/* yoshikoflow — dark documentation theme: sticky header + left nav tree + centered
   content + right on-page TOC. Hand-authored, no build step. */

:root {
  --bg:          #16161e;
  --bg-header:   rgba(18, 18, 26, 0.82);
  --surface:     #1e1e29;
  --surface-2:   #23232f;
  --surface-3:   #191922;
  --border:      #2a2a38;
  --border-hi:   #3a3a4e;
  --fg:          #d9d9e3;
  --fg-strong:   #f4f4f9;
  --fg-muted:    #9a9ab0;
  --fg-dim:      #6d6d84;
  --accent:      #a78bfa;
  --accent-hi:   #c4b5fd;
  --accent-soft: rgba(167, 139, 250, 0.14);
  --cyan:        #56d4e0;
  --green:       #5be5a0;
  --amber:       #f0c869;
  --radius:      8px;
  --header-h:    56px;
  --nav-w:       16rem;
  --toc-w:       14rem;
  --content-max: 48rem;
  --sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica,
          Arial, "Apple Color Emoji", sans-serif;
  --mono: "SFMono-Regular", "JetBrains Mono", "Fira Code", ui-monospace, Menlo,
          Consolas, "Liberation Mono", monospace;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; scroll-padding-top: calc(var(--header-h) + 12px); }

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--sans);
  font-size: 15px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--accent-hi); text-decoration: underline; text-underline-offset: 2px; }

.skip-link {
  position: absolute; left: -999px; top: 0; z-index: 100;
  background: var(--accent); color: #17131f; padding: 8px 14px; border-radius: 0 0 6px 0;
}
.skip-link:focus { left: 0; }

/* ---------- header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 30; height: var(--header-h);
  background: var(--bg-header); backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}
.header-inner {
  height: 100%; max-width: 90rem; margin: 0 auto; padding: 0 20px;
  display: flex; align-items: center; gap: 14px;
}
.brand { display: flex; align-items: center; gap: 9px; font-weight: 650; color: var(--fg-strong); font-size: 16px; }
.brand:hover { text-decoration: none; }
.brand-glyph {
  font-family: var(--mono); color: var(--accent); background: var(--accent-soft);
  border: 1px solid var(--border-hi); border-radius: 5px; padding: 1px 6px; font-size: 13px;
}
.brand-name { letter-spacing: -0.2px; }
.brand-version {
  color: var(--fg-dim); font-family: var(--mono); font-size: 12px; font-weight: 400;
  border: 1px solid var(--border); border-radius: 20px; padding: 1px 8px;
}
.header-spacer { flex: 1; }
.header-links { display: flex; gap: 6px; }
.header-link { color: var(--fg-muted); padding: 6px 10px; border-radius: 6px; font-size: 14px; }
.header-link:hover { color: var(--fg-strong); background: var(--surface); text-decoration: none; }
.ext-mark { color: var(--fg-dim); font-size: 11px; }

/* burger (mobile only) */
.nav-burger { display: none; cursor: pointer; padding: 6px; margin-left: -6px; border-radius: 6px; }
.nav-burger span { display: block; width: 20px; height: 2px; background: var(--fg-muted); border-radius: 2px; }
.nav-burger span + span { margin-top: 4px; }
.nav-burger:hover span { background: var(--fg-strong); }
.nav-toggle-state { position: absolute; }
.nav-scrim { display: none; }

/* ---------- layout ---------- */
.layout {
  max-width: 90rem; margin: 0 auto;
  display: grid;
  grid-template-columns: var(--nav-w) minmax(0, 1fr) var(--toc-w);
  align-items: start;
}

.sidebar {
  position: sticky; top: var(--header-h);
  height: calc(100vh - var(--header-h));
  overflow-y: auto; overscroll-behavior: contain;
}
.sidebar-inner { padding: 26px 16px 40px; }
.sidebar-nav { border-right: 1px solid var(--border); }
.sidebar-toc { border-left: 1px solid var(--border); }

/* thin scrollbars */
.sidebar::-webkit-scrollbar { width: 8px; }
.sidebar::-webkit-scrollbar-thumb { background: var(--border-hi); border-radius: 8px; }
.sidebar { scrollbar-width: thin; scrollbar-color: var(--border-hi) transparent; }

/* ---------- left nav ---------- */
.nav-group { margin-bottom: 22px; }
.nav-group-title {
  margin: 0 0 8px; padding: 0 10px; font-size: 11.5px; font-weight: 700;
  text-transform: uppercase; letter-spacing: 0.08em; color: var(--fg-dim);
}
.nav-subhead {
  margin: 12px 0 4px; padding: 0 10px; font-size: 11px; font-weight: 600;
  letter-spacing: 0.04em; color: var(--fg-dim);
}
.nav-list { list-style: none; margin: 0; padding: 0; }
.nav-sublist { margin-bottom: 6px; }
.nav-item {
  display: block; padding: 5px 10px; margin: 1px 0; border-radius: 6px;
  color: var(--fg-muted); font-size: 13.5px; line-height: 1.4;
  border-left: 2px solid transparent;
}
.nav-item:hover { color: var(--fg-strong); background: var(--surface); text-decoration: none; }
.nav-item.active {
  color: var(--accent-hi); background: var(--accent-soft);
  border-left-color: var(--accent); font-weight: 550;
}
.nav-leaf { padding-left: 16px; font-size: 13px; }
.nav-leaf code { font-family: var(--mono); font-size: 12px; background: none; border: none; padding: 0; color: inherit; }

/* ---------- content ---------- */
.content { min-width: 0; padding: 34px 48px 64px; }
.page { max-width: var(--content-max); }
.page-home { max-width: 54rem; }

.page-head { margin-bottom: 26px; padding-bottom: 18px; border-bottom: 1px solid var(--border); }
.page-title { font-size: 32px; line-height: 1.15; margin: 0; color: var(--fg-strong); letter-spacing: -0.5px; }
.page-sub { margin: 10px 0 0; color: var(--fg-muted); font-size: 16px; }

.page-body { font-size: 15px; color: var(--fg); }
.page-body h2 {
  font-size: 22px; margin: 42px 0 14px; padding-top: 6px; color: var(--fg-strong);
  letter-spacing: -0.3px; scroll-margin-top: calc(var(--header-h) + 12px);
}
.page-body h3 {
  font-size: 17px; margin: 28px 0 10px; color: var(--fg-strong);
  scroll-margin-top: calc(var(--header-h) + 12px);
}
.page-body p { margin: 0 0 14px; }
.page-body ul, .page-body ol { margin: 0 0 14px; padding-left: 1.4em; }
.page-body li { margin: 5px 0; }
.page-body li > ul, .page-body li > ol { margin: 6px 0; }
.page-body strong { color: var(--fg-strong); font-weight: 650; }
.page-body hr { border: none; border-top: 1px solid var(--border); margin: 34px 0; }
.page-body a { border-bottom: 1px solid transparent; }
.page-body a:hover { border-bottom-color: var(--accent); text-decoration: none; }

/* inline + block code */
.page-body :not(pre) > code {
  background: var(--surface-2); border: 1px solid var(--border); border-radius: 5px;
  padding: 1.5px 6px; color: var(--accent-hi); font-family: var(--mono); font-size: 12.5px;
}
.page-body pre {
  background: var(--surface-3); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 15px 16px; overflow-x: auto; margin: 0 0 18px;
  font-size: 13px; line-height: 1.6;
}
.page-body pre code { color: #d6d6e6; background: none; border: none; padding: 0; font-family: var(--mono); }
.highlight { background: transparent !important; }

/* tables */
.page-body table { border-collapse: collapse; width: 100%; margin: 4px 0 22px; font-size: 13.5px; display: block; overflow-x: auto; }
.page-body th, .page-body td { border: 1px solid var(--border); padding: 8px 12px; text-align: left; vertical-align: top; }
.page-body th { background: var(--surface-2); color: var(--fg-strong); font-weight: 600; }
.page-body tr:nth-child(even) td { background: var(--surface-3); }

/* callouts */
.page-body blockquote {
  margin: 18px 0; padding: 12px 16px; border-left: 3px solid var(--accent);
  background: var(--accent-soft); border-radius: 0 6px 6px 0; color: var(--fg);
}
.page-body blockquote p { margin: 6px 0; }
.page-body blockquote :not(pre) > code { background: rgba(0,0,0,0.25); }

/* images / diagrams (light-mode PNGs framed on the dark page) */
.page-body img {
  max-width: 100%; height: auto; border: 1px solid var(--border-hi);
  border-radius: var(--radius); background: #fff; padding: 10px; margin: 6px 0 20px;
}

/* ---------- right TOC ---------- */
.toc-title {
  margin: 0 0 10px; font-size: 11.5px; font-weight: 700; text-transform: uppercase;
  letter-spacing: 0.08em; color: var(--fg-dim);
}
.toc-list { list-style: none; margin: 0; padding: 0; border-left: 1px solid var(--border); }
.toc-item a {
  display: block; padding: 4px 12px; color: var(--fg-dim); font-size: 12.5px; line-height: 1.4;
  border-left: 2px solid transparent; margin-left: -1px;
}
.toc-item a:hover { color: var(--fg-strong); text-decoration: none; }
.toc-item a.active { color: var(--accent-hi); border-left-color: var(--accent); }
.toc-h3 a { padding-left: 24px; }

/* ---------- footer ---------- */
.content-footer { max-width: var(--content-max); margin-top: 56px; padding-top: 22px; border-top: 1px solid var(--border); }
.page-home .content-footer,
.content > .content-footer { max-width: var(--content-max); }
.footer-links { display: flex; gap: 18px; flex-wrap: wrap; margin-bottom: 8px; }
.footer-links a { color: var(--fg-muted); font-size: 13px; }
.footer-links a:hover { color: var(--accent-hi); text-decoration: none; }
.footer-meta { margin: 0; color: var(--fg-dim); font-size: 12.5px; }

/* ---------- home hero ---------- */
.hero { padding: 12px 0 6px; }
.hero-name { font-size: 46px; margin: 0 0 6px; letter-spacing: -1px; color: var(--fg-strong); }
.hero-sub { color: var(--accent-hi); font-size: 18px; margin: 0 0 16px; }
.hero-desc { color: var(--fg-muted); font-size: 16px; max-width: 42rem; margin: 0 0 22px; }
.hero-cta { display: flex; gap: 12px; flex-wrap: wrap; margin: 20px 0 8px; }
.btn {
  display: inline-block; padding: 9px 18px; border: 1px solid var(--border-hi);
  border-radius: 7px; color: var(--fg-strong); background: var(--surface); font-size: 14px; font-weight: 550;
}
.btn:hover { border-color: var(--accent); color: var(--accent-hi); text-decoration: none; }
.btn-primary { border-color: var(--accent); color: #17131f; background: var(--accent); }
.btn-primary:hover { background: var(--accent-hi); border-color: var(--accent-hi); color: #17131f; }

/* terminal block (hero install cmd) */
.term {
  border: 1px solid var(--border-hi); border-radius: var(--radius); overflow: hidden;
  background: var(--surface-3); margin: 8px 0 4px; box-shadow: 0 10px 34px rgba(0,0,0,0.4);
}
.term-bar { display: flex; align-items: center; gap: 7px; padding: 8px 12px; background: var(--surface-2); border-bottom: 1px solid var(--border); }
.term-bar .dot { width: 11px; height: 11px; border-radius: 50%; display: inline-block; }
.term-bar .dot:nth-child(1) { background: #ff5f56; }
.term-bar .dot:nth-child(2) { background: #ffbd2e; }
.term-bar .dot:nth-child(3) { background: #27c93f; }
.term-title { margin-left: auto; color: var(--fg-dim); font-size: 12px; }
.term-body { margin: 0; padding: 16px; overflow-x: auto; color: var(--fg); font-size: 13.5px; font-family: var(--mono); white-space: pre; }
.ps1 { color: var(--green); user-select: none; margin-right: 8px; }

/* feature cards */
.features { display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px; margin-top: 40px; }
.card {
  display: block; border: 1px solid var(--border); border-radius: var(--radius);
  padding: 18px; background: var(--surface); color: inherit; text-decoration: none;
  transition: border-color .12s, transform .12s, background .12s;
}
.card:hover { border-color: var(--accent); background: var(--surface-2); transform: translateY(-2px); text-decoration: none; }
.card h3 { margin: 0 0 8px; font-size: 15.5px; color: var(--fg-strong); display: flex; align-items: center; }
.card-arrow { margin-left: auto; color: var(--fg-dim); transition: color .12s, transform .12s; }
.card:hover .card-arrow { color: var(--accent); transform: translateX(3px); }
.card p { margin: 0 0 12px; color: var(--fg-muted); font-size: 13.5px; }
.mini { margin: 0; padding: 9px 12px; background: var(--surface-3); border: 1px solid var(--border); border-radius: 6px; color: var(--green); font-size: 12px; font-family: var(--mono); overflow-x: auto; }

/* 404 */
.notfound { text-align: center; padding: 50px 0; }
.notfound .code { font-size: 76px; color: var(--accent); margin: 0; font-weight: 700; }

/* ---------- responsive ---------- */
@media (max-width: 1180px) {
  :root { --toc-w: 0px; }
  .layout { grid-template-columns: var(--nav-w) minmax(0, 1fr); }
  .sidebar-toc { display: none; }
  .content { padding: 30px 40px 56px; }
}

@media (max-width: 860px) {
  .layout { grid-template-columns: minmax(0, 1fr); }
  .nav-burger { display: block; }
  .content { padding: 26px 22px 52px; }
  .features { grid-template-columns: 1fr; }
  .hero-name { font-size: 36px; }

  .sidebar-nav {
    position: fixed; top: var(--header-h); left: 0; z-index: 25;
    width: 17rem; max-width: 82vw; height: calc(100vh - var(--header-h));
    background: var(--surface-3); border-right: 1px solid var(--border);
    transform: translateX(-102%); transition: transform .22s ease;
  }
  #nav-toggle:checked ~ .layout .sidebar-nav { transform: translateX(0); box-shadow: 0 0 40px rgba(0,0,0,0.5); }
  #nav-toggle:checked ~ .nav-scrim {
    display: block; position: fixed; inset: var(--header-h) 0 0 0; z-index: 20;
    background: rgba(0,0,0,0.5);
  }
}