:root {
  --bg: #f6f3ec;
  --ink: #1c1a16;
  --muted: #5c564c;
  --accent: #0f5c4c;
  --accent-soft: #dceee8;
  --line: #d9d2c4;
  --sidebar: #efeae1;
  --code-bg: #1c1a16;
  --code-ink: #f3efe6;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: "Segoe UI", "Helvetica Neue", sans-serif;
  color: var(--ink);
  background:
    radial-gradient(ellipse 80% 50% at 10% -10%, #dceee8 0%, transparent 55%),
    radial-gradient(ellipse 60% 40% at 100% 0%, #efe6d4 0%, transparent 50%),
    var(--bg);
}

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

.layout {
  display: grid;
  grid-template-columns: minmax(240px, 300px) minmax(0, 1fr);
  min-height: 100vh;
}

.sidebar {
  position: sticky;
  top: 0;
  align-self: start;
  height: 100vh;
  overflow: auto;
  padding: 1.5rem 1.25rem 2rem;
  background: color-mix(in srgb, var(--sidebar) 92%, white);
  border-right: 1px solid var(--line);
}

.brand {
  color: var(--accent);
  font-size: 1.15rem;
  font-weight: 700;
  text-decoration: none;
  letter-spacing: 0.02em;
}

.tagline {
  margin: 0.35rem 0 1.25rem;
  color: var(--muted);
  font-size: 0.9rem;
}

.toc-section {
  margin: 1.1rem 0 0.35rem;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
}

.toc ul,
.mobile-nav ul,
.chapter-list {
  margin: 0;
  padding: 0;
  list-style: none;
}

.toc a,
.mobile-nav a {
  display: block;
  padding: 0.35rem 0.5rem;
  margin: 0.1rem 0;
  border-radius: 6px;
  color: var(--ink);
  text-decoration: none;
  font-size: 0.92rem;
  line-height: 1.35;
}

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

.toc li {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 0.25rem;
  align-items: start;
}

.toc-quiz {
  font-size: 0.75rem;
  padding: 0.3rem 0.4rem;
  color: var(--accent);
  text-decoration: none;
  white-space: nowrap;
}

.content-wrap {
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.mobile-bar {
  display: none;
  padding: 1rem 1.25rem;
  border-bottom: 1px solid var(--line);
  background: color-mix(in srgb, var(--bg) 80%, white);
}

.mobile-nav {
  margin-top: 0.75rem;
}

.mobile-nav summary {
  cursor: pointer;
  color: var(--accent);
  font-weight: 600;
}

main {
  flex: 1;
  width: min(820px, calc(100% - 2.5rem));
  margin: 0 auto;
  padding: 2rem 0 3rem;
}

.hero h1,
.chapter-head h1 {
  margin: 0 0 0.75rem;
  font-size: clamp(1.7rem, 3.5vw, 2.35rem);
  line-height: 1.15;
}

.hero p {
  margin: 0;
  color: var(--muted);
  font-size: 1.05rem;
  line-height: 1.55;
}

.hero-note {
  margin-top: 1rem !important;
  padding: 0.85rem 1rem;
  border-radius: 10px;
  border: 1px solid var(--line);
  background: color-mix(in srgb, var(--accent) 8%, var(--bg));
  font-size: 0.95rem !important;
  color: var(--text) !important;
}

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

.hero-cta {
  margin-top: 1.25rem !important;
}

.btn-secondary {
  display: inline-block;
  margin-left: 0.5rem;
  padding: 0.65rem 1rem;
  border-radius: 8px;
  background: transparent;
  border: 1px solid var(--accent);
  color: var(--accent) !important;
  text-decoration: none;
  font-weight: 600;
}

.quiz-link {
  font-size: 0.92rem;
}

.quiz-panel {
  margin: 2.25rem 0 0.5rem;
  padding: 0.35rem;
  border-radius: 16px;
  background:
    linear-gradient(145deg, #c8e6de 0%, #dceee8 40%, #efe6d4 100%);
  border: 1px solid color-mix(in srgb, var(--accent) 28%, var(--line));
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.55);
}

.quiz-fold {
  border-radius: 12px;
  background: color-mix(in srgb, white 82%, var(--accent-soft));
  overflow: hidden;
}

.quiz-fold-summary {
  list-style: none;
  cursor: pointer;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 0.35rem 1rem;
  padding: 1rem 1.15rem;
  font-weight: 700;
  color: var(--accent);
}

.quiz-fold-summary::-webkit-details-marker {
  display: none;
}

.quiz-fold-summary::after {
  content: "▸";
  margin-left: auto;
  color: var(--accent);
  transition: transform 0.15s ease;
}

.quiz-fold[open] > .quiz-fold-summary::after {
  transform: rotate(90deg);
}

.quiz-fold-title {
  font-size: 1.05rem;
}

.quiz-fold-meta {
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--muted);
}

.quiz-fold-body {
  padding: 0 1.15rem 1.25rem;
  border-top: 1px solid color-mix(in srgb, var(--accent) 18%, var(--line));
}

.quiz-intro {
  color: var(--muted);
  margin: 0.9rem 0 0;
}

.quiz-form {
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
  margin-top: 1rem;
}

.quiz-card {
  margin: 0;
  padding: 0.85rem 1rem 1rem;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: color-mix(in srgb, white 88%, var(--bg));
}

.quiz-card legend {
  padding: 0 0.35rem;
  font-size: 0.78rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--muted);
}

.quiz-q {
  margin: 0.35rem 0 0.85rem;
  font-weight: 600;
  line-height: 1.4;
  color: var(--ink);
}

.quiz-choices {
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
}

.quiz-choice {
  display: flex;
  gap: 0.6rem;
  align-items: flex-start;
  padding: 0.55rem 0.7rem;
  border-radius: 8px;
  border: 1px solid transparent;
  cursor: pointer;
}

.quiz-choice:hover {
  background: var(--accent-soft);
}

.quiz-choice input {
  margin-top: 0.2rem;
}

.score-card {
  padding: 1.25rem 1.4rem;
  border-radius: 14px;
  border: 1px solid var(--line);
  background: color-mix(in srgb, var(--accent-soft) 70%, white);
  margin-bottom: 1.75rem;
}

.score-num {
  margin: 0;
  font-size: 2rem;
  font-weight: 700;
  color: var(--accent);
}

.score-label {
  margin: 0.2rem 0 0.5rem;
  font-size: 1.2rem;
  font-weight: 700;
}

.score-hint {
  margin: 0;
  color: var(--muted);
}

.result-list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
}

.result-item {
  padding: 1rem 1.1rem;
  border-radius: 12px;
  border: 1px solid var(--line);
}

.result-item.is-ok {
  border-color: color-mix(in srgb, var(--accent) 45%, var(--line));
  background: color-mix(in srgb, var(--accent-soft) 55%, white);
}

.result-item.is-bad {
  border-color: #c47b6a;
  background: #fbf1ee;
}

.result-status {
  margin: 0 0 0.4rem;
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.result-item.is-ok .result-status { color: var(--accent); }
.result-item.is-bad .result-status { color: #9a3f2e; }

.result-line {
  margin: 0.35rem 0;
}

.result-ref {
  margin: 0.65rem 0 0;
  padding: 0.65rem 0.75rem;
  border-radius: 8px;
  background: #fff;
  border: 1px dashed #c47b6a;
}

.result-ref a {
  font-weight: 600;
}

.toc-home {
  margin-top: 2.5rem;
}

.toc-home h2 {
  margin: 1.75rem 0 0.6rem;
  font-size: 1.1rem;
}

.chapter-list li {
  margin: 0.35rem 0;
}

.chapter-list a {
  text-decoration: none;
  color: var(--ink);
  border-bottom: 1px solid transparent;
}

.chapter-list a:hover {
  color: var(--accent);
  border-bottom-color: color-mix(in srgb, var(--accent) 40%, transparent);
}

.eyebrow {
  margin: 0 0 0.5rem;
  font-size: 0.9rem;
}

.eyebrow a {
  text-decoration: none;
}

.prose {
  line-height: 1.65;
  font-size: 1.02rem;
}

.prose h1,
.prose h2,
.prose h3,
.prose h4 {
  line-height: 1.25;
  margin: 1.75rem 0 0.7rem;
}

.prose h1 { font-size: 1.6rem; }
.prose h2 { font-size: 1.35rem; }
.prose h3 { font-size: 1.15rem; }

.prose p,
.prose ul,
.prose ol,
.prose table,
.prose pre,
.prose blockquote {
  margin: 0 0 1rem;
}

.prose ul,
.prose ol {
  padding-left: 1.35rem;
}

.prose li {
  margin: 0.25rem 0;
}

.prose code {
  font-family: ui-monospace, "Cascadia Code", Consolas, monospace;
  font-size: 0.9em;
  background: color-mix(in srgb, var(--line) 55%, white);
  padding: 0.1em 0.35em;
  border-radius: 4px;
}

.prose pre {
  overflow-x: auto;
  padding: 1rem 1.1rem;
  border-radius: 10px;
  background: var(--code-bg);
  color: var(--code-ink);
}

.prose pre code {
  background: none;
  padding: 0;
  color: inherit;
}

.prose table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.95rem;
  display: block;
  overflow-x: auto;
}

.prose th,
.prose td {
  border: 1px solid var(--line);
  padding: 0.5rem 0.65rem;
  text-align: left;
  vertical-align: top;
}

.prose th {
  background: color-mix(in srgb, var(--sidebar) 80%, white);
}

.prose blockquote {
  margin-left: 0;
  padding: 0.2rem 0 0.2rem 1rem;
  border-left: 3px solid var(--accent);
  color: var(--muted);
}

.chapter-pager {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin-top: 2.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--line);
}

.pager-link {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  padding: 0.85rem 1rem;
  border: 1px solid var(--line);
  border-radius: 10px;
  text-decoration: none;
  color: var(--ink);
  background: color-mix(in srgb, white 70%, var(--bg));
}

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

.pager-next {
  text-align: right;
  justify-self: end;
}

.pager-label {
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--muted);
}

.pager-title {
  font-weight: 600;
  color: var(--accent);
}

.site-footer {
  width: min(820px, calc(100% - 2.5rem));
  margin: 0 auto;
  padding: 1rem 0 2rem;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.9rem;
}

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

@media (max-width: 900px) {
  .layout {
    grid-template-columns: 1fr;
  }

  .sidebar {
    display: none;
  }

  .mobile-bar {
    display: block;
  }

  .chapter-pager {
    grid-template-columns: 1fr;
  }

  .pager-next {
    text-align: left;
    justify-self: stretch;
  }
}