/* ============================================================
   Lean slide theme  —  a reveal.js theme for Verso-slides
   ------------------------------------------------------------
   Clean, light, academic Lean look: teal + Lean-blue on white,
   Source Sans 3 (light), left-aligned full-viewport slides.
   Design language after Leo de Moura's talks.

   USE WITH VERSO-SLIDES
     Verso emits reveal.js. Point its theme/extraCss at this file:
       slidesMain (config := { theme := .custom ⟨"lean.css", #[…assets]⟩ })
     or layer it over a built-in theme:
       { theme := "white", extraCss := #[⟨"lean.css"⟩] }
     (loads AFTER the base theme, so these rules win.)

   USE STANDALONE (hand-written reveal deck)
     <link rel="stylesheet" href=".../reveal/dist/theme/white.css">
     <link rel="stylesheet" href="lean.css">           <!-- last -->
   ============================================================ */

@import url("https://fonts.googleapis.com/css2?family=Source+Sans+3:ital,wght@0,300;0,400;0,500;0,600;1,400&family=JetBrains+Mono:wght@400;600&display=swap");

:root {
  --lean-teal: #0891b2; /* primary accent */
  --lean-blue: #0073a3; /* title band / section breaks (deep Lean blue) */
  --lean-blue-2: #3b82f6; /* lighter blue for rules / links */
  --ink: #1e293b; /* body text (slate-800) */
  --muted: #64748b; /* secondary text (slate-500) */
  --line: #e2e8f0; /* hairline borders (slate-200) */
  --code-bg: #f8fafc; /* code surface (slate-50) */
  --tint: #f0fdfa; /* teal-tinted callout bg */
  --tint-line: #99f6e4; /* teal-tinted callout border */
  --sans: "Source Sans 3", -apple-system, BlinkMacSystemFont, sans-serif;
  --mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
}

/* ---------- base ---------- */
.reveal {
  font-family: var(--sans);
  font-weight: 300;
  color: var(--ink);
  font-size: 3.4vh;
}
.reveal .slides {
  text-align: left;
}
.reveal .slides section {
  text-align: left;
  box-sizing: border-box;
  /* Reveal scales `.slides` (1280×720) to the viewport. Sizing sections to
     `100vw/100vh` makes them viewport-wide *before* that scale, so on any
     viewport ≠ 1280 the section is multiplied past the slide and content spills
     off the right edge. `100%` sizes them to Reveal's own (already-scaled) slide
     box, so padding always leaves a real margin and nothing touches the edge. */
  width: 100%;
  height: 100%;
}
/* Padding goes on the LEAF slides only. A vertical group (`vertical := some
   true`) wraps its sub-slides in an extra <section> that reveal.js tags
   `.stack`; without this exclusion that wrapper ALSO gets the padding and it
   stacks on top of the child's padding — pushing content right and down.
   Less left padding (3vw) than right (5vw) so content sits closer to the left.
   These are vars because the header slots measure against them (see --author). */
:root {
  --pad-t: 4vh;
  --pad-r: 5vw;
  --pad-b: 4vh;
  --pad-l: 3vw;
}
.reveal .slides section:not(.stack) {
  padding: var(--pad-t) var(--pad-r) var(--pad-b) var(--pad-l);
}
.reveal a {
  color: var(--lean-blue-2);
  text-decoration: none;
}
.reveal a:hover {
  text-decoration: underline;
}
.reveal strong {
  font-weight: 600;
}
.reveal em {
  color: var(--muted);
  font-style: italic;
}

/* ---------- headings ---------- */
.reveal h1,
.reveal h2,
.reveal h3,
.reveal h4 {
  font-family: var(--sans);
  text-transform: none;
  color: var(--ink);
  line-height: 1.15;
}
.reveal h1 {
  font-weight: 500;
  font-size: 1.4em;
  margin: 0 0 0.5em;
}
.reveal h2 {
  font-weight: 600;
  font-size: 1.3em;
  margin: 0 0 0.5em;
}
.reveal h3 {
  font-weight: 600;
  font-size: 1.05em;
  color: var(--muted);
  margin: 0 0 0.3em;
}

/* project header (Leo-style): the project name at the left, then a blue rule
   filling the rest, sitting above each slide title. Verso renders the `#` title
   as an <h2>, so we hang the header off it.
   NOTE: the name is PER-DECK — set --project (and --name-w) in the deck's own
   override css (e.g. slidesExample.css). These are only fallbacks. */
:root {
  --project: "Lean";
  --name-w: 3.4em;
  --rule-end: 4vw; /* right inset of the blue header rule → white space before the edge */
}
.reveal h2 {
  position: relative;
  padding-top: 1.8em;
}
.reveal h2::before {
  /* project name */
  content: var(--project);
  position: absolute;
  top: 0;
  left: 0;
  font-weight: 700;
  font-size: 1.05em;
  color: var(--ink);
  line-height: 1;
}
.reveal h2::after {
  /* blue rule, starting after the name, ending short of the right edge */
  content: "";
  position: absolute;
  top: 0.35em;
  left: var(--name-w);
  right: var(--rule-end);
  height: 3px;
  background: var(--lean-blue);
  border-radius: 2px;
}
/* full-colour slides (section-break / title) get no header */
.reveal .section-break h2,
.reveal .title-slide h2 {
  padding-top: 0;
}
.reveal .section-break h2::before,
.reveal .section-break h2::after,
.reveal .title-slide h2::before,
.reveal .title-slide h2::after {
  content: none;
}

/* optional header slot: your name / handle / a repo or paper ref, shown as PLAIN
   text ABOVE the blue rule, right-aligned, on every content slide. It sits in the
   slide's top padding so the rule keeps its full width and nothing overlaps.
   Set --author in the deck's own .css:
     --author: "A. Gupta · github.com/AnirudhG07";
   Leave it unset to hide the slot entirely.
   CSS content can only be static text, so this is NOT clickable — for a clickable
   repo/paper/email link, use :::class "links" on a slide instead. */
:root {
  --author: "";
}
/* The exclusions live in THIS selector rather than a later `content: none` rule:
   a separate `.reveal section[data-state="title"]::after` is specificity (0,2,2)
   and would LOSE to this rule's (0,3,2), so the slot would leak onto the title
   and section-break slides. Excluding inline can't lose. */
.reveal .slides section:not(.stack):not([data-state="title"]):not(:has(.section-break)):not(:has(.title-slide))::after {
  content: var(--author);
  position: absolute;
  top: 2.4vh; /* just above the rule — leaves a ~0.5vh gap under the text */
  /* The rule is on h2::after, so its `right: --rule-end` is measured from inside
     the section's padding. This slot is on the SECTION, so it must add that
     padding back to end flush with the rule instead of overhanging it. */
  right: calc(var(--pad-r) + var(--rule-end));
  font-size: 0.72em;
  font-weight: 400;
  color: var(--muted);
  line-height: 1;
  white-space: nowrap;
  pointer-events: none;
}

/* ---------- title / first slide ----------
   Mark the slide with  %%% state := "title" %%%  then author:
     # Big Header
     :::class "subheader"  … :::   (subtitle)
     :::class "byline"     … :::   (name · designation — *name* renders in blue)
     :::class "event"      … :::   (when · where) */
.reveal section[data-state="title"] {
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 6vh 7vw;
}
.reveal section[data-state="title"]::before {
  /* gradient accent bar */
  content: "";
  display: block;
  width: 4.5em;
  height: 5px;
  background: linear-gradient(90deg, var(--lean-blue), var(--lean-teal));
  border-radius: 3px;
  margin-bottom: 1.3em;
}
.reveal section[data-state="title"] h2 {
  /* the big header */
  font-size: 3em;
  font-weight: 300;
  line-height: 1.06;
  letter-spacing: -0.01em;
  color: var(--ink);
  padding-top: 0;
  margin: 0 0 0.32em;
}
.reveal section[data-state="title"] h2 strong {
  color: var(--lean-blue);
  font-weight: 600;
}
.reveal section[data-state="title"] h2::before,
.reveal section[data-state="title"] h2::after {
  content: none;
} /* no project header here */
.reveal .subheader {
  font-size: 1.45em;
  font-weight: 300;
  line-height: 1.35;
  color: var(--muted);
  max-width: 42ch;
  margin: 0 0 2.2em;
}
/* authors — one per line (blank line between them in source); name in blue,
   affiliation muted after the middot */
.reveal .byline {
  font-size: 1.15em;
  color: var(--muted);
  line-height: 1.45;
  margin: 0 0 0.3em;
}
.reveal .byline strong {
  color: var(--lean-blue);
  font-weight: 600;
}
/* venue / date / organizer — set off by a hairline divider above the FIRST
   line only (the `.event` right after a byline/subheader gets the rule; the
   following `.event + .event` lines don't) */
.reveal .event {
  font-size: 0.95em;
  color: var(--muted);
  line-height: 1.5;
  margin: 0.12em 0 0;
}
.reveal .byline + .event,
.reveal .subheader + .event {
  margin-top: 1.8em;
  padding-top: 1em;
  border-top: 1px solid var(--line);
}
.reveal .event strong {
  color: var(--ink);
  font-weight: 600;
}
/* contact / social — GitHub, email, homepage, etc. Write links in the source
   (`[GitHub](https://github.com/you)`, `[you@x.edu](mailto:you@x.edu)`); the
   middots between them come from the source too (` · `). Links are blue and
   underline on hover. */
.reveal .links {
  font-size: 1em;
  color: var(--muted);
  line-height: 1.6;
  margin: 0.5em 0 0;
}
.reveal .links a {
  color: var(--lean-blue);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.15s;
}
.reveal .links a:hover {
  border-bottom-color: var(--lean-blue);
}

/* ---------- body ---------- */
.reveal p {
  font-size: 0.95em;
  font-weight: 300;
  line-height: 1.7;
  margin: 0 0 0.6em;
}
.reveal ul,
.reveal ol {
  font-size: 0.95em;
  font-weight: 300;
  line-height: 1.75;
  margin: 0;
  padding-left: 1.2em;
}
.reveal li {
  margin-bottom: 0.3em;
}
.reveal ul ul,
.reveal ol ol {
  font-size: 1em;
}
.reveal li::marker {
  color: var(--lean-teal);
}

/* ---------- signature: logo + teal rule header ---------- */
.reveal .slide-header {
  display: flex;
  align-items: center;
  gap: 0.6em;
  margin-bottom: 0.6em;
}
.reveal .slide-header img {
  height: 6vh;
  flex-shrink: 0;
}
.reveal .slide-header .h {
  font-weight: 600;
  font-size: 1.15em;
  white-space: nowrap;
}
.reveal .slide-header::after {
  content: "";
  flex: 1;
  height: 1.5px;
  background: var(--lean-teal);
}

/* ---------- title slide (blue band) ---------- */
.reveal section.title-slide {
  padding: 0 !important;
  display: flex !important;
  flex-direction: column;
  align-items: stretch;
}
.reveal .title-slide .top-area {
  padding: 1.4em 1.6em 0.8em;
}
.reveal .title-slide .logo {
  height: 15vh;
}
.reveal .title-slide .blue-band {
  flex: 1;
  background: var(--lean-blue);
  color: #fff;
  padding: 1.2em 1.6em 1em;
  display: flex;
  flex-direction: column;
}
.reveal .title-slide .blue-band h1 {
  color: #fff;
  font-weight: 300;
  font-size: 2em;
  margin: 0 0 0.6em;
}
.reveal .title-slide .meta {
  font-size: 0.85em;
  font-weight: 300;
  line-height: 1.6;
}
.reveal .title-slide .meta strong {
  font-weight: 600;
}
.reveal .title-slide .date {
  font-size: 0.8em;
  margin-top: auto;
  opacity: 0.9;
}

/* ---------- section-break ----------
   Full-section version (hand-written decks) OR an inner :::class "section-break"
   block over a solid background set via  %%% backgroundColor := "#0073a3" %%% . */
.reveal section.section-break {
  display: flex !important;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  text-align: center;
  background: linear-gradient(
    135deg,
    var(--lean-blue) 0%,
    var(--lean-teal) 100%
  );
}
/* inner :::class "section-break" (not a whole section) → a blue banner panel */
.reveal .section-break:not(section) {
  background: linear-gradient(135deg, var(--lean-blue), var(--lean-teal));
  color: #fff;
  text-align: center;
  border-radius: 12px;
  padding: 1.1em 1.4em;
  margin: 0.6em 0;
}
.reveal .section-break:not(section) * {
  color: #fff;
  border-bottom: none;
}
.reveal .section-break:not(section) p,
.reveal .section-break:not(section) h2 {
  font-size: 1.6em;
  margin: 0;
  font-weight: 400;
}
/* the blue title band's h1 keeps no rule */
.reveal .title-slide h1 {
  border-bottom: none;
}

/* ---------- code ---------- */
.reveal code {
  font-family: var(--mono);
  font-size: 0.9em;
  background: #f1f5f9;
  padding: 0.1em 0.32em;
  border-radius: 3px;
}
/* Inline ELABORATED/HIGHLIGHTED code (Verso's {lean}`…`, {python}`…`, etc.)
   already carries its own token colours, so drop the grey chip. Plain
   `backtick` code (no `hl` class) keeps its chip. Works for any syntax.

   SPECIFICITY, load-bearing: Verso ships lib/slides-highlight.css, which loads
   AFTER this file and sets
       .reveal code.hl.lean.inline { background: rgba(0,0,0,.25); padding: …; }
   at (0,4,1) — a grey chip, and a 0.9em font that leaves the chip shorter than
   the line (the "white top"). A plain `.reveal code.hl.inline` is only (0,3,1),
   so it loses on specificity AND on order. Adding the two element selectors
   below makes this (0,4,2): it wins on element count without !important and
   without hard-coding `.lean`, so it still covers every syntax.
   Token backgrounds are deliberately untouched — those are the hover
   highlights, not the chip. */
.reveal .slides section code.hl.inline {
  background: transparent;
  padding: 0;
  font-size: 1em;
}
.reveal pre {
  font-family: var(--mono);
  font-size: 0.66em;
  width: 100%;
  margin: 0.5em 0;
  box-shadow: none;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--code-bg);
}
.reveal pre code {
  display: block;
  padding: 0.9em 1.1em;
  max-height: 68vh;
  background: transparent;
  border-radius: 8px;
  line-height: 1.5;
  overflow: auto;
}
/* Verso renders Lean with its own semantic token colors — we only style the frame. */

/* ---------- callouts & emphasis ---------- */
.reveal .accent {
  color: var(--lean-teal);
  font-weight: 600;
}
.reveal blockquote {
  font-size: 0.8em;
  border-left: 4px solid var(--lean-blue-2);
  padding: 0.4em 0.9em;
  margin: 0.6em 0;
  background: #f1f5f9;
  border-radius: 0 6px 6px 0;
  box-shadow: none;
}
.reveal .key-box {
  background: var(--tint);
  border: 1px solid var(--tint-line);
  border-radius: 8px;
  padding: 0.6em 1em;
  margin: 0.5em 0;
  font-size: 0.85em;
}
.reveal .key-box strong {
  color: var(--lean-teal);
}

/* ---------- layout helpers ---------- */
.reveal .two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5em;
  align-items: start;
}
.reveal .two-col.wide-left {
  grid-template-columns: 3fr 2fr;
}
.reveal .two-col.wide-right {
  grid-template-columns: 2fr 3fr;
}
.reveal .center {
  text-align: center;
}
.reveal .muted {
  color: var(--muted);
}

/* ---------- pipeline ( step → step → step ) ---------- */
.reveal .pipeline {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.2em;
  margin: 0.6em 0;
  font-size: 0.75em;
}
.reveal .pipeline .step {
  background: #e0f2fe;
  border: 1px solid var(--lean-teal);
  border-radius: 6px;
  padding: 0.4em 0.7em;
  font-weight: 500;
  color: var(--ink);
}
.reveal .pipeline .arrow {
  font-size: 1.2em;
  color: var(--lean-teal);
  padding: 0 0.15em;
}

/* ---------- spectrum bar ---------- */
.reveal .spectrum {
  display: flex;
  border-radius: 8px;
  overflow: hidden;
  margin: 0.8em 0;
  font-size: 0.78em;
}
.reveal .spectrum .seg {
  flex: 1;
  padding: 0.7em 0.5em;
  text-align: center;
  color: #fff;
  font-weight: 500;
}

/* ---------- reveal chrome ---------- */
.reveal .progress {
  color: var(--lean-teal);
}
.reveal .controls {
  color: var(--lean-teal);
}
.reveal .slide-number {
  background: transparent;
  color: var(--muted);
  font-family: var(--mono);
}