:root {
  color-scheme: light;
  --bg: #f6f7f5;
  --surface: #ffffff;
  --surface-muted: #eef1ee;
  --text: #202522;
  --muted: #66736b;
  --border: #dce3dd;
  --accent: #2f7d6d;
  --accent-strong: #185c50;
  --accent-soft: #dff2ed;
  --code-bg: #101615;
  --code-text: #d9f2ea;
  --shadow: 0 20px 50px rgba(29, 42, 35, 0.1);
  --font-body: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --font-code: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  --reader-size: 100%;
  --sidebar-width: 19rem;
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --bg: #111413;
  --surface: #181d1b;
  --surface-muted: #202724;
  --text: #edf3ef;
  --muted: #9da9a2;
  --border: #303a35;
  --accent: #75d0bd;
  --accent-strong: #a5eadc;
  --accent-soft: #173b34;
  --code-bg: #090c0b;
  --code-text: #d8fff4;
  --shadow: 0 20px 50px rgba(0, 0, 0, 0.3);
}

:root[data-font="serif"] {
  --font-body: ui-serif, Georgia, Cambria, "Times New Roman", serif;
}

:root[data-font="mono"] {
  --font-body: var(--font-code);
}

* {
  box-sizing: border-box;
}

html {
  background: var(--bg);
  color: var(--text);
}

body {
  margin: 0;
  min-height: 100vh;
  background:
    radial-gradient(circle at top left, rgba(47, 125, 109, 0.14), transparent 28rem),
    var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  font-size: var(--reader-size);
  line-height: 1.65;
}

a {
  color: var(--accent-strong);
  text-decoration-thickness: 0.08em;
  text-underline-offset: 0.18em;
}

button,
input,
select {
  font: inherit;
}

button,
select,
input[type="search"] {
  border: 1px solid var(--border);
  border-radius: 0.55rem;
  background: var(--surface);
  color: var(--text);
}

button {
  min-height: 2.25rem;
  padding: 0.35rem 0.7rem;
  cursor: pointer;
}

img {
  max-width: 100%;
}

.skip-link {
  position: fixed;
  top: 0.5rem;
  left: 0.5rem;
  z-index: 50;
  transform: translateY(-150%);
  background: var(--surface);
  padding: 0.5rem 0.7rem;
}

.skip-link:focus {
  transform: translateY(0);
}

.app-shell {
  display: grid;
  grid-template-columns: var(--sidebar-width) minmax(0, 1fr);
  min-height: 100vh;
}

.app-shell[data-sidebar-state="closed"],
html[data-sidebar-state="closed"] .app-shell {
  grid-template-columns: 0 minmax(0, 1fr);
}

.app-shell[data-sidebar-state="closed"] .site-sidebar,
html[data-sidebar-state="closed"] .site-sidebar {
  transform: translateX(-100%);
}

.site-sidebar {
  position: sticky;
  top: 0;
  height: 100vh;
  overflow-y: auto;
  border-right: 1px solid var(--border);
  background: color-mix(in srgb, var(--surface) 88%, transparent);
  backdrop-filter: blur(18px);
  padding: 1rem;
  transition: transform 0.2s ease;
  z-index: 20;
}

.brand-panel {
  display: grid;
  grid-template-columns: 4.5rem minmax(0, 1fr);
  gap: 0.9rem;
  align-items: center;
  margin-bottom: 1rem;
}

.brand-avatar {
  display: block;
  width: 4.5rem;
  height: 4.5rem;
  overflow: hidden;
  border: 2px solid var(--border);
  border-radius: 999px;
  background: var(--surface-muted);
}

.brand-avatar img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.brand-title {
  display: block;
  color: var(--text);
  font-size: 1.12rem;
  font-weight: 800;
  line-height: 1.1;
  text-decoration: none;
}

.brand-panel p {
  margin: 0.3rem 0 0;
  color: var(--muted);
  font-size: 0.85rem;
  line-height: 1.35;
}

.sidebar-search {
  display: grid;
  gap: 0.4rem;
  margin-bottom: 1rem;
}

.sidebar-search label,
.right-rail h2,
.eyebrow {
  color: var(--muted);
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.sidebar-search input {
  width: 100%;
  padding: 0.6rem 0.7rem;
}

.search-results {
  display: grid;
  gap: 0.35rem;
}

.search-filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
}

.search-filter-chip {
  min-height: 1.85rem;
  border-radius: 999px;
  padding: 0.15rem 0.5rem;
  color: var(--muted);
  font-size: 0.75rem;
  font-weight: 800;
}

.search-filter-chip[aria-pressed="true"] {
  border-color: var(--accent);
  background: var(--accent-soft);
  color: var(--accent-strong);
}

.search-results a {
  display: grid;
  gap: 0.1rem;
  padding: 0.5rem;
  border: 1px solid var(--border);
  border-radius: 0.55rem;
  background: var(--surface-muted);
  color: var(--text);
  text-decoration: none;
}

.search-results a.is-active,
.search-results a:focus-visible {
  border-color: var(--accent);
  outline: none;
}

.search-results span {
  color: var(--muted);
  font-size: 0.78rem;
}

.study-nav {
  display: grid;
  gap: 0.25rem;
}

.nav-section {
  display: grid;
  gap: 0.25rem;
  margin-top: 0.85rem;
  padding-top: 0.85rem;
  border-top: 1px solid var(--border);
}

.nav-section-label {
  padding: 0 0.55rem 0.25rem;
  color: var(--muted);
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.nav-leaf,
.nav-children a,
.nav-group summary {
  display: flex;
  align-items: center;
  min-height: 2.15rem;
  border-radius: 0.55rem;
  color: var(--text);
  text-decoration: none;
}

.nav-leaf,
.nav-group summary {
  padding: 0.25rem 0.55rem;
}

.nav-group summary {
  cursor: pointer;
  font-weight: 700;
}

.nav-children {
  display: grid;
  gap: 0.15rem;
  margin: 0.15rem 0 0.35rem 0.85rem;
  padding-left: 0.75rem;
  border-left: 1px solid var(--border);
}

.nav-children .nav-children {
  margin-left: 0.45rem;
}

.nav-children a {
  padding: 0.2rem 0.5rem;
  color: var(--muted);
}

.nav-level-2 summary,
.nav-level-2.nav-leaf {
  font-size: 0.93rem;
}

.nav-level-3.nav-leaf {
  min-height: 1.85rem;
  font-size: 0.86rem;
}

.nav-leaf:hover,
.nav-children a:hover,
.nav-group summary:hover,
.active {
  background: var(--accent-soft);
  color: var(--accent-strong) !important;
}

.page-shell {
  min-width: 0;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  align-items: center;
  min-height: 4rem;
  border-bottom: 1px solid var(--border);
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(18px);
  padding: 0.75rem clamp(1rem, 3vw, 2.5rem);
}

.topbar-left,
.toolbar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  align-items: center;
}

.toolbar label {
  display: flex;
  gap: 0.35rem;
  align-items: center;
  color: var(--muted);
  font-size: 0.85rem;
}

.toolbar input[type="range"] {
  width: 6rem;
}

.icon-button {
  display: none;
  width: 2.4rem;
  padding: 0;
}

.icon-button span,
.icon-button::before,
.icon-button::after {
  display: block;
  width: 1.1rem;
  height: 2px;
  margin: 0.18rem auto;
  background: var(--text);
  content: "";
}

.content-grid {
  display: grid;
  grid-template-columns: minmax(0, 52rem) minmax(12rem, 18rem);
  gap: clamp(1rem, 3vw, 2rem);
  align-items: start;
  width: min(100%, 78rem);
  margin: 0 auto;
  padding: clamp(1rem, 3vw, 2.5rem);
}

.content-card {
  min-width: 0;
  border: 1px solid var(--border);
  border-radius: 0.9rem;
  background: var(--surface);
  box-shadow: var(--shadow);
  padding: clamp(1.1rem, 3vw, 2.3rem);
}

.page-header {
  margin-bottom: 1.8rem;
  padding-bottom: 1.2rem;
  border-bottom: 1px solid var(--border);
}

.page-header h1 {
  margin: 0;
  font-size: clamp(2rem, 6vw, 4.5rem);
  line-height: 0.98;
  letter-spacing: 0;
}

.page-summary {
  max-width: 46rem;
  color: var(--muted);
  font-size: 1.08rem;
}

.content-card h2 {
  margin-top: 2rem;
  line-height: 1.2;
}

.version-callout,
.runbook-panel {
  margin: 1.2rem 0;
  border: 1px solid var(--border);
  border-left: 0.35rem solid var(--accent);
  border-radius: 0.7rem;
  background: var(--accent-soft);
  padding: 0.9rem 1rem;
}

.version-callout p,
.runbook-panel p {
  margin: 0;
}

.content-card table {
  display: block;
  width: 100%;
  overflow-x: auto;
  border-collapse: collapse;
}

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

.tag-list,
.tag-cloud {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
}

.tag-list a,
.tag-cloud a {
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--surface-muted);
  color: var(--accent-strong);
  padding: 0.2rem 0.55rem;
  font-size: 0.82rem;
  font-weight: 700;
  text-decoration: none;
}

.right-rail {
  position: sticky;
  top: 5rem;
  display: grid;
  gap: 1rem;
}

.right-rail section {
  border: 1px solid var(--border);
  border-radius: 0.8rem;
  background: var(--surface);
  padding: 1rem;
}

.right-rail a {
  display: block;
  margin-top: 0.35rem;
}

.right-rail button {
  width: 100%;
  margin-top: 0.35rem;
  text-align: left;
}

.right-rail button.page-complete {
  border-color: var(--accent);
  background: var(--accent-soft);
  color: var(--accent-strong);
  font-weight: 800;
}

.right-rail p {
  margin: 0;
  color: var(--muted);
  font-size: 0.9rem;
}

.right-rail .page-tool-status {
  margin: 0.25rem 0 0.65rem;
  padding-inline: 0.1rem;
}

.page-toc nav {
  display: grid;
  gap: 0.2rem;
}

.page-toc a {
  color: var(--text);
  font-size: 0.9rem;
  line-height: 1.35;
  text-decoration: none;
}

.page-toc .toc-depth-3 {
  padding-left: 0.85rem;
  color: var(--muted);
  font-size: 0.84rem;
}

.related-pages a,
.nav-neighbors a {
  line-height: 1.35;
}

div[class^="language-"],
.highlight {
  background: var(--code-bg);
  color: var(--code-text);
}

div[class^="language-"] {
  position: relative;
  margin: 1rem 0;
  overflow: hidden;
  border: 1px solid color-mix(in srgb, var(--accent) 30%, var(--border));
  border-radius: 0.75rem;
}

.highlight {
  position: relative;
  margin: 0;
  overflow-x: auto;
}

.copy-code-button {
  position: absolute;
  top: 0.45rem;
  right: 0.45rem;
  z-index: 2;
  min-height: 1.8rem;
  border-color: color-mix(in srgb, var(--accent) 45%, transparent);
  background: color-mix(in srgb, var(--code-bg) 88%, var(--surface));
  color: var(--code-text);
  padding: 0.1rem 0.45rem;
  font-size: 0.75rem;
  font-weight: 800;
}

.highlight pre {
  margin: 0;
  padding: 1rem;
  overflow-x: auto;
}

.mermaid-frame {
  position: relative;
  display: grid;
  box-sizing: border-box;
  width: 100%;
  margin: 1.5rem 0;
  overflow: hidden;
  border: 1px solid color-mix(in srgb, var(--accent) 34%, var(--border));
  border-radius: 0.7rem;
  background:
    linear-gradient(180deg, color-mix(in srgb, var(--surface) 72%, transparent), transparent),
    var(--surface-muted);
  box-shadow: inset 0 1px 0 color-mix(in srgb, var(--surface) 68%, transparent);
}

.mermaid-frame::after {
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  display: none;
  width: 3.5rem;
  pointer-events: none;
  content: "";
  background: linear-gradient(90deg, transparent, var(--surface-muted));
}

.mermaid-frame[data-diagram-layout="scroll"]::after {
  display: block;
}

.mermaid-tools {
  display: flex;
  justify-content: flex-end;
  gap: 0.5rem;
  border-bottom: 1px solid color-mix(in srgb, var(--accent) 22%, var(--border));
  padding: 0.55rem 0.65rem;
  background: color-mix(in srgb, var(--surface) 78%, transparent);
}

.mermaid-tools button {
  min-height: 1.9rem;
  border-color: color-mix(in srgb, var(--accent) 42%, var(--border));
  background: var(--surface);
  padding: 0.15rem 0.55rem;
  color: var(--accent-strong);
  font-size: 0.78rem;
  font-weight: 800;
}

.mermaid-viewport {
  width: 100%;
  overflow-x: auto;
  overflow-y: hidden;
  overscroll-behavior-inline: contain;
  padding: clamp(1rem, 2.5vw, 1.5rem);
  scrollbar-gutter: stable;
}

.mermaid-viewport::-webkit-scrollbar {
  height: 0.7rem;
}

.mermaid-viewport::-webkit-scrollbar-track {
  background: color-mix(in srgb, var(--surface) 74%, transparent);
}

.mermaid-viewport::-webkit-scrollbar-thumb {
  border: 2px solid color-mix(in srgb, var(--surface) 74%, transparent);
  border-radius: 999px;
  background: color-mix(in srgb, var(--accent) 62%, var(--border));
}

.mermaid-frame .mermaid {
  display: flex;
  justify-content: center;
  text-align: left;
}

.mermaid-frame[data-diagram-layout="scroll"] .mermaid {
  justify-content: flex-start;
  min-width: max-content;
}

.mermaid-frame svg {
  display: block;
  max-width: none;
  height: auto;
  margin: 0;
  overflow: visible;
  color: var(--text);
  font-family: var(--font-body);
}

.mermaid-frame svg .node rect,
.mermaid-frame svg .node circle,
.mermaid-frame svg .node ellipse,
.mermaid-frame svg .node polygon,
.mermaid-frame svg .node path {
  stroke-width: 1.5px;
}

.mermaid-frame svg text,
.mermaid-frame svg .nodeLabel,
.mermaid-frame svg .edgeLabel,
.mermaid-frame svg .messageText,
.mermaid-frame svg .actor {
  font-family: var(--font-body) !important;
  font-size: 17px !important;
  line-height: 1.35;
}

.mermaid-frame svg .edgeLabel,
.mermaid-frame svg .labelBkg {
  border-radius: 0.35rem;
}

.mermaid-frame.mermaid-error .mermaid {
  display: block;
  color: var(--muted);
  font-family: var(--font-code);
  text-align: left;
  white-space: pre;
}

.mermaid-frame.mermaid-error {
  padding: 1rem;
  overflow-x: auto;
}

.diagram-modal[hidden] {
  display: none;
}

.diagram-modal {
  position: fixed;
  inset: 0;
  z-index: 80;
  display: grid;
  background: color-mix(in srgb, var(--bg) 88%, rgba(0, 0, 0, 0.58));
  backdrop-filter: blur(14px);
  padding: clamp(0.75rem, 2vw, 1.25rem);
}

.diagram-modal-panel {
  display: grid;
  grid-template-rows: auto minmax(0, 1fr);
  min-height: 0;
  border: 1px solid color-mix(in srgb, var(--accent) 36%, var(--border));
  border-radius: 0.7rem;
  background: var(--surface);
  box-shadow: var(--shadow);
}

.diagram-modal-header {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  align-items: center;
  border-bottom: 1px solid var(--border);
  padding: 0.75rem clamp(0.85rem, 2vw, 1.25rem);
}

.diagram-modal-header span {
  color: var(--muted);
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.diagram-modal-header h2 {
  margin: 0.1rem 0 0;
  font-size: 1rem;
}

.diagram-modal-viewport {
  min-height: 0;
  overflow: auto;
  overscroll-behavior: contain;
  padding: clamp(1rem, 2.6vw, 2rem);
  background:
    linear-gradient(180deg, color-mix(in srgb, var(--surface-muted) 68%, transparent), transparent),
    var(--surface);
}

.diagram-modal-canvas {
  display: grid;
  min-width: max-content;
  justify-content: start;
}

.diagram-modal-canvas svg {
  display: block;
  max-width: none;
  height: auto;
  color: var(--text);
  font-family: var(--font-body);
}

.diagram-modal-canvas svg text,
.diagram-modal-canvas svg .nodeLabel,
.diagram-modal-canvas svg .edgeLabel,
.diagram-modal-canvas svg .messageText,
.diagram-modal-canvas svg .actor {
  font-family: var(--font-body) !important;
  font-size: 17px !important;
}

.diagram-modal-open {
  overflow: hidden;
}

code,
pre {
  font-family: var(--font-code);
}

pre code {
  color: inherit;
  white-space: pre;
}

code.highlighter-rouge {
  border-radius: 0.3rem;
  background: var(--surface-muted);
  padding: 0.1rem 0.25rem;
}

.highlight .c,
.highlight .c1,
.highlight .cm {
  color: #8da199;
}

.highlight .k,
.highlight .kd,
.highlight .kn {
  color: #7dd3fc;
}

.highlight .s,
.highlight .s1,
.highlight .s2 {
  color: #b9f6ca;
}

.highlight .nt,
.highlight .nb,
.highlight .nf {
  color: #f7d774;
}

.highlight .o,
.highlight .p {
  color: #f1f5f3;
}

.study-card-grid {
  display: none;
  grid-template-columns: repeat(auto-fit, minmax(14rem, 1fr));
  gap: 1rem;
}

.study-deck-launcher {
  display: flex;
  gap: 1rem;
  align-items: center;
  justify-content: space-between;
  border: 1px solid var(--border);
  border-radius: 0.75rem;
  background: var(--surface-muted);
  padding: 1rem;
}

.study-deck-launcher h3,
.study-deck-launcher p {
  margin: 0;
}

.study-deck-launcher p {
  color: var(--muted);
  font-size: 0.9rem;
}

.study-card {
  min-height: 11rem;
  perspective: 1000px;
  cursor: pointer;
}

.study-card-inner {
  position: relative;
  width: 100%;
  min-height: 11rem;
  transition: transform 0.35s ease;
  transform-style: preserve-3d;
}

.study-card.flipped .study-card-inner {
  transform: rotateY(180deg);
}

.study-card-face {
  position: absolute;
  inset: 0;
  display: grid;
  align-content: center;
  gap: 0.65rem;
  min-height: 11rem;
  border: 1px solid var(--border);
  border-radius: 0.9rem;
  backface-visibility: hidden;
  background: linear-gradient(145deg, var(--surface), var(--surface-muted));
  padding: 1rem;
}

.study-card-face span {
  color: var(--muted);
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.study-card-face p {
  margin: 0;
  font-size: 1.05rem;
  font-weight: 750;
}

.study-card-back {
  transform: rotateY(180deg);
  background: linear-gradient(145deg, var(--accent-soft), var(--surface));
}

.study-modal[hidden] {
  display: none;
}

.study-modal {
  position: fixed;
  inset: 0;
  z-index: 80;
  display: grid;
  place-items: center;
  overflow-y: auto;
  background:
    linear-gradient(180deg, color-mix(in srgb, var(--bg) 94%, transparent), color-mix(in srgb, var(--bg) 82%, rgba(0, 0, 0, 0.4))),
    rgba(0, 0, 0, 0.32);
  padding: clamp(0.75rem, 2vw, 1.5rem);
}

.study-open {
  overflow: hidden;
}

.study-modal-panel {
  display: grid;
  grid-template-rows: auto minmax(0, 1fr);
  gap: 1.1rem;
  width: min(100%, 82rem);
  max-height: min(94dvh, 62rem);
  overflow: auto;
  border: 1px solid var(--border);
  border-radius: 0.8rem;
  background: var(--surface);
  box-shadow: var(--shadow);
  padding: clamp(1rem, 2vw, 1.4rem);
}

.study-modal-header,
.study-progress,
.study-test-controls,
.study-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  align-items: center;
}

.study-modal-header,
.study-progress {
  justify-content: space-between;
}

.study-modal-header {
  min-height: 3.25rem;
  border-bottom: 1px solid var(--border);
  padding-bottom: 0.9rem;
}

.study-modal-header h2,
.study-modal-header p {
  margin: 0;
}

.study-modal-header h2 {
  font-size: 1.35rem;
  line-height: 1.1;
}

.study-modal-header p,
.study-progress,
.study-report {
  color: var(--muted);
}

.study-workspace {
  display: grid;
  grid-template-columns: minmax(16rem, 21rem) minmax(0, 1fr);
  gap: 1rem;
  min-height: 0;
}

.study-setup {
  display: grid;
  align-content: start;
  gap: 0.85rem;
  min-width: 0;
}

.study-filters {
  position: sticky;
  top: 0;
  max-height: calc(94dvh - 7rem);
  overflow-y: auto;
  padding-right: 0.2rem;
}

.study-topic-panel,
.study-option-panel,
.study-summary-panel,
.study-quick-panel {
  border: 1px solid var(--border);
  border-radius: 0.7rem;
  background: var(--surface-muted);
  padding: 0.85rem;
}

.study-summary-panel {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.55rem;
}

.study-summary-panel div {
  border: 1px solid var(--border);
  border-radius: 0.55rem;
  background: var(--surface);
  padding: 0.55rem;
}

.study-summary-panel span,
.study-due-counts,
.study-topic-chip small {
  color: var(--muted);
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.study-summary-panel strong {
  display: block;
  font-size: 1.25rem;
  line-height: 1.1;
}

.study-quick-panel {
  display: grid;
  gap: 0.55rem;
}

.study-quick-panel button {
  width: 100%;
  font-weight: 850;
}

.study-quick-panel button[aria-pressed="true"] {
  border-color: var(--accent);
  background: var(--accent-soft);
  color: var(--accent-strong);
}

.study-control-heading {
  display: flex;
  gap: 0.7rem;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.65rem;
}

.study-control-heading span {
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.study-setup label,
.study-topic-list label {
  display: flex;
  gap: 0.45rem;
  align-items: center;
}

.study-topic-list {
  display: grid;
  gap: 0.45rem;
  max-height: min(42vh, 24rem);
  overflow-y: auto;
}

.study-topic-chip,
.study-check-all {
  min-height: 2rem;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--surface);
  padding: 0.28rem 0.6rem;
  color: var(--muted);
  font-size: 0.88rem;
  font-weight: 750;
}

.study-topic-chip {
  display: grid !important;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 0.25rem 0.45rem;
  justify-content: space-between;
}

.study-topic-name,
.study-topic-chip small,
.study-topic-meter {
  grid-column: 2;
}

.study-topic-meter {
  display: block;
  height: 0.28rem;
  overflow: hidden;
  border-radius: 999px;
  background: var(--surface-muted);
}

.study-topic-meter span {
  display: block;
  width: 0;
  height: 100%;
  border-radius: inherit;
  background: var(--accent);
}

.study-topic-chip:has(input:checked),
.study-check-all:has(input:checked) {
  border-color: color-mix(in srgb, var(--accent) 65%, var(--border));
  background: var(--accent-soft);
  color: var(--accent-strong);
}

.study-topic-chip input,
.study-check-all input {
  margin: 0;
}

.study-setup select {
  width: 100%;
  margin-top: 0.25rem;
  padding: 0.45rem 0.55rem;
}

.study-option-panel {
  display: grid;
  gap: 0.75rem;
}

.study-option-panel label,
.study-mode-toggle legend {
  display: grid;
  gap: 0.25rem;
  color: var(--muted);
  font-size: 0.82rem;
  font-weight: 800;
}

.study-mode-toggle {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.35rem;
  margin: 0;
  border: 0;
  padding: 0;
}

.study-mode-toggle legend {
  grid-column: 1 / -1;
  margin-bottom: 0.2rem;
}

.study-mode-toggle label {
  display: flex;
  justify-content: center;
  min-height: 2.1rem;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--surface);
  color: var(--muted);
  padding: 0.3rem 0.55rem;
}

.study-mode-toggle label:has(input:checked) {
  border-color: color-mix(in srgb, var(--accent) 65%, var(--border));
  background: var(--accent-soft);
  color: var(--accent-strong);
}

.study-mode-toggle input {
  margin: 0;
}

.study-option-panel .study-toggle-option {
  display: flex;
  min-height: 2rem;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--surface);
  padding: 0.25rem 0.6rem;
}

.study-actions {
  justify-content: stretch;
}

.study-actions button {
  width: 100%;
}

.study-session {
  display: grid;
  grid-template-rows: auto minmax(18rem, 1fr) auto auto;
  gap: 1rem;
  min-width: 0;
}

.study-session-bar {
  display: grid;
  gap: 0.5rem;
}

.study-progress {
  min-height: 1.6rem;
  font-size: 0.9rem;
  font-weight: 800;
}

.study-progress-track {
  height: 0.45rem;
  overflow: hidden;
  border-radius: 999px;
  background: var(--surface-muted);
}

.study-progress-track span {
  display: block;
  width: 0;
  height: 100%;
  border-radius: inherit;
  background: var(--accent);
  transition: width 0.2s ease;
}

.study-stage-card {
  display: grid;
  align-content: center;
  gap: 1.2rem;
  min-height: 22rem;
  border: 1px solid var(--border);
  border-radius: 0.8rem;
  background: linear-gradient(145deg, var(--surface), var(--surface-muted));
  padding: clamp(1.25rem, 4vw, 3rem);
  cursor: pointer;
  outline: none;
  transition: border-color 0.2s ease, transform 0.2s ease, background 0.2s ease;
  touch-action: pan-y;
}

.study-stage-card:hover,
.study-stage-card:focus-visible {
  border-color: var(--accent);
  transform: translateY(-1px);
}

.study-stage-card[data-revealed="true"] {
  background: linear-gradient(145deg, var(--accent-soft), var(--surface));
}

.study-stage-card.is-advancing {
  opacity: 0.72;
  transform: translateX(0.5rem) scale(0.99);
}

.study-card-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem;
  align-items: center;
}

.study-stage-card span,
.study-state-badge {
  color: var(--muted);
  font-size: 0.75rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.study-state-badge {
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--surface);
  padding: 0.12rem 0.45rem;
  color: var(--accent-strong);
}

.study-stage-card p {
  margin: 0;
  max-width: 45rem;
  font-size: clamp(1.45rem, 4vw, 2.55rem);
  font-weight: 800;
  line-height: 1.25;
}

.study-stage-card small {
  color: var(--muted);
  font-size: 0.95rem;
  font-weight: 800;
}

.study-keyboard-hints {
  visibility: hidden;
  min-height: 1.5rem;
  color: var(--muted);
  font-size: 0.82rem;
  font-weight: 800;
  text-align: center;
}

.study-stage-card:focus-visible + .study-keyboard-hints {
  visibility: visible;
}

.study-bury-button {
  justify-self: center;
  min-height: 2rem;
  border-style: dashed;
  color: var(--muted);
}

.study-test-controls {
  justify-content: center;
}

.study-test-controls button {
  min-width: 9rem;
  min-height: 2.8rem;
  font-weight: 850;
}

.study-report {
  border: 1px solid var(--border);
  border-radius: 0.7rem;
  background: var(--surface-muted);
  padding: 0.8rem;
  font-weight: 800;
}

.path-grid,
.lab-grid {
  display: grid;
  gap: 1rem;
  margin: 1.2rem 0;
}

.path-grid {
  grid-template-columns: repeat(auto-fit, minmax(18rem, 1fr));
}

.path-card,
.lab-card {
  border: 1px solid var(--border);
  border-radius: 0.75rem;
  background: var(--surface-muted);
  padding: 1rem;
}

.path-card-header h2,
.path-card-header p,
.lab-card-header h2,
.lab-card-header p {
  margin: 0;
}

.path-card-header,
.lab-card-header {
  display: grid;
  gap: 0.35rem;
  margin-bottom: 0.9rem;
}

.lab-card-header span {
  color: var(--muted);
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.path-card-header p,
.lab-card-header p {
  color: var(--muted);
}

.path-progress {
  display: grid;
  gap: 0.35rem;
  margin: 0.8rem 0;
  color: var(--muted);
  font-size: 0.85rem;
  font-weight: 800;
}

.path-progress-track {
  height: 0.5rem;
  overflow: hidden;
  border-radius: 999px;
  background: var(--surface);
}

.path-progress-track span {
  display: block;
  width: 0;
  height: 100%;
  border-radius: inherit;
  background: var(--accent);
}

.path-step-list {
  display: grid;
  gap: 0.45rem;
  padding-left: 1.2rem;
}

.path-step-list li {
  padding-left: 0.15rem;
}

.path-step-list li span {
  display: block;
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 800;
}

.path-step-list li.is-complete span {
  color: var(--accent-strong);
}

.lab-card h3 {
  margin: 1rem 0 0.25rem;
}

.lab-card h3:first-of-type {
  margin-top: 0.4rem;
}

.lab-command-examples {
  display: grid;
  gap: 0.85rem;
  margin: 0.65rem 0 1rem;
}

.lab-command-example {
  display: grid;
  gap: 0.45rem;
  border: 1px solid var(--border);
  border-radius: 0.5rem;
  background: var(--surface);
  padding: 0.8rem;
}

.lab-command-example pre {
  margin: 0;
  overflow-x: auto;
  white-space: pre;
}

.lab-command-example p {
  margin: 0;
}

.lab-command-label {
  color: var(--muted);
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.lab-answer {
  border-left: 0.3rem solid var(--accent);
  background: var(--surface);
  padding: 0.7rem 0.85rem;
}

.embedded-labs {
  margin-top: 2rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border);
}

.tag-index,
.note-list {
  display: grid;
  gap: 1rem;
}

.tag-section {
  scroll-margin-top: 5rem;
}

.note-list a {
  display: grid;
  gap: 0.15rem;
  border: 1px solid var(--border);
  border-radius: 0.75rem;
  background: var(--surface-muted);
  padding: 0.8rem;
  text-decoration: none;
}

.note-list span {
  color: var(--muted);
}

.graph-board {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(13rem, 1fr));
  gap: 1rem;
}

.graph-controls {
  display: grid;
  gap: 0.75rem;
  margin: 1rem 0;
}

.graph-controls label {
  display: grid;
  gap: 0.35rem;
  color: var(--muted);
  font-size: 0.82rem;
  font-weight: 800;
}

.graph-controls input {
  width: 100%;
  padding: 0.55rem 0.65rem;
}

.graph-clusters {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.graph-clusters button {
  min-height: 2rem;
  border-radius: 999px;
  font-size: 0.82rem;
  font-weight: 800;
}

.graph-clusters button[aria-pressed="true"] {
  border-color: var(--accent);
  background: var(--accent-soft);
  color: var(--accent-strong);
}

.graph-node {
  border: 1px solid var(--border);
  border-radius: 0.9rem;
  background: var(--surface-muted);
  padding: 1rem;
}

.graph-title {
  color: var(--text);
  font-size: 1.1rem;
  font-weight: 800;
  text-decoration: none;
}

.graph-edges {
  display: grid;
  gap: 0.35rem;
  margin-top: 0.75rem;
}

.graph-title.is-current-page,
.graph-edges a.is-current-page {
  border-radius: 0.35rem;
  background: var(--accent-soft);
  color: var(--accent-strong);
  padding: 0.1rem 0.2rem;
}

.reader-mode .site-sidebar,
.reader-mode .right-rail {
  display: none;
}

.reader-mode .app-shell {
  display: block;
}

.reader-mode .content-grid {
  grid-template-columns: minmax(0, 46rem);
  justify-content: center;
}

.reader-mode .content-card {
  box-shadow: none;
}

.sidebar-scrim {
  display: none;
}

@media (max-width: 980px) {
  .app-shell,
  .app-shell[data-sidebar-state="closed"],
  html[data-sidebar-state="closed"] .app-shell {
    display: block;
  }

  .site-sidebar {
    position: fixed;
    left: 0;
    width: min(88vw, var(--sidebar-width));
    transform: translateX(-100%);
    box-shadow: var(--shadow);
  }

  .app-shell[data-mobile-sidebar="open"] .site-sidebar {
    transform: translateX(0);
  }

  .app-shell[data-mobile-sidebar="open"] + .sidebar-scrim {
    display: block;
    position: fixed;
    inset: 0;
    z-index: 15;
    background: rgba(0, 0, 0, 0.38);
  }

  .icon-button {
    display: inline-block;
  }

  .sidebar-collapse {
    display: none;
  }

  .topbar {
    align-items: flex-start;
    flex-direction: column;
  }

  .content-grid {
    grid-template-columns: minmax(0, 1fr);
  }

  .right-rail {
    position: static;
  }

  .study-workspace {
    grid-template-columns: minmax(0, 1fr);
  }

  .study-filters {
    position: static;
    max-height: none;
    overflow: visible;
  }

  .study-actions {
    justify-content: flex-start;
  }

  .study-topic-list {
    max-height: 10rem;
  }
}

@media (max-width: 640px) {
  .toolbar {
    width: 100%;
  }

  .toolbar label,
  .toolbar button {
    flex: 1 1 auto;
  }

  .content-grid {
    padding: 0.75rem;
  }

  .content-card {
    border-radius: 0.65rem;
    padding: 1rem;
  }

  .study-modal {
    align-items: stretch;
    padding: 0.5rem;
  }

  .study-modal-panel {
    max-height: calc(100dvh - 1rem);
    padding: 0.85rem;
  }

  .study-stage-card {
    min-height: 17rem;
  }

  .study-test-controls button {
    flex: 1 1 auto;
    min-width: 0;
  }
}