/* ─────────────────────────────────────────────────────────────────────────────
   RTI project page — retro-academic.
   Structure and typographic discipline of a paper page, with period accents:
   mono labels, hard 1px borders, filled chips, flat fills (no offset shadows),
   and a faint patch-grid ground.
   Series colours are the paper's (Google blue/red) plus a purple that passes
   the CVD + normal-vision checks against both surfaces; they are IDENTICAL in
   light and dark, which is why only the surfaces move below.
   ───────────────────────────────────────────────────────────────────────── */

:root {
  /* Google neutrals throughout: grey-50 ground, grey-900 ink, grey-300 hairlines */
  --bg:        #F8F9FA;   /* grey-50 */
  --surface:   #FFFFFF;
  --surface-2: #E8EAED;   /* grey-200 */
  --ink:       #202124;   /* grey-900 */
  --ink-2:     #3C4043;   /* grey-800 */
  --muted:     #5F6368;   /* grey-700 */
  --line:      #202124;   /* hard border, on every surface */
  --edge:      #202124;   /* the rules that divide the page */
  --rule:      #DADCE0;   /* grey-300 — hairline / grid */
  --tag-bg:    #202124;   /* filled chip */
  --tag-fg:    #F8F9FA;
  --grid:      rgba(32, 33, 36, 0.024);
  --accent:    #4285F4;   /* blue — ours */
  --accent-2:  #EA4335;   /* red — the competing reduction */
  --accent-3:  #9334E6;   /* purple — uniform grid (Google purple, stepped down
                             until it cleared the CVD + contrast checks) */
  --good:      #34A853;   /* green */
  --mono: "IBM Plex Mono", ui-monospace, "SF Mono", "DejaVu Sans Mono", Menlo, monospace;
  --serif: "IBM Plex Serif", Georgia, "Times New Roman", serif;
  --maxw: 1200px;
  /* one measure for running text: prose used to stop at 46–62em while the
     section rules ran the full container, so every block sat inset by a
     different amount. `none` = the container width itself. */
  --measure: none;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg:        #17181B;
    --surface:   #202124;   /* grey-900 */
    --surface-2: #292A2D;
    --ink:       #E8EAED;   /* grey-200 */
    --ink-2:     #BDC1C6;   /* grey-400 */
    --muted:     #9AA0A6;   /* grey-500 */
    --line:      #5F6368;   /* grey-700 */
    --edge:      #BDC1C6;
    --rule:      #3C4043;   /* grey-800 */
    --tag-bg:    #E8EAED;
    --tag-fg:    #202124;
    --grid:      rgba(232, 234, 237, 0.026);
  }
}
:root[data-theme="dark"] {
  --bg:        #17181B;
  --surface:   #202124;   /* grey-900 */
  --surface-2: #292A2D;
  --ink:       #E8EAED;   /* grey-200 */
  --ink-2:     #BDC1C6;   /* grey-400 */
  --muted:     #9AA0A6;   /* grey-500 */
  --line:      #5F6368;   /* grey-700 */
  --edge:      #BDC1C6;
  --rule:      #3C4043;   /* grey-800 */
  --tag-bg:    #E8EAED;
  --tag-fg:    #202124;
  --grid:      rgba(232, 234, 237, 0.026);
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background-color: var(--bg);
  /* graph paper: a 32x32 patch grid, the tokenisation the paper starts from */
  background-image:
    repeating-linear-gradient(0deg,  var(--grid) 0 1px, transparent 1px 32px),
    repeating-linear-gradient(90deg, var(--grid) 0 1px, transparent 1px 32px);
  color: var(--ink);
  font-family: var(--serif);
  font-size: 18.5px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

img, video { max-width: 100%; display: block; }
a { color: var(--ink); text-underline-offset: 3px; text-decoration-thickness: 1px; }
a:hover { color: var(--accent); }

.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 22px; }
/* every section runs at the same measure — the width used to step between
   1120 and 1300 from section to section, which read as a wobble down the page */
.wide { max-width: var(--maxw); }

/* ── top bar ─────────────────────────────────────────────────────────────── */
.topbar {
  position: sticky; top: 0; z-index: 50;
  background: var(--bg);
  border-bottom: 1px solid var(--edge);
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.09em;
  text-transform: uppercase;
}
.topbar .wrap { display: flex; align-items: center; gap: 18px; height: 44px; }
.topbar .brand { font-weight: 600; margin-right: auto; white-space: nowrap; }
.topbar nav { display: flex; gap: 16px; overflow-x: auto; scrollbar-width: none; }
.topbar nav::-webkit-scrollbar { display: none; }
.topbar a { text-decoration: none; color: var(--ink-2); white-space: nowrap; }
.topbar a:hover { color: var(--accent); }
.themebtn {
  font: inherit; letter-spacing: inherit; text-transform: inherit;
  background: var(--surface); color: var(--ink);
  border: 1px solid var(--line); padding: 3px 8px; cursor: pointer;
}
.themebtn:hover { background: var(--surface-2); }

/* ── hero ────────────────────────────────────────────────────────────────── */
header.hero { padding: 46px 0 10px; }
.kicker {
  font-family: var(--mono); font-size: 12px; letter-spacing: 0.16em;
  text-transform: uppercase; color: var(--muted); margin-bottom: 18px;
}
h1 {
  font-family: var(--serif); font-weight: 600;
  font-size: clamp(30px, 5.2vw, 52px); line-height: 1.1;
  letter-spacing: -0.015em; margin: 0 0 18px;
}
.authors { font-family: var(--mono); font-size: 17.5px; line-height: 1.8; color: var(--ink); margin-bottom: 9px; }
.authors a { color: inherit; text-decoration: none; border-bottom: 1px solid var(--rule); padding-bottom: 1px; }
.authors a:hover { color: var(--accent); border-bottom-color: var(--accent); }
.authors sup, .affil sup { font-size: 11px; vertical-align: super; color: var(--accent); }
.affil   { font-family: var(--mono); font-size: 14.5px; line-height: 1.65; color: var(--ink-2); }

.btnrow { display: flex; flex-wrap: wrap; gap: 12px; margin: 26px 0 8px; }
.btn {
  font-family: var(--mono); font-size: 13px; letter-spacing: 0.06em; text-transform: uppercase;
  text-decoration: none; color: var(--ink); background: var(--surface);
  border: 1px solid var(--line);
  padding: 9px 16px; display: inline-flex; align-items: center; gap: 9px;
  transition: transform .08s ease, border-color .08s ease, color .08s ease;
}
.btn:hover { transform: translateY(-1px); border-color: var(--accent); color: var(--accent); }
.btn:active { transform: translateY(0); }
.btn[aria-disabled="true"] { opacity: .45; border-color: var(--rule); cursor: not-allowed; }
.btn .ico { font-size: 15px; line-height: 1; }

.claim {
  font-size: clamp(18px, 2.0vw, 21px); line-height: 1.55; margin: 26px 0 0;
  max-width: var(--measure);
}
.claim + .claim { margin-top: 16px; }


.claim b {
  font-weight: 600;
  /* an inset box-shadow on a wrapping inline box bleeds past the text; a
     background image clipped to each line box does not */
  background-image: linear-gradient(rgba(66,133,244,.18), rgba(66,133,244,.18));
  background-repeat: no-repeat; background-size: 100% 0.42em; background-position: 0 86%;
  -webkit-box-decoration-break: clone; box-decoration-break: clone;
}

/* ── generic section furniture ───────────────────────────────────────────── */
section { padding: 56px 0 4px; scroll-margin-top: 60px; }
.sechead { display: flex; align-items: baseline; gap: 14px; border-bottom: 1px solid var(--edge); padding-bottom: 8px; margin-bottom: 24px; }
.sechead .num {
  font-family: var(--mono); font-size: 12px; letter-spacing: 0.12em;
  background: var(--tag-bg); color: var(--tag-fg); padding: 3px 7px;
}
.sechead h2 {
  font-family: var(--mono); font-weight: 600; font-size: 15px;
  letter-spacing: 0.16em; text-transform: uppercase; margin: 0;
}
.sechead .sub { font-family: var(--mono); font-size: 12px; color: var(--muted); margin-left: auto; text-align: right; }
.lede { max-width: var(--measure); color: var(--ink-2); }
p { margin: 0 0 16px; }
.small { font-size: 16.5px; }
.note {
  font-family: var(--mono); font-size: 13.5px; line-height: 1.62; color: var(--muted);
  border-left: 2px solid var(--rule); padding-left: 12px; margin: 14px 0 0; max-width: var(--measure);
}

.card {
  background: var(--surface); border: 1px solid var(--line); padding: 20px;
}


/* ── budget explorer ─────────────────────────────────────────────────────── */
.explorer { display: grid; grid-template-columns: 246px 1fr; gap: 22px; align-items: start; }
.promptlist { border: 1px solid var(--line); background: var(--surface); }
.promptlist .hd { font-family: var(--mono); font-size: 11px; letter-spacing: 0.12em; text-transform: uppercase; padding: 8px 10px; border-bottom: 1px solid var(--line); color: var(--muted); }
.thumbs { display: grid; grid-template-columns: repeat(3, 1fr); gap: 6px; padding: 8px; }
.thumbs button { padding: 0; border: 1px solid transparent; background: none; cursor: pointer; line-height: 0; }
.thumbs button img { width: 100%; height: auto; filter: saturate(.75) contrast(.95); }
.thumbs button:hover img { filter: none; }
.thumbs button[aria-pressed="true"] { border-color: var(--accent); box-shadow: 0 0 0 2px var(--accent); }
.thumbs button[aria-pressed="true"] img { filter: none; }

.viewer { min-width: 0; }
.slider-row { display: flex; align-items: center; gap: 16px; flex-wrap: wrap; margin-bottom: 14px; }
.slider-row label { font-family: var(--mono); font-size: 11.5px; letter-spacing: 0.1em; text-transform: uppercase; color: var(--muted); }
input[type="range"] { -webkit-appearance: none; appearance: none; background: none; width: 260px; height: 22px; cursor: pointer; }
input[type="range"]::-webkit-slider-runnable-track { height: 6px; background: var(--surface-2); border: 1px solid var(--line); }
input[type="range"]::-moz-range-track { height: 6px; background: var(--surface-2); border: 1px solid var(--line); }
input[type="range"]::-webkit-slider-thumb { -webkit-appearance: none; width: 14px; height: 20px; margin-top: -8px; background: var(--accent); border: 1px solid var(--line); }
input[type="range"]::-moz-range-thumb { width: 14px; height: 20px; border-radius: 0; background: var(--accent); border: 1px solid var(--line); }
.readout { font-family: var(--mono); font-size: 13px; }
.readout b { font-size: 15px; }
.readout .sp { color: var(--good); font-weight: 600; }

.panes { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; }
.pane { border: 1px solid var(--line); background: var(--surface); }
.pane .cap { display: flex; justify-content: space-between; gap: 8px; align-items: baseline; font-family: var(--mono); font-size: 11.5px; letter-spacing: 0.06em; text-transform: uppercase; padding: 7px 9px; border-bottom: 1px solid var(--line); }
.pane .cap .who { font-weight: 600; }
.pane.ours .cap { background: rgba(66,133,244,.10); }
.pane.ours .cap .who { color: var(--accent); }
.pane.base .cap .who { color: var(--accent-2); }
.pane .cap .r { color: var(--muted); }
.pane img { width: 100%; aspect-ratio: 1; background: var(--surface-2); }
.promptlist .selected { border-top: 1px solid var(--line); padding: 10px 11px 13px; }
.promptlist .selected .hd { padding: 0 0 6px; border: 0; }
.selname {
  font-family: var(--mono); font-size: 13px; font-weight: 600; letter-spacing: 0.06em;
  text-transform: uppercase; color: var(--accent);
}
.seltext { font-size: 14.5px; line-height: 1.5; color: var(--ink-2); margin: 7px 0 0; }

/* ── video blocks ────────────────────────────────────────────────────────── */
.tabs { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 14px; }
.tab {
  font-family: var(--mono); font-size: 12px; letter-spacing: 0.06em; text-transform: uppercase;
  background: var(--surface); color: var(--ink-2); border: 1px solid var(--line);
  padding: 6px 11px; cursor: pointer;
}
.tab:hover { background: var(--surface-2); }
.tab[aria-pressed="true"] { background: var(--tag-bg); color: var(--tag-fg); }
.videoframe { border: 1px solid var(--line); background: var(--surface); }
.videoframe video { width: 100%; }
.vlabels { display: grid; font-family: var(--mono); font-size: 11.5px; letter-spacing: 0.06em; text-transform: uppercase; border-top: 1px solid var(--line); }
.vlabels.two { grid-template-columns: 1fr 1fr; }
.vlabels span { padding: 7px 9px; color: var(--muted); }
.vlabels span + span { border-left: 1px solid var(--rule); }
.duo { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; }

/* ── figures ─────────────────────────────────────────────────────────────── */
figure { margin: 0 0 8px; }
figure img { width: 100%; }
figcaption { font-size: 15.5px; color: var(--muted); margin-top: 10px; max-width: var(--measure); }
figcaption b { color: var(--ink-2); }
.framed { border: 1px solid var(--line); background: var(--surface); padding: 14px; }

/* ── charts ──────────────────────────────────────────────────────────────── */
.chartgrid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.chart { border: 1px solid var(--line); background: var(--surface); padding: 14px 12px 10px; }
.chart h3 { font-family: var(--mono); font-size: 12px; letter-spacing: 0.08em; text-transform: uppercase; margin: 0 0 2px; font-weight: 600; }
.chart .hint { font-family: var(--mono); font-size: 11px; color: var(--muted); margin: 0 0 8px; }
.chart svg { width: 100%; height: auto; overflow: visible; }
.legend { display: flex; flex-wrap: wrap; gap: 14px; font-family: var(--mono); font-size: 11.5px; color: var(--ink-2); margin: 8px 0 0; }
.legend i { display: inline-block; width: 16px; height: 3px; margin-right: 6px; vertical-align: middle; }
.legend .dash { height: 0; border-top: 2px dashed var(--muted); }
details.data { margin-top: 10px; font-family: var(--mono); font-size: 11.5px; color: var(--muted); }
details.data summary { cursor: pointer; letter-spacing: 0.06em; text-transform: uppercase; }
details.data table { margin-top: 8px; }

.tip {
  position: fixed; pointer-events: none; z-index: 80; opacity: 0;
  transition: opacity .08s ease;
  background: var(--ink); color: var(--bg);
  font-family: var(--mono); font-size: 11.5px; line-height: 1.45;
  padding: 6px 8px; border: 1px solid var(--line); white-space: nowrap;
}

/* ── tables ──────────────────────────────────────────────────────────────── */
.tablewrap { overflow-x: auto; border: 1px solid var(--line); background: var(--surface); }
table { border-collapse: collapse; width: 100%; font-family: var(--mono); font-size: 13.5px; }
th, td { padding: 7px 12px; text-align: right; white-space: nowrap; border-bottom: 1px solid var(--rule); }
th:first-child, td:first-child { text-align: left; }
thead th { font-size: 11px; letter-spacing: 0.08em; text-transform: uppercase; color: var(--muted); border-bottom: 1px solid var(--edge); }
tbody tr.ours { background: rgba(66,133,244,.075); }
tbody tr.ours td:first-child { color: var(--accent); font-weight: 600; }
tbody tr.dense td { color: var(--ink-2); }
tbody tr.group td { background: var(--surface-2); font-size: 11px; letter-spacing: 0.1em; text-transform: uppercase; color: var(--muted); }
td.best { font-weight: 600; }
caption { caption-side: bottom; padding: 10px 12px; text-align: left; font-family: var(--serif); font-size: 15px; color: var(--muted); }

/* ── bibtex + footer ─────────────────────────────────────────────────────── */
pre.bib {
  font-family: var(--mono); font-size: 13.5px; line-height: 1.6;
  background: var(--surface-2); border: 1px solid var(--line); padding: 16px;
  overflow-x: auto; margin: 0;
}
footer { border-top: 1px solid var(--edge); margin-top: 64px; padding: 22px 0 60px; font-family: var(--mono); font-size: 13px; line-height: 1.6; color: var(--muted); }
footer p { margin: 0 0 10px; max-width: var(--measure); }
footer p:last-child { margin-bottom: 0; }
footer a { color: var(--ink-2); text-underline-offset: 3px; }
footer a:hover { color: var(--accent); }

/* ── responsive ──────────────────────────────────────────────────────────── */
@media (max-width: 1000px) {
  .chartgrid { grid-template-columns: 1fr; }
  .explorer { grid-template-columns: 1fr; }
  .thumbs { grid-template-columns: repeat(6, 1fr); }
  .duo { grid-template-columns: 1fr; }
}
@media (max-width: 700px) {
  body { font-size: 17px; }
  .panes { grid-template-columns: 1fr; }
  .thumbs { grid-template-columns: repeat(4, 1fr); }
}
@media (prefers-reduced-motion: reduce) {
  .btn { transition: none; }
}

/* ── chart internals (themed through CSS vars, so no redraw on theme change) ── */
svg text { fill: var(--muted); font-family: var(--mono); font-size: 10px; }
svg text.lab { fill: var(--ink-2); }
svg text.strong { fill: var(--ink); font-weight: 600; }
svg .axis { stroke: var(--muted); stroke-width: 1; fill: none; }
svg .grid { stroke: var(--rule); stroke-width: 1; }
svg .rule { stroke: var(--ink-2); stroke-width: 1.4; stroke-dasharray: 5 3; fill: none; }
svg .band { fill: var(--accent-2); opacity: .07; }
svg .hit { fill: transparent; }
svg .ring { stroke: var(--surface); stroke-width: 1.5; }

/* ── zoom figure column headers (the paper draws these in TikZ) ───────────── */
.zoomfig .zoomlabels { position: relative; height: 18px; margin-bottom: 6px; }
.zoomfig .zoomlabels span {
  position: absolute; transform: translateX(-50%); white-space: nowrap;
  font-family: var(--mono); font-size: 10.5px; letter-spacing: 0.04em;
  text-transform: uppercase; color: var(--muted);
}
.zoomfig .zoomlabels span.ours { color: var(--accent); font-weight: 600; }

/* ── two-row tab strip with keys ─────────────────────────────────────────── */
.tabrow { display: flex; flex-wrap: wrap; align-items: center; gap: 10px 14px; margin-bottom: 14px; }
.tabrow .tabs { margin-bottom: 0; }
.tabkey { font-family: var(--mono); font-size: 11px; letter-spacing: 0.12em; text-transform: uppercase; color: var(--muted); }
@media (max-width: 700px) {
  .zoomfig .zoomlabels { display: none; }
}

/* Paper figures carry their own white ground (the method diagram is a
   transparent SVG, whose black type would vanish on a dark surface), so they
   get an explicit plate in both themes rather than an accidental one. */
figure.framed img { background: #FFFFFF; }

/* ── magnifier: a crop row under the sample row ──────────────────────────── */
.imgwrap { position: relative; line-height: 0; cursor: crosshair; }
.cropbox {
  position: absolute; border: 2px solid var(--accent-2); pointer-events: none;
  box-shadow: 0 0 0 1px rgba(255,255,255,.55) inset;
}
.crop { width: 100%; aspect-ratio: 1; background-repeat: no-repeat; background-color: var(--surface-2); image-rendering: auto; }
.panes.crops { margin-top: 12px; }
.panes.crops .pane .cap .who { font-weight: 400; }
.magnote { display: flex; justify-content: flex-end; gap: 12px; flex-wrap: wrap; align-items: baseline; margin-top: 10px; }

/* ── method walk-through ─────────────────────────────────────────────────── */
.methodflow { columns: 2; column-gap: 32px; margin-top: 32px; }
.mblock { break-inside: avoid; margin: 0 0 26px; }
.mblock h3 {
  font-family: var(--mono); font-size: 12.5px; font-weight: 600; letter-spacing: 0.09em;
  text-transform: uppercase; color: var(--ink); margin: 0 0 8px;
  padding-bottom: 6px; border-bottom: 1px solid var(--rule);
}
.mblock p { font-size: 16.5px; margin: 0 0 12px; }
.mblock p:last-child { margin-bottom: 0; }
/* small displays set in the page's mono, so symbols line up without a math engine */
.eq {
  font-family: var(--mono); font-size: 14px; line-height: 1.9;
  background: var(--surface); border: 1px solid var(--rule);
  padding: 10px 12px; overflow-x: auto; white-space: nowrap; text-align: center;
}
.eq sub, .eq sup { font-size: 10.5px; }
@media (max-width: 900px) { .methodflow { columns: 1; } }

td.rule { text-align: left; white-space: normal; color: var(--muted); font-size: 12.5px; min-width: 20em; }

/* property marks: colour + weight together, same green/red as the charts */
td .yes, td .no {
  font-weight: 700; font-size: 15px;
  /* the mono's check/cross glyphs are hairline; the serif's are drawn solid */
  font-family: var(--serif);
}
td .yes { color: var(--good); }
td .no  { color: var(--accent-2); }
td .triv { color: var(--muted); font-family: var(--serif); font-size: 13.5px; }

/* minmax(0,1fr), not 1fr: the c2i table's intrinsic width was widening its own
   column and squeezing the other two */
.abgrid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 26px; align-items: start; }
.abgrid .tablewrap { box-shadow: none; }
.abgrid table { font-size: 12.5px; }
@media (max-width: 1000px) { .abgrid { grid-template-columns: 1fr; } }

/* ── references ──────────────────────────────────────────────────────────── */
.reflist { columns: 2; column-gap: 34px; margin: 0; padding-left: 1.6em; }
.reflist li { break-inside: avoid; font-size: 14.5px; line-height: 1.5; margin: 0 0 12px; color: var(--ink-2); }
.reflist li::marker { font-family: var(--mono); font-size: 12px; color: var(--muted); }
.reflist a { color: var(--muted); font-family: var(--mono); font-size: 12px; }
.reflist a:hover { color: var(--accent); }
.rtag { font-family: var(--mono); font-size: 11.5px; text-transform: uppercase; letter-spacing: 0.05em; color: var(--accent); }
a.cite {
  font-family: var(--mono); font-size: 10px; vertical-align: super; text-decoration: none;
  color: var(--accent); margin-left: 1px;
}
a.cite:hover { text-decoration: underline; }
:target { scroll-margin-top: 60px; }
@media (max-width: 900px) { .reflist { columns: 1; } }

/* ── acknowledgements + prompt inventory ─────────────────────────────────── */
.ackgrid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 26px; margin-top: 26px; }
.ackgrid h3 {
  font-family: var(--mono); font-size: 12.5px; font-weight: 600; letter-spacing: 0.09em;
  text-transform: uppercase; margin: 0 0 8px; padding-bottom: 6px; border-bottom: 1px solid var(--rule);
}
.pgroup { border: 1px solid var(--line); background: var(--surface); margin-bottom: 10px; }
.pgroup > summary {
  cursor: pointer; padding: 10px 12px; display: flex; gap: 12px; align-items: baseline;
  font-family: var(--mono); font-size: 12.5px; letter-spacing: 0.04em; text-transform: uppercase;
}
.pgroup > summary:hover { background: var(--surface-2); }
.pgroup[open] > summary { border-bottom: 1px solid var(--rule); }
.pgroup .pw { flex: 1; color: var(--ink); }
.pgroup .pn { color: var(--accent); font-weight: 600; }
.psrc { font-family: var(--mono); font-size: 11.5px; color: var(--muted); margin: 10px 12px 0; }
.pnote { font-size: 14.5px; color: var(--accent-2); margin: 8px 12px 0; }
.plist { margin: 8px 12px 14px; padding-left: 2.4em; }
.plist li { font-size: 15px; line-height: 1.5; color: var(--ink-2); margin-bottom: 6px; }
.plist li::marker { font-family: var(--mono); font-size: 11px; color: var(--muted); }
@media (max-width: 900px) { .ackgrid { grid-template-columns: 1fr; } }