:root {
  --ink: var(--platform-text, #141816);
  --muted: var(--platform-text-muted, #3d4740);
  --line: var(--platform-border, #b8c0b4);
  --paper: var(--platform-bg, #e7e9e4);
  --panel: var(--platform-surface, #f7f8f4);
  --accent: var(--platform-accent, #8a5a12);
  --accent-soft: var(--platform-accent-soft, rgba(138, 90, 18, 0.14));
  --font: var(--platform-font, "Bricolage Grotesque", ui-sans-serif, sans-serif);
  --mono: var(--platform-mono, ui-monospace, monospace);
  --radius: var(--platform-radius, 0.3rem);
}

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

html,
body {
  margin: 0;
  font-family: var(--font);
  color: var(--ink);
  background-color: var(--paper);
  background-image: var(--platform-hatch, none);
}

.shell {
  width: min(860px, calc(100% - 2rem));
  margin: 0 auto;
  padding: 1.25rem 0 3rem;
}

.lesson-layout {
  width: min(1120px, calc(100% - 2rem));
  margin: 0 auto;
  padding: 1.15rem 0 3rem;
  display: grid;
  grid-template-columns: minmax(200px, 240px) minmax(0, 1fr);
  gap: 1.35rem;
  align-items: start;
}

.app-top {
  margin-bottom: 0.85rem;
}

.app-top a {
  color: var(--accent);
  text-decoration: none;
  font-weight: 600;
}

.app-top a:hover {
  text-decoration: underline;
}

.hub-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  gap: 0.85rem;
}

.hub-card {
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
  padding: 1.05rem 1.1rem 1.15rem;
  border-radius: var(--radius);
  border: 1px solid var(--line);
  border-top: 3px solid var(--card-accent, var(--accent));
  background: var(--panel);
  color: var(--ink);
  text-decoration: none;
  transition: transform 0.15s ease, border-color 0.15s ease, background 0.15s ease;
}

.hub-card:hover {
  transform: translateY(-2px);
  border-color: var(--card-accent, var(--accent));
  background: color-mix(in srgb, var(--card-accent, var(--accent)) 8%, var(--panel));
}

.hub-card h2 {
  margin: 0;
  font-size: 1.1rem;
  color: var(--ink);
  font-weight: 700;
}

.hub-card p {
  margin: 0;
  color: var(--muted);
  font-size: 0.92rem;
  line-height: 1.5;
}

.lesson-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin: 0 0 1.1rem;
}

.lesson-nav a {
  display: inline-flex;
  align-items: center;
  padding: 0.35rem 0.75rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--ink);
  text-decoration: none;
  font-weight: 600;
  font-size: 0.88rem;
}

.lesson-nav a:hover,
.lesson-nav a.is-active {
  border-color: var(--accent);
  background: var(--accent-soft);
  color: var(--accent);
}

.docs-hero h1 {
  margin: 0 0 0.45rem;
  font-size: clamp(1.6rem, 3vw, 2.1rem);
  letter-spacing: -0.02em;
}

.docs-hero p {
  margin: 0;
  color: var(--muted);
  line-height: 1.55;
  max-width: 52rem;
}

.workbench-banner {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-start;
  justify-content: space-between;
  gap: 0.9rem 1.25rem;
  margin: 1.1rem 0 0.25rem;
  padding: 0.95rem 1.05rem;
  border: 1px solid var(--line);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius);
  background: color-mix(in srgb, var(--accent) 10%, var(--panel));
}

.workbench-banner p {
  margin: 0.2rem 0 0;
  color: var(--muted);
  line-height: 1.5;
}

.workbench-banner__label {
  margin: 0;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--ink);
}

.workbench-banner__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
}

.workbench-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.5rem 0.85rem;
  border-radius: 10px;
  border: 1px solid transparent;
  background: var(--accent);
  color: #fff;
  font: inherit;
  font-weight: 700;
  font-size: 0.88rem;
  text-decoration: none;
}

.workbench-btn:hover {
  filter: brightness(1.08);
}

.workbench-btn.ghost {
  background: transparent;
  border-color: var(--line);
  color: var(--ink);
}

.code-block {
  position: relative;
  margin: 0.75rem 0 1rem;
}

.copy-code {
  position: absolute;
  top: 0.45rem;
  right: 0.45rem;
  z-index: 1;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: color-mix(in srgb, var(--panel) 88%, #000);
  color: var(--ink);
  font: inherit;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 0.2rem 0.5rem;
  cursor: pointer;
}

.copy-code:hover {
  border-color: var(--accent);
}

.tutorial-readme pre {
  padding-top: 2.1rem;
}

.section {
  margin-top: 1.4rem;
}

.readme {
  margin-top: 0.5rem;
  padding: 1rem 1.1rem;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: color-mix(in srgb, var(--panel) 88%, transparent);
  overflow-x: auto;
}

.readme > :first-child {
  margin-top: 0;
}

.readme h1,
.readme h2,
.readme h3 {
  line-height: 1.25;
}

.readme h1 {
  font-size: 1.35rem;
}

.readme h2 {
  font-size: 1.1rem;
  margin-top: 1.4rem;
}

.readme p,
.readme li {
  color: color-mix(in srgb, var(--ink) 92%, var(--muted));
  line-height: 1.6;
}

.readme ul,
.readme ol {
  padding-left: 1.2rem;
}

.readme a {
  color: var(--accent);
}

.readme code,
.readme pre {
  font-family: var(--mono);
  font-size: 0.84rem;
}

.readme code {
  padding: 0.1rem 0.3rem;
  border-radius: 6px;
  background: rgba(0, 0, 0, 0.06);
}

.readme pre {
  padding: 0.85rem 1rem;
  border-radius: 10px;
  background: rgba(0, 0, 0, 0.08);
  overflow-x: auto;
}

.readme pre code {
  padding: 0;
  background: transparent;
}

.readme table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
}

.readme th,
.readme td {
  border: 1px solid var(--line);
  padding: 0.45rem 0.6rem;
  text-align: left;
}

.empty,
.loading,
.error {
  color: var(--muted);
  padding: 1rem 0;
}

.lesson-sidebar {
  position: sticky;
  top: 4.25rem;
  max-height: calc(100vh - 5rem);
  overflow: auto;
  padding: 0.85rem 0.9rem 1rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
}

.lesson-kicker {
  margin: 0 0 0.65rem;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--muted);
}

.lesson-kicker a {
  color: var(--accent);
  text-decoration: none;
}

.lesson-toc {
  display: grid;
  gap: 0.15rem;
}

.lesson-toc a {
  display: grid;
  grid-template-columns: 1.6rem minmax(0, 1fr);
  gap: 0.35rem;
  padding: 0.32rem 0.4rem;
  border-radius: 8px;
  color: var(--ink);
  text-decoration: none;
  font-size: 0.84rem;
  font-weight: 600;
  line-height: 1.35;
}

.lesson-toc a:hover,
.lesson-toc a.is-active {
  background: var(--accent-soft);
  color: var(--accent);
}

.lesson-toc .n {
  color: var(--muted);
  font-variant-numeric: tabular-nums;
  font-weight: 700;
  font-size: 0.75rem;
}

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

.lesson-pager {
  display: flex;
  justify-content: space-between;
  gap: 0.75rem;
  margin-top: 1.6rem;
  padding-top: 1rem;
  border-top: 1px solid var(--line);
}

.lesson-pager a {
  color: var(--accent);
  text-decoration: none;
  font-weight: 700;
}

.lesson-pager a:hover {
  text-decoration: underline;
}

.lesson-pager .spacer {
  flex: 1;
}

.callout {
  margin: 1rem 0;
  padding: 0.8rem 0.95rem;
  border: 1px solid var(--line);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius);
  background: color-mix(in srgb, var(--accent) 8%, var(--panel));
}

.callout p {
  margin: 0.25rem 0 0;
}

.callout strong {
  font-size: 0.78rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.readme .chapter-list,
.chapter-list {
  display: grid;
  gap: 0.45rem;
  margin: 1rem 0 0;
  padding: 0;
  list-style: none;
}

.chapter-list a {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0.35rem 0.75rem;
  padding: 0.7rem 0.85rem;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--panel);
  color: inherit;
  text-decoration: none;
}

.chapter-list a:hover {
  border-color: var(--accent);
}

.chapter-list strong {
  flex: 0 0 7.5rem;
}

.chapter-list span {
  flex: 1 1 16rem;
  color: var(--muted);
  font-size: 0.88rem;
}

@media (max-width: 860px) {
  .lesson-layout {
    grid-template-columns: 1fr;
  }

  .lesson-sidebar {
    position: static;
    max-height: none;
  }
}