* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
  color: #e2e8f0;
  background: #0a0a0f;
  background-image: radial-gradient(ellipse 120% 80% at 50% -20%, rgba(88, 28, 135, 0.25), transparent),
    radial-gradient(ellipse 80% 50% at 80% 50%, rgba(30, 58, 138, 0.15), transparent),
    radial-gradient(ellipse 60% 40% at 20% 80%, rgba(22, 163, 74, 0.08), transparent);
  min-height: 100vh;
  line-height: 1.6;
}
.container { max-width: 720px; margin: 0 auto; padding: 0 1.5rem; }

.site-header {
  background: rgba(15, 15, 22, 0.9);
  border-bottom: 1px solid rgba(148, 163, 184, 0.1);
  padding: 1rem 0;
  backdrop-filter: blur(8px);
}
.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.logo {
  display: flex;
  align-items: center;
  text-decoration: none;
}
.logo-img {
  height: 36px;
  width: auto;
  object-fit: contain;
  display: block;
}
.logo:hover .logo-img { opacity: 0.9; }
.nav-link {
  color: #94a3b8;
  text-decoration: none;
  margin-left: 1.5rem;
  font-weight: 500;
  padding: 0.35rem 0.6rem;
  border-radius: 6px;
  transition: color 0.2s, background 0.2s;
}
.nav-link:hover { color: #e2e8f0; background: rgba(148, 163, 184, 0.1); }
.nav-link.active {
  color: #4ade80;
  background: rgba(74, 222, 128, 0.12);
  box-shadow: 0 0 12px rgba(74, 222, 128, 0.2);
}

.page { padding: 2.5rem 0; }
.panel {
  background: rgba(20, 20, 28, 0.85);
  border: 1px solid rgba(148, 163, 184, 0.12);
  border-radius: 16px;
  padding: 1.75rem;
  margin-bottom: 1.5rem;
  backdrop-filter: blur(8px);
}
.page h1 {
  margin: 0 0 1rem;
  font-size: 1.65rem;
  font-weight: 600;
  color: #f1f5f9;
  letter-spacing: -0.02em;
}
.page p { margin: 0 0 1rem; color: #94a3b8; }
.page p:last-of-type { margin-bottom: 0; }
.page strong { color: #cbd5e1; }

.page h2 {
  margin: 1.5rem 0 0.75rem;
  font-size: 1.25rem;
  font-weight: 600;
  color: #e2e8f0;
}
.page h2:first-child { margin-top: 0; }
.page h3 {
  margin: 1.25rem 0 0.5rem;
  font-size: 1.1rem;
  font-weight: 600;
  color: #cbd5e1;
}
.content-list {
  margin: 0 0 1rem;
  padding-left: 1.5rem;
  color: #94a3b8;
}
.content-list li { margin-bottom: 0.5rem; }
.content-list-ordered { list-style: decimal; }
.content-link {
  color: #818cf8;
  text-decoration: none;
}
.content-link:hover { color: #a5b4fc; text-decoration: underline; }
.guide-section { margin-top: 1rem; }
.img-placeholder {
  margin: 1rem 0;
  padding: 2rem;
  background: rgba(30, 41, 59, 0.6);
  border: 1px dashed rgba(148, 163, 184, 0.35);
  border-radius: 12px;
  color: #64748b;
  font-size: 0.9rem;
  text-align: center;
}
.guide-img {
  margin: 1rem 0;
  max-width: 100%;
  border-radius: 12px;
  border: 1px solid rgba(148, 163, 184, 0.2);
  display: block;
}

.download-buttons { margin: 1.5rem 0; display: flex; flex-wrap: wrap; gap: 1rem; }
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 200px;
  padding: 1rem 1.75rem;
  font-size: 1rem;
  text-align: center;
  text-decoration: none;
  color: #fff;
  border-radius: 12px;
  font-weight: 600;
  border: none;
  cursor: pointer;
  transition: transform 0.2s, box-shadow 0.2s;
}
.btn:hover {
  transform: translateY(-1px);
  box-shadow: 0 8px 24px rgba(99, 102, 241, 0.35);
}
.btn-windows {
  background: linear-gradient(135deg, #4f46e5 0%, #7c3aed 50%, #a855f7 100%);
  box-shadow: 0 4px 14px rgba(99, 102, 241, 0.4);
}
.btn-windows:hover { box-shadow: 0 8px 28px rgba(124, 58, 237, 0.5); }
.btn-linux {
  background: linear-gradient(135deg, #059669 0%, #10b981 50%, #34d399 100%);
  box-shadow: 0 4px 14px rgba(16, 185, 129, 0.35);
}
.btn-linux:hover { box-shadow: 0 8px 28px rgba(52, 211, 153, 0.45); }

.note {
  margin-top: 1.5rem;
  padding: 1.25rem;
  background: rgba(30, 58, 138, 0.2);
  border: 1px solid rgba(99, 102, 241, 0.25);
  border-radius: 12px;
  color: #a5b4fc;
  font-size: 0.95rem;
}