:root {
  color-scheme: light;
  --ink: #152235;
  --ink-soft: #526174;
  --blue: #0b376e;
  --blue-bright: #1d67a4;
  --blue-pale: #e9f2f9;
  --cyan: #65b7dc;
  --paper: #ffffff;
  --ground: #f4f7fa;
  --line: #dbe3eb;
  --line-dark: #b8c7d6;
  --status: #a34628;
  --status-bg: #fff0e9;
  --sans: Inter, "PingFang SC", "Microsoft YaHei", "Noto Sans CJK SC", sans-serif;
  --serif: "Source Han Serif SC", "Noto Serif CJK SC", "Songti SC", STSong, serif;
  --shadow: 0 20px 60px rgba(19, 50, 84, 0.09);
}

* {
  box-sizing: border-box;
}

[hidden] {
  display: none !important;
}

html {
  scroll-behavior: smooth;
  background: var(--ground);
}

body {
  margin: 0;
  min-width: 320px;
  color: var(--ink);
  background:
    linear-gradient(90deg, rgba(11, 55, 110, 0.025) 1px, transparent 1px) 0 0 / 56px 56px,
    var(--ground);
  font-family: var(--sans);
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

body.reader-mode,
body.reader-mode main,
body.reader-mode .guide-view {
  background: #ffffff;
}

button,
a {
  -webkit-tap-highlight-color: transparent;
}

button {
  font: inherit;
}

a {
  color: var(--blue-bright);
  text-underline-offset: 0.2em;
}

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

.reading-progress {
  position: fixed;
  z-index: 100;
  inset: 0 0 auto;
  height: 3px;
  background: transparent;
  pointer-events: none;
}

.reading-progress span {
  display: block;
  width: 0;
  height: 100%;
  background: var(--cyan);
  transition: width 80ms linear;
}

.site-header {
  position: sticky;
  z-index: 50;
  top: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 78px;
  padding: 0 5vw;
  border-bottom: 1px solid rgba(219, 227, 235, 0.92);
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(18px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  color: var(--ink);
  text-decoration: none;
}

.brand-mark {
  display: grid;
  width: 42px;
  height: 42px;
  place-items: center;
  border-radius: 9px;
  color: white;
  background: var(--blue);
}

.brand-mark svg {
  width: 32px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.8;
  stroke-linejoin: round;
}

.brand-copy {
  display: grid;
  gap: 2px;
}

.brand-copy strong {
  font-size: 16px;
  letter-spacing: 0.04em;
}

.brand-copy small {
  color: var(--ink-soft);
  font-size: 10px;
  letter-spacing: 0.17em;
}

.main-nav {
  display: flex;
  align-self: stretch;
  gap: 2px;
}

.main-nav button {
  position: relative;
  padding: 0 18px;
  border: 0;
  color: var(--ink-soft);
  background: transparent;
  cursor: pointer;
}

.main-nav button::after {
  position: absolute;
  right: 18px;
  bottom: 0;
  left: 18px;
  height: 3px;
  background: var(--blue);
  content: "";
  transform: scaleX(0);
  transition: transform 180ms ease;
}

.main-nav button:hover,
.main-nav button[aria-current="page"] {
  color: var(--blue);
}

.main-nav button[aria-current="page"]::after {
  transform: scaleX(1);
}

main {
  min-height: calc(100vh - 150px);
}

.view {
  animation: view-in 360ms ease both;
}

@keyframes view-in {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: none; }
}

.intro-view {
  overflow: hidden;
}

.intro-shell {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(290px, 0.42fr);
  min-height: 680px;
  padding: clamp(72px, 9vw, 132px) max(6vw, calc((100vw - 1260px) / 2));
  overflow: hidden;
  isolation: isolate;
  color: var(--ink);
  background: #f8fafc;
}

.intro-shell::before,
.intro-shell::after {
  position: absolute;
  content: "";
  pointer-events: none;
}

.intro-shell::before {
  z-index: 0;
  inset: 0 0 0 53%;
  background: url("./assets/xmu-campus.jpg") center 54% / cover no-repeat;
  filter: saturate(0.82) contrast(0.94) brightness(1.04);
}

.intro-shell::after {
  z-index: 0;
  inset: 0;
  background: linear-gradient(
    90deg,
    #ffffff 0%,
    #ffffff 47%,
    rgba(255, 255, 255, 0.97) 55%,
    rgba(255, 255, 255, 0.44) 73%,
    rgba(255, 255, 255, 0.1) 100%
  );
}

.intro-copy {
  position: relative;
  z-index: 1;
  max-width: 780px;
  padding-right: 7vw;
}

.eyebrow {
  margin: 0 0 22px;
  color: var(--blue-bright);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.18em;
  text-transform: uppercase;
}

.intro-shell .eyebrow {
  margin-bottom: 14px;
  color: var(--blue-bright);
}

.version-stamp {
  display: inline-flex;
  margin: 0 0 22px;
  padding: 6px 10px;
  border: 1px solid #c8d9e7;
  border-radius: 999px;
  color: var(--blue);
  background: rgba(255, 255, 255, 0.82);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.04em;
}

.intro-copy h1 {
  margin: 0;
  color: var(--blue);
  font-family: var(--serif);
  font-size: clamp(58px, 7.2vw, 104px);
  font-weight: 650;
  letter-spacing: -0.055em;
  line-height: 1.08;
}

.intro-lead {
  max-width: 700px;
  margin: 38px 0 0;
  color: var(--ink-soft);
  font-family: var(--serif);
  font-size: clamp(17px, 1.45vw, 21px);
  line-height: 1.95;
}

.intro-actions {
  display: flex;
  align-items: center;
  gap: 28px;
  margin-top: 42px;
}

.primary-action,
.text-action {
  border: 0;
  cursor: pointer;
}

.primary-action {
  display: inline-flex;
  align-items: center;
  gap: 20px;
  min-height: 52px;
  padding: 0 22px;
  border-radius: 7px;
  color: white;
  background: var(--blue);
  font-weight: 700;
  box-shadow: 0 9px 24px rgba(19, 50, 84, 0.18);
  transition: transform 180ms ease, box-shadow 180ms ease;
}

.primary-action:hover {
  transform: translateY(-2px);
  box-shadow: 0 14px 30px rgba(19, 50, 84, 0.24);
}

.primary-action svg,
.back-button svg {
  width: 18px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.8;
}

.text-action {
  padding: 10px 0;
  border-bottom: 1px solid var(--line-dark);
  color: var(--blue);
  background: transparent;
}

.intro-index {
  position: relative;
  z-index: 1;
  align-self: center;
  padding: 30px;
  border: 1px solid rgba(184, 199, 214, 0.78);
  border-radius: 12px;
  background: rgba(255, 255, 255, 0.91);
  box-shadow: 0 18px 50px rgba(19, 50, 84, 0.14);
  backdrop-filter: blur(10px);
}

.index-label {
  color: var(--blue-bright);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.18em;
}

.index-line {
  width: 42px;
  height: 2px;
  margin: 20px 0 30px;
  background: var(--cyan);
}

.intro-index dl {
  display: grid;
  gap: 25px;
  margin: 0;
}

.intro-index dl > div {
  display: grid;
  gap: 3px;
}

.intro-index dt {
  color: var(--blue);
  font-family: var(--serif);
  font-size: 37px;
  line-height: 1;
}

.intro-index dd {
  margin: 0;
  color: var(--ink-soft);
  font-size: 13px;
}

.intro-note {
  display: grid;
  grid-template-columns: 86px minmax(0, 820px);
  gap: 30px;
  justify-content: center;
  padding: 80px 6vw 92px;
  border-bottom: 1px solid var(--line);
  background: var(--paper);
}

.note-number {
  color: var(--line-dark);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.16em;
}

.intro-note h2 {
  margin: -8px 0 22px;
  color: var(--blue);
  font-family: var(--serif);
  font-size: 30px;
}

.intro-note p {
  margin: 0 0 18px;
  color: var(--ink-soft);
  font-family: var(--serif);
  font-size: 17px;
  line-height: 1.9;
}

.intro-note .contact-line {
  margin: 28px 0 0;
  padding-top: 24px;
  border-top: 1px solid var(--line);
  color: var(--ink);
}

.page-heading {
  display: grid;
  grid-template-columns: 150px minmax(0, 1fr) auto;
  gap: 42px;
  align-items: end;
  max-width: 1240px;
  margin: 0 auto;
  padding: 84px 32px 50px;
  border-bottom: 1px solid var(--line-dark);
}

.page-heading .eyebrow {
  margin: 0 0 8px;
}

.page-heading h1 {
  margin: 0;
  color: var(--blue);
  font-family: var(--serif);
  font-size: clamp(42px, 5vw, 64px);
  letter-spacing: -0.045em;
  line-height: 1.12;
}

.page-heading > div > p {
  max-width: 620px;
  margin: 16px 0 0;
  color: var(--ink-soft);
  line-height: 1.7;
}

.status-key {
  padding: 12px 0;
  color: var(--ink-soft);
  font-size: 13px;
}

.status-key span,
.status-pill {
  display: inline-flex;
  align-items: center;
  min-height: 26px;
  padding: 3px 9px;
  border: 1px solid #e8b8a9;
  border-radius: 999px;
  color: var(--status);
  background: var(--status-bg);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.04em;
}

.directory {
  max-width: 1240px;
  margin: 0 auto;
  padding: 42px 32px 100px;
}

.category-section {
  display: grid;
  grid-template-columns: 150px minmax(0, 1fr);
  gap: 42px;
  padding: 38px 0 48px;
  border-bottom: 1px solid var(--line);
}

.category-section:last-child {
  border-bottom: 0;
}

.category-index {
  position: sticky;
  top: 110px;
  align-self: start;
}

.category-index span {
  display: block;
  margin-bottom: 10px;
  color: var(--blue-bright);
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.14em;
}

.category-index h2 {
  margin: 0;
  color: var(--blue);
  font-family: var(--serif);
  font-size: 21px;
  line-height: 1.45;
}

.course-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.course-card {
  position: relative;
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 14px;
  min-height: 118px;
  padding: 22px 22px 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  color: var(--ink);
  background: rgba(255, 255, 255, 0.88);
  text-align: left;
  cursor: pointer;
  transition: border-color 180ms ease, transform 180ms ease, box-shadow 180ms ease;
}

.course-card:hover {
  border-color: #96b2ca;
  box-shadow: 0 12px 30px rgba(19, 50, 84, 0.08);
  transform: translateY(-2px);
}

.course-card .course-name {
  margin: 0;
  color: var(--blue);
  font-family: var(--serif);
  font-size: 21px;
  font-weight: 650;
  line-height: 1.45;
}

.course-card small {
  align-self: end;
  color: var(--ink-soft);
  font-size: 12px;
  letter-spacing: 0.04em;
}

.course-card .card-arrow {
  grid-row: 1 / span 2;
  grid-column: 2;
  align-self: center;
  color: var(--blue-bright);
  font-size: 24px;
  font-weight: 300;
  transition: transform 180ms ease;
}

.course-card:hover .card-arrow {
  transform: translateX(3px);
}

.course-card .status-pill {
  align-self: end;
  justify-self: start;
}

.course-reader {
  max-width: 980px;
  margin: 0 auto;
  padding: 52px 42px 110px;
  color: #111111;
  background: #ffffff;
}

.reader-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.back-button {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 9px 0;
  border: 0;
  color: var(--blue-bright);
  background: transparent;
  font-weight: 650;
  cursor: pointer;
}

.reader-zoom-hint {
  margin: 0;
  padding: 6px 10px;
  border: 1px solid var(--line-dark);
  border-radius: 999px;
  color: #111111;
  background: #ffffff;
  font-size: 12px;
  letter-spacing: 0.03em;
}

.reader-heading {
  margin: 52px 0 48px;
  padding-bottom: 35px;
  border-bottom: 2px solid #111111;
}

.reader-heading .eyebrow {
  margin-bottom: 15px;
  color: #111111;
}

.reader-title-row {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}

.reader-title-row h1 {
  margin: 0;
  color: #111111;
  font-family: var(--serif);
  font-size: clamp(40px, 6vw, 64px);
  font-weight: 650;
  letter-spacing: -0.045em;
  line-height: 1.15;
}

.reader-author {
  margin: 18px 0 0;
  color: #111111;
  font-size: 14px;
  font-weight: 650;
}

.article-content {
  color: #111111;
  font-family: var(--serif);
  font-size: 17px;
  line-height: 1.95;
  overflow-wrap: anywhere;
}

.article-content p {
  margin: 0 0 1.35em;
}

.article-content strong {
  color: #111111;
  font-weight: 700;
}

.article-content p > strong:first-child:only-child,
.article-content p > strong:first-child {
  letter-spacing: 0.02em;
}

.article-content h2,
.article-content h3,
.article-content h4 {
  color: #111111;
  font-family: var(--serif);
  line-height: 1.45;
}

.article-content h2,
.article-content h3 {
  margin: 2.4em 0 1em;
  padding-bottom: 0.45em;
  border-bottom: 1px solid var(--line);
  font-size: 26px;
}

.article-content h4 {
  margin: 2em 0 0.8em;
  font-size: 20px;
}

.article-content ul,
.article-content ol {
  margin: 0.5em 0 1.5em;
  padding-left: 1.55em;
}

.article-content li {
  margin: 0.55em 0;
  padding-left: 0.2em;
}

.article-content li::marker {
  color: var(--blue-bright);
}

.article-content a {
  text-decoration-thickness: 1px;
}

.article-content .math {
  color: #111111;
  font-family: "STIX Two Math", "Cambria Math", serif;
}

.article-content .display {
  display: block;
  max-width: 100%;
  margin: 1.3em 0;
  padding: 14px 18px;
  overflow-x: auto;
  border-left: 3px solid var(--cyan);
  background: var(--blue-pale);
}

.article-content math[display="block"] {
  display: block;
  max-width: 100%;
  overflow-x: auto;
}

.article-content math[display="inline"] {
  display: inline-block;
  max-width: 100%;
  overflow-x: auto;
  overflow-y: hidden;
  vertical-align: -0.18em;
}

.footnotes {
  margin-top: 48px;
  padding-top: 22px;
  border-top: 1px solid var(--line);
  color: var(--ink-soft);
  font-size: 15px;
}

.reader-end {
  display: flex;
  align-items: center;
  gap: 20px;
  margin: 70px 0 28px;
  color: var(--line-dark);
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.2em;
}

.reader-end::before,
.reader-end::after {
  height: 1px;
  flex: 1;
  background: var(--line);
  content: "";
}

.bottom-back {
  margin: 0 auto;
  display: flex;
}

.thanks-view {
  padding-bottom: 100px;
}

.thanks-heading {
  grid-template-columns: 150px minmax(0, 1fr);
}

.thanks-list {
  max-width: 1040px;
  margin: 0 auto;
  padding: 46px 32px 0;
}

.year-group {
  display: grid;
  grid-template-columns: 105px minmax(0, 1fr);
  gap: 30px;
  padding: 36px 0;
  border-bottom: 1px solid var(--line);
}

.year-group > h2 {
  position: sticky;
  top: 110px;
  align-self: start;
  margin: 0;
  color: var(--blue-bright);
  font-family: var(--serif);
  font-size: 28px;
}

.people-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.people-grid article {
  display: grid;
  grid-template-columns: auto 1fr;
  align-items: baseline;
  gap: 4px 12px;
  padding: 19px 20px;
  border: 1px solid var(--line);
  border-radius: 7px;
  background: rgba(255, 255, 255, 0.88);
}

.people-grid h3 {
  margin: 0;
  color: var(--blue);
  font-family: var(--serif);
  font-size: 20px;
}

.people-grid p {
  margin: 0;
  color: var(--ink-soft);
  font-size: 12px;
}

.people-grid span {
  grid-column: 1 / -1;
  color: var(--ink-soft);
  font-size: 14px;
}

.site-footer {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  padding: 30px 5vw;
  border-top: 1px solid var(--line);
  color: var(--ink-soft);
  background: var(--paper);
  font-size: 13px;
}

.site-footer a {
  color: var(--ink-soft);
}

:focus-visible {
  outline: 3px solid #ffffff;
  outline-offset: 2px;
  box-shadow: 0 0 0 5px var(--blue);
}

@media (max-width: 900px) {
  .site-header {
    align-items: stretch;
    min-height: 68px;
    padding-right: 18px;
    padding-left: 18px;
  }

  .brand-copy small {
    display: none;
  }

  .main-nav button {
    padding: 0 10px;
    font-size: 14px;
  }

  .main-nav button::after {
    right: 10px;
    left: 10px;
  }

  .intro-shell {
    grid-template-columns: 1fr;
    min-height: auto;
    padding: 72px 7vw 64px;
  }

  .intro-shell::before {
    inset: auto 0 0;
    height: 450px;
    background-position: center 52%;
  }

  .intro-shell::after {
    background: linear-gradient(
      180deg,
      #ffffff 0%,
      #ffffff 49%,
      rgba(255, 255, 255, 0.97) 61%,
      rgba(255, 255, 255, 0.22) 100%
    );
  }

  .intro-copy {
    padding-right: 0;
  }

  .intro-index {
    width: min(100%, 620px);
    margin-top: 92px;
    padding: 28px;
  }

  .intro-index dl {
    grid-template-columns: repeat(2, 1fr);
  }

  .page-heading {
    grid-template-columns: 1fr;
    gap: 18px;
    padding-top: 62px;
  }

  .status-key {
    padding: 0;
  }

  .category-section {
    grid-template-columns: 1fr;
    gap: 22px;
  }

  .category-index {
    position: static;
  }
}

@media (max-width: 640px) {
  .site-header {
    position: relative;
    display: block;
    padding: 14px 16px 0;
  }

  .brand-mark {
    width: 38px;
    height: 38px;
  }

  .main-nav {
    width: 100%;
    height: 52px;
    margin-top: 10px;
    overflow-x: auto;
  }

  .main-nav button {
    flex: 1 0 auto;
    white-space: nowrap;
  }

  .intro-shell {
    padding-top: 62px;
  }

  .intro-shell::before {
    height: 370px;
  }

  .intro-copy h1 {
    font-size: clamp(52px, 17vw, 74px);
  }

  .intro-lead {
    margin-top: 28px;
    font-size: 17px;
  }

  .intro-actions {
    align-items: flex-start;
    flex-direction: column;
    gap: 18px;
  }

  .intro-index dl {
    gap: 12px;
  }

  .intro-index {
    margin-top: 104px;
    padding: 24px 20px;
  }

  .intro-index dt {
    font-size: 29px;
  }

  .intro-index dd {
    font-size: 11px;
  }

  .intro-note {
    grid-template-columns: 1fr;
    gap: 18px;
    padding: 56px 24px 64px;
  }

  .note-number {
    display: none;
  }

  .page-heading,
  .directory,
  .thanks-list {
    padding-right: 20px;
    padding-left: 20px;
  }

  .course-grid,
  .people-grid {
    grid-template-columns: 1fr;
  }

  .course-reader {
    padding: 36px 21px 80px;
  }

  .reader-toolbar {
    align-items: flex-start;
    flex-direction: column;
    gap: 12px;
  }

  .reader-heading {
    margin-top: 34px;
  }

  .article-content {
    font-size: 16.5px;
    line-height: 1.9;
  }

  .year-group {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  .year-group > h2 {
    position: static;
  }

  .site-footer {
    flex-direction: column;
  }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}