:root {
  --paper: #F0EEE6;
  --paper-2: #E8E5DA;
  --ink: #1F1E1D;
  --ink-soft: #57544D;
  --ink-faint: #8A8579;
  --coral: #D97757;
  --clay: #BD5D45;
  --line: rgba(31, 30, 29, 0.12);
  --serif: "Newsreader", Georgia, "Times New Roman", serif;
  --sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  --mono: ui-monospace, "SF Mono", "JetBrains Mono", Menlo, Consolas, monospace;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html, body {
  height: 100%;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow: hidden;
}

/* paper grain */
.grain {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 5;
  opacity: 0.5;
  mix-blend-mode: multiply;
  background-image:
    radial-gradient(rgba(31,30,29,0.05) 1px, transparent 1px);
  background-size: 3px 3px;
}

/* progress bar */
.progress {
  position: fixed;
  top: 0; left: 0;
  height: 3px;
  width: 0%;
  background: linear-gradient(90deg, var(--coral), var(--clay));
  z-index: 20;
  transition: width 0.5s cubic-bezier(0.22, 1, 0.36, 1);
}

/* deck + slides */
.deck { position: relative; height: 100%; width: 100%; }

.slide {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: flex-start;
  padding: clamp(2rem, 7vw, 9rem);
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transform: translateY(14px);
  transition: opacity 0.55s ease, transform 0.55s cubic-bezier(0.22, 1, 0.36, 1);
}
.slide.is-active {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
  transform: none;
}
.slide.is-active .slide__inner > * { animation: rise 0.6s cubic-bezier(0.22,1,0.36,1) backwards; }
.slide.is-active .slide__inner > *:nth-child(1) { animation-delay: 0.05s; }
.slide.is-active .slide__inner > *:nth-child(2) { animation-delay: 0.13s; }
.slide.is-active .slide__inner > *:nth-child(3) { animation-delay: 0.21s; }
.slide.is-active .slide__inner > *:nth-child(4) { animation-delay: 0.29s; }
.slide.is-active .slide__inner > *:nth-child(5) { animation-delay: 0.37s; }

@keyframes rise { from { opacity: 0; transform: translateY(16px); } to { opacity: 1; transform: none; } }

.slide__inner { max-width: 60rem; width: 100%; }

/* eyebrow / labels */
.eyebrow {
  font-family: var(--mono);
  font-size: 0.78rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--ink-soft);
  margin-bottom: 1.6rem;
  display: flex;
  align-items: center;
  gap: 0.55rem;
}
.ast { color: var(--coral); font-size: 1rem; }

.num {
  font-family: var(--mono);
  font-size: 0.95rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  color: var(--coral);
  margin-bottom: 1.4rem;
}
.num::before { content: ""; }

/* headings */
h1.title {
  font-family: var(--serif);
  font-weight: 500;
  font-size: clamp(2.8rem, 8.5vw, 7rem);
  line-height: 1.02;
  letter-spacing: -0.02em;
  margin-bottom: 1.8rem;
}
h1.title em { color: var(--coral); font-style: italic; }

.slide h2 {
  font-family: var(--serif);
  font-weight: 500;
  font-size: clamp(1.9rem, 4.6vw, 3.4rem);
  line-height: 1.1;
  letter-spacing: -0.015em;
  margin-bottom: 1.6rem;
  position: relative;
  padding-bottom: 1.1rem;
}
.slide h2::after {
  content: "";
  position: absolute;
  left: 0; bottom: 0;
  width: 3.5rem; height: 3px;
  background: var(--coral);
  border-radius: 2px;
}

.lede {
  font-size: clamp(1.05rem, 2vw, 1.5rem);
  line-height: 1.5;
  color: var(--ink-soft);
  max-width: 42rem;
  margin-bottom: 2.4rem;
}

.title__meta {
  display: inline-flex;
  align-items: center;
  gap: 1rem;
  font-family: var(--mono);
  font-size: 0.95rem;
  letter-spacing: 0.05em;
  color: var(--ink-soft);
  padding: 0.6rem 1.1rem;
  border: 1px solid var(--line);
  border-radius: 999px;
}
.title__meta .arrow { color: var(--coral); }

/* points */
.points { list-style: none; display: grid; gap: 1.05rem; }
.points li {
  position: relative;
  padding-left: 2rem;
  font-size: clamp(1.05rem, 2vw, 1.45rem);
  line-height: 1.45;
  color: var(--ink);
}
.points li::before {
  content: "";
  position: absolute;
  left: 0; top: 0.62em;
  width: 0.7rem; height: 0.7rem;
  background: var(--coral);
  border-radius: 50%;
}
.points strong { color: var(--clay); font-weight: 600; }

.aside {
  margin-top: 1.9rem;
  padding: 1rem 1.3rem;
  border-left: 3px solid var(--coral);
  background: rgba(217, 119, 87, 0.07);
  border-radius: 0 8px 8px 0;
  font-size: clamp(1rem, 1.8vw, 1.25rem);
  line-height: 1.45;
  color: var(--ink-soft);
}

/* chips */
.chips { display: flex; flex-wrap: wrap; gap: 0.7rem; margin-top: 2rem; }
.chip {
  font-family: var(--mono);
  font-size: 0.95rem;
  letter-spacing: 0.02em;
  padding: 0.55rem 1.1rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: rgba(255,255,255,0.35);
  color: var(--ink);
}

/* thesis slide */
.slide--thesis { background:
  radial-gradient(120% 120% at 80% 10%, rgba(217,119,87,0.10), transparent 55%); }
h2.thesis {
  font-size: clamp(2rem, 5vw, 4rem);
  line-height: 1.14;
  padding-bottom: 0;
  max-width: 52rem;
}
h2.thesis::after { display: none; }
h2.thesis em { color: var(--coral); font-style: italic; }

/* response slide */
.response { list-style: none; display: grid; gap: 1rem; margin-top: 0.5rem; counter-reset: r; }
.response li {
  display: flex;
  align-items: center;
  gap: 1.1rem;
  font-size: clamp(1.05rem, 2vw, 1.5rem);
  line-height: 1.3;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--line);
}
.response li:last-child { border-bottom: 0; }
.response li span {
  flex: 0 0 auto;
  width: 2.2rem; height: 2.2rem;
  display: grid; place-items: center;
  font-family: var(--mono);
  font-size: 0.95rem;
  font-weight: 600;
  color: #fff;
  background: var(--coral);
  border-radius: 50%;
}

/* nav arrows */
.nav {
  position: fixed;
  top: 50%;
  transform: translateY(-50%);
  z-index: 15;
  width: 3rem; height: 3rem;
  border: 1px solid var(--line);
  background: rgba(255,255,255,0.4);
  backdrop-filter: blur(6px);
  color: var(--ink);
  font-size: 1.6rem;
  line-height: 1;
  border-radius: 50%;
  cursor: pointer;
  display: grid; place-items: center;
  transition: all 0.2s ease;
  opacity: 0.55;
}
.nav:hover { opacity: 1; border-color: var(--coral); color: var(--coral); }
.nav--prev { left: 1.4rem; }
.nav--next { right: 1.4rem; }
.nav[disabled] { opacity: 0.15; cursor: default; }

/* HUD */
.hud {
  position: fixed;
  right: 1.6rem; bottom: 1.4rem;
  z-index: 15;
}
.counter {
  font-family: var(--mono);
  font-size: 0.85rem;
  letter-spacing: 0.1em;
  color: var(--ink-soft);
}
.counter #cur { color: var(--coral); font-weight: 600; }
.counter__sep { opacity: 0.4; margin: 0 0.15rem; }

/* hint */
.hint {
  position: fixed;
  left: 1.6rem; bottom: 1.4rem;
  z-index: 15;
  font-family: var(--mono);
  font-size: 0.75rem;
  color: var(--ink-faint);
  transition: opacity 0.6s ease;
}
.hint kbd {
  font-family: var(--mono);
  background: rgba(255,255,255,0.5);
  border: 1px solid var(--line);
  border-radius: 4px;
  padding: 0.05rem 0.35rem;
  font-size: 0.7rem;
}
.hint.is-hidden { opacity: 0; }

@media (max-width: 640px) {
  .nav { display: none; }
  .hint { display: none; }
  .slide { padding: 2rem 1.4rem 4.5rem; align-items: flex-start; padding-top: 4rem; overflow-y: auto; }
}

@media (prefers-reduced-motion: reduce) {
  .slide, .progress { transition: opacity 0.2s ease; }
  .slide.is-active .slide__inner > * { animation: none; }
  .slide { transform: none; }
}