:root {
  --bg: #0f1115;
  --bg-elev: #1a1d24;
  --bg-card: #20242c;
  --border: #2c313b;
  --fg: #e8eaef;
  --fg-dim: #9aa0aa;
  --accent: #6aa8ff;
  --accent-hot: #4a90ff;
  --accent-soft: rgba(106, 168, 255, 0.15);
  --danger: #ff6a6a;
  --radius: 10px;
  --shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
  --max-width: 1100px;
  --space: 1.25rem;
}

* {
  box-sizing: border-box;
}

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(15, 17, 21, 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;
}
@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(106, 168, 255, 0.12), transparent 70%);
}
.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%, #b58dff 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(255, 250, 220, 0.92);
  color: #333;
  padding: 0.6rem 0.9rem;
  border-radius: 6px;
  font-size: 0.9rem;
  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(-6deg); }
.float-note.n2 { top: 18%; right: 10%; background: rgba(220, 235, 255, 0.92); transform: rotate(4deg); animation-delay: 1.5s; }
.float-note.n3 { bottom: 18%; left: 14%; background: rgba(255, 224, 230, 0.92); transform: rotate(3deg); animation-delay: 3s; }
.float-note.n4 { bottom: 22%; right: 8%; background: rgba(220, 245, 220, 0.92); transform: rotate(-4deg); animation-delay: 4.5s; }

@keyframes floaty {
  0%, 100% { transform: translateY(0) rotate(var(--r, 0deg)); }
  50% { transform: translateY(-12px) rotate(var(--r, 0deg)); }
}

/* 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(106, 168, 255, 0.3);
}
.btn-primary:hover {
  background: var(--accent-hot);
  color: #0a0d12;
  box-shadow: 0 8px 28px rgba(74, 144, 255, 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);
}
.shot-note {
  text-align: center;
  font-size: 0.85rem;
  color: var(--fg-dim);
  margin-top: 1.5rem;
}

/* 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(280px, 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(106, 168, 255, 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;
}

/* 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);
}
.new-badge {
  display: inline-block;
  background: var(--accent);
  color: #0a0d12;
  font-size: 0.65rem;
  font-weight: 700;
  padding: 1px 6px;
  border-radius: 8px;
  margin-left: 0.4rem;
  vertical-align: middle;
  letter-spacing: 0.04em;
  font-family: ui-monospace, Consolas, monospace;
}

/* 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;
}
.footer-meta {
  margin: 0;
}
.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;
  }
}