/* =========================================================================
   cnumpy quickstart tutorial — shared stylesheet
   Aesthetic: engineer's field manual. Warm paper, ink serifs, dark
   terminal code panels, hairline rules. No external dependencies.
   ========================================================================= */

:root {
  --paper: #f6f2e9;
  --paper-deep: #efe9db;
  --grid-line: rgba(112, 98, 72, 0.07);
  --ink: #2b2620;
  --ink-soft: #5c5344;
  --ink-faint: #8a7f6b;
  --rule: #d8cfba;
  --accent: #b3541e;         /* burnt sienna */
  --accent-deep: #8a3d12;
  --seal: #9c2b1f;           /* stamp red */
  --code-bg: #23201a;
  --code-edge: #3a3527;
  --code-text: #e8e0cd;
  --code-comment: #857c66;
  --code-kw: #d9a05b;
  --code-str: #a3be7c;
  --code-num: #7fb4c9;
  --code-fn: #e8c66f;
  --code-out: #9fb8a4;
  --ok: #4a7c59;
  --warn: #a8552a;
  --toc-w: 15.5rem;
  --content-w: 46rem;
  font-size: 16px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  color: var(--ink);
  background-color: var(--paper);
  background-image:
    linear-gradient(var(--grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid-line) 1px, transparent 1px);
  background-size: 28px 28px;
  font-family: Georgia, "Times New Roman", "Songti SC", "SimSun", serif;
  line-height: 1.72;
  -webkit-font-smoothing: antialiased;
}

::selection { background: rgba(179, 84, 30, 0.22); }

/* ---------- masthead ---------- */

.masthead {
  border-bottom: 3px double var(--rule);
  background:
    linear-gradient(180deg, rgba(255,255,255,0.5), rgba(255,255,255,0) 70%),
    var(--paper-deep);
  padding: 0 1.5rem;
}

.masthead-inner {
  max-width: calc(var(--toc-w) + var(--content-w) + 5rem);
  margin: 0 auto;
  padding: 2.8rem 0 2.2rem;
  position: relative;
}

.masthead .kicker {
  font-family: "Consolas", "Cascadia Mono", monospace;
  font-size: 0.72rem;
  letter-spacing: 0.32em;
  text-transform: uppercase;
  color: var(--accent-deep);
  margin: 0 0 0.9rem;
}

.masthead h1 {
  font-size: clamp(2.2rem, 5.5vw, 3.6rem);
  line-height: 1.08;
  margin: 0 0 1rem;
  font-weight: 700;
  letter-spacing: -0.015em;
}

.masthead h1 .thin { font-weight: 400; font-style: italic; color: var(--ink-soft); }

.masthead .deck {
  max-width: 38rem;
  font-size: 1.06rem;
  color: var(--ink-soft);
  margin: 0;
}

.stamp {
  position: absolute;
  right: 0;
  top: 2.6rem;
  border: 2px solid var(--seal);
  color: var(--seal);
  font-family: "Consolas", "Cascadia Mono", monospace;
  font-size: 0.66rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  padding: 0.5rem 0.8rem;
  transform: rotate(4deg);
  border-radius: 2px;
  opacity: 0.82;
  text-align: center;
  line-height: 1.5;
  background: rgba(246, 242, 233, 0.6);
}

.lang-switch {
  position: absolute;
  right: 0;
  bottom: -1rem;
  display: flex;
  gap: 0;
  border: 1px solid var(--rule);
  border-radius: 3px;
  overflow: hidden;
  font-family: "Consolas", "Cascadia Mono", monospace;
  font-size: 0.78rem;
  background: var(--paper);
  box-shadow: 0 2px 6px rgba(43, 38, 32, 0.08);
}

.lang-switch a, .lang-switch span {
  padding: 0.42rem 0.95rem;
  text-decoration: none;
  color: var(--ink-soft);
}

.lang-switch span {
  background: var(--ink);
  color: var(--paper);
  font-weight: 700;
}

.lang-switch a:hover { background: var(--paper-deep); color: var(--ink); }

/* ---------- layout ---------- */

.page {
  max-width: calc(var(--toc-w) + var(--content-w) + 5rem);
  margin: 0 auto;
  padding: 3rem 1.5rem 6rem;
  display: grid;
  grid-template-columns: var(--toc-w) minmax(0, 1fr);
  gap: 3.5rem;
  align-items: start;
}

/* ---------- table of contents ---------- */

nav.toc {
  position: sticky;
  top: 1.6rem;
  font-size: 0.86rem;
  border-left: 2px solid var(--rule);
  padding-left: 1.1rem;
  max-height: calc(100vh - 3.2rem);
  overflow-y: auto;
  scrollbar-width: thin;
}

nav.toc .toc-title {
  font-family: "Consolas", "Cascadia Mono", monospace;
  font-size: 0.68rem;
  letter-spacing: 0.28em;
  text-transform: uppercase;
  color: var(--ink-faint);
  margin: 0 0 0.9rem;
}

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

nav.toc > ol > li { counter-increment: chapter; margin-bottom: 0.32rem; }

nav.toc > ol > li > a::before {
  content: counter(chapter, decimal-leading-zero);
  font-family: "Consolas", "Cascadia Mono", monospace;
  font-size: 0.68rem;
  color: var(--ink-faint);
  margin-right: 0.55rem;
}

nav.toc a {
  color: var(--ink-soft);
  text-decoration: none;
  display: block;
  padding: 0.14rem 0.4rem 0.14rem 0;
  border-radius: 2px;
  transition: color 0.15s ease;
}

nav.toc a:hover { color: var(--accent-deep); }

nav.toc ol ol { padding-left: 1.35rem; margin: 0.1rem 0 0.35rem; }

nav.toc ol ol a { font-size: 0.8rem; color: var(--ink-faint); }

nav.toc a.active {
  color: var(--accent-deep);
  font-weight: 700;
}

nav.toc a.active::after {
  content: "◀";
  font-size: 0.55rem;
  margin-left: 0.4rem;
  vertical-align: 1px;
}

/* ---------- article ---------- */

article { min-width: 0; }

article > section { margin-bottom: 4.2rem; }

h2 {
  font-size: 1.85rem;
  line-height: 1.2;
  margin: 0 0 1.1rem;
  padding-top: 0.4rem;
  letter-spacing: -0.01em;
  position: relative;
}

h2 .chapter-no {
  display: block;
  font-family: "Consolas", "Cascadia Mono", monospace;
  font-size: 0.7rem;
  font-weight: 400;
  letter-spacing: 0.3em;
  color: var(--accent);
  margin-bottom: 0.5rem;
  text-transform: uppercase;
}

h2::after {
  content: "";
  display: block;
  width: 3.2rem;
  height: 3px;
  background: var(--accent);
  margin-top: 0.7rem;
}

h3 {
  font-size: 1.22rem;
  margin: 2.4rem 0 0.7rem;
  letter-spacing: -0.005em;
}

h2 a.anchor, h3 a.anchor {
  color: inherit;
  text-decoration: none;
}

h2 a.anchor:hover::after, h3 a.anchor:hover::after {
  content: " #";
  color: var(--accent);
  font-weight: 400;
}

p { margin: 0 0 1.05rem; }

article a { color: var(--accent-deep); text-decoration-thickness: 1px; text-underline-offset: 2px; }
article a:hover { color: var(--accent); }

code {
  font-family: "Consolas", "Cascadia Mono", "Courier New", monospace;
  font-size: 0.86em;
  background: rgba(112, 98, 72, 0.12);
  border-radius: 3px;
  padding: 0.08em 0.35em;
  color: var(--accent-deep);
}

strong { color: var(--ink); }

ul, ol { margin: 0 0 1.05rem; padding-left: 1.4rem; }
li { margin-bottom: 0.3rem; }

/* ---------- callouts ---------- */

.note, .warn-box {
  border: 1px solid var(--rule);
  border-left: 4px solid var(--ok);
  background: rgba(74, 124, 89, 0.06);
  border-radius: 3px;
  padding: 0.85rem 1.1rem;
  margin: 1.3rem 0;
  font-size: 0.95rem;
}

.warn-box {
  border-left-color: var(--warn);
  background: rgba(168, 85, 42, 0.07);
}

.note .label, .warn-box .label {
  font-family: "Consolas", "Cascadia Mono", monospace;
  font-size: 0.66rem;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  display: block;
  margin-bottom: 0.35rem;
  color: var(--ok);
}

.warn-box .label { color: var(--warn); }

.note p:last-child, .warn-box p:last-child { margin-bottom: 0; }

/* ---------- code panels ---------- */

.codepanel {
  margin: 1.4rem 0 1.7rem;
  border-radius: 6px;
  overflow: hidden;
  border: 1px solid var(--code-edge);
  box-shadow: 0 10px 28px -14px rgba(43, 38, 32, 0.55);
}

.codepanel .bar {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  background-color: #2e2a22;
  border-bottom: 1px solid var(--code-edge);
  padding: 0.45rem 0.9rem;
}

.codepanel .dots { display: flex; gap: 0.32rem; }
.codepanel .dots i {
  width: 9px; height: 9px; border-radius: 50%;
  background: #57503e; display: block;
}
.codepanel .dots i:first-child { background: #8a5a3c; }

.codepanel .bar .fname {
  font-family: "Consolas", "Cascadia Mono", monospace;
  font-size: 0.72rem;
  color: #a89c82;
  letter-spacing: 0.06em;
}

.codepanel .bar .tag {
  margin-left: auto;
  font-family: "Consolas", "Cascadia Mono", monospace;
  font-size: 0.62rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: #6f6753;
  border: 1px solid #4a4434;
  padding: 0.14rem 0.5rem;
  border-radius: 2px;
}

.codepanel pre {
  margin: 0;
  padding: 1.05rem 1.2rem;
  background: var(--code-bg);
  color: var(--code-text);
  overflow-x: auto;
  font-family: "Consolas", "Cascadia Mono", "Courier New", monospace;
  font-size: 0.84rem;
  line-height: 1.62;
  tab-size: 4;
}

.codepanel pre code {
  background: transparent;
  padding: 0;
  border-radius: 0;
  color: inherit;
  font-size: inherit;
  font-family: inherit;
}

.codepanel pre::-webkit-scrollbar { height: 8px; }
.codepanel pre::-webkit-scrollbar-thumb { background: #4a4434; border-radius: 4px; }

/* output block attached under a code panel */
.codepanel .out {
  border-top: 1px dashed #4a4434;
  background: #1d1b15;
  padding: 0.8rem 1.2rem 0.9rem;
}

.codepanel .out .out-label {
  font-family: "Consolas", "Cascadia Mono", monospace;
  font-size: 0.6rem;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: #6f6753;
  display: block;
  margin-bottom: 0.4rem;
}

.codepanel .out pre {
  padding: 0;
  background: transparent;
  color: var(--code-out);
  font-size: 0.82rem;
}

/* syntax token colors */
.tok-c { color: var(--code-comment); font-style: italic; }
.tok-k { color: var(--code-kw); }
.tok-s { color: var(--code-str); }
.tok-n { color: var(--code-num); }
.tok-f { color: var(--code-fn); }
.tok-cls { color: #c9a2d8; }
.tok-op { color: #b8ad93; }

/* ---------- tables ---------- */

table {
  border-collapse: collapse;
  width: 100%;
  margin: 1.3rem 0 1.7rem;
  font-size: 0.92rem;
  background: rgba(255, 255, 255, 0.45);
}

th, td {
  border: 1px solid var(--rule);
  padding: 0.5rem 0.8rem;
  text-align: left;
  vertical-align: top;
}

th {
  background: var(--paper-deep);
  font-family: "Consolas", "Cascadia Mono", monospace;
  font-size: 0.72rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-soft);
}

td code { white-space: nowrap; }

/* ---------- shape diagram figures ---------- */

.figure {
  border: 1px solid var(--rule);
  background: rgba(255,255,255,0.5);
  border-radius: 4px;
  padding: 1.2rem 1.3rem 1rem;
  margin: 1.4rem 0 1.7rem;
  overflow-x: auto;
}

.figure figcaption {
  font-size: 0.82rem;
  color: var(--ink-faint);
  font-style: italic;
  margin-top: 0.7rem;
}

.figure svg { display: block; max-width: 100%; }

/* ---------- chapter divider ---------- */

.divider {
  display: flex;
  align-items: center;
  gap: 1rem;
  color: var(--ink-faint);
  margin: 3.4rem 0;
  font-size: 0.8rem;
  font-family: "Consolas", "Cascadia Mono", monospace;
  letter-spacing: 0.3em;
}

.divider::before, .divider::after {
  content: "";
  flex: 1;
  border-top: 1px solid var(--rule);
}

/* ---------- footer ---------- */

footer.colophon {
  border-top: 3px double var(--rule);
  margin-top: 2rem;
  padding: 2rem 1.5rem 3rem;
  text-align: center;
  font-size: 0.85rem;
  color: var(--ink-faint);
}

footer.colophon a { color: var(--accent-deep); }

/* ---------- print header link back ---------- */

.backline {
  font-family: "Consolas", "Cascadia Mono", monospace;
  font-size: 0.74rem;
  margin-bottom: 1.4rem;
}

/* ---------- responsive ---------- */

@media (max-width: 900px) {
  .page { grid-template-columns: 1fr; gap: 1.5rem; }
  nav.toc {
    position: static;
    border-left: none;
    border: 1px solid var(--rule);
    border-radius: 4px;
    padding: 1rem 1.2rem;
    max-height: none;
    background: rgba(255,255,255,0.5);
  }
  .stamp { display: none; }
  .lang-switch { position: static; margin-top: 1.4rem; display: inline-flex; }
}