/* =========================================================================
   SkillHowTo — root landing page
   Concept: "Lab Index" — a technical drafting catalog of learn-by-diagram labs
   ========================================================================= */

:root {
  /* --- palette (blueprint grey + drafting blue + vermilion annotation) --- */
  --ground:   #E9EDF0;
  --paper:    #FFFFFF;
  --ink:      #19222E;
  --ink-soft: #5A6675;
  --ink-faint:#8C97A4;
  --line:     #C9D2DA;
  --line-soft:#DEE4EA;
  --accent:   #1B5E8C;   /* drafting blue — brand */
  --accent-d: #134462;
  --signal:   #E2542B;   /* vermilion — annotation / CTA */
  --signal-d: #C1421E;

  /* per-lab accents */
  --poker:   #1F7A4D;
  --carcare: #2E6F9E;
  --soon:    #8C97A4;

  --maxw: 1180px;
  --pad: clamp(20px, 5vw, 64px);

  --font-sans: "IBM Plex Sans", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, "SF Mono", Menlo, monospace;

  --r: 4px; /* drafting = minimal radius */
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--ground);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: 17px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  /* faint engineering grid on the page ground */
  background-image:
    linear-gradient(var(--line-soft) 1px, transparent 1px),
    linear-gradient(90deg, var(--line-soft) 1px, transparent 1px);
  background-size: 32px 32px;
  background-position: -1px -1px;
}

/* ---- language visibility toggle ---- */
.ja { display: none; }
html[data-lang="ja"] .en { display: none; }
html[data-lang="ja"] .ja { display: inline; }
html[data-lang="ja"] .ja.block { display: block; }

/* ---- shared utilities ---- */
.wrap { max-width: var(--maxw); margin: 0 auto; padding-inline: var(--pad); }

.mono {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-soft);
}

a { color: inherit; }

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5em;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  text-decoration: none;
  padding: 13px 20px;
  border-radius: var(--r);
  border: 1px solid var(--ink);
  background: var(--ink);
  color: #fff;
  transition: transform .15s ease, background .15s ease, box-shadow .15s ease;
}
.btn:hover { transform: translateY(-2px); box-shadow: 0 6px 0 -2px var(--signal); }
.btn--ghost { background: transparent; color: var(--ink); border-color: var(--line); }
.btn--ghost:hover { border-color: var(--ink); box-shadow: 0 6px 0 -2px var(--accent); }
.btn--signal { background: var(--signal); border-color: var(--signal); }
.btn--signal:hover { background: var(--signal-d); box-shadow: 0 6px 0 -2px var(--ink); }

:focus-visible { outline: 2px solid var(--signal); outline-offset: 3px; }

/* =========================================================================
   header
   ========================================================================= */
.site-head {
  position: sticky;
  top: 0;
  z-index: 20;
  background: color-mix(in srgb, var(--ground) 88%, transparent);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
}
.site-head .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  height: 62px;
}
.brand { display: flex; align-items: baseline; gap: 10px; text-decoration: none; }
.brand__mark {
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: 19px;
  letter-spacing: -0.01em;
  color: var(--ink);
}
.brand__mark b { color: var(--accent); font-weight: 700; }
.brand__tld { font-family: var(--font-mono); font-size: 12px; color: var(--ink-faint); }

.head-nav { display: flex; align-items: center; gap: 22px; }
.head-nav a.navlink {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  text-decoration: none;
  color: var(--ink-soft);
}
.head-nav a.navlink:hover { color: var(--ink); }

.lang-toggle {
  display: inline-flex;
  border: 1px solid var(--line);
  border-radius: var(--r);
  overflow: hidden;
}
.lang-toggle button {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  padding: 7px 11px;
  border: 0;
  background: transparent;
  color: var(--ink-soft);
  cursor: pointer;
}
.lang-toggle button[aria-pressed="true"] { background: var(--ink); color: #fff; }

/* =========================================================================
   hero
   ========================================================================= */
.hero { padding-block: clamp(48px, 8vw, 96px) clamp(40px, 6vw, 72px); }
.hero .wrap {
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: clamp(28px, 5vw, 64px);
  align-items: center;
}
.hero__eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 22px;
}
.hero__eyebrow .dot {
  width: 8px; height: 8px; border-radius: 50%;
  background: var(--signal);
  box-shadow: 0 0 0 4px color-mix(in srgb, var(--signal) 22%, transparent);
}
.hero h1 {
  font-size: clamp(38px, 6vw, 64px);
  line-height: 1.02;
  letter-spacing: -0.025em;
  font-weight: 600;
  margin: 0 0 22px;
}
.hero h1 .u { color: var(--accent); }
.hero h1 .mark {
  position: relative;
  white-space: nowrap;
}
.hero h1 .mark::after {
  content: "";
  position: absolute;
  left: -2px; right: -2px; bottom: 4px; height: 10px;
  background: color-mix(in srgb, var(--signal) 32%, transparent);
  z-index: -1;
}
.hero p.lead {
  font-size: clamp(16px, 1.6vw, 19px);
  color: var(--ink-soft);
  max-width: 46ch;
  margin: 0 0 30px;
}
.hero__cta { display: flex; flex-wrap: wrap; gap: 12px; margin-bottom: 26px; }
.hero__stats {
  display: flex;
  gap: 28px;
  border-top: 1px solid var(--line);
  padding-top: 18px;
}
.stat .n {
  font-family: var(--font-mono);
  font-size: 24px;
  font-weight: 600;
  color: var(--ink);
  line-height: 1;
}
.stat .l { font-family: var(--font-mono); font-size: 11px; letter-spacing: 0.06em; text-transform: uppercase; color: var(--ink-faint); }

/* hero schematic canvas */
.hero__fig {
  position: relative;
  border: 1px solid var(--line);
  border-radius: var(--r);
  background:
    radial-gradient(120% 120% at 100% 0%, #fff 0%, var(--paper) 55%, #F2F5F8 100%);
  aspect-ratio: 1 / 1;
  overflow: hidden;
  box-shadow: 0 1px 0 #fff inset, 0 18px 40px -28px rgba(25,34,46,.55);
}
.hero__fig::before {
  /* corner registration label */
  content: "FIG.01 — SKILL MAP";
  position: absolute;
  top: 12px; left: 14px;
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.1em;
  color: var(--ink-faint);
  z-index: 2;
}
.hero__fig canvas { display: block; width: 100%; height: 100%; }
.corner { position: absolute; width: 12px; height: 12px; border: 1px solid var(--accent); z-index: 2; opacity: .55; }
.corner.tr { top: 8px; right: 8px; border-left: 0; border-bottom: 0; }
.corner.bl { bottom: 8px; left: 8px; border-right: 0; border-top: 0; }
.corner.br { bottom: 8px; right: 8px; border-left: 0; border-top: 0; }

/* =========================================================================
   section scaffolding (shared, class-scoped to avoid cascade fights)
   ========================================================================= */
.section { padding-block: clamp(54px, 8vw, 92px); }
.section--paper { background: var(--paper); border-block: 1px solid var(--line); background-image: none; }

.sec-head { margin-bottom: 40px; max-width: 60ch; }
.sec-head .kicker {
  display: block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--signal);
  margin-bottom: 14px;
}
.sec-head h2 {
  font-size: clamp(26px, 3.4vw, 38px);
  letter-spacing: -0.02em;
  font-weight: 600;
  margin: 0 0 12px;
  line-height: 1.08;
}
.sec-head p { color: var(--ink-soft); margin: 0; font-size: 16px; }

/* =========================================================================
   tenets (how the labs work)
   ========================================================================= */
.tenets { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
.tenet {
  border: 1px solid var(--line);
  border-radius: var(--r);
  padding: 24px 22px;
  background: var(--ground);
  background-image: none;
}
.tenet .key {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--accent);
  border: 1px solid color-mix(in srgb, var(--accent) 40%, var(--line));
  border-radius: 999px;
  padding: 3px 10px;
  display: inline-block;
  margin-bottom: 16px;
}
.tenet h3 { font-size: 19px; margin: 0 0 8px; letter-spacing: -0.01em; }
.tenet p { margin: 0; color: var(--ink-soft); font-size: 15px; }
.tenet svg { display: block; width: 100%; height: 64px; margin-top: 18px; }

/* =========================================================================
   labs index
   ========================================================================= */
.labs-ruler {
  display: flex;
  align-items: center;
  gap: 14px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink-faint);
  margin-bottom: 26px;
}
.labs-ruler .rule { flex: 1; height: 1px; background:
  repeating-linear-gradient(90deg, var(--line) 0 1px, transparent 1px 9px); }

.lab-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 22px; }

.lab {
  position: relative;
  display: flex;
  flex-direction: column;
  border: 1px solid var(--line);
  border-radius: var(--r);
  background: var(--paper);
  padding: 26px 26px 22px;
  text-decoration: none;
  color: inherit;
  overflow: hidden;
  transition: transform .18s ease, box-shadow .18s ease, border-color .18s ease;
  --lab: var(--accent);
}
.lab::before { /* left accent spine */
  content: "";
  position: absolute; left: 0; top: 0; bottom: 0; width: 4px;
  background: var(--lab);
}
.lab--live:hover {
  transform: translateY(-4px);
  border-color: color-mix(in srgb, var(--lab) 55%, var(--line));
  box-shadow: 0 22px 40px -26px color-mix(in srgb, var(--lab) 70%, #000);
}
.lab--soon { opacity: .72; cursor: default; }

.lab__top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 18px;
}
.lab__id { font-family: var(--font-mono); font-size: 12px; letter-spacing: 0.08em; color: var(--ink-faint); }
.lab__status {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 3px 9px;
  border-radius: 999px;
  display: inline-flex; align-items: center; gap: 6px;
}
.lab__status--live { color: var(--lab); background: color-mix(in srgb, var(--lab) 12%, #fff); }
.lab__status--live .pip { width: 7px; height: 7px; border-radius: 50%; background: var(--lab); box-shadow: 0 0 0 3px color-mix(in srgb, var(--lab) 24%, transparent); }
.lab__status--soon { color: var(--soon); background: color-mix(in srgb, var(--soon) 14%, #fff); }

.lab__chip {
  display: inline-flex; align-items: center; gap: 9px;
  margin-bottom: 14px;
}
.lab__chip .swatch { width: 26px; height: 26px; border-radius: 6px; background: var(--lab); flex: none; box-shadow: inset 0 0 0 1px rgba(0,0,0,.12); }
.lab__chip .dom { font-family: var(--font-mono); font-size: 13px; color: var(--ink-soft); }

.lab__name { font-size: 25px; letter-spacing: -0.02em; font-weight: 600; margin: 0 0 2px; line-height: 1.1; }
.lab__name-ja { font-size: 14px; color: var(--ink-faint); font-family: var(--font-mono); margin: 0 0 14px; }
.lab__desc { font-size: 15px; color: var(--ink-soft); margin: 0 0 18px; }

.lab__tags { display: flex; flex-wrap: wrap; gap: 7px; margin-bottom: 20px; }
.lab__tags span {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.03em;
  color: var(--ink-soft);
  border: 1px solid var(--line);
  border-radius: var(--r);
  padding: 3px 8px;
}
.lab__go {
  margin-top: auto;
  display: inline-flex; align-items: center; gap: 8px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.03em;
  color: var(--lab);
  font-weight: 500;
}
.lab__go .arr { transition: transform .18s ease; }
.lab--live:hover .lab__go .arr { transform: translateX(5px); }
.lab__go--muted { color: var(--ink-faint); }

/* =========================================================================
   network / closing band
   ========================================================================= */
.band {
  background: var(--ink);
  color: #E8ECF1;
  border-block: 1px solid var(--ink);
  background-image: none;
}
.band .wrap { display: grid; grid-template-columns: 1fr auto; gap: 40px; align-items: center; }
.band h2 { font-size: clamp(24px, 3vw, 34px); letter-spacing: -0.02em; margin: 0 0 12px; font-weight: 600; }
.band p { color: #A9B4C0; margin: 0; max-width: 52ch; }
.band .btn--ghost { color: #fff; border-color: #3A4757; }
.band .btn--ghost:hover { border-color: #fff; }

/* =========================================================================
   footer
   ========================================================================= */
.site-foot {
  background: var(--ground);
  border-top: 1px solid var(--line);
  padding-block: 40px 48px;
}
.site-foot .wrap { display: flex; flex-wrap: wrap; gap: 28px; justify-content: space-between; align-items: flex-start; }
.foot-brand .brand__mark { font-size: 17px; }
.foot-brand p { margin: 10px 0 0; color: var(--ink-soft); font-size: 14px; max-width: 38ch; }
.foot-cols { display: flex; gap: 56px; flex-wrap: wrap; }
.foot-col h4 { font-family: var(--font-mono); font-size: 11px; letter-spacing: 0.1em; text-transform: uppercase; color: var(--ink-faint); margin: 0 0 12px; font-weight: 600; }
.foot-col a { display: block; text-decoration: none; color: var(--ink-soft); font-size: 14px; padding: 3px 0; }
.foot-col a:hover { color: var(--ink); }
.foot-legal { width: 100%; border-top: 1px solid var(--line); margin-top: 8px; padding-top: 18px; font-family: var(--font-mono); font-size: 11.5px; letter-spacing: 0.04em; color: var(--ink-faint); }

/* =========================================================================
   responsive
   ========================================================================= */
@media (max-width: 860px) {
  .hero .wrap { grid-template-columns: 1fr; }
  .hero__fig { order: -1; max-width: 440px; }
  .tenets { grid-template-columns: 1fr; }
  .lab-grid { grid-template-columns: 1fr; }
  .band .wrap { grid-template-columns: 1fr; }
}
@media (max-width: 560px) {
  .head-nav .navlink { display: none; }
  .hero__stats { gap: 18px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { transition: none !important; }
}