:root {
  --bg: #0d1117;
  --bg-elev: #161b22;
  --bg-card: #1f2937;
  --border: #2c313b;
  --fg: #e8eaef;
  --fg-dim: #9aa0aa;
  --accent: #38bdf8;
  --accent-hot: #0ea5e9;
  --accent-soft: rgba(56, 189, 248, 0.15);
  --accent-2: #fb923c;
  --accent-3: #a3e635;
  --danger: #ff6a6a;
  --radius: 10px;
  --shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
  --max-width: 1100px;
  --space: 1.25rem;
}

* { box-sizing: border-box; }

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Kaku Gothic ProN", "Noto Sans JP", "Yu Gothic UI", sans-serif;
  background: var(--bg);
  color: var(--fg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color 0.15s ease;
}
a:hover { color: var(--accent-hot); }

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space);
}

.section { padding: 5rem 0; }
.section-title {
  font-size: 1.85rem;
  font-weight: 700;
  margin: 0 0 2rem;
  text-align: center;
  letter-spacing: 0.02em;
}
.section-title::after {
  content: "";
  display: block;
  width: 48px;
  height: 3px;
  background: var(--accent);
  margin: 0.6rem auto 0;
  border-radius: 2px;
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(13, 17, 23, 0.85);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}
.nav-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--fg);
  font-weight: 700;
  font-size: 1.1rem;
}
.brand:hover { color: var(--fg); }
.brand-mark { width: 28px; height: 28px; display: block; border-radius: 6px; }
.hero-icon {
  width: 120px;
  height: 120px;
  display: block;
  margin: 0 auto 1.5rem;
  filter: drop-shadow(0 12px 32px rgba(0, 0, 0, 0.45));
  animation: heroFloat 4s ease-in-out infinite;
  border-radius: 24px;
}
@keyframes heroFloat {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-8px); }
}
.site-nav { display: flex; gap: 1.8rem; font-size: 0.95rem; }
.site-nav a { color: var(--fg-dim); }
.site-nav a:hover { color: var(--fg); }
.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  width: 32px;
  height: 32px;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 4px;
}
.nav-toggle span { width: 22px; height: 2px; background: var(--fg); transition: transform 0.2s; }

/* Hero */
.hero {
  position: relative;
  min-height: 70vh;
  padding: 5rem 0 6rem;
  overflow: hidden;
  background:
    radial-gradient(ellipse at top, rgba(56, 189, 248, 0.14), transparent 70%),
    radial-gradient(ellipse at bottom right, rgba(163, 230, 53, 0.06), transparent 60%);
}
.hero-inner { position: relative; z-index: 2; text-align: center; }
.hero-title {
  font-size: clamp(2rem, 5vw, 3.4rem);
  line-height: 1.25;
  margin: 0 0 1.2rem;
  letter-spacing: 0.01em;
}
.accent {
  background: linear-gradient(120deg, var(--accent) 0%, var(--accent-3) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.hero-sub { font-size: 1.1rem; color: var(--fg-dim); margin: 0 0 2.2rem; }
.hero-cta {
  display: flex;
  gap: 0.8rem;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 1.5rem;
}
.hero-meta { font-size: 0.85rem; color: var(--fg-dim); margin: 0; }
.hero-decor { position: absolute; inset: 0; pointer-events: none; }
.float-note {
  position: absolute;
  background: rgba(31, 41, 55, 0.92);
  color: var(--accent);
  padding: 0.5rem 0.9rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 0.85rem;
  font-weight: 600;
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.3);
  animation: floaty 6s ease-in-out infinite;
}
.float-note.n1 { top: 12%; left: 8%; transform: rotate(-4deg); }
.float-note.n2 { top: 18%; right: 10%; color: var(--accent-2); transform: rotate(3deg); animation-delay: 1.5s; }
.float-note.n3 { bottom: 18%; left: 14%; color: var(--accent-3); transform: rotate(2deg); animation-delay: 3s; }
.float-note.n4 { bottom: 22%; right: 8%; color: #facc15; transform: rotate(-3deg); animation-delay: 4.5s; }
@keyframes floaty {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-12px); }
}

/* Buttons */
.btn {
  display: inline-block;
  padding: 0.85rem 1.8rem;
  border-radius: var(--radius);
  font-weight: 600;
  font-size: 1rem;
  border: 2px solid transparent;
  cursor: pointer;
  transition: transform 0.12s ease, background 0.15s ease, box-shadow 0.15s ease;
  text-align: center;
}
.btn:hover { transform: translateY(-2px); }
.btn-primary {
  background: var(--accent);
  color: #0a0d12;
  box-shadow: 0 6px 20px rgba(56, 189, 248, 0.3);
}
.btn-primary:hover {
  background: var(--accent-hot);
  color: #0a0d12;
  box-shadow: 0 8px 28px rgba(14, 165, 233, 0.45);
}
.btn-secondary {
  background: var(--bg-card);
  color: var(--fg);
  border-color: var(--border);
}
.btn-secondary:hover {
  background: var(--bg-elev);
  border-color: var(--accent);
  color: var(--fg);
}
.btn-ghost {
  background: transparent;
  color: var(--fg);
  border-color: var(--border);
}
.btn-ghost:hover { border-color: var(--accent); color: var(--accent); }

/* Features */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.2rem;
}
.feature {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.6rem;
  transition: transform 0.18s ease, border-color 0.18s ease;
}
.feature:hover { transform: translateY(-4px); border-color: var(--accent); }
.feature-icon { font-size: 2rem; margin-bottom: 0.6rem; }
.feature h3 { margin: 0 0 0.5rem; font-size: 1.1rem; }
.feature p { margin: 0; color: var(--fg-dim); font-size: 0.95rem; line-height: 1.65; }
kbd {
  display: inline-block;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 1px 6px;
  font-size: 0.85em;
  font-family: inherit;
}

/* Screenshots */
.shot-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
}
.shot { margin: 0; }
.shot-img {
  display: block;
  aspect-ratio: 16 / 10;
  background: #1a1d24;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  transition: transform 0.18s ease, border-color 0.18s ease;
}
.shot-img:hover { transform: translateY(-3px); border-color: var(--accent); }
.shot-img img { width: 100%; height: 100%; object-fit: cover; display: block; }
.shot figcaption { margin-top: 0.6rem; text-align: center; font-size: 0.9rem; color: var(--fg-dim); }

/* Download */
.download-version { text-align: center; color: var(--fg-dim); margin: -1rem 0 2.5rem; }
.dl-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1.2rem;
}
.dl-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem 1.5rem;
  text-align: center;
  position: relative;
  display: flex;
  flex-direction: column;
}
.dl-card.recommended {
  border-color: var(--accent);
  box-shadow: 0 8px 24px rgba(56, 189, 248, 0.18);
}
.dl-badge {
  position: absolute;
  top: -12px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--accent);
  color: #0a0d12;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 3px 10px;
  border-radius: 12px;
  letter-spacing: 0.04em;
}
.dl-card h3 { margin: 0 0 0.6rem; font-size: 1.15rem; }
.dl-desc { color: var(--fg-dim); font-size: 0.92rem; margin: 0 0 0.6rem; flex: 1 1 auto; }
.dl-size {
  font-size: 0.82rem;
  color: var(--fg-dim);
  margin: 0 0 0.4rem;
  font-family: ui-monospace, "SF Mono", Consolas, monospace;
}
.dl-count { font-size: 0.85rem; color: var(--fg-dim); margin: 0 0 1.2rem; letter-spacing: 0.02em; }
.dl-count strong {
  color: var(--accent);
  font-size: 1.1rem;
  font-weight: 700;
  font-family: ui-monospace, "SF Mono", Consolas, monospace;
  margin-right: 0.2rem;
}
.dl-total { text-align: center; margin-top: 2rem; font-size: 0.95rem; color: var(--fg-dim); }
.dl-total strong {
  color: var(--accent);
  font-size: 1.3rem;
  font-weight: 700;
  font-family: ui-monospace, "SF Mono", Consolas, monospace;
  margin: 0 0.2rem;
}
.dl-note {
  text-align: center;
  margin-top: 1.5rem;
  font-size: 0.85rem;
  color: var(--fg-dim);
  line-height: 1.7;
}

/* Changelog */
.changelog-list {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  max-width: 720px;
  margin: 0 auto;
}
.release {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem 1.8rem;
}
.release-header {
  display: flex;
  align-items: baseline;
  gap: 0.8rem;
  margin-bottom: 1rem;
  padding-bottom: 0.7rem;
  border-bottom: 1px solid var(--border);
}
.release-version {
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--accent);
  font-family: ui-monospace, "SF Mono", Consolas, monospace;
}
.release-date { font-size: 0.85rem; color: var(--fg-dim); }
.release ul { margin: 0; padding-left: 1.4rem; color: var(--fg-dim); line-height: 1.85; }
.release ul li { padding: 0.15rem 0; }
.release ul strong { color: var(--fg); }

/* Requirements */
.req-list {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem 2rem;
  list-style: none;
  margin: 0 auto;
  max-width: 720px;
}
.req-list li {
  padding: 0.4rem 0;
  border-bottom: 1px solid var(--border);
  color: var(--fg-dim);
}
.req-list li:last-child { border-bottom: none; }
.req-list strong {
  color: var(--fg);
  display: inline-block;
  min-width: 8em;
}
code {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 1px 6px;
  font-family: ui-monospace, "SF Mono", Consolas, monospace;
  font-size: 0.88em;
  color: var(--accent);
}

/* Quickstart */
.qs-list { max-width: 720px; margin: 0 auto; padding-left: 1.2rem; color: var(--fg-dim); }
.qs-list li { padding: 0.5rem 0; }

/* Footer */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 2rem 0;
  background: var(--bg-elev);
}
.footer-row {
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 0.5rem;
  font-size: 0.88rem;
  color: var(--fg-dim);
  text-align: center;
}
.site-footer p { margin: 0; }

/* Lightbox */
.lightbox {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.92);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 9999;
  padding: 2rem 4rem;
  cursor: zoom-out;
}
.lightbox.open { display: flex; }
.lightbox-img {
  max-width: 100%;
  max-height: 85vh;
  width: auto;
  height: auto;
  border-radius: 6px;
  box-shadow: 0 20px 80px rgba(0, 0, 0, 0.7);
  cursor: default;
  user-select: none;
}
.lightbox-caption {
  position: absolute;
  bottom: 1rem;
  left: 0;
  right: 0;
  text-align: center;
  color: #ddd;
  font-size: 0.95rem;
  padding: 0 2rem;
  pointer-events: none;
}
.lightbox-close,
.lightbox-prev,
.lightbox-next {
  position: absolute;
  background: rgba(255, 255, 255, 0.1);
  border: none;
  color: #fff;
  cursor: pointer;
  border-radius: 50%;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: background 0.15s ease;
}
.lightbox-close:hover,
.lightbox-prev:hover,
.lightbox-next:hover { background: rgba(255, 255, 255, 0.25); }
.lightbox-close { top: 1.2rem; right: 1.2rem; width: 44px; height: 44px; font-size: 1.6rem; line-height: 1; }
.lightbox-prev,
.lightbox-next { top: 50%; width: 56px; height: 56px; font-size: 2rem; transform: translateY(-50%); }
.lightbox-prev { left: 1rem; }
.lightbox-next { right: 1rem; }
@media (max-width: 720px) {
  .lightbox { padding: 1rem; }
  .lightbox-prev, .lightbox-next { width: 40px; height: 40px; font-size: 1.5rem; }
}

/* Reveal */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
.reveal.visible { opacity: 1; transform: translateY(0); }

/* Mobile */
@media (max-width: 720px) {
  .nav-toggle { display: flex; }
  .site-nav {
    display: none;
    position: absolute;
    top: 60px;
    left: 0;
    right: 0;
    background: var(--bg-elev);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    padding: 1rem var(--space);
    gap: 0.8rem;
  }
  .site-nav.open { display: flex; }
  .float-note { display: none; }
  .section { padding: 3.5rem 0; }
  .hero { padding: 3rem 0 4rem; min-height: auto; }
  .hero-cta { flex-direction: column; }
  .btn { width: 100%; }
  .req-list strong { min-width: auto; display: block; }
}