*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  color-scheme: light;
}

body {
  background-color: var(--c-bg);
  color: var(--c-ink);
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.7;
  min-height: 100svh;
  overflow-x: hidden;
}


.skip-link {
  position: absolute;
  top: -100%;
  left: var(--gutter);
  padding: 8px 16px;
  background: var(--c-ink);
  color: var(--c-surface);
  font-family: var(--font-display);
  font-size: 0.875rem;
  font-weight: 700;
  border-radius: var(--r-sm);
  z-index: 9999;
  text-decoration: none;
  transition: top var(--dur-fast);
}
.skip-link:focus {
  top: 8px;
}


.noscript-banner {
  background: var(--c-sun-tint);
  border-bottom: 2px solid var(--c-sun);
  padding: 12px var(--gutter);
  font-family: var(--font-display);
  font-size: 0.95rem;
  text-align: center;
  color: var(--c-ink);
  font-weight: 600;
}


:focus-visible {
  outline: 3px solid var(--accent, var(--c-blue));
  outline-offset: 3px;
  border-radius: var(--r-sm);
}


h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  font-weight: 800;
  line-height: 1.2;
  color: var(--c-ink);
}

a {
  color: var(--accent, var(--c-blue));
  text-decoration: underline;
  text-underline-offset: 2px;
}
a:hover {
  color: var(--accent-dark, var(--c-blue-dark));
}

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

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

ul, ol {
  list-style: none;
}


.container {
  width: 100%;
  max-width: 900px;
  margin-inline: auto;
  padding-inline: var(--gutter);
}
.container--wide {
  max-width: 1100px;
}


.view {
  display: none;
}
.view.is-active {
  display: block;
}
#view-home.is-active {
  display: flex;
}


@keyframes viewFadeUp {
  from {
    opacity: 0;
    transform: translateY(8px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}
.view.is-active {
  animation: viewFadeUp var(--dur-mid) var(--ease-out) both;
}


.state-loading, .state-error {
  padding: 48px var(--gutter);
  text-align: center;
  font-family: var(--font-display);
  color: var(--c-ink-soft);
}
.state-error {
  color: var(--c-coral-dark);
}
.btn-retry {
  display: inline-block;
  margin-top: 14px;
  padding: 10px 22px;
  background: var(--c-coral);
  color: var(--c-surface);
  border-radius: var(--r-pill);
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 0.95rem;
  box-shadow: 2px 2px 0 var(--c-ink);
  transition: background var(--dur-fast), transform var(--dur-fast);
}
.btn-retry:hover {
  background: var(--c-coral-dark);
  transform: translate(-1px, -1px);
}


.topic-content {
  max-width: 72ch;
  font-family: var(--font-body);
}
.topic-content h3 {
  font-size: 1.25rem;
  margin-block: 1.5em 0.5em;
  color: var(--accent, var(--c-blue));
}
.topic-content p {
  margin-bottom: 1.1em;
}
.topic-content ul, .topic-content ol {
  padding-left: 1.5em;
  margin-bottom: 1.1em;
}
.topic-content li {
  margin-bottom: 0.4em;
  list-style: disc;
}
.topic-content ol li {
  list-style: decimal;
}


.callout {
  background: var(--accent-tint, var(--c-blue-tint));
  border-left: 4px solid var(--accent, var(--c-blue));
  border-radius: 0 var(--r-md) var(--r-md) 0;
  padding: 14px 18px;
  margin-bottom: 1.2em;
}
.callout-title {
  display: block;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 6px;
  color: var(--accent-dark, var(--c-blue-dark));
}


.table-wrap {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  margin-bottom: 1.2em;
  border: 1px solid var(--c-line);
  border-radius: var(--r-md);
}
.table-wrap table {
  width: 100%;
  border-collapse: collapse;
  min-width: 460px;
}
.table-wrap th, .table-wrap td {
  padding: 10px 14px;
  border-bottom: 1px solid var(--c-line);
  font-size: 0.95rem;
  text-align: left;
}
.table-wrap th {
  background: var(--c-sun-tint);
  font-family: var(--font-display);
  font-weight: 700;
  color: var(--c-ink);
}
.table-wrap tr:last-child td {
  border-bottom: none;
}


.tex {
  font-family: var(--font-mono);
  font-size: 0.95em;
  background: var(--c-sun-tint);
  padding: 2px 6px;
  border-radius: var(--r-sm);
  color: var(--c-ink);
}
.tex-block {
  display: block;
  overflow-x: auto;
  padding: 14px 18px;
  background: var(--c-sun-tint);
  border-radius: var(--r-md);
  font-family: var(--font-mono);
  font-size: 0.95em;
  margin-bottom: 1.2em;
  border: 1.5px solid var(--c-line);
  color: var(--c-ink);
}
.tex-fallback {
  display: block;
  overflow-x: auto;
  background: var(--c-sun-tint);
  padding: 14px 18px;
  border-radius: var(--r-md);
  font-family: var(--font-mono);
  font-size: 0.95rem;
  border: 1.5px solid var(--c-line);
  margin-bottom: 1.2em;
}


.code-block {
  margin-bottom: 1.2em;
  border-radius: var(--r-md);
  overflow: hidden;
  border: 2px solid var(--c-ink);
  box-shadow: var(--shadow-hard);
}
.code-block-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 8px 16px;
  background: var(--c-ink);
}
.code-lang {
  color: var(--c-sun);
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}
.code-copy {
  color: color-mix(in srgb, var(--c-surface) 80%, transparent);
  font-family: var(--font-display);
  font-size: 0.82rem;
  font-weight: 700;
  padding: 4px 12px;
  border-radius: var(--r-sm);
  background: color-mix(in srgb, var(--c-surface) 12%, transparent);
  min-height: 32px;
  transition: color var(--dur-fast), background var(--dur-fast);
}
.code-copy:hover {
  color: var(--c-surface);
  background: color-mix(in srgb, var(--c-surface) 25%, transparent);
}
.code-block pre {
  margin: 0;
}
.code-block code {
  display: block;
  padding: 16px;
  background: var(--c-term-bg);
  color: var(--c-term-text);
  font-family: var(--font-mono);
  font-size: 0.9rem;
  line-height: 1.6;
  overflow-x: auto;
  tab-size: 4;
}


.py-kw  { color: var(--c-py-kw); font-weight: 700; }
.py-bi  { color: var(--c-py-bi); font-weight: 600; }
.py-str { color: var(--c-py-str); }
.py-num { color: var(--c-py-num); }
.py-com { color: var(--c-py-com); font-style: italic; }
.py-fn  { color: var(--c-py-fn); }


.coming-soon {
  padding: 24px 0;
  color: var(--c-ink-soft);
  font-style: italic;
}


.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 26px;
  background: var(--accent, var(--c-blue));
  color: var(--c-surface);
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1rem;
  border-radius: var(--r-pill);
  text-decoration: none;
  box-shadow: var(--shadow-hard);
  min-height: 44px;
  cursor: pointer;
  transition: background var(--dur-fast), transform var(--dur-fast), box-shadow var(--dur-fast);
}
.btn-primary:hover {
  background: var(--accent-dark, var(--c-blue-dark));
  transform: translate(-2px, -2px);
  box-shadow: 6px 6px 0 var(--c-ink);
  color: var(--c-surface);
  text-decoration: none;
}
.btn-primary:active {
  transform: translate(2px, 2px);
  box-shadow: 2px 2px 0 var(--c-ink);
}


.topic-list-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 12px;
  margin-block: 1.2em 1.5em;
}
.topic-list-item {
  background: var(--c-surface);
  border: 1.5px solid var(--c-line);
  border-radius: var(--r-md);
  padding: 14px 18px;
  font-size: 0.95rem;
  font-family: var(--font-display);
  font-weight: 600;
}


@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}