/*
 * wcstack tutorial pages. Same palette and type as /state/ and /signals/.
 *
 * Language: prose is written twice, side by side — an English element with
 * lang="en" and a Japanese one with lang="ja". tutorial.js sets
 * <html data-lang="en|ja"> and the other language is hidden. Without the
 * script both are shown, the Japanese one dimmed like the rest of the site.
 */

/* ── Reset & Base ── */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
:root {
  --bg: #060a10;
  --bg-card: #0c121a;
  --bg-code: #080d14;
  --border: #182230;
  --border-subtle: #101823;
  --text: #d3d9e0;
  --text-bright: #f7fafc;
  --text-dim: #6f7d8e;
  --accent: #38bdf8;
  --accent-glow: rgba(56, 189, 248, .12);
  --accent-hover: #6dd2fc;
  --c-green: #5bb98c;
  --c-salmon: #d48872;
  --c-gold: #d4a017;
  --font: 'Space Grotesk', system-ui, -apple-system, 'Hiragino Kaku Gothic ProN', 'Hiragino Sans', 'Noto Sans JP', 'Yu Gothic UI', Meiryo, sans-serif;
  --mono: 'JetBrains Mono', 'Fira Code', ui-monospace, monospace;
}
html { scroll-behavior: smooth; }
body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--accent); text-decoration: none; transition: color .2s; }
a:hover { color: var(--accent-hover); }
code, pre { font-family: var(--mono); }
.container { max-width: 920px; margin: 0 auto; padding: 0 24px; }

/* ── Language ── */
html[data-lang="en"] body [lang="ja"],
html[data-lang="ja"] body [lang="en"] { display: none !important; }
html:not([data-lang]) .doc p[lang="ja"],
html:not([data-lang]) .doc li[lang="ja"] { font-size: .84rem; color: var(--text-dim); }
html:not([data-lang]) h1 [lang="ja"],
html:not([data-lang]) h2 [lang="ja"],
html:not([data-lang]) h3 [lang="ja"] { display: block; font-size: .62em; color: var(--text-dim); font-weight: 500; }
html:not([data-lang]) .lang-switch { display: none; }
html:not([data-lang]) span[lang="en"] + span[lang="ja"]::before { content: " / "; }
html:not([data-lang]) :is(h1, h2, h3) span[lang="en"] + span[lang="ja"]::before { content: none; }
:lang(ja) { line-break: strict; }
.doc p:lang(ja), .doc li:lang(ja) { line-height: 1.85; }

/* ── Header ── */
header {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  background: rgba(6, 10, 16, .9);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-subtle);
}
header .container {
  display: flex; align-items: center; gap: 20px;
  height: 56px;
}
.logo { font-size: 1.1rem; font-weight: 700; letter-spacing: -.02em; color: var(--text-dim); white-space: nowrap; }
.logo span { color: var(--accent); }
nav { display: flex; gap: 22px; margin-left: auto; overflow-x: auto; scrollbar-width: none; }
nav a {
  font-size: .8rem; font-weight: 500;
  color: var(--text-dim); letter-spacing: .02em; white-space: nowrap;
}
nav a:hover { color: var(--text); }
nav a.active { color: var(--accent); }
.lang-switch {
  display: flex; flex-shrink: 0;
  border: 1px solid var(--border); border-radius: 999px; overflow: hidden;
}
.lang-switch button {
  font: 500 .72rem var(--font);
  padding: 3px 10px;
  background: none; border: 0; color: var(--text-dim); cursor: pointer;
}
.lang-switch button[aria-pressed="true"] { background: var(--accent-glow); color: var(--accent); }
.lang-switch button:focus-visible { outline: 2px solid var(--accent); outline-offset: -2px; }

/* ── Hero ── */
.doc-hero {
  padding: 130px 0 10px;
  background: radial-gradient(ellipse 60% 40% at 50% 0%, var(--accent-glow), transparent 70%);
}
.section-label {
  font-size: .7rem; font-weight: 600; text-transform: uppercase;
  letter-spacing: .15em; color: var(--accent); margin-bottom: 14px;
}
.page-title {
  font-size: clamp(1.7rem, 4.5vw, 2.5rem);
  font-weight: 700; letter-spacing: -.02em; line-height: 1.25;
  color: var(--text-bright);
}
.lead {
  margin-top: 14px;
  font-size: clamp(.95rem, 2vw, 1.05rem);
  color: var(--text-dim);
  max-width: 720px;
}
.lead code { font-size: .88em; color: var(--accent); }
html:not([data-lang]) .lead[lang="ja"] { margin-top: 8px; font-size: .86rem; }

/* step progress */
.progress { display: flex; gap: 6px; margin-top: 24px; list-style: none; flex-wrap: wrap; }
.progress a {
  display: grid; place-items: center;
  width: 30px; height: 30px; border-radius: 50%;
  font: 500 .74rem var(--mono);
  border: 1px solid var(--border); color: var(--text-dim); background: var(--bg-card);
}
.progress a:hover { color: var(--text); border-color: var(--text-dim); }
.progress a.done { color: var(--c-green); border-color: rgba(91, 185, 140, .35); }
.progress a[aria-current="page"] { color: var(--bg); background: var(--accent); border-color: var(--accent); }

/* ── Doc sections ── */
section.doc { padding: 56px 0 4px; }
section.doc + section.doc { border-top: 1px solid var(--border-subtle); margin-top: 48px; }
.doc h2 {
  font-size: clamp(1.25rem, 3vw, 1.6rem);
  font-weight: 700; letter-spacing: -.02em;
  color: var(--text-bright);
}
.doc h3 {
  margin-top: 36px; margin-bottom: 4px;
  font-size: 1.05rem; font-weight: 600;
  color: var(--text-bright);
}
.doc p { margin-top: 12px; font-size: .94rem; }
.doc p code, .doc li code, .doc td code, .doc h3 code, .note code {
  font-size: .84em;
  background: var(--bg-code);
  border: 1px solid var(--border-subtle);
  border-radius: 4px;
  padding: 1px 6px;
  color: var(--accent);
  overflow-wrap: anywhere;
}
.doc ul.list, .doc ol.list { margin: 12px 0 0 22px; font-size: .92rem; }
.doc ul.list li, .doc ol.list li { margin-top: 8px; }
.doc strong { color: var(--text-bright); }

/* ── Tables ── */
.table-wrap { overflow-x: auto; margin-top: 18px; }
table { width: 100%; border-collapse: collapse; font-size: .86rem; }
th {
  text-align: left; padding: 8px 12px;
  border-bottom: 1px solid var(--border);
  color: var(--text-dim);
  font-size: .68rem; font-weight: 600;
  text-transform: uppercase; letter-spacing: .1em;
  white-space: nowrap;
}
td { padding: 8px 12px; border-bottom: 1px solid var(--border-subtle); vertical-align: top; }

/* ── Code blocks ── */
.code-block {
  margin-top: 18px;
  border: 1px solid var(--border);
  border-radius: 10px;
  overflow: hidden;
}
.code-header {
  display: flex; align-items: center; justify-content: space-between; gap: 12px;
  padding: 8px 18px;
  background: rgba(12, 18, 26, .8);
  border-bottom: 1px solid var(--border);
  font-size: .72rem; color: var(--text-dim);
}
.code-header .filename { font-family: var(--mono); font-weight: 500; }
.code-header .tag { color: var(--c-green); }
.code-header .tag.bad { color: var(--c-salmon); }
pre {
  padding: 18px 22px;
  background: var(--bg-code);
  overflow-x: auto;
  font-size: .8rem;
  line-height: 1.7;
  tab-size: 2;
}
pre.terminal { color: var(--text); }
pre.terminal .prompt { color: var(--text-dim); user-select: none; }
pre.terminal .warn { color: var(--c-gold); }
pre.terminal .err { color: var(--c-salmon); }
pre.terminal .ok { color: var(--c-green); }
pre.terminal .dim { color: var(--text-dim); }
code[class*="language-"], pre[class*="language-"] { color: var(--text); text-shadow: none; background: none; }
pre > code[class*="language-"] { padding: 0; }
.token.comment, .token.prolog, .token.doctype, .token.cdata { color: #5a6d84; font-style: italic; }
.token.punctuation { color: #6b819a; }
.token.tag { color: #38bdf8; }
.token.attr-name { color: #a78bfa; }
.token.attr-value { color: #5bb98c; }
.token.string, .token.template-string { color: #5bb98c; }
.token.keyword { color: #d48872; }
.token.function { color: #d4a017; }
.token.number, .token.boolean { color: #d48872; }
.token.operator { color: #6b819a; }
.token.property { color: #d3d9e0; }

details.source { margin-top: 18px; }
details.source summary {
  cursor: pointer;
  font-size: .86rem; font-weight: 500; color: var(--accent);
}
details.source summary:hover { color: var(--accent-hover); }

/* ── Callouts ── */
.note, .try {
  margin-top: 20px;
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  border-radius: 8px;
  background: var(--bg-card);
  padding: 14px 20px;
}
.try { border-left-color: var(--c-green); }
.note.warn { border-left-color: var(--c-salmon); }
.note p, .try p { margin-top: 0; font-size: .88rem; }
.note p + p, .try p + p { margin-top: 8px; }
.callout-label {
  display: block; margin-bottom: 4px;
  font-size: .68rem; font-weight: 600; text-transform: uppercase; letter-spacing: .12em;
  color: var(--c-green);
}
.note .callout-label { color: var(--accent); }
.note.warn .callout-label { color: var(--c-salmon); }

/* mistakes */
.mistake { margin-top: 26px; }
.mistake h3 { margin-top: 0; }

/* ── Live demo ── */
.demo {
  margin-top: 20px;
  border: 1px solid var(--border);
  border-radius: 10px;
  overflow: hidden;
  background: #fbf7f1;
}
.demo-bar {
  display: flex; align-items: center; justify-content: space-between; gap: 12px;
  padding: 8px 16px;
  background: var(--bg-card);
  border-bottom: 1px solid var(--border);
  font-size: .74rem; color: var(--text-dim);
}
.demo-bar .dot { display: inline-block; width: 8px; height: 8px; border-radius: 50%; background: var(--c-green); margin-right: 8px; }
.demo iframe { display: block; width: 100%; height: 520px; border: 0; }
.demo.short iframe { height: 380px; }
.demo.tall iframe { height: 720px; }
/* two copies of the same page side by side (step 11: the cart they share) */
.demo-pair { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px; }
@media (max-width: 900px) { .demo-pair { grid-template-columns: minmax(0, 1fr); } }

/* ── Step list (index) ── */
.steps { list-style: none; margin-top: 22px; display: grid; gap: 12px; }
.steps a {
  display: grid; grid-template-columns: 44px 1fr; gap: 14px; align-items: start;
  padding: 16px 20px;
  border: 1px solid var(--border); border-radius: 10px;
  background: var(--bg-card); color: var(--text);
}
.steps a:hover { border-color: rgba(56, 189, 248, .4); }
.steps .num {
  display: grid; place-items: center;
  width: 36px; height: 36px; border-radius: 50%;
  font: 500 .82rem var(--mono); color: var(--accent);
  border: 1px solid rgba(56, 189, 248, .35);
}
.steps .title { display: block; font-weight: 600; color: var(--text-bright); }
.steps .desc { display: block; margin-top: 2px; font-size: .86rem; color: var(--text-dim); }
.steps .chips { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 8px; }
.steps .chips code {
  font-size: .7rem; padding: 1px 7px; border-radius: 4px;
  background: var(--bg-code); border: 1px solid var(--border-subtle); color: var(--accent);
}
.steps li.later a { opacity: .55; pointer-events: none; }
.steps li.later .num { color: var(--text-dim); border-color: var(--border); }

/* ── Prev / next ── */
.step-nav {
  display: grid; grid-template-columns: 1fr 1fr; gap: 14px;
  margin-top: 64px;
}
.step-nav a {
  display: block; padding: 14px 18px;
  border: 1px solid var(--border); border-radius: 10px; background: var(--bg-card);
}
.step-nav a:hover { border-color: rgba(56, 189, 248, .4); }
.step-nav .dir { display: block; font-size: .68rem; font-weight: 600; text-transform: uppercase; letter-spacing: .12em; color: var(--text-dim); }
.step-nav .name { display: block; margin-top: 2px; font-weight: 600; color: var(--text-bright); }
.step-nav .next { grid-column: 2; text-align: right; }

/* ── Footer ── */
footer {
  border-top: 1px solid var(--border-subtle);
  margin-top: 80px;
  padding: 40px 0;
  text-align: center;
}
footer p { font-size: .8rem; color: var(--text-dim); }
.footer-links { display: flex; gap: 24px; justify-content: center; margin-bottom: 16px; flex-wrap: wrap; }
.footer-links a { font-size: .8rem; font-weight: 500; color: var(--text-dim); }
.footer-links a:hover { color: var(--text); }

@media (max-width: 640px) {
  .container { padding: 0 16px; }
  header .container { gap: 12px; }
  .logo { font-size: .95rem; }
  nav { gap: 14px; }
  nav a { font-size: .74rem; }
  nav a.wide-only { display: none; }
  pre { font-size: .74rem; padding: 14px; }
  .demo iframe { height: 600px; }
  .demo.short iframe { height: 420px; }
  .demo.tall iframe { height: 900px; }
  .step-nav { grid-template-columns: 1fr; }
  .step-nav .next { grid-column: 1; }
}