:root {
  --bg: #f5f4f1;
  --paper: #ffffff;
  --ink: #171717;
  --muted: #555555;
  --light: #7a7a7a;
  --line: #d6d2ca;
  --penn-blue: #011f5b;
  --penn-red: #990000;
  --penn-blue-soft: #e7edf7;
  --penn-red-soft: #f5e7e7;
  --card-border: #cbd3df;
  --card-shadow: 0 16px 38px rgba(1, 31, 91, 0.11);
  --accent: var(--penn-blue);
  --accent-soft: var(--penn-blue-soft);
  --active: var(--penn-red);
  --sidebar: 280px;
  --font-heading: "Google Sans", "Noto Sans", sans-serif;
  --font-body: "Noto Sans", Arial, sans-serif;
  --font-mono: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background:
    linear-gradient(180deg, #f8f7f3 0, var(--bg) 420px),
    var(--bg);
  color: var(--ink);
  font-family: var(--font-body);
}

a {
  color: inherit;
  text-decoration: none;
}

.toc {
  position: fixed;
  top: 100px;
  width: var(--sidebar);
  z-index: 1000;
  display: none;
  max-height: calc(100vh - 280px);
  overflow-y: auto;
  padding-right: 10px;
  opacity: 0;
  scrollbar-width: none;
  transition: opacity 0.3s ease-in-out;
}

.toc::-webkit-scrollbar {
  display: none;
}

@media (min-width: 1320px) {
  .toc.show {
    left: max(20px, calc(50vw - 770px));
    display: block;
    opacity: 1;
  }
}

.toc h3 {
  margin: 0 0 10px;
  color: #202020;
  font-family: var(--font-heading);
  font-size: 24px;
  font-weight: 700;
}

.toc hr {
  height: 1px;
  margin: 0 0 15px;
  border: 0;
  background-color: #cccccc;
}

.toc ul {
  margin: 0;
  padding: 0;
  list-style: none;
}

.toc li {
  margin-bottom: 6px;
}

.toc nav a {
  position: relative;
  color: #333333;
  font-family: var(--font-heading);
  font-size: 16px;
  line-height: 1.3;
  transition:
    color 0.16s ease,
    font-weight 0.16s ease;
}

.toc nav a:hover {
  color: #000000;
  text-decoration: underline;
  text-underline-offset: 3px;
}

.toc nav a.active {
  color: var(--active);
  font-weight: 900;
  padding-left: 12px;
  text-shadow: 0.02em 0 0 currentColor;
}

.toc nav a.active::before {
  position: absolute;
  left: 0;
  color: var(--active);
  font-weight: 900;
  text-shadow: 0.02em 0 0 currentColor;
  content: "|";
}

.page {
  width: min(960px, calc(100% - 32px));
  margin: 0 auto;
  padding: 0 0 80px;
}

.hero {
  position: relative;
  width: 100vw;
  margin: 0 0 74px calc(50% - 50vw);
}

.video-placeholder {
  position: relative;
  overflow: hidden;
  width: 100%;
  height: 100vh;
  min-height: 620px;
  border: 0;
  border-radius: 0;
  background:
    linear-gradient(180deg, rgba(0, 0, 0, 0.16), rgba(0, 0, 0, 0.72)),
    linear-gradient(135deg, #2b2b2b, #111111 58%, #393226);
}

.video-placeholder::after {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 50% 46%, rgba(1, 31, 91, 0.06), rgba(1, 31, 91, 0.28) 52%, rgba(1, 31, 91, 0.54)),
    linear-gradient(180deg, rgba(1, 31, 91, 0.24), rgba(0, 0, 0, 0.58));
  content: "";
  pointer-events: none;
}

.video-placeholder video {
  width: 100%;
  height: 100%;
  display: block;
  object-fit: cover;
}

.video-overlay {
  position: absolute;
  z-index: 1;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: clamp(28px, 6vw, 80px);
  color: white;
  text-align: center;
}

h1 {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.16em;
  max-width: 1100px;
  margin: 0;
  font-family: var(--font-heading);
  font-size: clamp(44px, 6.2vw, 88px);
  font-weight: 500;
  line-height: 1.05;
  letter-spacing: -0.045em;
}

.title-highlight {
  display: inline-block;
  font-weight: 900;
}

.video-overlay .title-highlight {
  padding: 0.02em 0.18em 0.08em;
  background: rgb(153, 0, 0);
  color: #ffffff;
  box-decoration-break: clone;
  -webkit-box-decoration-break: clone;
  -webkit-font-smoothing: antialiased;
}

.title-rest {
  display: block;
  font-size: 0.6em;
  font-weight: 500;
  letter-spacing: -0.035em;
  text-shadow: 0 4px 26px rgba(0, 0, 0, 0.42);
}

.scroll-cue {
  position: absolute;
  z-index: 2;
  bottom: clamp(24px, 5vh, 54px);
  left: 50%;
  display: grid;
  width: 52px;
  height: 52px;
  place-items: center;
  border: 2px solid rgba(255, 255, 255, 0.78);
  background: rgba(1, 31, 91, 0.42);
  color: #ffffff;
  font-family: var(--font-heading);
  font-size: 30px;
  font-weight: 800;
  line-height: 1;
  text-decoration: none;
  transform: translateX(-50%);
  animation: scroll-cue-bob 1.7s ease-in-out infinite;
  backdrop-filter: blur(8px);
}

.scroll-cue:hover,
.scroll-cue:focus-visible {
  border-color: #ffffff;
  background: rgba(153, 0, 0, 0.72);
  color: #ffffff;
}

.scroll-cue span {
  transform: translateY(-2px);
}

@keyframes scroll-cue-bob {
  0%,
  100% {
    transform: translate(-50%, 0);
  }

  50% {
    transform: translate(-50%, 9px);
  }
}

.publication-header .title-highlight {
  display: inline;
  padding: 0;
  background: transparent;
  color: inherit;
}

.publication-header {
  max-width: 980px;
  margin: 46px auto 0;
  color: var(--ink);
  text-align: center;
  scroll-margin-top: 24px;
}

.publication-header h2 {
  display: block;
  max-width: 1040px;
  margin: 0 auto 20px;
  padding: 0;
  border: 0;
  background: transparent;
  color: var(--ink);
  font-family: var(--font-heading);
  font-size: clamp(23px, 3.3vw, 43px);
  font-weight: 500;
  line-height: 1.13;
  letter-spacing: -0.025em;
}

.authors {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: baseline;
  gap: 6px 28px;
  max-width: 900px;
  margin: 0 auto;
  color: #232323;
  font-family: var(--font-heading);
  font-size: 17px;
  line-height: 1.35;
}

.authors span {
  white-space: nowrap;
}

.authors sup,
.author-note sup {
  color: var(--penn-red);
  font-weight: 900;
  vertical-align: baseline;
  position: relative;
  top: -0.5em;
  font-size: 0.75em;
}

.authors a {
  color: var(--penn-blue);
  text-decoration: underline;
  text-decoration-color: rgba(1, 31, 91, 0.38);
  text-underline-offset: 3px;
  transition:
    background 160ms ease,
    color 160ms ease,
    text-decoration-color 160ms ease;
}

.authors a:hover,
.authors a:focus-visible {
  background: var(--penn-blue-soft);
  color: var(--penn-red);
  text-decoration-color: var(--penn-red);
}

.author-note {
  margin: 8px auto 0;
  color: var(--muted);
  font-family: var(--font-heading);
  font-size: 14px;
  line-height: 1.35;
}

.paper-link-row {
  margin: 14px auto 0;
  color: var(--muted);
  font-family: var(--font-heading);
  font-size: 15px;
  font-weight: 800;
  line-height: 1.35;
}

.paper-link-row a {
  color: var(--penn-blue);
  text-decoration: underline;
  text-decoration-color: rgba(1, 31, 91, 0.36);
  text-underline-offset: 4px;
  transition:
    color 150ms ease,
    text-decoration-color 150ms ease;
}

.paper-link-row a:hover,
.paper-link-row a:focus-visible {
  color: var(--penn-red);
  text-decoration-color: var(--penn-red);
}

.lead {
  max-width: 860px;
  margin: 30px auto 0;
  border-left: 5px solid var(--penn-red);
  padding: 18px 22px;
  background: #ffffff;
  color: #373737;
  font-size: 17px;
  line-height: 1.58;
  text-align: left;
  box-shadow: var(--card-shadow);
}

.lead strong {
  color: var(--penn-blue);
  font-weight: 900;
}

.method-badge {
  display: inline-block;
  padding: 0.08em 0.42em 0.12em;
  color: #ffffff;
  font-family: var(--font-heading);
  font-weight: 900;
  line-height: 1.18;
  vertical-align: baseline;
}

.method-l2c {
  background: #f19d19;
}

.method-rbf {
  background: #333333;
}

.method-mia {
  background: #b0abab;
}

.section {
  margin: 0 0 76px;
  scroll-margin-top: 28px;
}

h2 {
  display: inline-block;
  margin: 0 0 20px;
  padding: 8px 16px 9px;
  border-bottom: 4px solid var(--penn-red);
  background: var(--penn-blue);
  color: #ffffff;
  font-family: var(--font-heading);
  font-size: 29px;
  line-height: 1.1;
  letter-spacing: -0.025em;
}

.section-heading-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  margin-bottom: 20px;
}

.section-heading-row h2 {
  margin-bottom: 0;
}

.copy-bib-button {
  border: 1px solid var(--penn-blue);
  border-radius: 999px;
  padding: 8px 16px;
  background: #ffffff;
  color: var(--penn-blue);
  cursor: pointer;
  font-family: var(--font-heading);
  font-size: 14px;
  font-weight: 800;
  transition:
    background 150ms ease,
    color 150ms ease,
    border-color 150ms ease;
}

.copy-bib-button:hover,
.copy-bib-button:focus-visible {
  border-color: var(--penn-red);
  background: var(--penn-red);
  color: #ffffff;
}

.copy-bib-button.copied {
  border-color: var(--penn-blue);
  background: var(--penn-blue);
  color: #ffffff;
}

.section p {
  max-width: 100%;
  margin: 0 0 16px;
  color: var(--muted);
  font-size: 17px;
  line-height: 1.68;
}

.citation-note {
  border-left: 4px solid var(--penn-red);
  padding: 10px 14px;
  background: var(--penn-red-soft);
  color: #202020 !important;
  font-weight: 700;
}

.coach-highlight {
  color: var(--penn-red);
  font-weight: 800;
}

.question-highlight {
  color: var(--penn-red);
  padding: 0;
  font-weight: 900;
}

figure {
  margin: 24px 0 0;
  border: 1px solid var(--card-border);
  border-radius: 6px;
  background: var(--paper);
  overflow: hidden;
  box-shadow: var(--card-shadow);
}

figure img {
  display: block;
  width: auto;
  max-width: 100%;
  height: auto;
  max-height: 80vh;
  margin: 0 auto;
  padding: 16px;
  background: white;
  object-fit: contain;
}

figcaption {
  border-top: 1px solid var(--card-border);
  padding: 11px 16px;
  background: var(--penn-blue-soft);
  color: var(--muted);
  font-size: 17px;
  line-height: 1.5;
}

.youtube-embed {
  position: relative;
  overflow: hidden;
  width: 100%;
  margin: 24px 0 0;
  border: 1px solid var(--card-border);
  border-radius: 6px;
  background: #000000;
  box-shadow: var(--card-shadow);
  aspect-ratio: 16 / 9;
}

.youtube-embed iframe {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  border: 0;
}

.yt-thumb {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.yt-play {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 68px;
  height: 48px;
  border: none;
  border-radius: 12px;
  background: #ff0000;
  cursor: pointer;
  opacity: 0.9;
  transition: opacity 0.15s ease;
}

.yt-play::after {
  content: "";
  position: absolute;
  top: 50%;
  left: 55%;
  transform: translate(-50%, -50%);
  border-style: solid;
  border-width: 10px 0 10px 18px;
  border-color: transparent transparent transparent #ffffff;
}

.yt-play:hover {
  opacity: 1;
}

pre {
  overflow-x: auto;
  border: 1px solid var(--card-border);
  border-radius: 6px;
  background: #ffffff;
  color: #202020;
  padding: 18px;
  box-shadow: var(--card-shadow);
}

code {
  font-family: var(--font-mono);
  font-size: 14px;
}

@media (max-width: 980px) {
  .toc {
    display: none !important;
  }

  .page {
    width: min(100% - 32px, 960px);
    margin: 0 auto;
    padding-top: 0;
  }
}

@media (max-width: 640px) {
  .video-placeholder {
    min-height: 100svh;
  }

  .video-overlay {
    padding: 22px;
  }

  .lead {
    padding: 16px;
    font-size: 17px;
  }

  figure img {
    padding: 10px;
  }

  h1 {
    font-size: clamp(36px, 12vw, 52px);
    letter-spacing: -0.045em;
  }
}