:root {
  --paper: #f2ede4;
  --ink: #1d1b18;
  --ink-soft: #4a453d;
  --muted: #8a8276;
  --rule: rgba(29, 27, 24, 0.16);
  --bar: #9d9488;
  --accent: #c8452b;
  --accent-soft: rgba(200, 69, 43, 0.1);
  --ok: #4f6b4a;
  --desync: #3d5a80;
}
html, body { margin: 0; height: 100%; overflow: hidden; background: var(--paper); }
#gl, #css { position: fixed; inset: 0; }
#css { pointer-events: none; }
#vignette {
  position: fixed; inset: 0; pointer-events: none;
  background: radial-gradient(ellipse at center, transparent 55%, rgba(60, 45, 25, 0.13) 100%);
}

/* ---------- slide frame (1600 x 900; arrow owns the band below ~620px) ---------- */
#slides, #finale { position: absolute; left: -99999px; }
.slide {
  width: 1600px; height: 900px; box-sizing: border-box;
  padding: 78px 120px 0;
  font-family: 'Inter', system-ui, sans-serif; color: var(--ink);
  -webkit-font-smoothing: antialiased;
}
.slide b { font-weight: 600; }
.slide em { font-style: italic; }

.eyebrow {
  font: 500 21px/1 'Inter', sans-serif; letter-spacing: 0.2em; text-transform: uppercase;
  color: var(--accent);
}
.slide h1 { font: 400 190px/0.9 'Instrument Serif', serif; margin: 30px 0 0; letter-spacing: -0.015em; }
.slide h1 em, .slide h2 em { color: var(--accent); }
.slide h2 { font: 400 80px/1 'Instrument Serif', serif; margin: 18px 0 0; letter-spacing: -0.01em; }
.slide h3 { font: 600 27px/1.2 'Inter', sans-serif; margin: 0 0 10px; }
.lede { font: 400 36px/1.35 'Inter', sans-serif; color: var(--ink-soft); max-width: 1120px; margin: 30px 0 0; }
.lede.sm { font-size: 28px; margin-top: 20px; }
.byline { font: 400 22px/1.4 'Inter', sans-serif; color: var(--muted); margin: 34px 0 0; }
.byline b { color: var(--ink); }
.body { font: 400 26px/1.45 'Inter', sans-serif; color: var(--ink-soft); margin: 22px 0 0; }
.small { font: 400 19px/1.45 'Inter', sans-serif; color: var(--muted); margin: 14px 0 0; }
.note {
  font: 400 22px/1.45 'Inter', sans-serif; color: var(--ink-soft); margin: 30px 0 0; max-width: 1300px;
  padding-left: 18px; border-left: 3px solid var(--accent);
}
.note b { color: var(--ink); }
.slide code, .code { font-family: 'JetBrains Mono', monospace; }
.slide code { font-size: 0.88em; background: rgba(29, 27, 24, 0.06); padding: 1px 6px; border-radius: 4px; }

/* ---------- layout ---------- */
.grid { display: grid; gap: 34px; margin-top: 40px; }
.grid.tight { margin-top: 26px; gap: 24px; }
.g2 { grid-template-columns: 1fr 1fr; }
.g3 { grid-template-columns: repeat(3, 1fr); }
.g4 { grid-template-columns: repeat(4, 1fr); }
.g2x { grid-template-columns: 1fr 1fr 0.8fr; align-items: stretch; }
.split { display: grid; grid-template-columns: 1fr 1fr; gap: 64px; align-items: start; }
.split.wide-left { grid-template-columns: 1.35fr 1fr; }
.split.img-right { grid-template-columns: 0.85fr 1.15fr; }
.split.img-left { grid-template-columns: 1.15fr 0.85fr; }

.card { border-top: 2px solid var(--ink); padding-top: 18px; }
.card p { font: 400 21px/1.45 'Inter', sans-serif; color: var(--ink-soft); margin: 0 0 10px; }
.card .small { font-size: 17px; margin: 6px 0 0; }
.card.side { background: rgba(255, 255, 255, 0.35); border-top: 0; border-left: 2px solid var(--ink); padding: 18px 26px; margin-top: 44px; }
.card.big p { margin-top: 8px; }
.card .num { font: 400 46px/1 'Instrument Serif', serif; color: var(--accent); margin-bottom: 12px; }
.tag { font: 500 16px/1 'Inter', sans-serif; letter-spacing: 0.12em; text-transform: uppercase; color: var(--accent); margin-bottom: 14px; }
.tag.muted { color: var(--muted); }
.need { font: 500 18px/1.3 'Inter', sans-serif !important; color: var(--accent) !important; margin-top: 12px !important; }
.q { font: italic 400 25px/1.35 'Instrument Serif', serif !important; color: var(--ink) !important; font-size: 27px !important; }

.chips { display: flex; gap: 14px; margin-top: 44px; flex-wrap: wrap; }
.chips span { font: 500 20px/1 'Inter', sans-serif; padding: 12px 20px; border: 1.5px solid var(--ink); border-radius: 999px; }

blockquote { font: 400 58px/1.12 'Instrument Serif', serif; margin: 26px 0 0; max-width: 1340px; letter-spacing: -0.005em; }
blockquote em { color: var(--accent); }
.mini { font: 400 20px/1.45 'Inter', sans-serif; color: var(--ink-soft); border-top: 1.5px solid var(--rule); padding-top: 14px; }
.mini b { color: var(--ink); }

/* key-value lists */
.kv { margin-top: 28px; display: grid; gap: 14px; }
.kv > div { display: grid; grid-template-columns: 190px 1fr; gap: 20px; align-items: baseline; border-bottom: 1px solid var(--rule); padding-bottom: 12px; }
.kv .k { font: 500 17px/1.3 'Inter', sans-serif; letter-spacing: 0.08em; text-transform: uppercase; color: var(--muted); }
.kv .v { font: 400 23px/1.35 'Inter', sans-serif; color: var(--ink); }
.kv.compact { margin-top: 16px; gap: 9px; }
.kv.compact > div { grid-template-columns: 130px 1fr; padding-bottom: 8px; }
.kv.compact .v { font-size: 20px; }
.kv.nums .v b { font-size: 24px; }
.t { font-style: normal; display: inline-block; font-size: 18px; padding: 5px 12px; margin: 0 8px 6px 0; border-radius: 6px; background: var(--accent-soft); color: var(--accent); }

/* image placeholder: replace with <img class="shot" src="…"> */
.ph {
  height: 470px; border: 2px dashed rgba(29, 27, 24, 0.35); border-radius: 14px;
  display: flex; align-items: center; justify-content: center; text-align: center; padding: 30px; box-sizing: border-box;
  font: 500 22px/1.4 'Inter', sans-serif; color: var(--muted);
  background: repeating-linear-gradient(45deg, rgba(29, 27, 24, 0.035) 0 2px, transparent 2px 16px);
}
.ph::before { content: 'IMAGE'; position: absolute; transform: translateY(-60px); font-size: 14px; letter-spacing: 0.3em; color: var(--accent); }
.shot { width: 100%; height: 470px; object-fit: cover; border-radius: 14px; box-shadow: 0 18px 50px rgba(40, 30, 15, 0.18); }

/* activity graph */
.node-card { margin-top: 28px; border: 2px solid var(--ink); border-radius: 14px; padding: 18px 24px; background: rgba(255, 255, 255, 0.4); }
.node-title { font: italic 400 32px/1.1 'Instrument Serif', serif; }
.steps { margin: 44px 0 0; padding: 0; list-style: none; counter-reset: s; position: relative; }
.steps::before { content: ''; position: absolute; left: 19px; top: 20px; bottom: 20px; width: 2px; background: var(--rule); }
.steps li { counter-increment: s; position: relative; padding-left: 62px; font: 400 22px/1 'Inter', sans-serif; color: var(--ink-soft); height: 30px; margin-bottom: 29px; display: flex; align-items: center; }
.steps li::before {
  content: counter(s); position: absolute; left: 0; width: 40px; height: 40px; border-radius: 50%;
  border: 2px solid var(--ink); background: var(--paper); box-sizing: border-box;
  font: 500 17px/36px 'Inter', sans-serif; text-align: center; color: var(--ink);
}
.steps li.hl { color: var(--ink); font-weight: 600; }
.steps li.hl::before { background: var(--accent); border-color: var(--accent); color: #fff; }

/* tables */
.tbl { border-collapse: collapse; font: 400 20px/1.2 'Inter', sans-serif; margin-top: 44px; width: 100%; }
.tbl th { font: 500 15px/1.2 'Inter', sans-serif; letter-spacing: 0.1em; text-transform: uppercase; color: var(--muted); text-align: left; padding: 0 12px 12px; border-bottom: 2px solid var(--ink); }
.tbl td { padding: 9px 12px; border-bottom: 1px solid var(--rule); color: var(--ink-soft); }
.tbl td:not(:first-child), .tbl th:not(:first-child) { text-align: center; }
.tbl tr.sum td { font-weight: 600; color: var(--ink); border-bottom: 0; border-top: 2px solid var(--ink); }
.tbl.num td { font-variant-numeric: tabular-nums; }
.tbl .hl { color: var(--accent); font-weight: 600; }
.tbl.side { margin-top: 64px; }

/* architecture flow */
.flow { display: flex; align-items: center; gap: 18px; margin-top: 50px; }
.fbox { border: 2px solid var(--ink); border-radius: 14px; padding: 18px 20px; min-width: 210px; background: rgba(255, 255, 255, 0.4); }
.fbox.muted { border-style: dashed; background: transparent; }
.fbox b { display: block; font: 600 25px/1.2 'Inter', sans-serif; }
.fbox span { display: block; font: 400 17px/1.4 'Inter', sans-serif; color: var(--ink-soft); margin-top: 6px; }
.tier { font: 500 14px/1 'Inter', sans-serif; letter-spacing: 0.14em; text-transform: uppercase; color: var(--accent); margin-bottom: 8px; }
.farrow { font: 400 17px/1 'Inter', sans-serif; color: var(--muted); white-space: nowrap; }
.verdicts { display: flex; flex-direction: column; gap: 10px; }
.verdicts span { font: 600 16px/1 'Inter', sans-serif; letter-spacing: 0.04em; padding: 11px 14px; border-radius: 8px; border: 1.5px solid; white-space: nowrap; }
.v-m { color: var(--accent); border-color: var(--accent); background: var(--accent-soft); }
.v-o { color: var(--ok); border-color: var(--ok); }
.v-d { color: var(--desync); border-color: var(--desync); }

.verdict { border-top-width: 4px; }
.verdict .vt { font: 600 30px/1 'JetBrains Mono', monospace; margin-bottom: 14px; }
.verdict.m { border-color: var(--accent); } .verdict.m .vt { color: var(--accent); }
.verdict.o { border-color: var(--ok); } .verdict.o .vt { color: var(--ok); }
.verdict.d { border-color: var(--desync); } .verdict.d .vt { color: var(--desync); }

.formula { font: italic 400 34px/1.2 'Instrument Serif', serif; margin-top: 26px; padding: 16px 22px; border-radius: 10px; background: rgba(255, 255, 255, 0.45); display: inline-block; }

/* bar charts: thin bars, rounded data end, text in ink tokens */
.bars { margin-top: 6px; }
.split > .bars:last-child { margin-top: 70px; }
.bars-title { font: 500 16px/1 'Inter', sans-serif; letter-spacing: 0.1em; text-transform: uppercase; color: var(--muted); margin-bottom: 22px; }
.bars-title span { text-transform: none; letter-spacing: 0; }
.bars h2 { margin-bottom: 30px; }
.bar-row { display: grid; grid-template-columns: 250px 1fr 76px; align-items: center; gap: 16px; height: 44px; }
.bar-row.tall { height: 96px; }
.bl { font: 400 20px/1.2 'Inter', sans-serif; color: var(--ink-soft); }
.bl small { font-size: 15px; color: var(--muted); }
.bar-row.me .bl { color: var(--ink); }
.track { height: 16px; position: relative; border-left: 1.5px solid var(--ink); }
.bar-row.tall .track { height: 26px; }
.fill { position: absolute; left: 0; top: 0; bottom: 0; background: var(--bar); border-radius: 0 4px 4px 0; }
.fill.hl { background: var(--accent); }
.bv { font: 500 20px/1 'Inter', sans-serif; font-variant-numeric: tabular-nums; color: var(--ink); text-align: right; }
.bars-foot { font: 400 18px/1.4 'Inter', sans-serif; color: var(--ink-soft); margin-top: 20px; }
/* grow bars in on reveal */
.slide .fill { transform-origin: left; transform: scaleX(0); transition: transform 1.1s cubic-bezier(0.2, 0.7, 0.2, 1) 0.35s; }
.slide.shown .fill { transform: scaleX(1); }

/* hero numbers */
.stat { font: 400 76px/1 'Instrument Serif', serif; color: var(--ink); letter-spacing: -0.01em; }
.stat small { font: 400 22px/1 'Inter', sans-serif; color: var(--muted); letter-spacing: 0; }
.stat em { color: var(--accent); font-style: normal; }
.stat.md { font-size: 58px; margin-bottom: 8px; }
.stat.xl { font-size: 130px; }
.stat .arrow { color: var(--muted); font-size: 0.7em; }
.hero { display: flex; flex-direction: column; justify-content: center; }
.hero p { font: 400 20px/1.3 'Inter', sans-serif; color: var(--muted); margin: 10px 0 0; }
.hero.center { align-items: center; text-align: center; height: 420px; }

/* frame buffers */
.buffers { display: grid; grid-template-columns: 1fr 1fr; gap: 56px; margin-top: 42px; }
.buf-head { display: flex; justify-content: space-between; align-items: baseline; }
.buf-head b { font: 600 26px/1.2 'Inter', sans-serif; }
.buf-head span { font: 400 17px/1.2 'Inter', sans-serif; color: var(--muted); }
.buf p { font: 400 22px/1.45 'Inter', sans-serif; color: var(--ink-soft); margin: 14px 0 0; }
.ticks { height: 64px; margin-top: 18px; border-bottom: 2px solid var(--ink); position: relative; }
.ticks::after { content: ''; position: absolute; bottom: 0; top: 10px; }
.ticks.dense::after { right: 0; width: 34%; background: repeating-linear-gradient(90deg, var(--accent) 0 3px, transparent 3px 6.3px); }
.ticks.dense::before { content: 'stream →'; position: absolute; left: 0; bottom: 8px; font: 400 15px/1 'Inter', sans-serif; color: var(--muted); }
.ticks.sparse { border-left: 2px solid var(--ink); border-right: 2px solid var(--ink); }
.ticks.sparse::after { left: 1%; right: 1%; background: repeating-linear-gradient(90deg, var(--accent) 0 3px, transparent 3px 3.1%); }

/* rules / lists */
.rules { margin: 34px 0 0; padding-left: 0; list-style: none; counter-reset: r; }
.rules li { counter-increment: r; font: 400 25px/1.4 'Inter', sans-serif; color: var(--ink-soft); padding: 0 0 18px 64px; position: relative; }
.rules li::before { content: counter(r); position: absolute; left: 0; top: -6px; font: 400 46px/1 'Instrument Serif', serif; color: var(--accent); }
.rules li b { color: var(--ink); }
.dots { margin: 20px 0 0; padding-left: 0; list-style: none; }
.dots li { font: 400 21px/1.45 'Inter', sans-serif; color: var(--ink-soft); padding: 0 0 12px 26px; position: relative; }
.dots li::before { content: ''; position: absolute; left: 2px; top: 12px; width: 8px; height: 8px; border-radius: 50%; background: var(--accent); }
.dots.two { display: grid; grid-template-columns: 1fr 1fr; column-gap: 48px; margin-top: 28px; }
.dots.two li { font-size: 23px; }
.code { font-size: 19px; line-height: 1.6; background: #1d1b18; color: #efe9dd; padding: 22px 26px; border-radius: 12px; margin: 30px 0 0; white-space: pre; }

/* recorded files */
.files { margin-top: 70px; display: grid; gap: 14px; }
.file { display: grid; grid-template-columns: 250px 1fr; align-items: center; padding: 18px 22px; border: 1.5px solid var(--rule); border-radius: 10px; background: rgba(255, 255, 255, 0.35); }
.file code { font-size: 20px !important; background: none !important; padding: 0 !important; }
.file span { font: 400 20px/1.3 'Inter', sans-serif; color: var(--ink-soft); }
.file.hl { border-color: var(--accent); } .file.hl code { color: var(--accent); }

/* versions timeline */
.timeline { display: grid; grid-template-columns: repeat(6, 1fr); gap: 22px; margin-top: 60px; position: relative; }
.timeline::before { content: ''; position: absolute; left: 0; right: 0; top: 9px; height: 2px; background: var(--ink); }
.tl { position: relative; padding-top: 36px; }
.tl-dot { position: absolute; top: 0; left: 0; width: 20px; height: 20px; border-radius: 50%; background: var(--paper); border: 2px solid var(--ink); box-sizing: border-box; }
.tl.hl .tl-dot { background: var(--accent); border-color: var(--accent); }
.tl b { font: 600 22px/1.2 'Inter', sans-serif; display: block; }
.tl.hl b { color: var(--accent); }
.tl p { font: 400 18px/1.45 'Inter', sans-serif; color: var(--ink-soft); margin: 10px 0 0; }

/* future work */
.future { margin: 36px 0 0; padding: 0; list-style: none; counter-reset: f; display: grid; grid-template-columns: 1fr 1fr; column-gap: 60px; row-gap: 22px; }
.future li { counter-increment: f; font: 400 21px/1.4 'Inter', sans-serif; color: var(--ink-soft); padding-left: 56px; position: relative; }
.future li::before { content: counter(f); position: absolute; left: 0; top: -6px; font: 400 42px/1 'Instrument Serif', serif; color: var(--accent); }
.future li b { color: var(--ink); display: block; font-size: 23px; margin-bottom: 2px; }

/* ---------- staggered reveal when the arrow arrives ---------- */
.reveal > * {
  opacity: 0; transform: translateY(22px);
  transition: opacity 0.6s ease, transform 0.9s cubic-bezier(0.2, 0.7, 0.2, 1);
}
.slide.shown .reveal > * { opacity: 1; transform: none; }
.reveal > *:nth-child(2) { transition-delay: 0.08s; }
.reveal > *:nth-child(3) { transition-delay: 0.16s; }
.reveal > *:nth-child(4) { transition-delay: 0.24s; }
.reveal > *:nth-child(5) { transition-delay: 0.32s; }
.reveal > *:nth-child(6) { transition-delay: 0.4s; }
.slide:not(.shown) .reveal > * { transition-delay: 0s; }
.slide.no-anim *, .slide.no-anim .reveal > * { transition: none !important; }

/* ---------- THE END ---------- */
#the-end { width: 1600px; height: 560px; display: flex; flex-direction: column; align-items: center; justify-content: flex-start; color: var(--ink); }
.end-title { font: 400 300px/1 'Instrument Serif', serif; letter-spacing: 0.02em; display: flex; }
.end-title span { display: inline-block; opacity: 0; transform: translateY(40px) rotate(-4deg); transition: opacity 0.9s ease, transform 1.3s cubic-bezier(0.2, 0.7, 0.2, 1); }
.end-title .sp { width: 90px; }
#the-end.shown .end-title span { opacity: 1; transform: none; }
.end-title span:nth-child(1) { transition-delay: 1.0s; } .end-title span:nth-child(2) { transition-delay: 1.08s; }
.end-title span:nth-child(3) { transition-delay: 1.16s; } .end-title span:nth-child(5) { transition-delay: 1.3s; }
.end-title span:nth-child(6) { transition-delay: 1.38s; } .end-title span:nth-child(7) { transition-delay: 1.46s; }
.end-sub { font: 500 34px/1 'Inter', sans-serif; letter-spacing: 0.24em; text-transform: uppercase; color: var(--muted); margin-top: 120px; opacity: 0; transition: opacity 1s ease 2.8s; }
#the-end.shown .end-sub { opacity: 1; }
#the-end:not(.shown) * { transition-delay: 0s !important; transition-duration: 0.3s !important; }

/* ---------- hud ---------- */
#hud {
  position: fixed; right: 28px; bottom: 22px; display: flex; gap: 18px; align-items: baseline;
  font: 500 13px/1 'Inter', sans-serif; color: var(--muted); letter-spacing: 0.08em; user-select: none;
}
#counter { color: var(--ink); font-variant-numeric: tabular-nums; }