/* Automotive AI Skills — "factory service manual" design system
   paper #F4F5F1 · ink #1A2028 · manual blue #2456A6 · safety orange #E8541E · grease #66707D
   Theme: [data-theme] is set on <html> before paint (theme-init include);
   dark = "night shift in the garage" — same manual, work-light palette. */

:root {
  color-scheme: light;
  --paper: #f4f5f1;
  --paper-raised: #fdfdfb;
  --ink: #1a2028;
  --ink-soft: #3d4650;
  --grease: #66707d;
  --blue: #2456a6;
  --blue-deep: #193d78;
  --orange: #e8541e;
  --rule: #c9cdc6;
  --rule-strong: #1a2028;
  --code-bg: #1a2028;
  --code-fg: #e8ebe6;
  --inline-code: #e9ebe5;
  --card-hover: #ffffff;
  --caution-a: #f8ede5;
  --caution-b: #fdf6f0;
  --shadow: rgba(26, 32, 40, 0.14);
  --mono: "IBM Plex Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  --display: "Archivo Narrow", "Arial Narrow", system-ui, sans-serif;
  --body: system-ui, -apple-system, "Segoe UI", "Hiragino Kaku Gothic ProN", "Noto Sans JP", Meiryo, sans-serif;
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --paper: #12161c;
  --paper-raised: #1a2028;
  --ink: #e6e9e3;
  --ink-soft: #b7bfc7;
  --grease: #8d97a3;
  --blue: #7aa5ee;
  --blue-deep: #a9c5f5;
  --orange: #ff7038;
  --rule: #2b333d;
  --rule-strong: #d6dad1;
  --code-bg: #0b0e13;
  --code-fg: #ccd3c9;
  --inline-code: #232b35;
  --card-hover: #222a34;
  --caution-a: #26190f;
  --caution-b: #1d1410;
  --shadow: rgba(0, 0, 0, 0.55);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--body);
  font-size: 1rem;
  line-height: 1.65;
  -webkit-text-size-adjust: 100%;
  transition: background-color 0.25s ease, color 0.25s ease;
}

::selection { background: var(--orange); color: #fff; }

a { color: var(--blue); text-decoration-thickness: 1px; text-underline-offset: 2px; }
a:hover { color: var(--blue-deep); }
:focus-visible { outline: 2px solid var(--orange); outline-offset: 2px; }

/* ---------- shared shell ---------- */

.shell-header {
  border-bottom: 2px solid var(--rule-strong);
  background: var(--paper);
}
.shell-header .bar {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0.7rem 1.25rem;
  display: flex;
  align-items: baseline;
  gap: 1.5rem;
  flex-wrap: wrap;
}
.wordmark {
  font-family: var(--display);
  font-weight: 700;
  font-size: 1.05rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink);
  text-decoration: none;
  white-space: nowrap;
}
.wordmark:hover { color: var(--ink); }
.wordmark .tick { color: var(--orange); }
.shell-nav {
  display: flex;
  gap: 1.1rem;
  margin-left: auto;
  flex-wrap: wrap;
}
.shell-nav a {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--ink-soft);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  padding-bottom: 1px;
}
.shell-nav a:hover { color: var(--ink); border-bottom-color: var(--orange); }

.theme-toggle {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--ink-soft);
  background: none;
  border: 0;
  border-bottom: 1px solid transparent;
  padding: 0 0 1px;
  cursor: pointer;
}
.theme-toggle:hover { color: var(--ink); border-bottom-color: var(--orange); }
.theme-toggle .tt-light { display: none; }
:root[data-theme="dark"] .theme-toggle .tt-dark { display: none; }
:root[data-theme="dark"] .theme-toggle .tt-light { display: inline; }

/* document bar — title block of each service document */
.docbar {
  border-bottom: 1px solid var(--rule);
  background: var(--paper-raised);
}
.docbar .bar {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0.45rem 1.25rem;
  display: flex;
  align-items: baseline;
  gap: 1rem;
  flex-wrap: wrap;
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.06em;
  color: var(--grease);
}
.docbar .doc-tag {
  color: var(--paper);
  background: var(--blue);
  padding: 0.05rem 0.5rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  white-space: nowrap;
}
.docbar .doc-path { overflow-wrap: anywhere; }
.docbar .doc-langs { margin-left: auto; display: flex; gap: 0.7rem; }
.docbar .doc-langs a {
  color: var(--grease);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  padding-bottom: 1px;
}
.docbar .doc-langs a:hover { color: var(--ink); border-bottom-color: var(--orange); }
.docbar .doc-langs a.on { color: var(--orange); border-bottom-color: var(--orange); }

.shell-footer {
  border-top: 2px solid var(--rule-strong);
  margin-top: 4rem;
}
.shell-footer .bar {
  max-width: 1080px;
  margin: 0 auto;
  padding: 1.2rem 1.25rem 2.2rem;
  display: flex;
  gap: 1.5rem;
  flex-wrap: wrap;
  font-family: var(--mono);
  font-size: 0.72rem;
  color: var(--grease);
}
.shell-footer a { color: var(--grease); }
.shell-footer a:hover { color: var(--ink); }

/* ---------- docs pages (rendered markdown) ---------- */

.doc {
  max-width: 820px;
  margin: 0 auto;
  padding: 2.5rem 1.25rem 1rem;
  counter-reset: docsec;
}
.doc h1, .doc h2, .doc h3, .doc h4 {
  font-family: var(--display);
  line-height: 1.15;
  letter-spacing: 0.01em;
  color: var(--ink);
}
.doc h1 {
  font-size: clamp(1.9rem, 4.5vw, 2.6rem);
  font-weight: 700;
  text-transform: uppercase;
  border-bottom: 3px solid var(--rule-strong);
  padding-bottom: 0.5rem;
  margin: 0 0 1.2rem;
}
.doc h2 {
  font-size: 1.45rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  margin: 2.6rem 0 0.8rem;
  padding-top: 0.9rem;
  border-top: 1px solid var(--rule);
  counter-increment: docsec;
}
.doc h2::before {
  content: counter(docsec, decimal-leading-zero);
  font-family: var(--mono);
  font-weight: 400;
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  color: var(--orange);
  margin-right: 0.65rem;
  vertical-align: 0.4em;
}
.doc h3 { font-size: 1.15rem; margin: 1.8rem 0 0.5rem; }
.doc p, .doc li { color: var(--ink-soft); }
.doc li::marker { color: var(--orange); }
.doc strong { color: var(--ink); }
.doc blockquote {
  margin: 1.2rem 0;
  padding: 0.6rem 1rem;
  border-left: 4px solid var(--orange);
  background: var(--paper-raised);
  color: var(--ink-soft);
}
.doc blockquote p { margin: 0.3rem 0; }
.doc code {
  font-family: var(--mono);
  font-size: 0.86em;
  background: var(--inline-code);
  padding: 0.1em 0.35em;
  border-radius: 3px;
}
.doc pre {
  background: var(--code-bg);
  color: var(--code-fg);
  padding: 1rem 1.2rem;
  overflow-x: auto;
  border-radius: 4px;
  border-left: 4px solid var(--orange);
}
.doc pre code { background: none; padding: 0; color: inherit; font-size: 0.84rem; }
.doc table {
  border-collapse: collapse;
  width: 100%;
  margin: 1.2rem 0;
  font-size: 0.92rem;
  display: block;
  overflow-x: auto;
}
.doc th {
  font-family: var(--mono);
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  text-align: left;
  background: var(--ink);
  color: var(--paper);
  padding: 0.45rem 0.7rem;
}
.doc td {
  padding: 0.45rem 0.7rem;
  border-bottom: 1px solid var(--rule);
  vertical-align: top;
  color: var(--ink-soft);
}
.doc tr:nth-child(even) td { background: var(--paper-raised); }
.doc hr { border: 0; border-top: 1px solid var(--rule); margin: 2rem 0; }
.doc img { max-width: 100%; }

/* ---------- landing page ---------- */

.landing { max-width: 1080px; margin: 0 auto; padding: 0 1.25rem; }

.hero { padding: 3.2rem 0 2.4rem; border-bottom: 2px solid var(--rule-strong); }
.hero .eyebrow {
  font-family: var(--mono);
  font-size: 0.75rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--blue);
  margin: 0 0 0.9rem;
}
.hero h1 {
  font-family: var(--display);
  font-weight: 700;
  text-transform: uppercase;
  font-size: clamp(2.8rem, 9vw, 5.6rem);
  line-height: 0.94;
  letter-spacing: 0.005em;
  margin: 0 0 1.1rem;
}
.hero h1 .line2 { color: var(--blue); display: block; }
.hero .lede {
  max-width: 620px;
  font-size: 1.08rem;
  color: var(--ink-soft);
  margin: 0 0 1.6rem;
}
.hero .lang-row {
  font-family: var(--mono);
  font-size: 0.78rem;
  margin: 0 0 1.8rem;
  color: var(--grease);
}
.hero .lang-row a { margin-right: 0.9rem; }

/* spec plate — the signature element */
.spec-plate {
  display: inline-block;
  border: 2px solid var(--rule-strong);
  background: var(--paper-raised);
  box-shadow: 4px 4px 0 var(--shadow);
  margin: 0 0 1.8rem;
}
.spec-plate table { border-collapse: collapse; }
.spec-plate td {
  font-family: var(--mono);
  padding: 0.5rem 1.1rem;
  border-right: 1px solid var(--rule);
  border-bottom: 0;
}
.spec-plate td:last-child { border-right: 0; }
.spec-plate .k {
  display: block;
  font-size: 0.62rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--grease);
}
.spec-plate .v { font-size: 1.02rem; font-weight: 600; color: var(--ink); }
.spec-plate .v.orange { color: var(--orange); }

.cta-row { display: flex; gap: 0.8rem; flex-wrap: wrap; }
.btn {
  font-family: var(--mono);
  font-size: 0.82rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  text-decoration: none;
  padding: 0.65rem 1.3rem;
  border: 2px solid var(--rule-strong);
}
.btn-primary { background: var(--ink); color: var(--paper); }
.btn-primary:hover { background: var(--blue-deep); border-color: var(--blue-deep); color: var(--paper); }
.btn-ghost { background: transparent; color: var(--ink); }
.btn-ghost:hover { border-color: var(--orange); color: var(--ink); }

/* caution strip */
.caution {
  border-bottom: 2px solid var(--rule-strong);
  background: repeating-linear-gradient(-45deg, var(--caution-a), var(--caution-a) 14px, var(--caution-b) 14px, var(--caution-b) 28px);
}
.caution .inner {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0.8rem 1.25rem;
  font-size: 0.9rem;
  color: var(--ink-soft);
}
.caution .tag {
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  color: #fff;
  background: var(--orange);
  padding: 0.15rem 0.5rem;
  margin-right: 0.6rem;
  white-space: nowrap;
}

/* section headings on landing */
.landing section { padding: 2.8rem 0 0.4rem; }
.sec-head {
  display: flex;
  align-items: baseline;
  gap: 1rem;
  border-bottom: 3px solid var(--rule-strong);
  padding-bottom: 0.4rem;
  margin-bottom: 1.4rem;
}
.sec-head h2 {
  font-family: var(--display);
  font-weight: 700;
  text-transform: uppercase;
  font-size: clamp(1.4rem, 3vw, 1.9rem);
  letter-spacing: 0.02em;
  margin: 0;
}
.sec-head .count {
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--grease);
  margin-left: auto;
}

/* procedure steps */
.steps { display: grid; grid-template-columns: repeat(auto-fit, minmax(230px, 1fr)); gap: 1.2rem; }
.step { border-left: 3px solid var(--blue); padding-left: 1rem; }
.step .no {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  color: var(--blue);
  display: block;
  margin-bottom: 0.2rem;
}
.step h3 { font-family: var(--display); text-transform: uppercase; font-size: 1.05rem; margin: 0 0 0.3rem; }
.step p { font-size: 0.92rem; color: var(--ink-soft); margin: 0; }

/* skill index cards */
.skill-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(245px, 1fr));
  gap: 0;
  border: 2px solid var(--rule-strong);
  background: var(--rule);
  gap: 1px;
}
.skill-card {
  background: var(--paper-raised);
  padding: 1rem 1.1rem 1.1rem;
  text-decoration: none;
  color: var(--ink);
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
  transition: background 0.15s ease;
}
.skill-card:hover { background: var(--card-hover); color: var(--ink); }
.skill-card .sec {
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.1em;
  color: var(--grease);
}
.skill-card:hover .sec { color: var(--orange); }
.skill-card h3 {
  font-family: var(--display);
  font-weight: 700;
  text-transform: uppercase;
  font-size: 1.02rem;
  letter-spacing: 0.02em;
  margin: 0;
}
.skill-card p { font-size: 0.85rem; color: var(--ink-soft); margin: 0; flex-grow: 1; }
.skill-card .langs {
  font-family: var(--mono);
  font-size: 0.65rem;
  letter-spacing: 0.08em;
  color: var(--blue);
  margin-top: 0.35rem;
}

/* resources two-column */
.res-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 1.6rem; }
.res-block h3 {
  font-family: var(--mono);
  font-size: 0.75rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--orange);
  margin: 0 0 0.6rem;
}
.res-block ul { list-style: none; margin: 0; padding: 0; }
.res-block li {
  padding: 0.45rem 0;
  border-bottom: 1px solid var(--rule);
  font-size: 0.94rem;
}
.res-block li span { color: var(--grease); font-size: 0.85rem; }

/* load animation */
@media (prefers-reduced-motion: no-preference) {
  .hero .eyebrow, .hero h1, .hero .lede, .hero .lang-row, .hero .spec-plate, .hero .cta-row {
    animation: rise 0.55s cubic-bezier(0.2, 0.7, 0.3, 1) both;
  }
  .hero h1 { animation-delay: 0.06s; }
  .hero .lede { animation-delay: 0.14s; }
  .hero .lang-row { animation-delay: 0.2s; }
  .hero .spec-plate { animation-delay: 0.26s; }
  .hero .cta-row { animation-delay: 0.34s; }
  @keyframes rise {
    from { opacity: 0; transform: translateY(14px); }
    to { opacity: 1; transform: none; }
  }
}

@media (max-width: 560px) {
  .spec-plate table, .spec-plate tbody { display: block; }
  .spec-plate tr { display: flex; flex-wrap: wrap; }
  .spec-plate td { border-right: 0; border-bottom: 1px solid var(--rule); flex: 1 1 45%; }
  .shell-nav { gap: 0.8rem; }
}


/* Text-based demo remains accessible, selectable and crawlable. */
.demo-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 1rem; margin: 1.5rem 0; }
.demo-reading { display: grid; gap: .35rem; padding: 1.4rem; border: 1px solid var(--rule); background: var(--paper-raised); }
.demo-reading .k { font-family: var(--mono); font-size: .8rem; color: var(--ink-soft); }
.demo-reading strong { font-family: var(--display); font-size: clamp(1.8rem, 4vw, 2.7rem); line-height: 1.2; color: var(--blue); }
.demo-reading > span:last-child { font-size: .9rem; color: var(--ink-soft); }
@media (max-width: 620px) { .demo-grid { grid-template-columns: 1fr; } }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } body { transition: none; } }