bow::before { animation: slide 7s linear infinite; }
  .glow::before { animation: turn-a 28s linear infinite; }
  .glow::after { animation: turn-b 19s linear infinite; }
  @supports (animation-timeline: view()) {
    .read { animation: read linear both; animation-timeline: scroll(root); }
    body::after { content: none; }   /* the bar at the top says how far the page has been read: no ribbon down the side as well */
  }
}

/* --------------------------------------------------------- narrower windows -- */
/* THE GLOW STAYS CLEAR OF THE WORDS. In a narrower window the words run further across the top of a page, so the
 * glow is made smaller and kept up in the corner: its bright part never lies under the paragraph, whose ink is
 * the quieter one (looked at 1000, 760, 390 and 320 wide). */
@media (max-width: 1200px) {
  .page-hero .glow { left: 64vw; width: min(44vw, 470px); translate: 0 -34%; }
}
@media (max-width: 900px) {
  body { font-size: 17px; }
  .mast { position: sticky; }
  .top { flex-wrap: nowrap; }
  .top nav { flex-wrap: nowrap; gap: 2px; }
  .page-hero .glow { left: auto; right: -16.5vw; width: min(78vw, 380px); translate: 0 -40%; }
  .close .glow { width: 150%; }
}
/* the same bar as the front page's on a phone: the name and Sign in. The other pages are a press away at the foot
 * of every page, and the name leads to the front page. (A bar with every page on it has more than fits: there it
 * runs on to a second line, and does not stay at the top of the window.) */
@media (max-width: 1000px) {
  .mast:has(nav a:nth-of-type(6)) { position: static; }
  .mast:has(nav a:nth-of-type(6)) .top, .mast:has(nav a:nth-of-type(6)) .top nav { flex-wrap: wrap; }
}
@media (max-width: 760px) {
  .top nav a:not(.btn) { display: none; }
  .mast:has(nav a:nth-of-type(6)) { position: sticky; }
}
@media (max-width: 560px) {
  .wrap { padding: 0 17px; }
  .brand { font-size: 20px; }
  .btn { padding: 16px 20px; }
  .btn.small { padding: 13px 15px; font-size: 15.5px; }
  .top { padding-top: 8px; padding-bottom: 8px; }
  .page-hero h1 { font-size: clamp(46px, 14.5vw, 64px); }
}

/* the narrowest phones (320 wide): the name and Sign in still fit on one line, so the page never slides sideways */
@media (max-width: 350px) {
  .top { gap: 8px; }
  .brand { gap: 8px; font-size: 17px; }
  .brand svg { width: 24px; height: 24px; }
  .mast .btn.small { margin-left: 0; padding: 12px 12px; font-size: 15px; }
}

@media print {
  .read, .glow, .bow, .mast nav { display: none !important; }
  .mast { position: static; }
}