@import url("https://fonts.googleapis.com/css2?family=Noto+Serif+SC:wght@400;600;700;900&family=Noto+Sans+SC:wght@300;400;500;700&family=Source+Code+Pro:wght@400;500&display=swap");

:root {
  --color-primary: #4a2142;
  --color-accent: #2f7d73;
  --color-accent-light: #e8f4f1;
  --color-bg: #faf9f6;
  --color-text: #2c2c2c;
  --color-text-light: #5a5a5a;
  --color-border: #d4cfc4;
  --font-serif: "Noto Serif SC", Georgia, serif;
  --font-sans: "Noto Sans SC", "Helvetica Neue", sans-serif;
  --font-mono: "Source Code Pro", monospace;
}

.md-typeset .page-wrapper {
  max-width: 820px;
  margin: 0 auto;
  padding: 0 2.5rem 6rem;
  font-family: var(--font-serif);
  color: var(--color-text);
  line-height: 1.78;
  font-size: 0.782rem;
}

.md-typeset .page-wrapper p {
  margin: 0 0 0.95rem;
  text-align: justify;
}

.md-typeset .page-wrapper strong {
  font-weight: 600;
}

.md-typeset .page-wrapper em {
  font-style: italic;
}

.md-typeset .page-wrapper code {
  font-family: var(--font-mono);
}

.md-typeset .breadcrumb {
  font-family: var(--font-sans);
  font-size: 0.646rem;
  color: var(--color-text-light);
  padding: 0.8rem 0;
  border-bottom: 1px solid var(--color-border);
  letter-spacing: 0.02em;
}

.md-typeset .breadcrumb a {
  color: var(--color-accent);
  text-decoration: none;
}

.md-typeset .breadcrumb a:hover {
  text-decoration: underline;
}

.md-typeset .breadcrumb span {
  margin: 0 0.4em;
}

.md-typeset .chapter-header {
  padding: 3rem 0 2.2rem;
  border-bottom: 3px solid var(--color-primary);
  margin-bottom: 2.2rem;
}

.md-typeset .chapter-header-inner {
  position: relative;
}

.md-typeset .chapter-part {
  font-family: var(--font-sans);
  font-size: 0.646rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  color: var(--color-accent);
  margin-bottom: 0.6rem;
}

.md-typeset .chapter-number {
  font-family: var(--font-serif);
  font-size: 3.57rem;
  font-weight: 900;
  color: var(--color-primary);
  line-height: 1;
  margin-bottom: 0.2rem;
  opacity: 0.12;
  position: absolute;
  right: 0;
  top: 1.1rem;
}

.md-typeset .chapter-title {
  font-family: var(--font-serif);
  font-size: 1.7rem;
  font-weight: 700;
  color: var(--color-primary);
  line-height: 1.3;
  margin: 0 0 0.9rem;
}

.md-typeset .chapter-subtitle {
  font-family: var(--font-sans);
  font-size: 0.782rem;
  color: var(--color-text-light);
  font-weight: 300;
  line-height: 1.58;
  max-width: 640px;
  margin: 0;
}

.md-typeset .chapter-toc {
  background: #f5f3ee;
  border-left: 4px solid var(--color-primary);
  padding: 1.3rem 1.5rem;
  margin-bottom: 2.2rem;
  border-radius: 0 4px 4px 0;
}

.md-typeset .chapter-toc h3 {
  font-family: var(--font-sans);
  font-size: 0.646rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-primary);
  margin: 0 0 0.7rem;
}

.md-typeset .chapter-toc ol {
  list-style: none;
  counter-reset: toc;
  padding: 0;
  margin: 0;
}

.md-typeset .chapter-toc li {
  counter-increment: toc;
  font-family: var(--font-sans);
  font-size: 0.714rem;
  line-height: 1.45;
  padding: 0.18rem 0;
  color: var(--color-text);
  margin: 0;
}

.md-typeset .chapter-toc li::before {
  content: counter(toc) ".  ";
  font-weight: 600;
  color: var(--color-accent);
  min-width: 2.5em;
  display: inline-block;
}

.md-typeset .learning-guide {
  margin: 1.8rem 0 2.2rem;
  padding: 1.15rem 1.25rem;
  background: #f8fbfa;
  border: 1px solid #d9ebe7;
  border-left: 4px solid var(--color-accent);
  border-radius: 0 6px 6px 0;
  font-family: var(--font-sans);
  font-size: 0.7rem;
  line-height: 1.58;
}

.md-typeset .learning-guide-title {
  font-weight: 700;
  color: var(--color-primary);
  font-size: 0.72rem;
  margin-bottom: 0.55rem;
}

.md-typeset .learning-guide p {
  margin: 0.45rem 0;
  text-align: left;
}

.md-typeset .learning-guide strong {
  color: var(--color-primary);
}

.md-typeset .biology-primer {
  margin: 1.4rem 0 2rem;
  padding: 1.05rem 1.2rem;
  background: #fffaf0;
  border: 1px solid #efe0bd;
  border-left: 4px solid #c7922b;
  border-radius: 0 6px 6px 0;
  font-family: var(--font-sans);
  font-size: 0.7rem;
  line-height: 1.62;
}

.md-typeset .biology-primer-title {
  font-weight: 700;
  color: #7a4c00;
  font-size: 0.72rem;
  margin-bottom: 0.55rem;
}

.md-typeset .biology-primer p {
  margin: 0.45rem 0;
  text-align: left;
}

.md-typeset .biology-primer strong {
  color: #7a4c00;
}

.md-typeset .page-wrapper h2 {
  font-family: var(--font-serif);
  font-size: 1.139rem;
  font-weight: 700;
  color: var(--color-primary);
  margin: 2.5rem 0 0.9rem;
  padding-bottom: 0.42rem;
  border-bottom: 1px solid var(--color-border);
  line-height: 1.35;
}

.md-typeset .page-wrapper h2 .section-num {
  font-family: var(--font-sans);
  font-weight: 700;
  color: var(--color-accent);
  margin-right: 0.5em;
}

.md-typeset .page-wrapper h3 {
  font-family: var(--font-serif);
  font-size: 0.893rem;
  font-weight: 600;
  color: var(--color-text);
  margin: 1.7rem 0 0.55rem;
  line-height: 1.4;
}

.md-typeset .keyword {
  font-weight: 600;
  color: var(--color-primary);
}

.md-typeset .gene {
  font-family: var(--font-mono);
  font-style: italic;
  font-size: 0.765em;
  color: #333;
}

.md-typeset .english-term {
  font-family: var(--font-sans);
  font-size: 0.714em;
  color: var(--color-text-light);
}

.md-typeset .mechanism-steps {
  margin: 1.2rem 0 1.5rem;
  padding: 0;
  list-style: none;
  counter-reset: step;
}

.md-typeset .mechanism-steps li {
  counter-increment: step;
  padding: 0.35rem 0 0.35rem 2.5rem;
  position: relative;
  border-left: 2px solid var(--color-accent-light);
  margin: 0 0 0 0.8rem;
}

.md-typeset .mechanism-steps li::before {
  content: counter(step);
  position: absolute;
  left: -0.76rem;
  top: 0.35rem;
  width: 1.5rem;
  height: 1.5rem;
  background: var(--color-accent);
  color: #fff;
  border-radius: 50%;
  font-family: var(--font-sans);
  font-size: 0.629rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  line-height: 1;
}

.md-typeset .mechanism-steps li:last-child {
  border-left-color: transparent;
}

.md-typeset .box {
  margin: 1.4rem 0;
  padding: 1.1rem 1.2rem;
  border-radius: 4px;
  font-size: 0.748rem;
  line-height: 1.65;
}

.md-typeset .box-title {
  font-family: var(--font-sans);
  font-weight: 700;
  font-size: 0.646rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 0.5rem;
  display: flex;
  align-items: center;
  gap: 0.5em;
}

.md-typeset .box-cognition {
  background: #fdf6e3;
  border-left: 4px solid #d4a017;
}

.md-typeset .box-cognition .box-title {
  color: #b8860b;
}

.md-typeset .box-cognition .box-title::before {
  content: "◆";
}

.md-typeset .box-experiment {
  background: var(--color-accent-light);
  border-left: 4px solid var(--color-accent);
}

.md-typeset .box-experiment .box-title {
  color: var(--color-primary);
}

.md-typeset .box-experiment .box-title::before {
  content: "⬡";
}

.md-typeset .box-question {
  background: #f3e5f5;
  border-left: 4px solid #7b1fa2;
}

.md-typeset .box-question .box-title {
  color: #6a1b9a;
}

.md-typeset .box-question .box-title::before {
  content: "?";
  font-weight: 900;
}

.md-typeset .page-wrapper table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.2rem 0 1.5rem;
  font-family: var(--font-sans);
  font-size: 0.714rem;
  line-height: 1.5;
}

.md-typeset .page-wrapper thead {
  background: var(--color-primary);
  color: #fff;
}

.md-typeset .page-wrapper th {
  padding: 0.55rem 0.7rem;
  text-align: left;
  font-weight: 600;
  font-size: 0.629rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.md-typeset .page-wrapper td {
  padding: 0.5rem 0.7rem;
  border-bottom: 1px solid #e0ddd4;
  vertical-align: top;
}

.md-typeset .page-wrapper tbody tr:hover {
  background: #f9f7f2;
}

.md-typeset .ref {
  font-style: italic;
  color: var(--color-text-light);
  font-size: 0.714em;
}

.md-typeset .figure {
  margin: 1.5rem 0;
  padding: 1.1rem;
  background: #f9f8f5;
  border: 1px solid #e8e5dc;
  border-radius: 4px;
  text-align: center;
}

.md-typeset .figure img {
  display: block;
  max-width: 100%;
  height: auto;
  margin: 0 auto 0.7rem;
  border-radius: 3px;
}

.md-typeset .figure svg {
  display: block;
  max-width: 100%;
  height: auto;
  margin: 0 auto 0.7rem;
}

.md-typeset .figure-placeholder {
  height: 170px;
  background: linear-gradient(135deg, #e8f5e9 0%, #f1f8e9 50%, #fff8e1 100%);
  border: 2px dashed var(--color-border);
  border-radius: 4px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-light);
  font-family: var(--font-sans);
  font-size: 0.697rem;
  margin-bottom: 0.7rem;
}

.md-typeset .figure-caption {
  font-family: var(--font-sans);
  font-size: 0.655rem;
  line-height: 1.45;
  color: var(--color-text-light);
  text-align: left;
}

.md-typeset .figure-caption strong {
  color: var(--color-primary);
}

.md-typeset .source-figure {
  margin: 1.6rem 0 1.8rem;
  padding: 0.9rem;
  background: #fff;
  border: 1px solid #e2ded4;
  border-radius: 6px;
  box-shadow: 0 8px 22px rgba(50, 45, 35, 0.06);
}

.md-typeset .source-figure img {
  display: block;
  width: 100%;
  max-height: 440px;
  object-fit: contain;
  margin: 0 auto 0.8rem;
  background: #fff;
}

.md-typeset .source-figure figcaption {
  font-family: var(--font-sans);
  font-size: 0.64rem;
  line-height: 1.5;
  color: var(--color-text-light);
  text-align: left;
}

.md-typeset .source-figure figcaption strong {
  color: var(--color-primary);
}

.md-typeset .source-figure figcaption a {
  color: var(--color-accent);
}

.md-typeset .figure-reading {
  margin: 1.2rem 0 1.5rem;
  padding: 1rem 1.1rem;
  background: #f7fbfb;
  border-left: 4px solid var(--color-accent);
  border-radius: 0 6px 6px 0;
  font-family: var(--font-sans);
  font-size: 0.69rem;
  line-height: 1.6;
}

.md-typeset .figure-reading-title {
  font-weight: 700;
  color: var(--color-primary);
  margin-bottom: 0.35rem;
}

.md-typeset .figure-reading a {
  color: var(--color-accent);
}

.md-typeset .questions-list {
  list-style: none;
  padding: 0;
  margin: 1rem 0;
}

.md-typeset .questions-list li {
  padding: 0.6rem 0 0.6rem 1.6rem;
  position: relative;
  border-bottom: 1px dotted var(--color-border);
  font-size: 0.757rem;
  margin: 0;
}

.md-typeset .questions-list li::before {
  content: "?";
  position: absolute;
  left: 0;
  top: 0.55rem;
  width: 1.2rem;
  height: 1.2rem;
  background: #f3e5f5;
  color: #7b1fa2;
  border-radius: 50%;
  font-family: var(--font-sans);
  font-size: 0.578rem;
  font-weight: 900;
  display: flex;
  align-items: center;
  justify-content: center;
}

.md-typeset .questions-list li:last-child {
  border-bottom: 0;
}

.md-typeset .reading-section {
  margin-top: 2.2rem;
  padding-top: 1.4rem;
  border-top: 2px solid var(--color-primary);
}

.md-typeset .reading-level {
  margin-bottom: 1.1rem;
}

.md-typeset .reading-level h4 {
  font-family: var(--font-sans);
  font-size: 0.697rem;
  font-weight: 700;
  margin: 0 0 0.55rem;
  display: flex;
  align-items: center;
  gap: 0.4em;
}

.md-typeset .level-essential h4 {
  color: #c62828;
}

.md-typeset .level-important h4 {
  color: #e65100;
}

.md-typeset .level-extended h4 {
  color: var(--color-accent);
}

.md-typeset .reading-item {
  display: flex;
  gap: 0.7rem;
  padding: 0.55rem 0;
  border-bottom: 1px dotted var(--color-border);
  align-items: flex-start;
}

.md-typeset .reading-item:last-child {
  border-bottom: 0;
}

.md-typeset .reading-ref {
  flex: 1;
  font-size: 0.714rem;
}

.md-typeset .reading-ref .authors {
  font-weight: 600;
  color: var(--color-text);
}

.md-typeset .reading-ref .title {
  font-style: italic;
}

.md-typeset .reading-ref .journal {
  font-family: var(--font-sans);
  font-size: 0.655rem;
  color: var(--color-text-light);
}

.md-typeset .reading-reason {
  flex: 0 0 250px;
  font-family: var(--font-sans);
  font-size: 0.646rem;
  color: var(--color-text-light);
  line-height: 1.4;
  padding-left: 1rem;
  border-left: 2px solid #eee;
}

.md-typeset .chapter-nav {
  display: flex;
  justify-content: space-between;
  margin-top: 2.5rem;
  padding-top: 1rem;
  border-top: 1px solid var(--color-border);
  font-family: var(--font-sans);
  font-size: 0.697rem;
}

.md-typeset .chapter-nav a {
  color: var(--color-accent);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 0.3em;
}

.md-typeset .chapter-nav a:hover {
  text-decoration: underline;
}

.md-typeset .nav-label {
  font-size: 0.578rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-text-light);
  display: block;
  margin-bottom: 0.2rem;
}

@media (max-width: 76.1875em) {
  .md-typeset .page-wrapper {
    padding: 0 1.6rem 4rem;
  }

  .md-typeset .chapter-number {
    font-size: 2.72rem;
  }
}

@media (max-width: 50em) {
  .md-typeset .page-wrapper {
    padding: 0 1.2rem 3rem;
  }

  .md-typeset .chapter-title {
    font-size: 1.233rem;
  }

  .md-typeset .chapter-number {
    font-size: 2.295rem;
  }

  .md-typeset .reading-item {
    flex-direction: column;
  }

  .md-typeset .reading-reason {
    flex: none;
    padding-left: 0;
    border-left: 0;
    padding-top: 0.4rem;
  }

  .md-typeset .chapter-nav {
    flex-direction: column;
    gap: 1rem;
  }
}

/* Keep reading entries stacked vertically to avoid unintended two-column feel */
.md-typeset .reading-item {
  display: block;
}

.md-typeset .reading-reason {
  border-left: 0;
  border-top: 1px solid #eee;
  margin-top: 0.4rem;
  padding: 0.5rem 0 0;
}

/* Ensure chapter navigation sidebars remain visible on desktop widths */
@media screen and (min-width: 60em) {
  .md-sidebar--primary {
    display: block !important;
  }
}

@media screen and (min-width: 76.25em) {
  .md-sidebar--secondary {
    display: block !important;
  }
}