/* The guide is a scrolling document, so it can't share style.css: that
   file puts display:flex, height:100vh, and overflow:hidden on body for
   the app's fixed, non-scrolling viewport. What it borrows instead is the
   token block below, copied from style.css's :root so the pages read
   as one site. Only the tokens this page actually uses are copied, which
   keeps the drift surface small; if a value changes there, change it here
   too. Same rule as the app: dark is the default regardless of the
   system setting, and light applies only when the toggle has written
   data-theme="light" (see the blocking script in this page's head, which
   reads the same flield-theme key the app writes). */
:root {
  color-scheme: dark;
  --bg: #09090b;
  --well: #0f0f11;
  --panel: #18181b;
  --muted: #27272a;
  --border: rgba(255, 255, 255, 0.1);
  --border-strong: rgba(255, 255, 255, 0.18);
  --input: rgba(255, 255, 255, 0.05);
  --text: #fafafa;
  --text-muted: #a1a1aa;
  --text-subtle: #71717a;
  --primary: #e4e4e7;
  --radius-sm: 8px;
  --radius: 10px;
  --radius-lg: 14px;
  /* Shared by the header's padding and the contents menu's offset, so the
     menu keeps clearing the header's bottom border if this ever changes. */
  --header-pad-y: 14px;
}

:root[data-theme="light"] {
  color-scheme: light;
  --bg: #f4f4f5;
  --well: #fafafa;
  --panel: #ffffff;
  --muted: #f4f4f5;
  --border: #e4e4e7;
  --border-strong: #d4d4d8;
  --input: #ffffff;
  --text: #09090b;
  --text-muted: #71717a;
  --text-subtle: #a1a1aa;
  --primary: #18181b;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Inter, Roboto, sans-serif;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  background: var(--bg);
  color: var(--text);
  font-size: 17px;
  line-height: 1.65;
}

/* One column, capped at a comfortable measure. The app is edge to edge by
   necessity; prose shouldn't be. This width holds a line to roughly 70
   characters at the 17px base, the range prose is easiest to read in; it
   was 90 at the first pass, which is well past comfortable. */
.wrap {
  max-width: 640px;
  margin: 0 auto;
  padding: 0 24px 96px;
}

/* Site header: the wordmark returns to the app, which is the only
   navigation a document page needs. */
.site-header {
  border-bottom: 1px solid var(--border);
  background: var(--panel);
  position: sticky;
  top: 0;
  z-index: 10;
}

.site-header .wrap {
  /* Positioning context for the contents menu on narrow screens, where it
     spans the header's gutters instead of hanging off its button. */
  position: relative;
  padding: var(--header-pad-y) 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.wordmark {
  font-size: 18px;
  font-weight: 650;
  letter-spacing: -0.01em;
  color: var(--text);
  text-decoration: none;
}

.wordmark span {
  color: var(--text-subtle);
  font-weight: 500;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

/* Fixed height rather than padding alone: these are inline-flex, so a
   button holding a 16px icon sizes to the icon while a text-only one sizes
   to the 1.65 line-height it inherits from body, and the two come out
   several pixels apart. 32px and 0 12px are the app's own button metrics
   (see .controls button in style.css), so the pages match. */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  height: 32px;
  padding: 0 12px;
  font-size: 13px;
  font-weight: 500;
  font-family: inherit;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-strong);
  background: var(--input);
  color: var(--text);
  text-decoration: none;
  cursor: pointer;
  white-space: nowrap;
}

.btn:hover {
  background: var(--muted);
}

.btn-primary {
  background: var(--primary);
  border-color: var(--primary);
  color: var(--bg);
}

.btn-primary:hover {
  opacity: 0.9;
  background: var(--primary);
}

h1, h2, h3 {
  /* Short blocks, so even line lengths matter more than orphan avoidance. */
  text-wrap: balance;
}

/* The header is sticky, so an anchor jump would otherwise park the heading
   underneath it. Clears its height plus the h2 border and padding. */
h2[id], h3[id] {
  scroll-margin-top: 88px;
}

html {
  scroll-behavior: smooth;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  .nav-toc-caret {
    transition: none;
  }
}

h1 {
  font-size: clamp(30px, 5vw, 40px);
  line-height: 1.15;
  letter-spacing: -0.02em;
  margin: 56px 0 14px;
}

.lede {
  font-size: 18px;
  color: var(--text-muted);
  margin: 0 0 40px;
  text-wrap: balance;
}

h2 {
  font-size: 25px;
  letter-spacing: -0.015em;
  margin: 56px 0 14px;
  padding-top: 20px;
  border-top: 1px solid var(--border);
}

h3 {
  font-size: 18px;
  letter-spacing: -0.01em;
  margin: 34px 0 10px;
}

p, li, td {
  color: var(--text-muted);
  /* Keeps a line's last word from being left alone on a line of its own.
     Ignored by browsers that don't support it, which just wrap as before. */
  text-wrap: pretty;
}

p {
  margin: 0 0 16px;
}

strong {
  color: var(--text);
  font-weight: 600;
}

/* Secondary detail: an enumeration a reader scans rather than reads, set
   down a step so it doesn't compete with the paragraph it follows. */
.meta {
  font-size: 15px;
  color: var(--text-subtle);
}

a {
  color: var(--text);
  text-decoration-color: var(--text-subtle);
  text-underline-offset: 3px;
}

a:hover {
  text-decoration-color: var(--text);
}

ul, ol {
  padding-left: 22px;
  margin: 0 0 16px;
}

li {
  margin-bottom: 8px;
}

/* Contents popover. The header's .wrap is the positioning context, so the
   menu hangs off the button without any measuring in script. */
.nav-toc {
  position: relative;
}

.btn-icon {
  width: 32px;
  padding: 0;
}

.nav-toc-caret {
  opacity: 0.6;
  transition: transform 0.15s ease;
}

#tocBtn[aria-expanded="true"] .nav-toc-caret {
  transform: rotate(180deg);
}

.nav-toc-menu {
  position: absolute;
  top: calc(100% + var(--header-pad-y) + 8px);
  right: 0;
  z-index: 20;
  min-width: 264px;
  max-height: min(70vh, 460px);
  overflow-y: auto;
  padding: 6px;
  background: var(--panel);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius);
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.35);
}

.nav-toc-menu ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

.nav-toc-menu li {
  margin: 0;
}

.nav-toc-menu a {
  display: block;
  padding: 7px 10px;
  border-radius: var(--radius-sm);
  font-size: 14px;
  color: var(--text-muted);
  text-decoration: none;
}

.nav-toc-menu a:hover {
  background: var(--muted);
  color: var(--text);
}

/* Filled in by the scroll spy, so the menu says where you are as well as
   where you can go. */
.nav-toc-menu a[aria-current="true"] {
  background: var(--input);
  color: var(--text);
  font-weight: 550;
}

/* Below this the header runs out of room for four controls. GitHub is the
   one to drop: the page footer carries the same link.

   The menu also stops hanging off its button here. Anchored to the button,
   a menu wider than the button's distance from the right edge runs off the
   left of the screen; anchored to the header it spans gutter to gutter
   instead, which is also the easier tap target. */
@media (max-width: 600px) {
  .btn-github {
    display: none;
  }
  .nav-toc {
    position: static;
  }
  .nav-toc-menu {
    top: calc(100% + 8px);
    left: 24px;
    right: 24px;
    width: auto;
    min-width: 0;
  }
}

@media (max-width: 420px) {
  .nav-toc-label {
    display: none;
  }
}

/* Figures. Every image declares its intrinsic size in the markup, so the
   aspect-ratio box is reserved before the bytes arrive and nothing below
   jumps as they land. */
.shot {
  margin: 0 0 32px;
}

.shot img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--well);
}

.shot figcaption {
  margin-top: 10px;
  font-size: 14px;
  color: var(--text-subtle);
  text-wrap: pretty;
}

.shot figcaption strong {
  color: var(--text-muted);
}

/* Stacked rather than side by side: at this column width a three-up row
   would leave each clip near 190px across, too small to read the motion
   these are here to show. */
.shot-row {
  margin: 0 0 12px;
}

/* Tables carry a lot of this guide's comparisons, so they get the panel
   surface and a header that holds while the row list runs long. */
.table-scroll {
  overflow-x: auto;
  margin: 0 0 20px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

table {
  border-collapse: collapse;
  width: 100%;
  font-size: 14px;
  min-width: 420px;
}

th, td {
  text-align: left;
  padding: 10px 14px;
  border-bottom: 1px solid var(--border);
  color: var(--text-muted);
  vertical-align: top;
}

th {
  background: var(--well);
  color: var(--text);
  font-weight: 600;
  white-space: nowrap;
}

tr:last-child td {
  border-bottom: 0;
}

/* A control's on-screen name, matching the .ui-ref treatment the in-app
   tutorial uses for the same purpose. Where the real control carries an
   icon, the chip carries the same one, so a reader can match the sentence
   to the button without a screenshot for every reference. Inline-flex so
   icon and label sit on a shared baseline box; the em-based size keeps the
   glyph tied to the surrounding text rather than to a fixed pixel value. */
.ui-ref {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 1px 6px;
  border: 1px solid var(--border-strong);
  border-radius: 6px;
  background: var(--input);
  color: var(--text);
  font-size: 0.88em;
  font-weight: 500;
  white-space: nowrap;
  vertical-align: baseline;
}

.ui-ref-icon {
  width: 1.05em;
  height: 1.05em;
  flex-shrink: 0;
  opacity: 0.85;
}

/* The help button shows only its glyph, so its chip does too. */
.ui-ref-icon-only {
  padding: 2px 4px;
}

.note {
  border-left: 2px solid var(--border-strong);
  background: var(--well);
  border-radius: 0 var(--radius) var(--radius) 0;
  padding: 14px 18px;
  margin: 0 0 20px;
}

.note p:last-child {
  margin-bottom: 0;
}

/* 404. Centred in the viewport rather than sitting under the header like
   a document, since there is nothing to scroll. */
.notfound {
  min-height: calc(100vh - 200px);
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: flex-start;
  max-width: 30em;
}

.notfound-code {
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.12em;
  color: var(--text-subtle);
  margin: 0 0 8px;
}

.notfound h1 {
  margin: 0 0 14px;
}

.notfound-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 10px 0 28px;
}

.notfound code {
  font-size: 0.92em;
  padding: 1px 5px;
  border: 1px solid var(--border);
  border-radius: 5px;
  background: var(--input);
  color: var(--text-muted);
}

.site-footer {
  border-top: 1px solid var(--border);
  margin-top: 64px;
  padding-top: 24px;
  display: flex;
  flex-direction: column;
  gap: 14px;
  font-size: 13px;
  color: var(--text-subtle);
}

/* Two rows, the other pages above the site's own links. Someone who has
   reached the bottom of a page is looking for the next one to read, and
   in a single line those sat among GitHub and a personal site. */
.site-footer-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
}

.site-footer a {
  color: var(--text-subtle);
}

.site-footer a:hover {
  color: var(--text);
}

/* Matches the app: keep the keyboard ring consistent across every page. */
a:focus-visible,
button:focus-visible {
  outline: 2px solid var(--text-subtle);
  outline-offset: 2px;
  border-radius: 4px;
}

/* Demo furniture for the explainer pages (flow-fields, seamless-backgrounds),
   which run the real generator on the page rather than showing a screenshot.
   Lives here rather than in either page so the two can't drift apart, same
   reason the token block at the top of this file is copied once. */
  .demo {
    margin: 28px 0;
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    background: var(--panel);
    overflow: hidden;
  }

  .demo-canvases {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1px;
    background: var(--border);
  }

  @media (max-width: 520px) {
    .demo-canvases { grid-template-columns: 1fr; }
  }

  .demo-pane {
    background: var(--well);
    padding: 14px;
  }

  .demo-pane canvas {
    display: block;
    width: 100%;
    height: auto;
    border-radius: var(--radius-sm);
    /* The art is cell-based; smoothing it on upscale would blur exactly
       the edges the page is about. */
    image-rendering: pixelated;
  }

  .demo-label {
    margin: 0 0 10px;
    font-size: 13px;
    letter-spacing: 0.02em;
    text-transform: uppercase;
    color: var(--text-subtle);
  }

  .demo-controls {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 16px;
    padding: 14px;
    border-top: 1px solid var(--border);
  }

  .demo-control {
    display: flex;
    align-items: center;
    gap: 10px;
    flex: 1 1 200px;
  }

  .demo-control label {
    font-size: 14px;
    color: var(--text-muted);
    white-space: nowrap;
  }

  .demo-control input[type="range"] {
    flex: 1;
    accent-color: var(--text);
    min-width: 90px;
  }

  .demo-value {
    font-variant-numeric: tabular-nums;
    font-size: 14px;
    color: var(--text-subtle);
    min-width: 3.5em;
    text-align: right;
  }

  .demo-caption {
    margin: 0;
    padding: 14px;
    border-top: 1px solid var(--border);
    font-size: 15px;
    color: var(--text-muted);
  }

  pre {
    background: var(--well);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 16px;
    overflow-x: auto;
    font-size: 14px;
    line-height: 1.55;
  }

  code {
    font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
    font-size: 0.92em;
  }

  p > code, li > code {
    background: var(--input);
    border-radius: 4px;
    padding: 1px 5px;
  }