:root {
  --ink: #f3f0df;
  --muted: #aaa88f;
  --bg: #0b0d0c;
  --panel: #151814;
  --panel-2: #1b1f19;
  --line: #363c31;
  --amber: #e3a93d;
  --cyan: #42d4d1;
  --lime: #a9c74d;
  --red: #e35b4f;
  --max: 1120px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at 85% 0%, #213128 0, transparent 28rem),
    linear-gradient(180deg, #0d100e, var(--bg));
  font-family: Inter, "Noto Sans JP", "Noto Sans SC", system-ui, sans-serif;
  line-height: 1.7;
}
a { color: var(--cyan); }
code { color: #f2c66d; }
img { max-width: 100%; }

.site-header {
  position: sticky;
  z-index: 20;
  top: 0;
  border-bottom: 1px solid var(--line);
  background: rgb(11 13 12 / 88%);
  backdrop-filter: blur(14px);
}
.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: min(var(--max), calc(100% - 32px));
  min-height: 64px;
  margin: auto;
  gap: 20px;
}
.brand { color: var(--ink); font-weight: 800; letter-spacing: .08em; text-decoration: none; }
.brand span { color: var(--amber); }
.nav-links, .languages { display: flex; align-items: center; gap: 16px; }
.nav a { text-decoration: none; }
.languages a { color: var(--muted); font-size: .88rem; }
.languages a[aria-current="page"] { color: var(--amber); font-weight: 700; }

main { width: min(var(--max), calc(100% - 32px)); margin: auto; }
.hero { padding: 88px 0 60px; }
.eyebrow { color: var(--lime); font-weight: 800; letter-spacing: .15em; text-transform: uppercase; }
h1 { max-width: 850px; margin: 12px 0 18px; font-size: clamp(2.5rem, 7vw, 5.5rem); line-height: .98; letter-spacing: -.045em; }
.lede { max-width: 760px; color: #cbc8b3; font-size: clamp(1.08rem, 2vw, 1.35rem); }
.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 30px; }
.button {
  display: inline-flex;
  min-height: 46px;
  align-items: center;
  justify-content: center;
  padding: 0 18px;
  border: 1px solid var(--amber);
  border-radius: 6px;
  color: #11140f;
  background: var(--amber);
  font-weight: 800;
  text-decoration: none;
}
.button.secondary { color: var(--ink); background: transparent; border-color: var(--line); }

.facts, .source-grid, .parameter-grid, .steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
}
.fact, .card, .step {
  padding: 22px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: linear-gradient(145deg, var(--panel), #10130f);
}
.fact strong { display: block; color: var(--amber); font-size: 1.5rem; }
.fact span, .card p, .step p { color: var(--muted); }

section { padding: 64px 0; border-top: 1px solid #242820; }
h2 { margin: 0 0 16px; font-size: clamp(1.9rem, 4vw, 3rem); line-height: 1.1; }
h3 { margin: 0 0 8px; }
.section-intro { max-width: 760px; margin: 0 0 28px; color: var(--muted); font-size: 1.06rem; }
.source-grid { grid-template-columns: repeat(6, 1fr); }
.source-grid .card { min-height: 155px; padding: 16px; }
.source-grid h3 { color: var(--cyan); font-size: 1rem; letter-spacing: .05em; }
.source-grid p { margin: 6px 0 0; font-size: .92rem; }

.skin-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
  margin: 28px 0;
}
.skin-card {
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
}
.skin-preview {
  display: grid;
  place-items: center;
  min-height: 130px;
  border-bottom: 1px solid var(--line);
  font-weight: 900;
  letter-spacing: .16em;
}
.skin-shot {
  display: block;
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  border-bottom: 1px solid var(--line);
  background: #050706;
}
.skin-shot[src] + .skin-preview { display: none; }
.skin-card[data-skin="wood"] .skin-preview {
  color: #f0dca4;
  background:
    repeating-linear-gradient(92deg, #ffffff08 0 1px, transparent 1px 18px),
    linear-gradient(135deg, #24130d, #6b351b 55%, #28150e);
  box-shadow: inset 0 0 0 3px #b48236;
}
.skin-card[data-skin="metal"] .skin-preview {
  color: #e8eef0;
  background:
    repeating-linear-gradient(0deg, #ffffff12 0 1px, transparent 1px 3px),
    linear-gradient(135deg, #202b30, #77858c 52%, #273238);
  box-shadow: inset 0 0 0 3px #aab5ba;
}
.skin-card[data-skin="neon"] .skin-preview {
  color: #65f5ed;
  background:
    linear-gradient(90deg, #21d9d833 1px, transparent 1px),
    linear-gradient(#d94fc533 1px, transparent 1px),
    radial-gradient(circle at 70% 35%, #d94fc555, transparent 24%),
    #04090b;
  background-size: 26px 26px, 26px 26px, auto, auto;
  box-shadow: inset 0 0 0 3px #24d7d4, inset 0 0 28px #d94fc555;
}
.skin-copy { padding: 18px; }
.skin-copy h3 { margin-bottom: 6px; }
.skin-copy p { margin: 0; color: var(--muted); }

.sim-figure {
  margin: 30px 0;
  overflow: hidden;
  border: 1px solid #4c523f;
  border-radius: 10px;
  background: #050706;
  box-shadow: 0 24px 70px #0008;
}
.sim-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 48px;
  padding: 8px 14px;
  color: var(--muted);
  background: #141712;
  border-bottom: 1px solid var(--line);
}
.sim-toolbar strong { color: var(--ink); }
.capture-status { color: var(--lime); font-size: .86rem; }
.sim-shot {
  display: block;
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: contain;
  background: #0a0c0a;
}
.callouts {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
  padding: 14px;
  border-top: 1px solid var(--line);
}
.callout { color: var(--muted); font-size: .9rem; }
.callout b {
  display: inline-grid;
  place-items: center;
  width: 24px;
  height: 24px;
  margin-right: 5px;
  border-radius: 50%;
  color: #0b0d0c;
  background: var(--amber);
}

.parameter-grid { grid-template-columns: repeat(2, 1fr); }
.parameter-grid .card { border-left: 3px solid var(--amber); }
.parameter-list { display: grid; gap: 10px; margin: 16px 0 0; }
.parameter {
  display: grid;
  grid-template-columns: 72px 1fr;
  gap: 12px;
  padding-top: 10px;
  border-top: 1px solid var(--line);
}
.parameter dt { color: var(--amber); font-weight: 800; }
.parameter dd { margin: 0; color: var(--muted); }

.envelope {
  position: relative;
  height: 260px;
  margin: 24px 0;
  overflow: hidden;
  border: 1px solid #39564e;
  border-radius: 8px;
  background:
    linear-gradient(#17342e55 1px, transparent 1px),
    linear-gradient(90deg, #17342e55 1px, transparent 1px),
    #07110f;
  background-size: 10% 25%;
}
.env-canvas {
  position: absolute;
  top: 18px;
  left: 3%;
  width: 94%;
  height: 170px;
}
.env-label { position: absolute; bottom: 10px; font-weight: 800; }
.env-label small { display: block; color: var(--muted); font-weight: 400; }
.env-label.a { left: 8%; color: var(--red); }
.env-label.d { left: 31%; color: var(--amber); }
.env-label.s { left: 53%; color: var(--lime); }
.env-label.r { right: 8%; color: var(--cyan); }

.signal-chain { display: flex; flex-wrap: wrap; align-items: center; gap: 8px; margin: 22px 0; }
.signal-chain span { padding: 10px 14px; border: 1px solid var(--line); border-radius: 5px; background: var(--panel-2); }
.signal-chain i { color: var(--red); font-style: normal; font-weight: 900; }

.steps { counter-reset: step; }
.step { position: relative; padding-top: 60px; }
.step::before {
  counter-increment: step;
  content: counter(step);
  position: absolute;
  top: 18px;
  left: 22px;
  color: var(--cyan);
  font: 800 1.7rem/1 monospace;
}

.piano {
  position: relative;
  display: flex;
  height: 190px;
  margin: 24px 0;
  padding: 10px;
  border: 1px solid var(--line);
  background: #070807;
}
.white-key { flex: 1; border: 1px solid #817a67; border-radius: 0 0 4px 4px; background: linear-gradient(#eee5cb, #bbb198); }
.black-key {
  position: absolute;
  z-index: 2;
  top: 10px;
  width: 5.4%;
  height: 58%;
  border: 1px solid #383b34;
  border-radius: 0 0 4px 4px;
  background: linear-gradient(90deg, #111, #30312c, #0b0b0a);
}
.keyboard-notes { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; }
.keyboard-notes div { padding: 14px; border-left: 3px solid var(--lime); background: var(--panel); color: var(--muted); }

table { width: 100%; border-collapse: collapse; background: var(--panel); }
th, td { padding: 12px 14px; border: 1px solid var(--line); text-align: left; vertical-align: top; }
th { color: var(--amber); background: #1c201a; }
td { color: #c1bfab; }
.note { padding: 16px 18px; border-left: 3px solid var(--cyan); background: #10201d; color: #c7d8d2; }

.footer { padding: 40px 0 60px; color: var(--muted); border-top: 1px solid var(--line); }

@media (max-width: 900px) {
  .nav-links { display: none; }
  .facts, .source-grid, .skin-grid { grid-template-columns: repeat(2, 1fr); }
  .callouts, .steps { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 640px) {
  .hero { padding-top: 58px; }
  .facts, .source-grid, .skin-grid, .parameter-grid, .steps, .keyboard-notes, .callouts { grid-template-columns: 1fr; }
  .languages { gap: 9px; }
  .parameter { grid-template-columns: 60px 1fr; }
  .piano { height: 130px; }
  table { font-size: .88rem; }
}

@media print {
  .site-header, .hero-actions { display: none; }
  body { color: #111; background: white; }
  main { width: 100%; }
  section { break-inside: avoid; }
  .card, .fact, .step { color: #111; background: white; box-shadow: none; }
}