/* research.techaimag.com — AI Research Digest.
   A research journal on cool lab paper: Source Serif 4 for reading, IBM Plex Sans for interface and data, one cobalt
   accent. The one loud move: "Explain it Like I'm 12" turns the article into a highlighter-yellow sheet set in
   Atkinson Hyperlegible, so the reading level is something you see. */

:root {
  --paper: #F6F7F9;
  --sheet: #FFFFFF;
  --ink: #17202B;
  --ink-2: #3D4855;
  --muted: #5F6B79;
  --rule: #D8DDE4;
  --cobalt: #2546C9;
  --cobalt-soft: #E4E9FB;
  --ghost: #C9D0DA;
  --up: #1F7A4D;
  --down: #A23B2A;
  --eli-bg: #FFF4BF;
  --eli-ink: #2A2410;
  --eli-mark: #FFE173;
  --f-read: "Source Serif 4", Georgia, "Times New Roman", serif;
  --f-ui: "IBM Plex Sans", system-ui, -apple-system, "Segoe UI", sans-serif;
  --f-eli: "Atkinson Hyperlegible", var(--f-ui);
  --measure: 66ch;
  --gutter: clamp(16px, 4vw, 40px);
  color-scheme: light;
}
:root[data-theme="dark"] {
  --paper: #0E131A; --sheet: #151C25; --ink: #E7EBF1; --ink-2: #C3CBD6; --muted: #93A0B0; --rule: #2A3441;
  --cobalt: #93A9FF; --cobalt-soft: #1E2847; --ghost: #364253; --up: #5FD49A; --down: #F08B76;
  --eli-bg: #2B2814; --eli-ink: #F6EDC4; --eli-mark: #6B5C12; color-scheme: dark;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --paper: #0E131A; --sheet: #151C25; --ink: #E7EBF1; --ink-2: #C3CBD6; --muted: #93A0B0; --rule: #2A3441;
    --cobalt: #93A9FF; --cobalt-soft: #1E2847; --ghost: #364253; --up: #5FD49A; --down: #F08B76;
    --eli-bg: #2B2814; --eli-ink: #F6EDC4; --eli-mark: #6B5C12; color-scheme: dark;
  }
}

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; background: var(--paper); color: var(--ink); font: 400 1.0625rem/1.65 var(--f-read);
  font-optical-sizing: auto; overflow-x: hidden; }
a { color: var(--cobalt); text-underline-offset: .18em; text-decoration-thickness: 1px; }
a:hover { text-decoration-thickness: 2px; }
:focus-visible { outline: 2px solid var(--cobalt); outline-offset: 3px; border-radius: 2px; }
img, svg { max-width: 100%; }
[hidden] { display: none !important; }
.skip { position: absolute; left: -999px; top: 8px; background: var(--sheet); padding: 8px 12px; z-index: 10; font-family: var(--f-ui); }
.skip:focus { left: 8px; }

/* masthead */
.mast { border-bottom: 1px solid var(--rule); background: var(--sheet); }
.mast-in { max-width: 1180px; margin: 0 auto; padding: 12px var(--gutter); display: flex; align-items: center; gap: 20px; }
.brand { display: flex; align-items: center; gap: 12px; color: var(--ink); text-decoration: none; }
.brand svg { height: 30px; width: auto; --accent: var(--cobalt); }
.brand-name { font: 600 1rem/1 var(--f-ui); padding-left: 12px; border-left: 1px solid var(--rule); white-space: nowrap; }
.mast-nav { display: flex; gap: 18px; margin-left: auto; font: 500 .9rem/1 var(--f-ui); }
.mast-nav a { color: var(--ink-2); text-decoration: none; }
.mast-nav a:hover { color: var(--cobalt); }
.mast-acct { font: 500 .9rem/1 var(--f-ui); }
.theme { width: 34px; height: 34px; border: 1px solid var(--rule); background: transparent; border-radius: 50%; cursor: pointer; padding: 0; display: grid; place-items: center; }
.theme span { width: 14px; height: 14px; border-radius: 50%; background: linear-gradient(90deg, var(--ink) 50%, transparent 50%); border: 1.5px solid var(--ink); }
@media (max-width: 720px) {
  .mast-in { flex-wrap: wrap; gap: 10px 14px; }
  .brand svg { height: 24px; }
  .mast-nav { order: 3; width: 100%; margin: 0; gap: 16px; }
  .mast-acct { margin-left: auto; }
}

/* buttons */
.btn, .btn-line, .btn-quiet { font: 600 .92rem/1 var(--f-ui); display: inline-block; padding: 11px 16px; border-radius: 6px; text-decoration: none; }
.btn { background: var(--cobalt); color: #fff; }
:root[data-theme="dark"] .btn { color: #0E131A; }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) .btn { color: #0E131A; } }
.btn:hover { filter: brightness(1.08); }
.btn-line { border: 1px solid var(--cobalt); color: var(--cobalt); }
.btn-line:hover { background: var(--cobalt-soft); }
.btn-quiet { padding: 8px 0; color: var(--ink-2); }

/* shared type */
main { max-width: 1180px; margin: 0 auto; padding: 0 var(--gutter); }
.kicker { font: 600 .85rem/1.2 var(--f-ui); color: var(--cobalt); margin: 0 0 10px; }
.h-small { font: 600 .82rem/1.3 var(--f-ui); color: var(--muted); margin: 0 0 10px; }
.sec { padding: 56px 0; border-top: 1px solid var(--rule); }
.sec-h { font: 700 clamp(1.6rem, 3vw, 2.2rem)/1.15 var(--f-read); margin: 0 0 8px; letter-spacing: -.01em; }
.sec-dek { color: var(--muted); margin: 0 0 28px; max-width: var(--measure); }
.fields { list-style: none; padding: 0; margin: 10px 0; display: flex; flex-wrap: wrap; gap: 6px; font: 500 .78rem/1 var(--f-ui); }
.fields li { padding: 5px 8px; border-radius: 4px; background: var(--cobalt-soft); color: var(--ink-2); }

/* cover: the issue's identity. Issue number + month set as a journal running head, headline at display size. */
.cover { padding: 56px 0 48px; }
.cover-id { display: flex; gap: 18px; font: 500 .95rem/1 var(--f-ui); color: var(--muted); margin-bottom: 22px; }
.cover-id span:first-child { color: var(--ink); font-weight: 600; }
.cover-h { font: 700 clamp(2.3rem, 6.4vw, 4.9rem)/1.02 var(--f-read); letter-spacing: -.025em; margin: 0; max-width: 17ch; font-variation-settings: "opsz" 60; }
.cover-dek { font: 400 clamp(1.15rem, 2vw, 1.4rem)/1.45 var(--f-read); color: var(--ink-2); max-width: 46ch; margin: 18px 0 40px; }
.cover-grid { display: grid; grid-template-columns: minmax(0, 1.1fr) minmax(0, 1fr); gap: 48px; }
.note p { margin: 0; max-width: var(--measure); }
.toc ul { list-style: none; margin: 0; padding: 0; border-top: 1px solid var(--rule); }
.toc li { border-bottom: 1px solid var(--rule); }
.toc a { display: grid; gap: 2px; padding: 11px 0; text-decoration: none; color: var(--ink); }
.toc a:hover .toc-t { color: var(--cobalt); }
.toc-k { font: 500 .8rem/1.3 var(--f-ui); color: var(--muted); }
.toc-t { font: 600 1.02rem/1.35 var(--f-read); }
@media (max-width: 820px) { .cover-grid { grid-template-columns: 1fr; gap: 32px; } }

/* paper of the month */
.feature { padding: 56px 0; border-top: 3px solid var(--ink); }
.feature-h { font: 700 clamp(1.8rem, 4vw, 3rem)/1.08 var(--f-read); letter-spacing: -.02em; margin: 0; max-width: 24ch; }
.feature-h a, .br-h a, .panel-h a, .gem-h a { color: inherit; text-decoration: none; }
.feature-h a:hover, .br-h a:hover, .panel-h a:hover, .gem-h a:hover { color: var(--cobalt); }
.feature-dek { font-size: 1.22rem; color: var(--ink-2); max-width: 52ch; margin: 14px 0 28px; }
.feature-cols { display: grid; grid-template-columns: minmax(0, 1.6fr) minmax(0, 1fr); gap: 40px; align-items: start; margin-bottom: 24px; }
.feature-sum { margin: 0; max-width: var(--measure); font-size: 1.1rem; }
.paper-card { background: var(--sheet); border: 1px solid var(--rule); border-radius: 8px; padding: 18px 18px 14px; font-family: var(--f-ui); }
.pc-title { font: 600 1rem/1.35 var(--f-read); margin: 0 0 6px; }
.pc-title a { color: inherit; }
.pc-auth { font-size: .86rem; color: var(--muted); margin: 0 0 6px; line-height: 1.45; }
.pc-links { display: flex; flex-wrap: wrap; gap: 14px; font: 600 .88rem/1 var(--f-ui); margin: 12px 0 4px; }
.pc-stat { font-size: .84rem; color: var(--muted); margin: 8px 0 0; }
.eli-chip { font: 600 .82rem/1 var(--f-eli); background: var(--eli-mark); color: var(--eli-ink); padding: 6px 9px; border-radius: 4px; margin-left: 10px; white-space: nowrap; display: inline-block; }
@media (max-width: 820px) { .feature-cols { grid-template-columns: 1fr; gap: 20px; } .eli-chip { margin: 12px 0 0; } }

/* five breakthroughs: a ranked list, so the numbers are real */
.brs { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 0 48px; }
.br { display: grid; grid-template-columns: 2.6rem minmax(0, 1fr); gap: 4px; padding: 20px 0; border-top: 1px solid var(--rule); }
.br-n { font: 700 2rem/1 var(--f-read); color: var(--cobalt); font-variant-numeric: lining-nums; }
.br-h { font: 700 1.22rem/1.25 var(--f-read); margin: 0 0 6px; }
.br-dek { margin: 0 0 6px; color: var(--ink-2); font-size: 1rem; }
.br-meta { margin: 0; font: 400 .84rem/1.4 var(--f-ui); color: var(--muted); }
@media (max-width: 820px) { .brs { grid-template-columns: 1fr; } }

/* explained + unsolved */
.pair { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 48px; }
.panel-h { font: 700 1.6rem/1.15 var(--f-read); margin: 0 0 10px; letter-spacing: -.01em; }
.panel-dek { color: var(--ink-2); margin: 0 0 12px; font-size: 1.08rem; }
.panel-sum { margin: 0 0 18px; max-width: var(--measure); }
.panel-concept, .panel-oq { font: 500 .88rem/1.3 var(--f-ui); color: var(--muted); margin: -4px 0 16px; }
.panel-unsolved { padding-left: 28px; border-left: 3px solid var(--ink); }
@media (max-width: 820px) { .pair { grid-template-columns: 1fr; } .panel-unsolved { padding-left: 18px; } }

/* radar */
.rr-key { display: flex; flex-wrap: wrap; gap: 18px; font: 500 .82rem/1 var(--f-ui); color: var(--muted); margin: 0 0 14px; }
.rr-key i { display: inline-block; width: 18px; height: 8px; border-radius: 2px; margin-right: 6px; vertical-align: middle; }
.k-cur { background: var(--cobalt); } .k-prev { background: var(--ghost); }
.rrs { list-style: none; margin: 0 0 24px; padding: 0; }
.rr { display: grid; grid-template-columns: 13rem minmax(0, 1fr) 4.2rem 4.4rem; grid-template-areas: "l bar n d" ". h h h"; gap: 4px 14px; align-items: center; padding: 12px 0; border-top: 1px solid var(--rule); font-family: var(--f-ui); }
.rr-l { grid-area: l; font-weight: 600; font-size: .95rem; }
.rr-bar { grid-area: bar; position: relative; height: 14px; display: block; min-width: 60px; }
.rr-prev, .rr-cur { position: absolute; left: 0; border-radius: 2px; }
.rr-prev { top: 0; height: 14px; background: var(--ghost); }
.rr-cur { top: 4px; height: 6px; background: var(--cobalt); }
.rr-n { grid-area: n; text-align: right; font-variant-numeric: tabular-nums; font-weight: 600; }
.rr-d { grid-area: d; text-align: right; font-size: .86rem; color: var(--muted); font-variant-numeric: tabular-nums; }
.rr-d.up { color: var(--up); } .rr-d.down { color: var(--down); }
.rr-h { grid-area: h; font: 400 .98rem/1.4 var(--f-read); color: var(--ink-2); }
@media (max-width: 720px) {
  .rr { grid-template-columns: minmax(0, 1fr) 3.6rem 3.8rem; grid-template-areas: "l n d" "bar bar bar" "h h h"; }
}

/* open source */
.oss { background: var(--sheet); border: 1px solid var(--rule); border-radius: 10px; padding: 28px; margin-bottom: 48px; }
.oss-repo { font: 500 .9rem/1.4 var(--f-ui); color: var(--muted); margin: 0 0 14px; }
.oss-repo a { font-weight: 600; margin-right: 8px; }
.gems { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 0 40px; }
.gem { padding: 18px 0; border-top: 1px solid var(--rule); }
.gem-h { font: 600 1.05rem/1.3 var(--f-ui); margin: 0 0 4px; word-break: break-word; }
.gem-meta { font: 400 .82rem/1.3 var(--f-ui); color: var(--muted); margin: 0 0 10px; }
.gem p { margin: 0 0 8px; font-size: 1rem; }
.gem-why { color: var(--ink-2); }
.gem-try { font: 400 .9rem/1.45 var(--f-ui); color: var(--ink-2); }
.gem-try span { font-weight: 600; color: var(--ink); }

.lab { list-style: none; padding: 0; margin: 0; columns: 2 320px; column-gap: 40px; }
.lab li { break-inside: avoid; padding: 10px 0; border-top: 1px solid var(--rule); }
.lab span { display: block; font: 400 .82rem/1.3 var(--f-ui); color: var(--muted); margin-top: 2px; }

/* article */
.art, .radar-page, .archive { padding: 40px 0 64px; }
.art-head { max-width: 860px; margin-bottom: 36px; }
.art-crumb { font: 500 .88rem/1 var(--f-ui); margin: 0 0 22px; }
.art-crumb a { color: var(--muted); }
.art-h { font: 700 clamp(2rem, 5vw, 3.6rem)/1.06 var(--f-read); letter-spacing: -.022em; margin: 0; }
.art-dek { font-size: clamp(1.15rem, 2vw, 1.35rem); color: var(--ink-2); margin: 16px 0 14px; max-width: 54ch; }
.art-meta { font: 400 .88rem/1.3 var(--f-ui); color: var(--muted); margin: 0; }
.art-grid { display: grid; grid-template-columns: 250px minmax(0, var(--measure)); gap: 56px; align-items: start; }
.art-side { position: sticky; top: 20px; }
.srcs { padding-left: 18px; margin: 0; font-size: .9rem; }
.srcs li { margin-bottom: 8px; }
@media (max-width: 920px) { .art-grid { grid-template-columns: 1fr; gap: 28px; } .art-side { position: static; } }

.mode { display: inline-flex; border: 1px solid var(--rule); border-radius: 8px; padding: 3px; margin-bottom: 26px; background: var(--sheet); }
.mode button { font: 600 .9rem/1 var(--f-ui); border: 0; background: transparent; color: var(--ink-2); padding: 10px 14px; border-radius: 6px; cursor: pointer; }
.mode button[aria-selected="true"] { background: var(--ink); color: var(--paper); }
.mode button#tab-eli12[aria-selected="true"] { background: var(--eli-mark); color: var(--eli-ink); font-family: var(--f-eli); }

.art-summary p { font-size: 1.15rem; margin: 0 0 24px; }
.art-body { font-size: 1.1rem; line-height: 1.72; }
.art-body h3 { font: 700 1.35rem/1.25 var(--f-read); margin: 2em 0 .5em; }
.art-body p, .art-body ul, .art-body ol { margin: 0 0 1.1em; }
.art-body blockquote { margin: 1.4em 0; padding-left: 20px; border-left: 3px solid var(--cobalt); color: var(--ink-2); }
.art-body code { font: .92em/1 ui-monospace, "SF Mono", Menlo, monospace; background: var(--cobalt-soft); padding: 2px 4px; border-radius: 3px; }
.kp, .gl, .oq { margin: 2.2em 0 0; padding: 22px 24px; background: var(--sheet); border: 1px solid var(--rule); border-radius: 8px; font-size: 1rem; }
.kp h2, .gl h2, .oq h2 { font: 600 .95rem/1.2 var(--f-ui); margin: 0 0 12px; }
.kp ul, .oq ol { margin: 0; padding-left: 20px; }
.kp li, .oq li { margin-bottom: 8px; }
.gl dl { margin: 0; display: grid; grid-template-columns: max-content 1fr; gap: 8px 16px; }
.gl dt { font: 600 .92rem/1.5 var(--f-ui); }
.gl dd { margin: 0; }
@media (max-width: 600px) { .gl dl { grid-template-columns: 1fr; gap: 2px; } .gl dd { margin-bottom: 8px; } }

/* Explain it Like I'm 12: the page changes reading level visibly */
body.is-eli12 .art-main { background: var(--eli-bg); color: var(--eli-ink); margin: -8px -24px 0; padding: 8px 24px 24px; border-radius: 12px; transition: background-color .25s ease; }
.eli12 { font: 400 1.22rem/1.75 var(--f-eli); color: var(--eli-ink); }
.eli12 h2.eli-t { font: 700 1.6rem/1.2 var(--f-eli); margin: 0 0 18px; }
.eli12 strong { background: var(--eli-mark); padding: 0 3px; border-radius: 2px; }
body.is-eli12 .art-summary { display: none; }
@media (prefers-reduced-motion: reduce) { body.is-eli12 .art-main { transition: none; } }

.lock { margin-top: 8px; padding: 28px; border-radius: 10px; background: var(--sheet); border: 1px solid var(--rule); border-top: 3px solid var(--cobalt); font-family: var(--f-ui); }
.lock-h { font: 700 1.3rem/1.3 var(--f-read); margin: 0 0 10px; }
.lock-p { color: var(--ink-2); margin: 0 0 18px; }
.lock-actions { display: flex; flex-wrap: wrap; gap: 12px; margin: 0; }
.art-next { margin-top: 48px; padding-top: 18px; border-top: 1px solid var(--rule); font: 400 .95rem/1.4 var(--f-ui); color: var(--muted); }

/* radar page */
.fieldgrid { display: grid; grid-template-columns: repeat(auto-fill, minmax(320px, 1fr)); gap: 0 48px; }
.field { padding: 26px 0; border-top: 1px solid var(--rule); }
.field-l { font: 600 .95rem/1.2 var(--f-ui); margin: 0 0 8px; color: var(--muted); }
.field-h { font: 700 1.3rem/1.25 var(--f-read); margin: 0 0 14px; }
.field-num { display: flex; align-items: baseline; gap: 10px; font: 400 .88rem/1.3 var(--f-ui); color: var(--muted); margin-bottom: 8px; }
.field-num .big { font: 700 2rem/1 var(--f-read); color: var(--ink); font-variant-numeric: lining-nums tabular-nums; }
.field .rr-bar { margin-bottom: 16px; }
.field-note { margin: 0 0 16px; }
.topics { list-style: none; padding: 0; margin: 0 0 16px; display: flex; flex-wrap: wrap; gap: 6px; font: 500 .82rem/1 var(--f-ui); }
.topics li { padding: 6px 8px; border: 1px solid var(--rule); border-radius: 4px; }
.topics span { color: var(--muted); margin-left: 4px; }
.tops { margin: 0; padding-left: 18px; font-size: .98rem; }
.tops li { margin-bottom: 6px; }
.method { font: 400 .86rem/1.5 var(--f-ui); color: var(--muted); max-width: var(--measure); margin-top: 32px; }

/* archive */
.ar { list-style: none; margin: 0; padding: 0; max-width: 860px; }
.ar a { display: grid; grid-template-columns: 6rem 10rem minmax(0, 1fr); gap: 16px; padding: 18px 0; border-top: 1px solid var(--rule); text-decoration: none; color: var(--ink); align-items: baseline; }
.ar-n, .ar-m { font: 500 .9rem/1.3 var(--f-ui); color: var(--muted); }
.ar-h { font: 700 1.2rem/1.3 var(--f-read); }
.ar a:hover .ar-h { color: var(--cobalt); }
@media (max-width: 600px) { .ar a { grid-template-columns: 1fr; gap: 4px; } }

/* footer */
.foot { border-top: 1px solid var(--rule); background: var(--sheet); margin-top: 40px; }
.foot-in { max-width: 1180px; margin: 0 auto; padding: 40px var(--gutter); display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1.3fr); gap: 48px; font: 400 .92rem/1.55 var(--f-ui); color: var(--ink-2); }
.foot-up-h { font: 700 1.3rem/1.25 var(--f-read); color: var(--ink); margin: 0 0 8px; }
.foot-meta p { margin: 0 0 12px; }
.foot-meta a + a { margin-left: 14px; }
.foot-small { color: var(--muted); font-size: .84rem; }
[data-access="1"] [data-show="visitor"] { display: none; }
@media (max-width: 820px) { .foot-in { grid-template-columns: 1fr; gap: 28px; } }