:root {
  --stanford-red: #b1042c;
  --stanford-red-dark: #870024;
  --ink: #202124;
  --muted: #666a70;
  --line: #dedede;
  --paper: #ffffff;
  --soft: #f6f5f3;
  --theory: #2563a6;
  --theory-soft: #eaf2fb;
  --mixed: #5c6f2b;
  --mixed-soft: #f2f6e8;
  --lab: #a23b16;
  --lab-soft: #fff0e8;
  --sidebar-width: 324px;
  --shadow: 0 18px 42px rgba(30, 30, 30, 0.08);
}

* {
  box-sizing: border-box;
}

.profile-home-link {
  display: inline-block;
  align-self: flex-start;
  margin: -12px 0 24px;
  padding: 8px 0;
  color: #fff;
  font-size: 14px;
  text-decoration: none;
}

.profile-home-link:hover { text-decoration: underline; }
a:focus-visible, button:focus-visible { outline: 3px solid #b98628; outline-offset: 4px; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto !important; }
  *, *::before, *::after { transition: none !important; }
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 92px;
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: "Avenir Next", Avenir, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  font-size: 16px;
  line-height: 1.65;
}

a {
  color: inherit;
}

.skip-link {
  position: fixed;
  left: 16px;
  top: -60px;
  z-index: 100;
  padding: 10px 14px;
  color: #fff;
  background: #111;
  border-radius: 4px;
  transition: top 0.2s ease;
}

.skip-link:focus {
  top: 12px;
}

.course-sidebar {
  position: fixed;
  inset: 0 auto 0 0;
  z-index: 20;
  width: var(--sidebar-width);
  min-height: 100vh;
  padding: 46px 32px 34px;
  color: #fff;
  background:
    linear-gradient(180deg, rgba(135, 0, 36, 0.08), rgba(135, 0, 36, 0.3)),
    var(--stanford-red);
  box-shadow: 8px 0 28px rgba(37, 20, 24, 0.12);
  display: flex;
  flex-direction: column;
}

.brand-block {
  padding-bottom: 30px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.24);
}

.course-code {
  display: inline-block;
  color: #fff;
  font-family: Georgia, "Times New Roman", serif;
  font-size: 46px;
  font-weight: 700;
  line-height: 1;
  letter-spacing: -1.5px;
  text-decoration: none;
}

.course-name {
  margin: 7px 0 25px;
  color: rgba(255, 255, 255, 0.78);
  font-size: 21px;
  letter-spacing: 0.01em;
}

.course-meta,
.course-term {
  margin: 0;
}

.course-meta {
  font-size: 16px;
  font-weight: 600;
}

.course-term {
  color: rgba(255, 255, 255, 0.72);
  font-size: 15px;
}

.sidebar-nav {
  display: grid;
  gap: 3px;
  margin-top: 26px;
}

.sidebar-nav a {
  position: relative;
  padding: 10px 12px 10px 17px;
  color: rgba(255, 255, 255, 0.78);
  font-size: 15px;
  font-weight: 600;
  text-decoration: none;
  border-radius: 4px;
  transition: color 0.2s ease, background 0.2s ease;
}

.sidebar-nav a::before {
  position: absolute;
  left: 0;
  top: 50%;
  width: 3px;
  height: 0;
  content: "";
  background: #fff;
  transform: translateY(-50%);
  transition: height 0.2s ease;
}

.sidebar-nav a:hover,
.sidebar-nav a:focus-visible,
.sidebar-nav a.active {
  color: #fff;
  background: rgba(255, 255, 255, 0.1);
}

.sidebar-nav a.active::before {
  height: 22px;
}

.sidebar-note {
  margin-top: auto;
  padding-top: 24px;
  border-top: 1px solid rgba(255, 255, 255, 0.22);
}

.sidebar-note .note-icon {
  font-size: 30px;
  line-height: 1;
}

.sidebar-note p {
  margin: 8px 0 0;
  color: rgba(255, 255, 255, 0.8);
  font-family: Georgia, "Times New Roman", serif;
  font-size: 15px;
  font-style: italic;
}

.page-shell {
  min-height: 100vh;
  margin-left: var(--sidebar-width);
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 15;
  height: 78px;
  padding: 0 clamp(28px, 5vw, 72px);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  background: rgba(255, 255, 255, 0.96);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(12px);
}

.topbar-title {
  display: flex;
  align-items: baseline;
  gap: 12px;
}

.topbar-title .eyebrow {
  color: var(--stanford-red);
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.14em;
}

.topbar-title strong {
  font-size: 18px;
}

.language-switch {
  display: inline-flex;
  align-items: center;
  height: 39px;
  padding: 3px;
  border: 1px solid #d3d3d3;
  border-radius: 999px;
  background: #f5f5f5;
}

.language-icon {
  margin: 0 5px 0 8px;
  color: var(--stanford-red);
  font-family: Georgia, "Times New Roman", serif;
  font-weight: 700;
}

.language-option {
  height: 31px;
  min-width: 46px;
  padding: 0 10px;
  color: #616161;
  background: transparent;
  border: 0;
  border-radius: 999px;
  font: inherit;
  font-size: 12px;
  font-weight: 800;
  cursor: pointer;
}

.language-option:hover,
.language-option:focus-visible {
  color: var(--stanford-red);
}

.language-option.active {
  color: #fff;
  background: var(--stanford-red);
  box-shadow: 0 2px 6px rgba(120, 0, 30, 0.22);
}

.content-wrap {
  width: min(1180px, calc(100% - 64px));
  margin: 0 auto;
}

.section {
  padding: 68px 0;
  border-bottom: 1px solid var(--line);
}

.section-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.75fr) minmax(280px, 0.75fr);
  gap: clamp(42px, 6vw, 82px);
}

.section-heading {
  margin-bottom: 28px;
}

.section-heading.compact {
  margin-bottom: 22px;
}

.section-kicker {
  margin: 0 0 5px;
  color: var(--stanford-red);
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.16em;
}

h1,
h2,
h3,
p {
  overflow-wrap: anywhere;
}

h1,
h2,
h3 {
  color: #1d1d1f;
}

h1,
h2 {
  margin: 0;
  font-family: Georgia, "Times New Roman", "Songti SC", serif;
  line-height: 1.2;
}

h1 {
  font-size: clamp(36px, 4.4vw, 57px);
  letter-spacing: -0.025em;
}

h2 {
  font-size: clamp(27px, 3vw, 38px);
  letter-spacing: -0.015em;
}

h3 {
  margin: 0;
  line-height: 1.35;
}

.intro-copy {
  max-width: 760px;
}

.intro-copy p {
  display: grid;
  grid-template-columns: 28px 1fr;
  gap: 7px;
  margin: 0 0 19px;
  color: #363636;
  font-size: 17px;
}

.course-info-card {
  align-self: start;
  overflow: hidden;
  border: 1px solid #d8d8d8;
  border-top: 4px solid var(--stanford-red);
  background: #fff;
  box-shadow: var(--shadow);
}

.course-info-card h2 {
  padding: 21px 23px 16px;
  font-family: inherit;
  font-size: 21px;
  border-bottom: 1px solid var(--line);
}

.instructor-details {
  display: grid;
  gap: 0;
  margin: 0;
  padding: 5px 23px 14px;
  list-style: none;
}

.instructor-details li {
  display: grid;
  grid-template-columns: 24px minmax(0, 1fr);
  gap: 8px;
  padding: 13px 0;
  border-bottom: 1px solid #ececec;
  font-size: 14px;
}

.instructor-details li:last-child {
  border-bottom: 0;
}

.instructor-details a {
  color: var(--stanford-red);
  overflow-wrap: anywhere;
  text-underline-offset: 3px;
}

.instructor-details a:hover,
.instructor-details a:focus-visible {
  color: var(--stanford-red-dark);
}

.schedule-table-wrap {
  overflow-x: auto;
  border: 1px solid #d7d7d7;
}

.schedule-table {
  width: 100%;
  min-width: 680px;
  border-collapse: collapse;
  table-layout: fixed;
}

.schedule-table th,
.schedule-table td {
  padding: 15px 14px;
  text-align: left;
  vertical-align: top;
  border-right: 1px solid #e1e1e1;
  border-bottom: 1px solid #e4e4e4;
}

.schedule-table th:last-child,
.schedule-table td:last-child {
  border-right: 0;
}

.schedule-table tr:last-child td {
  border-bottom: 0;
}

.schedule-table th {
  color: #303030;
  background: #f6f6f6;
  font-size: 12px;
  letter-spacing: 0.035em;
}

.schedule-table th:nth-child(1) {
  width: 80px;
}

.schedule-table th:nth-child(2) {
  width: 110px;
}

.schedule-table th:nth-child(3) {
  width: auto;
}

.schedule-table th:nth-child(4) {
  width: 110px;
}

.schedule-table th:nth-child(5) {
  width: 140px;
}

.schedule-table td {
  color: #464646;
  font-size: 14px;
}

.schedule-table td strong {
  display: block;
  color: #202020;
  font-family: Georgia, "Times New Roman", "Songti SC", serif;
  font-size: 17px;
  font-weight: 500;
  line-height: 1.4;
}

.schedule-table td p {
  margin: 5px 0 0;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.5;
}

.lecture-links {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 1px;
  margin-top: 0;
}

.schedule-table td:nth-child(5) {
  color: #383838;
}

.assignment-document {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  margin-top: 0;
  color: var(--stanford-red);
  font-size: 13px;
  line-height: 1.55;
  text-decoration-thickness: 1px;
  text-underline-offset: 2px;
}

.assignment-document:hover,
.assignment-document:focus-visible {
  color: var(--stanford-red-dark);
}

.lecture-links a {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  color: var(--stanford-red);
  font-size: 13px;
  line-height: 1.55;
  text-decoration-thickness: 1px;
  text-underline-offset: 2px;
}

.lecture-links a:hover,
.lecture-links a:focus-visible {
  color: var(--stanford-red-dark);
}

.week-number {
  font-family: Georgia, "Times New Roman", serif;
  font-size: 19px;
  font-weight: 700;
}

.mode-badge {
  display: inline-block;
  min-width: 65px;
  padding: 4px 8px;
  white-space: nowrap;
  text-align: center;
  border-radius: 999px;
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.03em;
}

.mode-badge.theory {
  color: var(--theory);
  background: var(--theory-soft);
}

.mode-badge.review {
  color: #5f6368;
  background: #f0f1f2;
}

.mode-badge.mixed {
  color: var(--mixed);
  background: var(--mixed-soft);
}

.mode-badge.lab {
  color: var(--lab);
  background: var(--lab-soft);
}

.mixed-row td:first-child {
  box-shadow: inset 4px 0 0 var(--mixed);
}

.mixed-row {
  background: #fdfef9;
}

.lab-row td:first-child {
  box-shadow: inset 4px 0 0 var(--lab);
}

.lab-row {
  background: #fffdfa;
}

.cycle-end td {
  border-bottom: 3px solid #d9d6d1;
}

.weekly-learning-notes {
  margin-top: 18px;
  border: 1px solid #dedbd7;
  border-radius: 4px;
  font-size: 14px;
  line-height: 1.75;
}

.weekly-learning-notes summary {
  padding: 14px 18px;
  color: var(--stanford-red-dark);
  font-weight: 600;
  cursor: pointer;
}

.weekly-learning-notes summary:focus-visible {
  outline: 3px solid #2563a6;
  outline-offset: 3px;
}

.weekly-learning-content {
  padding: 0 18px 14px;
  overflow-wrap: anywhere;
}

.weekly-learning-content h3 {
  margin: 22px 0 8px;
  font-size: 16px;
}

.weekly-learning-content ul {
  padding-left: 22px;
}

.weekly-learning-content li {
  margin: 7px 0;
}

.schedule-note {
  display: flex;
  gap: 8px;
  margin-top: 18px;
  padding: 15px 18px;
  color: #4b4b4b;
  background: var(--soft);
  border-left: 4px solid var(--mixed);
  font-size: 14px;
}

.schedule-note strong {
  flex: 0 0 auto;
  color: #232323;
}

.learning-flow {
  display: grid;
  grid-template-columns: 1fr auto 1fr auto 1fr auto 1fr;
  align-items: center;
  gap: 16px;
}

.learning-flow article {
  min-height: 164px;
  padding: 24px;
  border: 1px solid var(--line);
  background: #fff;
}

.learning-flow article > span {
  display: grid;
  width: 31px;
  height: 31px;
  place-items: center;
  color: #fff;
  background: var(--stanford-red);
  border-radius: 50%;
  font-size: 13px;
  font-weight: 800;
}

.learning-flow h3 {
  margin-top: 16px;
  font-size: 17px;
}

.learning-flow p {
  margin: 5px 0 0;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.45;
}

.learning-flow > i {
  color: #aaa;
  font-style: normal;
}

.support-note {
  display: flex;
  gap: 13px;
  margin-top: 24px;
  padding: 18px 21px;
  background: var(--soft);
  border-left: 4px solid var(--stanford-red);
}

.support-note p {
  margin: 0;
  color: #444;
}

.grading-content {
  max-width: 780px;
  color: #333;
  font-size: 16px;
  line-height: 1.7;
}

.grading-content > p {
  margin: 0 0 18px;
}

.grading-content h3 {
  margin: 30px 0 8px;
  font-family: Georgia, "Times New Roman", serif;
  font-size: 25px;
}

.grading-breakdown {
  margin: 12px 0 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--line);
}

.grading-breakdown li {
  padding: 13px 0;
  border-bottom: 1px solid var(--line);
}

.resources-section {
  border-bottom: 0;
}

.resource-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 18px;
}

.resource-grid article {
  min-height: 210px;
  padding: 25px;
  border: 1px solid var(--line);
  border-top: 3px solid var(--stanford-red);
  background: #fff;
}

.resource-tag {
  display: inline-block;
  padding: 3px 7px;
  font-size: 9px;
  font-weight: 900;
  letter-spacing: 0.1em;
}

.resource-tag.primary {
  color: #8c0628;
  background: #fae8ed;
}

.resource-tag.local {
  color: #225b8e;
  background: #e8f2fa;
}

.resource-tag.modern {
  color: #78551c;
  background: #faf0d9;
}

.resource-tag.tool {
  color: #286248;
  background: #e7f4ed;
}

.resource-grid h3 {
  margin-top: 21px;
  font-family: Georgia, "Times New Roman", "Songti SC", serif;
  font-size: 19px;
}

.resource-grid p {
  margin: 9px 0 0;
  color: var(--muted);
  font-size: 14px;
}

.resource-link {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  margin-top: 18px;
  color: var(--stanford-red);
  font-size: 14px;
  font-weight: 750;
  text-underline-offset: 3px;
}

.resource-link:hover,
.resource-link:focus-visible {
  color: var(--stanford-red-dark);
}

.scope-note {
  margin-top: 22px;
  padding: 18px 21px;
  color: #4f4f4f;
  background: var(--soft);
  font-size: 14px;
}

.scope-note strong {
  color: #222;
}

footer {
  display: flex;
  justify-content: space-between;
  gap: 30px;
  padding: 30px clamp(28px, 5vw, 72px);
  color: rgba(255, 255, 255, 0.76);
  background: #252525;
  font-size: 13px;
}

footer p {
  margin: 0;
}

footer a {
  color: #fff;
  font-weight: 700;
  text-decoration: none;
}

:focus-visible {
  outline: 3px solid #f2b41b;
  outline-offset: 3px;
}

@media (max-width: 1180px) {
  :root {
    --sidebar-width: 276px;
  }

  .course-sidebar {
    padding-inline: 26px;
  }

  .learning-flow {
    grid-template-columns: repeat(2, 1fr);
  }

  .learning-flow > i {
    display: none;
  }
}

@media (max-width: 900px) {
  :root {
    --sidebar-width: 0px;
  }

  html {
    scroll-padding-top: 78px;
  }

  .course-sidebar {
    position: relative;
    width: 100%;
    min-height: auto;
    padding: 30px clamp(22px, 6vw, 48px);
    box-shadow: none;
  }

  .brand-block {
    padding-bottom: 18px;
  }

  .course-code {
    font-size: 38px;
  }

  .course-name {
    margin-bottom: 15px;
  }

  .sidebar-nav {
    grid-template-columns: repeat(5, auto);
    overflow-x: auto;
    margin-top: 16px;
    padding-bottom: 4px;
  }

  .sidebar-nav a {
    white-space: nowrap;
  }

  .sidebar-note {
    display: none;
  }

  .page-shell {
    margin-left: 0;
  }

  .topbar-title .eyebrow {
    display: none;
  }

  .section-grid {
    grid-template-columns: 1fr;
  }

  .course-info-card {
    width: min(100%, 470px);
  }

  .resource-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 720px) {
  body {
    font-size: 15px;
  }

  .topbar {
    height: 68px;
    padding-inline: 18px;
  }

  .sidebar-nav {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    overflow-x: visible;
    gap: 5px;
  }

  .sidebar-nav a {
    padding-inline: 12px;
    text-align: center;
  }

  .topbar-title strong {
    font-size: 15px;
  }

  .language-icon {
    display: none;
  }

  .language-switch {
    height: 37px;
  }

  .language-option {
    min-width: 43px;
    padding-inline: 8px;
  }

  .content-wrap {
    width: min(100% - 36px, 1180px);
  }

  .section {
    padding: 48px 0;
  }

  .intro-copy p {
    font-size: 15px;
  }

  .schedule-table-wrap {
    overflow: visible;
    border: 0;
  }

  .schedule-table,
  .schedule-table tbody,
  .schedule-table tr,
  .schedule-table td {
    display: block;
    width: 100%;
  }

  .schedule-table {
    min-width: 0;
  }

  .schedule-table thead {
    position: absolute;
    width: 1px;
    height: 1px;
    overflow: hidden;
    clip: rect(0 0 0 0);
  }

  .schedule-table tr {
    margin-bottom: 14px;
    padding: 15px 16px;
    border: 1px solid var(--line);
    border-left: 4px solid var(--theory);
    background: #fff;
  }

  .schedule-table tr.lab-row {
    border-left-color: var(--lab);
    background: #fffdfa;
  }

  .schedule-table tr.mixed-row {
    border-left-color: var(--mixed);
    background: #fdfef9;
  }

  .schedule-table th,
  .schedule-table td,
  .cycle-end td {
    padding: 8px 0;
    border: 0;
    box-shadow: none;
  }

  .schedule-table td::before {
    display: block;
    margin-bottom: 2px;
    color: #888;
    content: attr(data-label);
    font-size: 9px;
    font-weight: 800;
    letter-spacing: 0.09em;
    text-transform: uppercase;
  }

  .schedule-table td:nth-child(1),
  .schedule-table td:nth-child(2) {
    display: inline-block;
    width: auto;
    margin-right: 24px;
  }

  .schedule-table td:nth-child(1)::before,
  .schedule-table td:nth-child(2)::before {
    display: none;
  }

  .schedule-note {
    display: block;
  }

  .schedule-note strong {
    display: block;
    margin-bottom: 4px;
  }

  .learning-flow {
    grid-template-columns: 1fr;
  }

  .learning-flow article {
    min-height: auto;
  }

  footer {
    display: block;
    padding-inline: 20px;
  }

  footer a {
    display: inline-block;
    margin-top: 8px;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
  }
}