/* BlattBot landing — iron-gall ink and laid paper, typeset like a paper. */

:root {
  --ink: #12151d;
  --ink-2: #191d27;
  --ink-3: #212633;
  --rule: #2d3342;
  --paper: #e8e4d8;
  --paper-dim: #b9b6ab;
  --graphite: #7d8294;
  --leaf: #8fb573;
  --leaf-deep: #4f7942;
  --pencil: #e06552;
  --gold: #cfa75b;

  --serif: "Spectral", Georgia, serif;
  --sans: "IBM Plex Sans", system-ui, sans-serif;
  --mono: "IBM Plex Mono", ui-monospace, monospace;

  --measure: 66rem;
}

* {
  box-sizing: border-box;
  margin: 0;
  scrollbar-width: thin;
  scrollbar-color: var(--rule) transparent;
}

html {
  scroll-behavior: smooth;
}

body {
  background: var(--ink);
  color: var(--paper);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

::selection {
  background: color-mix(in srgb, var(--leaf) 35%, transparent);
}

:focus-visible {
  outline: 2px solid var(--leaf);
  outline-offset: 2px;
  border-radius: 2px;
}

a {
  color: var(--leaf);
  text-decoration: none;
}
a:hover {
  text-decoration: underline;
  text-underline-offset: 0.2em;
}

code {
  font-family: var(--mono);
  font-size: 0.88em;
  background: var(--ink-3);
  padding: 0.1em 0.35em;
  border-radius: 4px;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}

/* --- TeX wordmark: raised a, lowered o ---------------------------------- */

.tex-logo {
  font-family: var(--serif);
  font-weight: 600;
  letter-spacing: 0.01em;
}
.tex-logo .up {
  display: inline-block;
  transform: translateY(-0.22em);
  font-size: 0.78em;
  margin: 0 -0.04em;
  transition: transform 0.16s ease-out;
}
.tex-logo .down {
  display: inline-block;
  transform: translateY(0.13em);
  font-size: 0.78em;
  margin: 0 -0.02em;
  transition: transform 0.16s ease-out;
}
.tex-logo:hover .up,
.tex-logo:hover .down,
a:hover .tex-logo .up,
a:hover .tex-logo .down {
  transform: translateY(0);
}

/* Letters slide together once, on load (hero only). */
.tex-logo .lt {
  display: inline-block;
  animation: logo-slide-in 0.3s cubic-bezier(0.2, 0.6, 0.25, 1) backwards;
}
.tex-logo .lt:nth-child(1) { animation-delay: 0ms;   --lx: -0.5em; }
.tex-logo .lt:nth-child(2) { animation-delay: 40ms;  --lx: -0.36em; }
.tex-logo .lt:nth-child(3) { animation-delay: 80ms;  --lx: -0.24em; }
.tex-logo .lt:nth-child(4) { animation-delay: 120ms; --lx: -0.12em; }
.tex-logo .lt:nth-child(5) { animation-delay: 160ms; --lx: 0.12em; }
.tex-logo .lt:nth-child(6) { animation-delay: 200ms; --lx: 0.24em; }
.tex-logo .lt:nth-child(7) { animation-delay: 240ms; --lx: 0.36em; }
.tex-logo .lt:nth-child(8) { animation-delay: 280ms; --lx: 0.5em; }
@keyframes logo-slide-in {
  from {
    opacity: 0;
    transform: translateX(var(--lx, 0));
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

/* --- Booktabs: the double rule from academic tables --------------------- */

hr.booktabs {
  border: none;
  border-top: 2px solid var(--rule);
  position: relative;
  max-width: var(--measure);
  margin: 0 auto;
  width: calc(100% - 3rem);
}
hr.booktabs::after {
  content: "";
  position: absolute;
  top: 3px;
  left: 0;
  right: 0;
  border-top: 1px solid var(--rule);
}

/* --- Header ------------------------------------------------------------- */

.site-head {
  max-width: var(--measure);
  margin: 0 auto;
  padding: 1.1rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  color: var(--paper);
}
.brand:hover {
  text-decoration: none;
}
.brand-leaf {
  width: 18px;
  height: 34px;
}
.brand-mark {
  font-size: 1.25rem;
}
.site-nav {
  display: flex;
  gap: 1.4rem;
  font-size: 0.92rem;
}
.site-nav a {
  color: var(--paper-dim);
}
.site-nav a:hover {
  color: var(--leaf);
}

/* --- Hero --------------------------------------------------------------- */

.hero {
  max-width: var(--measure);
  margin: 0 auto;
  padding: 3.5rem 1.5rem 4.5rem;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
}
.hero-leaf {
  width: 34px;
  height: 64px;
  margin-bottom: 0.6rem;
}
.hero-mark {
  font-size: clamp(3.1rem, 9vw, 5.4rem);
  line-height: 1.1;
  font-weight: 600;
}
.claim {
  font-family: var(--serif);
  font-size: clamp(1.15rem, 2.6vw, 1.45rem);
  color: var(--paper);
  margin-top: 1.1rem;
  max-width: 34em;
  text-wrap: balance;
}
.claim em {
  color: var(--leaf);
  font-style: italic;
}

.install {
  margin-top: 1.9rem;
  display: inline-flex;
  align-items: baseline;
  gap: 0.7rem;
  font-family: var(--mono);
  font-size: 1.05rem;
  color: var(--paper);
  background: var(--ink-2);
  border: 1px solid var(--rule);
  border-radius: 8px;
  padding: 0.72rem 1.1rem 0.72rem 1.2rem;
  cursor: pointer;
  transition: border-color 0.15s ease-out;
}
.install:hover {
  border-color: var(--leaf-deep);
}
.install-prompt {
  color: var(--graphite);
}
.install-hint {
  font-size: 0.72rem;
  color: var(--graphite);
  border: 1px solid var(--rule);
  border-radius: 5px;
  padding: 0.15rem 0.5rem;
  margin-left: 0.35rem;
  transition: color 0.15s ease-out, border-color 0.15s ease-out;
}
.install:hover .install-hint {
  color: var(--paper-dim);
}
.install.is-copied {
  border-color: var(--leaf-deep);
}
.install.is-copied .install-hint {
  color: var(--leaf);
  border-color: var(--leaf-deep);
}

.subline {
  margin-top: 1.1rem;
  font-size: 0.95rem;
  color: var(--graphite);
}

/* --- Figures (screenshots as numbered figures) -------------------------- */

.shot {
  width: 100%;
}
.shot img,
.shot video {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--rule);
  border-radius: 10px;
  background: var(--ink-2);
  box-shadow: 0 24px 60px -24px rgb(0 0 0 / 0.6);
}
.shot figcaption {
  margin-top: 0.8rem;
  font-family: var(--serif);
  font-size: 0.92rem;
  color: var(--paper-dim);
  text-align: center;
  font-style: italic;
}
.fig-n {
  font-style: normal;
  font-variant-caps: all-small-caps;
  letter-spacing: 0.04em;
  color: var(--gold);
}

/* The demo video dominates the fold: wide, raised on load,
   straightening from a slight 3D tilt as it scrolls into view.
   The rise runs on the figure, the tilt on the video itself,
   so the two transforms never fight. */
.hero-shot {
  margin-top: 3.2rem;
  width: min(1200px, 92vw);
  max-width: none;
  animation: hero-rise 0.7s cubic-bezier(0.22, 1, 0.36, 1) 0.35s backwards;
}
.hero-shot video {
  /* Reserve the frame before any media arrives: no layout shift. */
  aspect-ratio: 1440 / 900;
  border-radius: 12px;
  box-shadow:
    0 24px 50px -20px rgb(0 0 0 / 0.55),
    0 60px 130px -40px rgb(0 0 0 / 0.6);
}
@keyframes hero-rise {
  from {
    opacity: 0;
    transform: translateY(24px) scale(0.96);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

/* Primary tilt implementation: CSS scroll-driven animation.
   Browsers without support get the same effect from the JS fallback. */
@media (min-width: 881px) {
  @supports (animation-timeline: view()) {
    .hero-shot video {
      animation: hero-untilt linear both;
      animation-timeline: view();
      animation-range: entry 0% entry 100%;
    }
  }
}
@keyframes hero-untilt {
  from {
    transform: perspective(1200px) rotateX(7deg) scale(0.96);
  }
  to {
    transform: perspective(1200px) rotateX(0deg) scale(1);
  }
}
@keyframes hero-rise-flat {
  from {
    opacity: 0;
    transform: translateY(18px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

/* --- Click-to-enlarge figures ------------------------------------------- */

/* The screenshot sits inside a real <button> so Enter/Space work for free. */
.figure-zoom {
  display: block;
  width: 100%;
  padding: 0;
  border: 0;
  background: none;
  font: inherit;
  cursor: zoom-in;
  border-radius: 10px;
}
.figure-zoom img {
  transition: transform 0.16s ease-out, border-color 0.16s ease-out;
}
.figure-zoom:hover img,
.figure-zoom:focus-visible img {
  transform: scale(1.01);
  border-color: color-mix(in srgb, var(--leaf) 40%, transparent);
}

.lightbox {
  position: fixed;
  inset: 0;
  z-index: 100;
  outline: none;
}
.lightbox-backdrop {
  position: absolute;
  inset: 0;
  background: rgb(18 21 29 / 0.85);
  -webkit-backdrop-filter: blur(6px);
  backdrop-filter: blur(6px);
  cursor: zoom-out;
  opacity: 0;
  transition: opacity 0.35s cubic-bezier(0.22, 1, 0.36, 1);
}
.lightbox.in .lightbox-backdrop {
  opacity: 1;
}
.lightbox-img {
  position: absolute;
  border: 1px solid var(--rule);
  border-radius: 10px;
  background: var(--ink-2);
  box-shadow: 0 40px 100px -30px rgb(0 0 0 / 0.75);
  cursor: zoom-out;
  transform-origin: top left;
  transition: transform 0.35s cubic-bezier(0.22, 1, 0.36, 1);
  will-change: transform;
}
.lightbox-caption {
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
  width: max-content;
  max-width: min(92vw, 46rem);
  font-family: var(--serif);
  font-size: 1.02rem;
  font-style: italic;
  color: var(--paper-dim);
  text-align: center;
  opacity: 0;
  transition: opacity 0.25s ease-out;
}
.lightbox.in .lightbox-caption {
  opacity: 1;
  transition: opacity 0.35s ease-out 0.1s;
}

.will-reveal {
  opacity: 0;
  transform: translateY(14px);
}
.will-reveal.in {
  opacity: 1;
  transform: none;
  transition: opacity 0.55s ease-out, transform 0.55s ease-out;
}

/* --- Feature sections ---------------------------------------------------- */

.feature {
  max-width: var(--measure);
  margin: 0 auto;
  padding: 4.2rem 1.5rem;
  display: grid;
  grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
  gap: 2.8rem 3.4rem;
  align-items: center;
}
.feature.flip .feature-text {
  order: 2;
}

.eyebrow {
  font-family: var(--mono);
  font-size: 0.82rem;
  color: var(--leaf);
  margin-bottom: 0.9rem;
}
.eyebrow.end {
  margin-top: 1.6rem;
  margin-bottom: 0;
}

.feature-text h2 {
  font-family: var(--serif);
  font-weight: 600;
  font-size: clamp(1.5rem, 3vw, 1.9rem);
  line-height: 1.25;
  text-wrap: balance;
}
.feature-text p {
  margin-top: 0.9rem;
  color: var(--paper-dim);
  font-size: 1rem;
  max-width: 34em;
}

/* --- How it works -------------------------------------------------------- */

.how {
  max-width: var(--measure);
  margin: 0 auto;
  padding: 4.2rem 1.5rem 4.6rem;
}
.how h2 {
  font-family: var(--serif);
  font-weight: 600;
  font-size: clamp(1.5rem, 3vw, 1.9rem);
}
.pipeline {
  margin-top: 1.4rem;
  font-family: var(--mono);
  font-size: 0.82rem;
  line-height: 1.7;
  color: var(--gold);
  background: var(--ink-2);
  border: 1px solid var(--rule);
  border-radius: 8px;
  padding: 1rem 1.2rem;
  overflow-x: auto;
}
.steps {
  margin-top: 2rem;
  padding: 0;
  list-style: none;
  counter-reset: step;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 2rem;
}
.steps li {
  counter-increment: step;
  border-top: 1px solid var(--rule);
  padding-top: 1rem;
}
.steps li::before {
  content: counter(step) ".";
  font-family: var(--mono);
  font-size: 0.85rem;
  color: var(--gold);
  display: block;
  margin-bottom: 0.5rem;
}
.steps h3 {
  font-family: var(--serif);
  font-weight: 600;
  font-size: 1.12rem;
}
.steps h3 code {
  font-size: 0.86em;
  color: var(--leaf);
}
.steps p {
  margin-top: 0.45rem;
  font-size: 0.94rem;
  color: var(--paper-dim);
}
.requirements {
  margin-top: 2.4rem;
  font-size: 0.92rem;
  color: var(--graphite);
}
.requirements strong {
  color: var(--paper-dim);
  font-weight: 500;
}

/* --- Footer -------------------------------------------------------------- */

.site-foot {
  padding-bottom: 3rem;
}
.foot-row {
  max-width: var(--measure);
  margin: 0 auto;
  padding: 1.6rem 1.5rem 0;
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
}
.foot-brand {
  color: var(--paper-dim);
  font-size: 0.95rem;
}
.foot-brand .tex-logo {
  font-size: 1.05rem;
  color: var(--paper);
}
.foot-links {
  font-size: 0.92rem;
  color: var(--graphite);
}

/* --- Responsive ---------------------------------------------------------- */

@media (max-width: 880px) {
  .feature {
    grid-template-columns: minmax(0, 1fr);
    padding: 3rem 1.25rem;
    gap: 1.6rem;
  }
  .feature.flip .feature-text {
    order: 0;
  }
  .steps {
    grid-template-columns: minmax(0, 1fr);
    gap: 1.4rem;
  }
  .hero {
    padding: 2.4rem 1.25rem 3.2rem;
  }
  .site-head {
    padding: 0.9rem 1.25rem;
  }
  .how {
    padding: 3rem 1.25rem 3.4rem;
  }
  .foot-row {
    padding-left: 1.25rem;
    padding-right: 1.25rem;
  }
  hr.booktabs {
    width: calc(100% - 2.5rem);
  }
  /* Screenshots and the demo video run edge to edge on small screens */
  .feature .shot,
  .hero-shot {
    width: calc(100% + 2.5rem);
    margin-left: -1.25rem;
  }
  .hero-shot {
    align-self: stretch;
    max-width: none;
    /* No tilt on small screens, just a clean fade-up. */
    animation-name: hero-rise-flat;
  }
  .hero-shot video {
    animation: none;
    transform: none;
  }
  .shot img,
  .shot video {
    border-radius: 0;
    border-left: none;
    border-right: none;
  }
  .shot figcaption {
    padding: 0 1.25rem;
  }
}

/* --- Reduced motion ------------------------------------------------------ */

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  .tex-logo .lt {
    animation: none;
  }
  .tex-logo .up,
  .tex-logo .down {
    transition: none;
  }
  .will-reveal {
    opacity: 1;
    transform: none;
  }
  .will-reveal.in {
    transition: none;
  }
  .hero-shot {
    animation: none;
  }
  .hero-shot video {
    animation: none;
    transform: none;
  }
  .figure-zoom img {
    transition: none;
  }
  .figure-zoom:hover img,
  .figure-zoom:focus-visible img {
    transform: none;
  }
  .lightbox-backdrop,
  .lightbox-img,
  .lightbox-caption,
  .lightbox.in .lightbox-caption {
    transition: none;
  }
}