[hidden] {
  display: none !important;
}

:root {
  --bg: #f4f5f7;
  --panel: #ffffff;
  --panel-2: #f8f9fb;
  --text: #17191d;
  --muted: #6c727c;
  --line: #dfe3e8;
  --accent: #20242a;
  --accent-text: #ffffff;
  --hover: #eef1f4;
  --code-bg: #17191d;
  --code-text: #eef2f6;
  --shadow: 0 12px 40px rgba(20, 24, 32, .08);
  --radius: 14px;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

:root[data-theme="dark"] {
  --bg: #111316;
  --panel: #171a1f;
  --panel-2: #1d2127;
  --text: #eef1f4;
  --muted: #a5acb5;
  --line: #303640;
  --accent: #f0f2f5;
  --accent-text: #111316;
  --hover: #22272e;
  --code-bg: #0b0d10;
  --code-text: #f2f4f7;
  --shadow: 0 12px 40px rgba(0, 0, 0, .26);
}

* { box-sizing: border-box; }

html { scroll-behavior: auto; }

body {
  margin: 0;
  min-width: 320px;
  background: var(--bg);
  color: var(--text);
}

button, input { font: inherit; }

button { cursor: pointer; }

a { color: inherit; }

.app-shell {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 20;
  min-height: 68px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  padding: 10px 18px;
  border-bottom: 1px solid var(--line);
  background: color-mix(in srgb, var(--panel) 94%, transparent);
  backdrop-filter: blur(14px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 11px;
  text-decoration: none;
}

.brand-mark {
  width: 38px;
  height: 38px;
  border-radius: 10px;
  display: block;
  object-fit: cover;
}

.brand strong, .brand small { display: block; }
.brand strong { font-size: .98rem; }
.brand small { color: var(--muted); font-size: .72rem; margin-top: 1px; }

.top-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

.ghost-button {
  min-height: 38px;
  padding: 0 12px;
  color: var(--text);
  background: transparent;
  border: 1px solid var(--line);
  border-radius: 9px;
}

.ghost-button:hover { background: var(--hover); }
.icon-button { width: 38px; padding: 0; }

.layout {
  width: min(1500px, 100%);
  margin: 0 auto;
  padding: 18px;
  display: grid;
  grid-template-columns: minmax(300px, 390px) minmax(0, 1fr);
  gap: 18px;
  flex: 1;
}

.browser-panel,
.reader-panel {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.browser-panel {
  min-height: calc(100vh - 124px);
  padding: 14px;
  align-self: start;
  position: sticky;
  top: 86px;
  max-height: calc(100vh - 104px);
  overflow: auto;
}

.search-wrap label {
  display: block;
  margin-bottom: 7px;
  font-size: .77rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .08em;
  color: var(--muted);
}

.search-box {
  position: relative;
}

.search-box input {
  width: 100%;
  height: 42px;
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 0 48px 0 12px;
  background: var(--panel-2);
  color: var(--text);
  outline: none;
}

.search-box input:focus {
  border-color: var(--muted);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--text) 8%, transparent);
}

.search-box kbd {
  position: absolute;
  top: 9px;
  right: 10px;
  min-width: 25px;
  height: 24px;
  display: grid;
  place-items: center;
  border: 1px solid var(--line);
  border-radius: 6px;
  color: var(--muted);
  background: var(--panel);
  font-size: .75rem;
}

.search-hint {
  margin: 7px 2px 13px;
  color: var(--muted);
  font-size: .77rem;
}

.search-hint code { font-family: ui-monospace, SFMono-Regular, Menlo, monospace; }

.breadcrumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 4px;
  padding: 8px 0 10px;
  border-bottom: 1px solid var(--line);
}

.crumb {
  appearance: none;
  border: 0;
  padding: 3px 5px;
  border-radius: 5px;
  background: transparent;
  color: var(--muted);
  font-size: .8rem;
}

.crumb:hover { background: var(--hover); color: var(--text); }
.crumb-separator { color: var(--muted); opacity: .65; }

.browser-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  min-height: 41px;
  color: var(--muted);
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: .76rem;
}

.file-browser {
  display: flex;
  flex-direction: column;
  gap: 3px;
}

.entry {
  width: 100%;
  min-height: 42px;
  display: grid;
  grid-template-columns: 26px minmax(0, 1fr) auto;
  align-items: center;
  gap: 8px;
  padding: 6px 8px;
  border: 0;
  border-radius: 8px;
  background: transparent;
  color: var(--text);
  text-align: left;
}

.entry:hover,
.entry:focus-visible {
  background: var(--hover);
  outline: none;
}

.entry-icon {
  width: 24px;
  display: grid;
  place-items: center;
  color: var(--muted);
  font-size: 1rem;
}

.entry-main { min-width: 0; }

.entry-name {
  display: block;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  font-size: .9rem;
}

.entry-meta {
  display: block;
  margin-top: 2px;
  color: var(--muted);
  font-size: .72rem;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.entry-arrow { color: var(--muted); }

.search-results h2 {
  margin: 10px 0 6px;
  font-size: .85rem;
}

.no-results {
  padding: 18px 8px;
  color: var(--muted);
  font-size: .88rem;
}

.reader-panel {
  min-height: calc(100vh - 124px);
  padding: clamp(22px, 4vw, 58px);
  overflow: hidden;
}

.welcome {
  max-width: 820px;
  margin: 7vh auto 0;
}

.eyebrow {
  margin: 0 0 14px;
  color: var(--muted);
  font-size: .78rem;
  font-weight: 800;
  letter-spacing: .14em;
}

.welcome h1 {
  margin: 0 0 18px;
  max-width: 760px;
  font-size: clamp(2rem, 6vw, 4.8rem);
  line-height: .98;
  letter-spacing: -.045em;
}

.welcome-text {
  max-width: 680px;
  margin: 0;
  color: var(--muted);
  font-size: clamp(1rem, 1.7vw, 1.2rem);
  line-height: 1.65;
}

.welcome-start {
  margin-top: 34px;
}

.welcome-start-label {
  margin: 0 0 10px;
  color: var(--muted);
  font-size: .78rem;
  font-weight: 800;
  letter-spacing: .08em;
  text-transform: uppercase;
}

.welcome-links {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.welcome-link,
.welcome-about {
  appearance: none;
  min-height: 38px;
  padding: 0 12px;
  border: 1px solid var(--line);
  border-radius: 9px;
  background: var(--panel-2);
  color: var(--text);
  font: inherit;
  font-size: .88rem;
  cursor: pointer;
}

.welcome-link:hover,
.welcome-link:focus-visible,
.welcome-about:hover,
.welcome-about:focus-visible {
  background: var(--hover);
  outline: none;
}

.welcome-meta {
  margin-top: 28px;
  padding-top: 16px;
  border-top: 1px solid var(--line);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
}

.welcome-stats {
  color: var(--muted);
  font-size: .78rem;
  line-height: 1.45;
}

.welcome-about {
  flex: 0 0 auto;
  background: transparent;
}

.markdown-body {
  max-width: 900px;
  margin: 0 auto;
  line-height: 1.7;
  overflow-wrap: anywhere;
}

.markdown-body > :first-child { margin-top: 0; }

.markdown-body h1,
.markdown-body h2,
.markdown-body h3,
.markdown-body h4 {
  line-height: 1.22;
  scroll-margin-top: 86px;
}

.markdown-body h1 {
  margin: 0 0 1.1em;
  padding-bottom: .35em;
  border-bottom: 1px solid var(--line);
  font-size: clamp(2rem, 5vw, 3.2rem);
  letter-spacing: -.035em;
}

.markdown-body h2 {
  margin-top: 2.1em;
  padding-bottom: .28em;
  border-bottom: 1px solid var(--line);
  font-size: 1.65rem;
}

.markdown-body h3 { margin-top: 1.8em; font-size: 1.28rem; }
.markdown-body h4 { margin-top: 1.5em; font-size: 1.08rem; }

.markdown-body p,
.markdown-body ul,
.markdown-body ol,
.markdown-body blockquote {
  margin: 1em 0;
}

.markdown-body ul,
.markdown-body ol { padding-left: 1.55em; }

.markdown-body li + li { margin-top: .32em; }

.markdown-body blockquote {
  margin-left: 0;
  padding: .6em 1em;
  border-left: 4px solid var(--line);
  color: var(--muted);
  background: var(--panel-2);
  border-radius: 0 8px 8px 0;
}

.markdown-body code {
  padding: .14em .38em;
  border-radius: 5px;
  background: var(--panel-2);
  border: 1px solid var(--line);
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: .9em;
}

.markdown-body pre {
  overflow-x: hidden;
  white-space: pre-wrap;
  overflow-wrap: anywhere;
  word-break: normal;
  margin: 1.25em 0;
  padding: 16px;
  border-radius: 10px;
  background: var(--code-bg);
  color: var(--code-text);
  border: 1px solid color-mix(in srgb, var(--code-text) 12%, transparent);
  line-height: 1.55;
}

.markdown-body pre code {
  display: block;
  white-space: inherit;
  overflow-wrap: inherit;
  word-break: inherit;
  padding: 0;
  border: 0;
  background: transparent;
  color: inherit;
}

.markdown-body table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.3em 0;
  display: block;
  overflow-x: auto;
}

.markdown-body th,
.markdown-body td {
  padding: .62em .75em;
  border: 1px solid var(--line);
  text-align: left;
  white-space: nowrap;
}

.markdown-body th { background: var(--panel-2); }

.markdown-body a {
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}

.markdown-body hr {
  border: 0;
  border-top: 1px solid var(--line);
  margin: 2em 0;
}

.reader-error {
  max-width: 700px;
  margin: 12vh auto 0;
  color: var(--muted);
}

.footer {
  width: min(1500px, 100%);
  margin: 0 auto;
  padding: 0 18px 18px;
  display: flex;
  justify-content: space-between;
  gap: 16px;
  color: var(--muted);
  font-size: .75rem;
}

@media (max-width: 860px) {
  .topbar { position: relative; }
  .layout {
    grid-template-columns: 1fr;
    padding: 10px;
    gap: 10px;
  }

  .browser-panel {
    position: relative;
    top: auto;
    min-height: 0;
    max-height: none;
  }

  .reader-panel {
    min-height: 55vh;
    padding: 24px 18px 40px;
  }

  .welcome { margin-top: 3vh; }
  .welcome h1 { font-size: clamp(2.2rem, 9vw, 3.4rem); }
  .welcome-link:nth-child(n+4) { display: none; }

  .footer { padding: 0 12px 14px; }
}

@media (max-width: 520px) {
  .topbar { padding: 8px 10px; }
  .brand small { display: none; }
  .top-actions .ghost-button:not(.icon-button) { padding: 0 9px; font-size: .82rem; }
  .layout { padding: 7px; }
  .browser-panel { padding: 10px; border-radius: 11px; }
  .reader-panel { border-radius: 11px; }
  .entry { min-height: 46px; }
  .markdown-body h1 { font-size: 2rem; }
  .welcome { margin-top: 1vh; }
  .welcome-start { margin-top: 22px; }
  .welcome-meta { margin-top: 20px; align-items: flex-start; flex-direction: column; }
}

@media print {
  .topbar, .browser-panel, .footer { display: none !important; }
  .layout { display: block; padding: 0; }
  .reader-panel { border: 0; box-shadow: none; padding: 0; }
}


.language-picker,
.mode-picker {
  display: inline-flex;
  align-items: center;
}

.language-picker select,
.mode-picker select {
  min-height: 36px;
  padding: 0 28px 0 10px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  color: var(--text);
  font: inherit;
  font-weight: 700;
  cursor: pointer;
}

:root[data-mode="junior"] {
  --radius: 18px;
}

:root[data-mode="junior"] .entry {
  min-height: 48px;
}

:root[data-mode="junior"] .markdown-body {
  max-width: 780px;
  font-size: 1.03rem;
}

:root[data-mode="junior"] .markdown-body h1 {
  line-height: 1.08;
}

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


/* Mobile top bar: keep all controls inside the viewport. */
@media (max-width: 700px) {
  .topbar {
    position: relative;
    flex-wrap: wrap;
    align-items: center;
    gap: 8px;
    padding: 8px 10px 10px;
  }

  .brand {
    min-width: 0;
    max-width: 100%;
  }

  .top-actions {
    width: 100%;
    min-width: 0;
    display: grid;
    grid-template-columns: 68px minmax(112px, 1fr) auto 38px;
    gap: 6px;
  }

  .language-picker,
  .mode-picker {
    min-width: 0;
  }

  .language-picker select,
  .mode-picker select {
    width: 100%;
    min-width: 0;
    padding-left: 9px;
    padding-right: 24px;
  }

  .top-actions .ghost-button {
    min-width: 0;
    padding-left: 9px;
    padding-right: 9px;
    white-space: nowrap;
  }

  .top-actions .icon-button {
    width: 38px;
    padding: 0;
  }
}

@media (max-width: 390px) {
  .top-actions {
    grid-template-columns: 62px minmax(102px, 1fr) auto 36px;
    gap: 5px;
  }

  .language-picker select,
  .mode-picker select,
  .top-actions .ghost-button:not(.icon-button) {
    font-size: .78rem;
  }

  .top-actions .icon-button {
    width: 36px;
  }
}


.browser-toolbar #locationLabel {
  color: var(--text);
  font-family: inherit;
  font-weight: 650;
}

@media (max-width: 860px) {
  html { scroll-behavior: auto; }

  .markdown-body pre {
    max-width: 100%;
    white-space: pre-wrap;
    overflow-x: hidden;
    overflow-wrap: anywhere;
  }
}

.reader-top-wrap {
  position: fixed;
  right: 22px;
  bottom: 22px;
  z-index: 40;
  margin: 0;
  padding: 0;
  border: 0;
  pointer-events: none;
}

.reader-top {
  pointer-events: auto;
  width: 48px;
  height: 48px;
  display: inline-grid;
  place-items: center;
  padding: 0;
  border: 1px solid var(--line);
  border-radius: 50%;
  background: var(--panel);
  color: var(--text);
  box-shadow: var(--shadow);
  font: inherit;
  font-size: 1.25rem;
  line-height: 1;
}

.reader-top:hover,
.reader-top:focus-visible {
  background: var(--hover);
  outline: none;
}

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

@media (max-width: 520px) {
  .reader-top-wrap {
    right: 14px;
    bottom: 14px;
  }

  .reader-top {
    width: 46px;
    height: 46px;
  }
}

.crumb.current {
  cursor: default;
  color: var(--text);
  font-weight: 650;
}


.related-articles {
  margin-top: 2.5em;
  padding-top: 1.2em;
  border-top: 1px solid var(--line);
}

.related-articles h2 {
  margin-top: 0;
  font-size: 1.2rem;
}

.related-articles ul {
  margin-bottom: 0;
}