:root {
  --menu-bg: rgba(255,255,255,0.92);
  --menu-fg: #111;
  --menu-accent: #444;
  --menu-border: rgba(0,0,0,0.08);
}

.site-menu {
  position: fixed;
  top: 0; left: 0; right: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.85rem 1.5rem;
  background: var(--menu-bg);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--menu-border);
  z-index: 9999;
  font-family: var(--font-serif, 'Sorts Mill Goudy', Georgia, 'Times New Roman', serif);
  font-size: 0.92rem;
  transform: translateY(0);
  transition: transform 0.3s ease, opacity 0.3s ease;
}

.site-menu.hidden {
  transform: translateY(-100%);
}

.site-menu .brand {
  font-family: var(--font-serif, 'Sorts Mill Goudy', Georgia, 'Times New Roman', serif);
  font-weight: 500;
  font-size: 1.15rem;
  color: var(--menu-fg);
  text-decoration: none;
  letter-spacing: 0;
}

.site-menu nav {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.site-menu nav a,
.site-menu nav button {
  color: var(--menu-fg);
  text-decoration: none;
  background: none;
  border: none;
  font: inherit;
  cursor: pointer;
  padding: 0.25rem 0;
  position: relative;
  transition: opacity 0.2s;
}

.site-menu nav a:hover,
.site-menu nav button:hover { opacity: 0.55; }

.site-menu nav a::after {
  content: '';
  position: absolute;
  left: 0; right: 0; bottom: -2px;
  height: 1px;
  background: var(--menu-fg);
  transform: scaleX(0);
  transform-origin: right;
  transition: transform 0.3s ease;
}
.site-menu nav a:hover::after {
  transform: scaleX(1);
  transform-origin: left;
}

.scroll-top {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--menu-fg);
  color: #fff;
  border: none;
  font-size: 1.2rem;
  cursor: pointer;
  opacity: 0;
  pointer-events: none;
  transform: translateY(10px);
  transition: opacity 0.3s ease, transform 0.3s ease, background 0.2s;
  z-index: 9998;
  box-shadow: 0 4px 14px rgba(0,0,0,0.15);
}

.scroll-top.visible {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
}

.scroll-top:hover { background: var(--menu-accent); }

body { padding-top: 0; }
@media (max-width: 600px) {
  .site-menu { padding: 0.7rem 1rem; font-size: 0.85rem; }
  .site-menu nav { gap: 0.9rem; }
  .scroll-top { bottom: 1rem; right: 1rem; width: 40px; height: 40px; }
}