:root {
  --bg: #f7f6f3;
  --panel: #ffffff;
  --ink: #1c1b18;
  --muted: #6f6a60;
  --line: #e5e1d8;
  --accent: #c05f08;
  --code-bg: #f1efe9;
  --mono: ui-monospace, "SF Mono", Menlo, monospace;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #16150f;
    --panel: #201f18;
    --ink: #ece9e2;
    --muted: #9b968a;
    --line: #34322a;
    --accent: #f09a4a;
    --code-bg: #2a2921;
    color-scheme: dark;
  }
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

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

body {
  min-width: 0;
  min-height: 100vh;
  margin: 0;
  overflow-x: hidden;
  background: var(--bg);
  color: var(--ink);
  font: 16px/1.6 -apple-system, "SF Pro Text", "Segoe UI", system-ui, sans-serif;
}

button,
input,
textarea {
  font: inherit;
}

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

a {
  color: inherit;
  text-decoration-color: var(--line);
  text-underline-offset: 0.2em;
}

a:hover {
  color: var(--accent);
  text-decoration-color: currentColor;
}

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

img {
  height: auto;
}

button:focus-visible,
a:focus-visible,
[tabindex="0"]:focus-visible,
summary:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}

[hidden] {
  display: none !important;
}

.site-container {
  width: min(100% - 32px, 1080px);
  margin-inline: auto;
}

.reading-container {
  width: min(100% - 32px, 840px);
  margin-inline: auto;
}

.site-header {
  border-bottom: 1px solid var(--line);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  min-height: 72px;
  padding-block: 12px;
}

.brand-link,
.footer-brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  font-weight: 670;
  text-decoration: none;
}

.brand-link:hover,
.footer-brand:hover {
  color: var(--ink);
}

.relay-logo {
  width: 44px;
  height: 44px;
  flex: 0 0 auto;
  border: 0;
  border-radius: 9px;
  box-shadow: none;
  object-fit: cover;
}

.relay-logo-small {
  width: 32px;
  height: 32px;
}

.preview-note {
  margin: 0;
  color: var(--muted);
  font-size: 0.82rem;
  text-align: right;
}

.site-main {
  padding-block: 56px 80px;
}

.home-main {
  padding-top: 64px;
}

.hero {
  max-width: 860px;
  margin-bottom: 40px;
}

.hero h1,
.page-title,
.lesson-title {
  margin: 0;
  letter-spacing: -0.02em;
  line-height: 1.08;
  text-wrap: balance;
}

.hero h1 {
  max-width: 830px;
  font-size: clamp(1.6rem, 3vw, 2.2rem);
  font-weight: 690;
}

.progress-line {
  display: block;
  width: fit-content;
  max-width: 100%;
  margin: 22px 0 0;
  color: var(--muted);
  font-size: 0.92rem;
  white-space: normal;
}

.showpiece-band {
  display: block;
  margin-bottom: 56px;
  padding: 28px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--panel);
  color: var(--ink);
  text-decoration: none;
  transition: border-color 180ms ease, transform 180ms ease;
}

.showpiece-band:hover {
  color: var(--ink);
  border-color: color-mix(in srgb, var(--accent) 42%, var(--line));
  transform: translateY(-2px);
}

.showpiece-band h2,
.section-heading,
.page-title {
  letter-spacing: -0.01em;
}

.showpiece-band h2 {
  margin: 0 0 22px;
  font-size: clamp(1.35rem, 3vw, 2rem);
  line-height: 1.2;
}

h2::after {
  display: block;
  height: 1px;
  margin-top: 10px;
  background: var(--line);
  content: "";
}

.showpiece-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
}

.showpiece-preview {
  min-width: 0;
}

.showpiece-preview img {
  width: 100%;
  aspect-ratio: 4 / 3;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--code-bg);
  object-fit: cover;
  object-position: top;
}

.verdict {
  margin: 10px 0 0;
  color: var(--muted);
  font-size: 0.86rem;
  line-height: 1.4;
}

.progression-section {
  margin-bottom: 52px;
}

.section-heading {
  margin: 0 0 22px;
  font-size: 1.35rem;
}

.progression {
  position: relative;
  display: grid;
  grid-template-columns: repeat(7, minmax(0, 1fr));
  gap: 0;
  margin: 0;
  padding: 22px 8px 32px;
  list-style: none;
}

.progression::before {
  position: absolute;
  top: 28px;
  right: calc(7.14% + 8px);
  left: calc(7.14% + 8px);
  height: 1px;
  background: var(--line);
  content: "";
}

.progression-node {
  position: relative;
  display: flex;
  justify-content: center;
  min-width: 0;
  cursor: default;
}

.progression-dot {
  position: relative;
  z-index: 1;
  width: 13px;
  height: 13px;
  border: 3px solid var(--panel);
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 1px var(--line);
}

.progression-label {
  position: absolute;
  top: 24px;
  left: 50%;
  max-width: 120px;
  padding: 3px 7px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--panel);
  color: var(--muted);
  font-size: 0.72rem;
  line-height: 1.3;
  opacity: 1;
  pointer-events: none;
  text-align: center;
  transform: translate(-50%, 0);
  white-space: nowrap;
}

.progression-node:hover .progression-label,
.progression-node:focus-visible .progression-label {
  color: var(--ink);
  border-color: color-mix(in srgb, var(--accent) 45%, var(--line));
}

.course-sections {
  display: grid;
  gap: 12px;
}

.section-card {
  overflow: clip;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--panel);
}

.section-toggle {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto auto;
  align-items: center;
  width: 100%;
  gap: 14px;
  padding: 20px 22px;
  border: 0;
  background: transparent;
  color: var(--ink);
  cursor: pointer;
  text-align: left;
}

.section-number {
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.78rem;
}

.section-title-wrap {
  min-width: 0;
}

.section-title {
  display: block;
  font-size: 1.05rem;
  font-weight: 650;
  line-height: 1.3;
}

.section-owner {
  display: block;
  margin-top: 2px;
  color: var(--muted);
  font-size: 0.78rem;
}

.status-chip {
  display: inline-flex;
  align-items: center;
  width: fit-content;
  max-width: 100%;
  min-height: 26px;
  padding: 3px 9px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--code-bg);
  color: var(--muted);
  font-size: 0.74rem;
  font-weight: 600;
  line-height: 1.25;
  white-space: normal;
}

.section-chevron {
  color: var(--muted);
  font-size: 1.05rem;
  line-height: 1;
  transition: transform 180ms ease;
}

.section-card.is-open .section-chevron {
  transform: rotate(45deg);
}

.section-collapse {
  display: grid;
  grid-template-rows: 0fr;
  transition: grid-template-rows 240ms ease;
}

.section-card.is-open .section-collapse {
  grid-template-rows: 1fr;
}

.section-collapse-inner {
  min-height: 0;
  overflow: hidden;
}

.lesson-list {
  margin: 0;
  padding: 0 22px 18px;
  border-top: 1px solid var(--line);
  list-style: none;
}

.lesson-row,
.empty-row {
  border-bottom: 1px solid var(--line);
}

.lesson-row:last-child,
.empty-row:last-child {
  border-bottom: 0;
}

.lesson-link {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: center;
  gap: 18px;
  padding: 14px 0;
  color: var(--ink);
  text-decoration: none;
}

.lesson-link:hover {
  color: var(--accent);
}

.lesson-card-title {
  display: block;
  max-height: 2.8em;
  overflow: hidden;
  font-weight: 570;
  line-height: 1.4;
  overflow-wrap: normal;
  text-wrap: pretty;
  word-break: normal;
}

.empty-row {
  padding: 17px 0;
  color: var(--muted);
  font-size: 0.9rem;
}

.breadcrumb {
  margin: 0 0 18px;
  color: var(--muted);
  font-size: 0.82rem;
}

.breadcrumb a {
  color: inherit;
}

.lesson-heading,
.page-heading {
  margin-bottom: 30px;
}

.lesson-heading .status-chip {
  margin-top: 16px;
}

.lesson-title {
  max-width: 780px;
  font-size: clamp(2rem, 5vw, 3.65rem);
  overflow-wrap: normal;
  text-wrap: balance;
  word-break: normal;
}

.page-title {
  font-size: clamp(2rem, 5vw, 3.35rem);
}

.page-intro {
  max-width: 720px;
  margin: 16px 0 0;
  color: var(--muted);
  font-size: 1.04rem;
}

.video-frame,
.video-placeholder {
  width: 100%;
  margin: 0 0 34px;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--panel);
}

.video-frame {
  position: relative;
  aspect-ratio: 16 / 9;
}

.video-frame iframe,
.video-frame video {
  width: 100%;
  height: 100%;
  border: 0;
  object-fit: contain;
}

.video-placeholder {
  display: grid;
  min-height: 250px;
  place-items: center;
  padding: 38px;
  text-align: center;
}

.video-placeholder p {
  max-width: 520px;
  margin: 0;
  color: var(--muted);
  font-size: 1rem;
}

.video-placeholder p + p {
  margin-top: 5px;
}

.lesson-blurb {
  margin: 0 0 36px;
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--panel);
}

.lesson-blurb p {
  margin: 0;
}

.tab-row {
  display: flex;
  gap: 8px;
  margin: 0 0 14px;
  overflow-x: auto;
  padding: 1px 1px 3px;
  scrollbar-width: thin;
}

.tab-button,
.copy-ai,
.copybtn,
.copy-block-button,
.button-link {
  border: 1px solid var(--line);
  border-radius: 7px;
  background: var(--panel);
  color: var(--muted);
  cursor: pointer;
  font-weight: 620;
  text-decoration: none;
  transition: border-color 150ms ease, color 150ms ease, transform 150ms ease;
}

.tab-button {
  flex: 0 0 auto;
  padding: 8px 13px;
  font-size: 0.8rem;
}

.tab-button.is-active,
.tab-button:hover,
.copy-ai:hover,
.copybtn:hover,
.copy-block-button:hover,
.button-link:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.tab-button[aria-selected="true"] {
  background: var(--code-bg);
}

.lesson-panel {
  position: relative;
  min-width: 0;
  padding: 40px 46px 48px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--panel);
}

.copy-ai {
  float: right;
  margin: 0 0 18px 20px;
  padding: 7px 11px;
  font-size: 0.76rem;
}

.lesson-content {
  min-width: 0;
}

.lesson-content::after {
  display: table;
  clear: both;
  content: "";
}

.lesson-content h1 {
  margin: 0 0 14px;
  font-size: 1.75rem;
  line-height: 1.24;
  letter-spacing: -0.015em;
}

.lesson-content h2 {
  margin: 32px 0 10px;
  font-size: 1.2rem;
  line-height: 1.35;
  letter-spacing: -0.01em;
}

.lesson-content h3 {
  margin: 22px 0 6px;
  font-size: 1rem;
}

.lesson-content p {
  margin: 10px 0;
}

.lesson-content ul,
.lesson-content ol {
  margin: 10px 0 10px 24px;
  padding: 0;
}

.lesson-content li {
  margin: 5px 0;
}

.lesson-content strong {
  font-weight: 650;
}

code {
  border-radius: 4px;
  background: var(--code-bg);
  font-family: var(--mono);
  font-size: 0.86em;
  overflow-wrap: anywhere;
  padding: 1px 5px;
}

pre {
  max-width: 100%;
  margin: 12px 0;
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--code-bg);
  padding: 14px 16px;
}

pre code {
  padding: 0;
  background: none;
  font-size: 13px;
  line-height: 1.55;
  white-space: pre-wrap;
}

pre.big code {
  font-size: 13.5px;
}

.codewrap {
  position: relative;
  min-width: 0;
}

.copybtn {
  position: absolute;
  z-index: 1;
  top: 8px;
  right: 8px;
  padding: 4px 10px;
  background: var(--panel);
  font-size: 0.72rem;
}

.transcript-details {
  margin-top: 34px;
  border-top: 1px solid var(--line);
  padding-top: 20px;
}

.transcript-details summary {
  width: fit-content;
  color: var(--muted);
  cursor: pointer;
  font-size: 0.86rem;
  font-weight: 620;
}

.transcript-text {
  max-height: 560px;
  margin-top: 14px;
  overflow: auto;
  white-space: pre-wrap;
}

.copy-source {
  position: fixed;
  width: 1px;
  height: 1px;
  opacity: 0;
  pointer-events: none;
}

.resource-list,
.download-grid {
  display: grid;
  gap: 12px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.resource-card,
.download-card {
  display: block;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--bg);
  color: var(--ink);
  text-decoration: none;
  transition: border-color 150ms ease, transform 150ms ease;
}

.resource-card:hover,
.download-card:hover {
  border-color: var(--accent);
  color: var(--ink);
  transform: translateY(-2px);
}

.resource-card strong,
.download-card strong {
  display: block;
  margin-bottom: 3px;
}

.resource-card span,
.download-card span {
  display: block;
  color: var(--muted);
  font-size: 0.84rem;
}

.lesson-navigation {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
  margin-top: 34px;
}

.lesson-nav-link {
  display: flex;
  min-width: 0;
  min-height: 104px;
  flex-direction: column;
  justify-content: center;
  padding: 16px 18px;
  border: 1px solid var(--line);
  border-radius: 9px;
  background: var(--panel);
  color: var(--ink);
  text-decoration: none;
  transition: border-color 150ms ease, transform 150ms ease;
}

.lesson-nav-link:hover {
  border-color: var(--accent);
  color: var(--ink);
  transform: translateY(-2px);
}

.lesson-nav-link.next {
  text-align: right;
}

.nav-direction,
.nav-section {
  color: var(--muted);
  font-size: 0.72rem;
}

.nav-section {
  margin-top: 2px;
}

.nav-title {
  margin-top: 5px;
  font-weight: 620;
  line-height: 1.35;
  overflow-wrap: normal;
  word-break: normal;
}

.exhibit-stack {
  display: grid;
  gap: 30px;
}

.exhibit-panel {
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--panel);
}

.exhibit-link {
  display: block;
  color: var(--ink);
  text-decoration: none;
}

.exhibit-link:hover {
  color: var(--ink);
}

.exhibit-frame {
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--code-bg);
}

.exhibit-frame img {
  width: 100%;
}

.exhibit-meta {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 18px;
  margin-top: 14px;
}

.exhibit-meta h2 {
  margin: 0;
  font-size: 1.1rem;
}

.exhibit-meta h2::after {
  display: none;
}

.open-label {
  flex: 0 0 auto;
  color: var(--muted);
  font-size: 0.76rem;
}

.exhibit-panel .verdict {
  margin-top: 7px;
}

.download-grid {
  margin-bottom: 36px;
}

.download-card {
  padding: 22px;
  background: var(--panel);
}

.copy-block {
  position: relative;
  margin-top: 14px;
}

.copy-block pre {
  margin: 0;
  padding: 22px 96px 22px 22px;
}

.copy-block-button {
  position: absolute;
  z-index: 1;
  top: 12px;
  right: 12px;
  padding: 6px 10px;
  background: var(--panel);
  font-size: 0.74rem;
}

.button-link {
  display: inline-flex;
  align-items: center;
  min-height: 38px;
  margin-top: 18px;
  padding: 7px 12px;
  font-size: 0.8rem;
}

.site-footer {
  border-top: 1px solid var(--line);
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 22px;
  min-height: 86px;
  padding-block: 18px;
}

.footer-note {
  margin: 0;
  color: var(--muted);
  font-size: 0.82rem;
  text-align: right;
}

@keyframes page-in {
  from {
    opacity: 0;
    transform: translateY(4px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (max-width: 760px) {
  .home-main,
  .site-main {
    padding-block: 40px 60px;
  }

  .showpiece-band {
    padding: 20px;
  }

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

  .progression {
    grid-template-columns: 1fr;
    gap: 0;
    padding: 2px 0;
  }

  .progression::before {
    top: 12px;
    bottom: 12px;
    left: 6px;
    width: 1px;
    height: auto;
  }

  .progression-node {
    justify-content: flex-start;
    min-height: 42px;
  }

  .progression-label {
    top: 1px;
    left: 26px;
    max-width: calc(100vw - 92px);
    transform: translate(0, 3px);
  }

  .progression-node:hover .progression-label,
  .progression-node:focus-visible .progression-label {
    transform: translate(0, 0);
  }

  .section-toggle {
    grid-template-columns: auto minmax(0, 1fr) auto;
    gap: 11px;
    padding: 17px 16px;
  }

  .section-toggle .status-chip {
    grid-column: 2 / 4;
    grid-row: 2;
  }

  .section-chevron {
    grid-column: 3;
    grid-row: 1;
  }

  .lesson-list {
    padding-inline: 16px;
  }

  .lesson-link {
    grid-template-columns: minmax(0, 1fr);
    gap: 7px;
  }

  .lesson-panel {
    padding: 28px 22px 34px;
  }

  .lesson-navigation {
    grid-template-columns: 1fr;
  }

  .lesson-nav-link.next {
    text-align: left;
  }

  .exhibit-panel {
    padding: 14px;
  }

  .exhibit-meta {
    display: block;
  }

  .open-label {
    display: block;
    margin-top: 4px;
  }
}

@media (max-width: 480px) {
  .site-container,
  .reading-container {
    width: min(100% - 24px, 1080px);
  }

  .header-inner {
    gap: 14px;
  }

  .preview-note {
    max-width: 155px;
    font-size: 0.72rem;
    line-height: 1.35;
  }

  .relay-logo {
    width: 40px;
    height: 40px;
  }

  .hero h1 {
    font-size: 2.2rem;
  }

  .showpiece-band {
    margin-bottom: 42px;
    padding: 16px;
  }

  .showpiece-band h2 {
    font-size: 1.3rem;
  }

  .video-placeholder {
    min-height: 210px;
    padding: 26px 20px;
  }

  .lesson-panel {
    padding: 24px 18px 30px;
  }

  .copy-ai {
    float: none;
    margin: 0 0 18px;
  }

  .copy-block pre {
    padding: 58px 16px 18px;
  }

  .footer-inner {
    align-items: flex-start;
    flex-direction: column;
    gap: 10px;
  }

  .footer-note {
    text-align: left;
  }
}

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

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
  }
}

.lesson-static { opacity: 0.55; cursor: default; }
.lesson-static:hover { background: none; }