:root {
  --ink: #17344c;
  --muted: #4e667c;
  --blue: #0e4c8a;
  --blue-bright: #1a73c7;
  --line: #d5e5f3;
  --paper: #f4f8fc;
  --white: #ffffff;
  --shadow: 0 18px 50px rgba(18, 62, 110, 0.08);
  --content: 1080px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(900px 420px at 50% -40px, rgba(46, 130, 206, 0.16), transparent 70%),
    var(--paper);
  font-family: "Nunito Sans", "Segoe UI", sans-serif;
  font-size: 20px;
  line-height: 1.65;
}

img, video { max-width: 100%; }

a { color: var(--blue-bright); text-decoration-thickness: 1px; text-underline-offset: 3px; }
a:hover { color: var(--blue); }

.skip {
  position: absolute;
  left: 12px;
  top: -40px;
  background: var(--blue);
  color: white;
  padding: 8px 12px;
  border-radius: 8px;
  z-index: 30;
}
.skip:focus { top: 12px; }

.topnav {
  position: sticky;
  top: 0;
  z-index: 20;
  background: rgba(244, 248, 252, 0.88);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--line);
}

.topnav nav {
  max-width: var(--content);
  margin: 0 auto;
  padding: 0 22px;
  display: flex;
  justify-content: center;
  gap: 8px 22px;
  overflow-x: auto;
}

.topnav a {
  color: #5d7388;
  text-decoration: none;
  font-size: 16.5px;
  font-weight: 700;
  letter-spacing: 0.01em;
  padding: 16px 0 14px;
  border-bottom: 2px solid transparent;
  white-space: nowrap;
}

.topnav a:hover,
.topnav a.active {
  color: var(--blue);
  border-bottom-color: var(--blue);
}

.wrap {
  max-width: var(--content);
  margin: 0 auto;
  padding: 0 22px;
}

.hero {
  text-align: center;
  padding: 72px 0 28px;
}

.venue {
  display: inline-block;
  margin: 0 0 18px;
  padding: 4px 12px;
  border-radius: 999px;
  background: #e5f1fb;
  color: var(--blue);
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 0.14em;
}

.wordmark {
  margin: 0;
  font-family: Fraunces, Georgia, serif;
  font-weight: 650;
  font-size: clamp(4.4rem, 11vw, 7.4rem);
  letter-spacing: -0.045em;
  line-height: 0.9;
  background: linear-gradient(180deg, #08315f 0%, #0e4c8a 42%, #5eb0ef 78%, #0e4c8a 100%);
  background-size: 100% 220%;
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  animation: sheen 10s ease-in-out infinite;
}

.subtitle {
  max-width: 760px;
  margin: 22px auto 0;
  font-size: clamp(1.25rem, 2.4vw, 1.7rem);
  font-weight: 750;
  letter-spacing: -0.02em;
  line-height: 1.35;
  color: #1d3e5c;
}

.authors {
  max-width: 820px;
  margin: 22px auto 0;
  font-size: 1.05rem;
  font-weight: 800;
  line-height: 1.7;
}

.authors a {
  color: var(--blue);
  text-decoration: none;
  margin: 0 0.35rem;
}

.authors a:hover { text-decoration: underline; }

.authors sup, .affil sup {
  font-size: 0.72em;
  color: var(--blue-bright);
}

.affil, .emails {
  margin: 4px auto 0;
  color: var(--muted);
  font-size: 15px;
}

.emails a {
  color: var(--muted);
  margin: 0 0.35rem;
  font-size: 13.5px;
  text-decoration: none;
}

.emails a:hover { color: var(--blue); }

.deck {
  max-width: 720px;
  margin: 18px auto 0;
  color: var(--muted);
  font-size: 1.02rem;
}

.actions {
  display: flex;
  justify-content: center;
  gap: 12px;
  margin-top: 28px;
}

.button {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--blue);
  color: white;
  text-decoration: none;
  border: 0;
  border-radius: 999px;
  padding: 11px 18px;
  font: inherit;
  font-size: 15px;
  font-weight: 800;
  box-shadow: 0 8px 20px rgba(14, 76, 138, 0.22);
  cursor: pointer;
}

.button:hover { background: #0b3e72; color: white; }
.button.ghost {
  background: white;
  color: var(--blue);
  box-shadow: none;
  border: 1px solid #c5daf0;
}
.button.ghost:hover { background: #eef6fd; }

.button svg { width: 16px; height: 16px; fill: currentColor; }

section.page { padding: 120px 0 28px; }

h2 {
  margin: 0 0 22px;
  text-align: center;
  font-size: clamp(2.15rem, 3.6vw, 2.8rem);
  letter-spacing: -0.03em;
  line-height: 1.15;
}

.lead, .prose {
  max-width: 760px;
  margin: 0 auto 28px;
  color: #2c4a63;
}

.prose p { margin: 0 0 14px; }

.stage, .compare, .video-frame, .thumb img {
  border-radius: 16px;
  box-shadow: var(--shadow);
}

.stage {
  background: white;
  border: 1px solid var(--line);
  overflow: hidden;
}

.stage img, .video-frame video {
  display: block;
  width: 100%;
  height: auto;
  background: #071421;
}

.caption {
  margin: 14px 0 0;
  text-align: center;
  color: var(--muted);
  font-size: 16.5px;
}

.tabs, .segment {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 8px;
}

.tabs { margin: 8px 0 18px; }
.segment { margin: 0 0 16px; }

.tabs button, .segment button, .thumbs button {
  font: inherit;
  cursor: pointer;
}

.tabs button, .segment button {
  border: 1px solid #c9dff1;
  background: white;
  color: var(--blue);
  border-radius: 999px;
  padding: 7px 14px;
  font-size: 15.5px;
  font-weight: 800;
}

.tabs button[aria-pressed="true"],
.segment button[aria-pressed="true"] {
  background: var(--blue);
  border-color: var(--blue);
  color: white;
}

.thumbs {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 10px;
  margin-top: 14px;
}

.thumbs button {
  padding: 0;
  border: 2px solid transparent;
  border-radius: 12px;
  background: transparent;
  overflow: hidden;
}

.thumbs button[aria-pressed="true"] { border-color: var(--blue); }
.thumbs img { display: block; width: 100%; height: 74px; object-fit: cover; border-radius: 10px; box-shadow: none; }
.thumbs span {
  display: block;
  padding: 6px 4px 2px;
  color: var(--muted);
  font-size: 12px;
  font-weight: 800;
}

.pair {
  display: grid;
  gap: 18px;
}

.pair figure { margin: 0; }

.pair img {
  display: block;
  width: 100%;
  height: auto;
  border-radius: 16px;
  background: #071421;
  border: 1px solid var(--line);
  box-shadow: var(--shadow);
}

.pair figcaption {
  margin-top: 8px;
  text-align: center;
  color: var(--blue);
  font-size: 14px;
  font-weight: 800;
}

.diagram {
  margin: 28px 0 0;
  padding: 18px 18px 12px;
  background: white;
  border: 1px solid var(--line);
  border-radius: 16px;
  box-shadow: var(--shadow);
  transition: transform 0.35s ease, box-shadow 0.35s ease;
}

.diagram:hover {
  transform: translateY(-4px);
  box-shadow: 0 22px 48px rgba(14, 76, 138, 0.14);
}

.diagram img {
  display: block;
  width: 100%;
  height: auto;
  background: white;
}

.diagram figcaption {
  margin: 12px 0 4px;
  text-align: center;
  color: var(--muted);
  font-size: 15px;
}

.compare {
  position: relative;
  overflow: hidden;
  background: #071421;
  border: 1px solid var(--line);
  touch-action: none;
}

.compare .base {
  display: block;
  width: 100%;
  height: auto;
}

.compare .clip {
  position: absolute;
  top: 0;
  left: 0;
  bottom: 0;
  width: 50%;
  overflow: hidden;
}

.compare .over {
  position: absolute;
  top: 0;
  left: 0;
  max-width: none;
  object-fit: fill;
}

.handle {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 50%;
  width: 2px;
  background: white;
  transform: translateX(-1px);
  pointer-events: none;
  z-index: 2;
  box-shadow: 0 0 0 1px rgba(14, 76, 138, 0.25);
}

.handle::after {
  content: "";
  position: absolute;
  left: 50%;
  top: 50%;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  transform: translate(-50%, -50%);
  background:
    linear-gradient(#fff, #fff) 13px 50% / 2px 14px no-repeat,
    linear-gradient(#fff, #fff) 50% 50% / 2px 14px no-repeat,
    linear-gradient(#fff, #fff) 29px 50% / 2px 14px no-repeat,
    #0e4c8a;
  border: 3px solid white;
  box-shadow: 0 8px 18px rgba(8, 30, 58, 0.28);
}

.compare input[type="range"] {
  position: absolute;
  inset: 0;
  width: 100%;
  margin: 0;
  opacity: 0;
  cursor: ew-resize;
}

.tag {
  position: absolute;
  top: 14px;
  z-index: 2;
  padding: 4px 10px;
  border-radius: 999px;
  background: rgba(8, 28, 48, 0.72);
  color: white;
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0.04em;
  pointer-events: none;
}
.tag.before { left: 14px; }
.tag.after { right: 14px; }

.reasons {
  max-width: 760px;
  margin: 0 auto;
  padding: 0;
  list-style: none;
}

.reasons li {
  position: relative;
  margin: 0 0 14px;
  padding-left: 28px;
  color: #2c4a63;
}

.reasons li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.55em;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: linear-gradient(180deg, #3d97e0, #0e4c8a);
}

.pipeline {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 14px;
  margin: 34px 0 8px;
  padding: 0;
  list-style: none;
}

.pipeline li {
  background: white;
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 18px 16px 16px;
  box-shadow: var(--shadow);
}

.pipeline .step {
  display: block;
  color: var(--blue-bright);
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 0.08em;
}

.pipeline h3 {
  margin: 6px 0 8px;
  font-size: 1.05rem;
  letter-spacing: -0.02em;
}

.pipeline p {
  margin: 0;
  color: var(--muted);
  font-size: 15.5px;
  line-height: 1.5;
}

.video-frame {
  overflow: hidden;
  background: #071421;
  border: 1px solid var(--line);
}

.video-frame video { background: #071421; }

.levels {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 12px;
  margin-top: 10px;
}

.levels article {
  background: white;
  border: 1px solid var(--line);
  border-radius: 16px;
  overflow: hidden;
  box-shadow: var(--shadow);
}

.levels img { display: block; width: 100%; height: 92px; object-fit: cover; }
.levels h3 {
  margin: 12px 14px 0;
  font-size: 15px;
}
.levels p {
  margin: 6px 14px 14px;
  color: var(--muted);
  font-size: 13.5px;
  line-height: 1.45;
}

.swatch {
  height: 6px;
}
.swatch.s1 { background: #d7ebf9; }
.swatch.s2 { background: #9dcef0; }
.swatch.s3 { background: #4f9ed8; }
.swatch.s4 { background: #1d6fbf; }
.swatch.s5 { background: #0e4c8a; }

.bib {
  max-width: 760px;
  margin: 0 auto;
  position: relative;
}

.bib pre {
  margin: 0;
  padding: 22px 22px 56px;
  overflow: auto;
  background: #0d2c4a;
  color: #e7f3ff;
  border-radius: 16px;
  font-size: 14px;
  line-height: 1.55;
  box-shadow: var(--shadow);
}

.bib .button {
  position: absolute;
  right: 14px;
  bottom: 14px;
}

.footer {
  padding: 48px 0 36px;
  text-align: center;
  color: var(--muted);
  font-size: 14px;
}

.footer a { font-weight: 800; }

.method-steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin: 8px 0 6px;
  padding: 0;
  list-style: none;
}

.method-steps li {
  position: relative;
  background:
    linear-gradient(180deg, rgba(61, 151, 224, 0.08), transparent 42%),
    white;
  border: 1px solid var(--line);
  border-radius: 18px;
  padding: 22px 18px 18px;
  box-shadow: var(--shadow);
}

.method-steps .num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  margin-bottom: 12px;
  border-radius: 50%;
  background: linear-gradient(160deg, #5eb0ef, #0e4c8a);
  color: white;
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 0.04em;
  box-shadow: 0 8px 18px rgba(14, 76, 138, 0.28);
}

.method-steps h3 {
  margin: 0 0 8px;
  font-size: 1.15rem;
  letter-spacing: -0.02em;
}

.method-steps p {
  margin: 0;
  color: var(--muted);
  font-size: 15px;
  line-height: 1.55;
}

.method-split {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  align-items: stretch;
}

.method-split .diagram {
  margin: 18px 0 0;
  display: flex;
  flex-direction: column;
}

.method-split figcaption { margin-top: auto; }

.method-note { margin-top: 22px; }

.stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
  margin: 6px 0 26px;
}

.stats article {
  background: white;
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 16px 12px 14px;
  text-align: center;
  box-shadow: var(--shadow);
}

.stats strong {
  display: block;
  font-family: Fraunces, Georgia, serif;
  font-size: clamp(1.6rem, 2.4vw, 2rem);
  font-weight: 650;
  letter-spacing: -0.03em;
  color: var(--blue);
  line-height: 1.1;
}

.stats span {
  display: block;
  margin-top: 6px;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.35;
}

.sub { padding: 72px 0 8px; }

.sub > h3 {
  margin: 0 0 14px;
  text-align: center;
  font-size: clamp(1.75rem, 2.8vw, 2.25rem);
  letter-spacing: -0.03em;
}

.levels article,
.method-steps li,
.stats article {
  transition: transform 0.35s ease, box-shadow 0.35s ease;
}

.levels article:hover,
.method-steps li:hover,
.stats article:hover {
  transform: translateY(-4px);
  box-shadow: 0 18px 40px rgba(14, 76, 138, 0.12);
}

body::before {
  content: "";
  position: fixed;
  z-index: -1;
  inset: -12% -8% auto;
  height: 62vh;
  pointer-events: none;
  background:
    radial-gradient(380px 240px at 16% 30%, rgba(94, 176, 239, 0.28), transparent 70%),
    radial-gradient(460px 280px at 86% 8%, rgba(14, 76, 138, 0.16), transparent 72%);
  animation: drift 16s ease-in-out infinite alternate;
}

.reveal {
  opacity: 0;
  transform: translateY(18px);
}

.reveal.in {
  animation: rise 0.75s ease forwards;
  animation-delay: var(--d, 0ms);
}

@keyframes sheen {
  0%, 100% { background-position: 50% 0%; }
  50% { background-position: 50% 100%; }
}

@keyframes drift {
  from { transform: translate3d(0, 0, 0); }
  to { transform: translate3d(2%, 28px, 0); }
}

@keyframes rise {
  to { opacity: 1; transform: none; }
}

@media (max-width: 860px) {
  .pipeline, .levels, .method-steps, .method-split, .stats { grid-template-columns: 1fr; }
  .stats { grid-template-columns: 1fr 1fr; }
  .levels img { height: 160px; }
  .thumbs { grid-template-columns: repeat(5, minmax(72px, 1fr)); }
  .hero { padding-top: 48px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .wordmark, body::before, .reveal.in { animation: none; }
  .reveal { opacity: 1; transform: none; }
  .diagram:hover, .levels article:hover, .method-steps li:hover, .stats article:hover { transform: none; }
}