:root {
  --ink: var(--platform-text, #141816);
  --muted: var(--platform-text-muted, #2f3933);
  --subtle: var(--platform-text-subtle, #5a655c);
  --line: var(--platform-border, #a7b0a4);
  --paper: var(--platform-bg, #e7e9e4);
  --panel: var(--platform-surface, #f7f8f4);
  /* Prefer suite pine; still tracks platform when shell sets emerald. */
  --accent: #0f6b52;
  --accent-soft: rgba(15, 107, 82, 0.12);
  --font: "DM Sans", var(--platform-font, "Bricolage Grotesque"), ui-sans-serif, sans-serif;
  --display: "Libre Baskerville", "Iowan Old Style", Georgia, "Times New Roman", serif;
  --mono: var(--platform-mono, "IBM Plex Mono", ui-monospace, monospace);
  --radius: var(--platform-radius, 0.3rem);
  --cat-blog: #0f6b52;
  --cat-social: #1d4e89;
  --cat-ecommerce: #9a3412;
  --cat-library: #5b4b8a;
  --cat-desktop: #0e7490;
  --cat-starter: #854d0e;
  --cat-devops: #0f766e;
  --cat-sysdesign: #1d4ed8;
  --cat-sysadmin: #b45309;
  --cat-interview: #7c3aed;
  --cat-languages: #0369a1;
  --cat-os: #334155;
  --cat-diagnosis: #be123c;
  --cat-networking: #0e7490;
  --cat-prompt: #047857;
  --cat-roadmap: #1d4ed8;
  --cat-gdev: #1a73e8;
  --cat-ghdev: #24292f;
}

*,
*::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 {
  margin-bottom: 0.35rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid color-mix(in srgb, var(--line) 70%, transparent);
}

.docs-hero__eyebrow {
  margin: 0 0 0.4rem;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--accent);
}

.docs-hero h1 {
  margin: 0 0 0.55rem;
  font-family: var(--display);
  font-size: clamp(1.55rem, 2.8vw, 2.05rem);
  font-weight: 700;
  letter-spacing: -0.015em;
  line-height: 1.2;
  color: var(--ink);
}

.docs-hero p {
  margin: 0;
  color: var(--muted);
  line-height: 1.6;
  max-width: 46rem;
  font-size: 1.02rem;
}

.lesson-tip {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0.65rem 0.85rem;
  margin: 1rem 0 1.25rem;
  padding: 0.85rem 1rem;
  border: 1px solid color-mix(in srgb, var(--accent) 35%, var(--line));
  border-radius: var(--radius);
  background: color-mix(in srgb, var(--accent) 7%, var(--panel));
}

.lesson-tip__icon {
  width: 1.55rem;
  height: 1.55rem;
  display: grid;
  place-items: center;
  border-radius: 999px;
  background: var(--accent);
  color: #fff;
  font-size: 0.85rem;
  font-weight: 700;
  line-height: 1;
}

.lesson-tip strong {
  display: block;
  margin: 0 0 0.2rem;
  font-size: 0.82rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--ink);
}

.lesson-tip p {
  margin: 0;
  color: var(--muted);
  line-height: 1.5;
  font-size: 0.94rem;
}

.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;
}

.hub-author {
  margin-top: 0.75rem;
  font-size: 0.95rem;
  color: var(--muted);
}

.featured-lessons {
  margin: 1.5rem 0 2rem;
}

.featured-lead {
  max-width: 42rem;
  color: var(--muted);
  margin: 0.35rem 0 1.25rem;
}

.featured-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(16rem, 1fr));
  gap: 1rem;
}

.featured-card {
  --card-accent: var(--accent);
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
  padding: 1.05rem 1.1rem 1.15rem;
  border: 1px solid var(--line);
  border-top: 3px solid var(--card-accent);
  border-radius: 10px;
  background: var(--panel);
  color: inherit;
  text-decoration: none;
  transition: border-color 0.15s ease, transform 0.15s ease, background 0.15s ease;
}

.featured-card[data-category="blog"] { --card-accent: var(--cat-blog); }
.featured-card[data-category="social"] { --card-accent: var(--cat-social); }
.featured-card[data-category="ecommerce"] { --card-accent: var(--cat-ecommerce); }
.featured-card[data-category="library"] { --card-accent: var(--cat-library); }
.featured-card[data-category="desktop"] { --card-accent: var(--cat-desktop); }
.featured-card[data-category="starter"] { --card-accent: var(--cat-starter); }
.featured-card[data-category="devops"] { --card-accent: var(--cat-devops); }
.featured-card[data-category="sysdesign"] { --card-accent: var(--cat-sysdesign); }
.featured-card[data-category="sysadmin"] { --card-accent: var(--cat-sysadmin); }
.featured-card[data-category="interview"] { --card-accent: var(--cat-interview); }
.featured-card[data-category="languages"] { --card-accent: var(--cat-languages); }
.featured-card[data-category="os"] { --card-accent: var(--cat-os); }
.featured-card[data-category="diagnosis"] { --card-accent: var(--cat-diagnosis); }
.featured-card[data-category="networking"] { --card-accent: var(--cat-networking); }
.featured-card[data-category="prompt"] { --card-accent: var(--cat-prompt); }
.featured-card[data-category="roadmap"] { --card-accent: var(--cat-roadmap); }
.featured-card[data-category="gdev"] { --card-accent: var(--cat-gdev); }
.featured-card[data-category="ghdev"] { --card-accent: var(--cat-ghdev); }

.featured-card:hover {
  border-color: var(--card-accent);
  background: color-mix(in srgb, var(--card-accent) 7%, var(--panel));
  transform: translateY(-2px);
}

.featured-card__top {
  display: flex;
  align-items: center;
  gap: 0.65rem;
}

.featured-card__icon {
  flex: 0 0 auto;
  min-width: 2.6rem;
  height: 2.6rem;
  padding: 0 0.35rem;
  display: grid;
  place-items: center;
  border-radius: 0.45rem;
  background: color-mix(in srgb, var(--card-accent) 16%, var(--panel));
  color: var(--card-accent);
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.02em;
  text-transform: uppercase;
  line-height: 1;
}

.featured-card h3 {
  margin: 0;
  font-family: var(--display);
  font-size: 1.08rem;
  line-height: 1.3;
  color: var(--ink);
}

.featured-card p {
  margin: 0;
  flex: 1;
  color: var(--muted);
  font-size: 0.92rem;
  line-height: 1.5;
}

.featured-card__cta {
  font-size: 0.88rem;
  color: var(--card-accent);
  font-weight: 700;
}

.practice-drawer {
  margin: 0 0 2.5rem;
  padding: 0.85rem 1rem;
  border: 1px dashed var(--line);
  border-radius: 12px;
}

.practice-drawer summary {
  cursor: pointer;
  font-weight: 600;
}

.practice-note {
  margin: 0.75rem 0;
  color: var(--muted);
  font-size: 0.92rem;
}

.lesson-nav--practice {
  margin-top: 0.5rem;
}

.project-meta-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.65rem 1.25rem;
  margin: 0 0 1.25rem;
  padding: 0;
  list-style: none;
  color: var(--muted);
  font-size: 0.92rem;
}

.project-meta-list span {
  display: block;
  font-size: 0.72rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  font-weight: 700;
  color: var(--ink, inherit);
}

.project-overview p {
  max-width: 46rem;
}

.project-cta {
  margin: 0 0 1.75rem;
  padding: 1rem 1.15rem;
  border-left: 3px solid var(--accent);
  border-radius: var(--radius);
  background: color-mix(in srgb, var(--accent) 8%, var(--panel));
}

.project-cta-label {
  margin: 0 0 0.55rem;
  font-weight: 700;
}

.project-cta-copy {
  margin: 0 0 0.75rem;
  max-width: 42rem;
  color: var(--muted);
  font-size: 0.98rem;
}

.project-cta-path {
  margin: 0.65rem 0 0.85rem;
  font-size: 0.92rem;
}

.project-cta-run-label {
  margin: 0 0 0.35rem;
  font-weight: 600;
  font-size: 0.92rem;
}

.project-run {
  margin: 0;
  overflow-x: auto;
}

.project-run code {
  white-space: pre;
}

.project-github-btn {
  display: inline-block;
  margin: 0.35rem 0 1rem;
  color: var(--accent);
  font-weight: 700;
  text-decoration: none;
}

.project-github-btn:hover {
  text-decoration: underline;
}

.tutorial-readme .related,
.tutorial-readme .topic-desc {
  margin-top: 1.5rem;
}

.tutorial-readme ul.plain {
  padding-left: 1.2rem;
}

.featured-card__meta {
  margin: 0;
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  color: var(--subtle, var(--muted));
  line-height: 1.35;
}
  margin: 0;
  font-size: 0.8rem;
  color: var(--muted);
}

.catalog-search-form {
  display: flex;
  gap: 0.5rem;
  margin: 0 0 1rem;
  max-width: 40rem;
}

.catalog-search {
  flex: 1;
  min-width: 0;
  padding: 0.65rem 0.85rem;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--panel);
  color: inherit;
  font: inherit;
}

.catalog-search:focus {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}

.catalog-search-form button {
  padding: 0.65rem 1rem;
  border: 0;
  border-radius: 10px;
  background: var(--accent);
  color: #fff;
  font: inherit;
  font-weight: 600;
  cursor: pointer;
}

.catalog-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  margin: 0 0 0.85rem;
}

.catalog-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.35rem 0.7rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--panel);
  color: inherit;
  text-decoration: none;
  font-size: 0.88rem;
}

.catalog-chip span {
  color: var(--muted);
}

.catalog-chip.is-active {
  border-color: var(--accent);
  background: color-mix(in srgb, var(--accent) 12%, var(--panel));
}

.catalog-status,
.catalog-empty {
  color: var(--muted);
  margin: 0 0 1rem;
}

.catalog-pager {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  margin: 1.5rem 0 0;
}

.catalog-pager__btn {
  padding: 0.4rem 0.8rem;
  border: 1px solid var(--line);
  border-radius: 8px;
  text-decoration: none;
  color: inherit;
}

.catalog-pager__btn.is-disabled {
  opacity: 0.45;
  pointer-events: none;
}

.catalog-pager__status {
  margin: 0;
  color: var(--muted);
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.not-found {
  text-align: center;
  padding: 4rem 1.25rem 5rem;
  max-width: 36rem;
  margin: 0 auto;
}

.not-found h1 {
  margin: 0 0 0.65rem;
  font-size: clamp(3rem, 10vw, 4.5rem);
  letter-spacing: -0.04em;
  line-height: 1;
}

.not-found p {
  margin: 0;
  color: var(--color-muted, var(--platform-text-muted, #3d4740));
  font-size: 1.05rem;
  line-height: 1.55;
}

.not-found a {
  color: var(--color-brand, var(--platform-accent, #8a5a12));
}

/* Docs: cheatsheets / reference / resources */
.docs-shell {
  padding-bottom: 3rem;
}

.docs-subnav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem 0.75rem;
  margin: 0 0 1.25rem;
  padding: 0.35rem 0 0.85rem;
  border-bottom: 1px solid var(--line);
}

.docs-subnav__link {
  color: var(--muted);
  text-decoration: none;
  font-weight: 600;
  font-size: 0.95rem;
}

.docs-subnav__link:hover,
.docs-subnav__link.is-active {
  color: var(--accent);
}

.docs-card-grid {
  margin-top: 0.5rem;
}

.cheat-section {
  margin: 0 0 1.75rem;
}

.cheat-section h2 {
  margin: 0 0 0.65rem;
  font-size: 1.15rem;
}

.cheat-table-wrap {
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: 0.55rem;
  background: var(--panel);
}

.cheat-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.94rem;
}

.cheat-table th,
.cheat-table td {
  padding: 0.7rem 0.85rem;
  text-align: left;
  vertical-align: top;
  border-bottom: 1px solid var(--line);
}

.cheat-table th {
  background: color-mix(in srgb, var(--accent) 8%, var(--panel));
  font-size: 0.82rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

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

.cheat-table code {
  font-family: var(--mono);
  font-size: 0.88rem;
  word-break: break-word;
}

.ref-list {
  margin: 0;
  border: 1px solid var(--line);
  border-radius: 0.55rem;
  background: var(--panel);
  overflow: hidden;
}

.ref-list__row {
  display: grid;
  grid-template-columns: minmax(8rem, 0.4fr) 1fr;
  gap: 0.75rem;
  padding: 0.75rem 0.9rem;
  border-bottom: 1px solid var(--line);
}

.ref-list__row:last-child {
  border-bottom: 0;
}

.ref-list dt {
  margin: 0;
}

.ref-list dd {
  margin: 0;
  color: var(--muted);
}

.resource-list {
  list-style: none;
  margin: 0;
  padding: 0;
  border: 1px solid var(--line);
  border-radius: 0.55rem;
  background: var(--panel);
}

.resource-list li {
  display: grid;
  gap: 0.2rem;
  padding: 0.85rem 1rem;
  border-bottom: 1px solid var(--line);
}

.resource-list li:last-child {
  border-bottom: 0;
}

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

.resource-list a:hover {
  text-decoration: underline;
}

.resource-list span {
  color: var(--muted);
  font-size: 0.92rem;
}

.docs-back {
  margin: 1.5rem 0 0;
  color: var(--muted);
}

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

.docs-back a:hover {
  text-decoration: underline;
}

@media (max-width: 640px) {
  .ref-list__row {
    grid-template-columns: 1fr;
  }
}

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

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