:root {
  --alberti-red: #b5121b;
  --alberti-dark: #760b12;
  --alberti-ink: #292929;
  --alberti-soft: #fff5f5;
  --alberti-line: #efcdd0;
}

.reveal {
  color: var(--alberti-ink);
  font-family: "Segoe UI", system-ui, sans-serif;
  font-size: 30px;
  background: radial-gradient(ellipse at 100% 0%, #b5121b0d, transparent 34%), #fff;
}

.reveal .slides section {
  box-sizing: border-box;
  padding: .3em .6em;
  text-align: left;
}

.reveal h1,
.reveal h2,
.reveal h3 {
  color: var(--alberti-dark);
  font-family: "Segoe UI", system-ui, sans-serif;
  font-weight: 800;
  letter-spacing: -.025em;
  text-wrap: balance;
}

.reveal h1 {
  display: inline-block;
  padding: .12em .34em;
  border-radius: .18em;
  background: linear-gradient(120deg, var(--alberti-red), #d6323b);
  color: #fff;
  font-size: 1.55em;
}

.reveal h2 {
  display: table;
  margin: 0 auto .28em;
  padding: 0 0 .1em;
  border-bottom: .06em solid var(--alberti-red);
  font-size: 1.12em;
  text-align: center;
}

.reveal h3 { color: var(--alberti-red); font-size: .88em; }
.reveal p, .reveal li { line-height: 1.22; }
.reveal li { margin-bottom: .14em; }
.reveal ul { margin-top: .3em; margin-bottom: .3em; }
.reveal ul li::marker { color: var(--alberti-red); }
.reveal strong { color: var(--alberti-dark); }
.reveal a { color: var(--alberti-red); }

.reveal img {
  max-width: 72%;
  max-height: 36vh;
  margin: .25em auto;
  border: 0;
  border-radius: 14px;
  box-shadow: none;
  object-fit: contain;
}

.reveal .activity-timeline {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: .28em;
  margin: .45em 0;
}

.reveal .activity-timeline div {
  display: flex;
  min-height: 2.15em;
  flex-direction: column;
  justify-content: center;
  padding: .25em .38em;
  border-left: .12em solid var(--alberti-red);
  border-radius: .12em;
  background: var(--alberti-soft);
  font-size: .64em;
  line-height: 1.12;
}

.reveal .activity-timeline b { color: var(--alberti-red); }
.reveal .activity-timeline span { margin-top: .12em; }
.reveal table { font-size: .62em; }
.reveal .slide-number { color: var(--alberti-red); }

.reveal .slides section:has(.question-poster) ul,
.reveal .slides section:has(.folding-guide) ul {
  max-width: 64%;
}

.reveal .question-poster,
.reveal .folding-guide {
  position: absolute;
  z-index: 1;
  top: 20%;
  right: 4%;
  display: block;
  width: 25%;
  text-align: center;
}

.reveal .question-poster img {
  width: auto;
  max-width: 100%;
  max-height: 58vh;
  margin: 0;
}

.reveal .folding-guide {
  top: 18%;
  width: 27%;
}

.reveal .folding-guide img {
  width: 100%;
  max-width: 100%;
  max-height: 62vh;
  margin: 0;
}

@media (max-height: 760px) {
  .reveal { font-size: 26px; }
  .reveal img { max-height: 30vh; }
  .reveal .activity-timeline div { min-height: 1.8em; }
}

@media (max-width: 700px) {
  .reveal { font-size: 22px; }
  .reveal .slides section { padding: .3em; }
  .reveal .activity-timeline { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .reveal img { max-width: 88%; max-height: 27vh; }
}