/* layout —— 顶部导航 / 页脚 / 移动端菜单 */

.site-main { display: block; min-height: 60vh; }

/* ---------- 顶部导航 ---------- */
.site-nav {
  position: sticky;
  top: 0;
  z-index: 50;
  transition: background-color var(--dur) var(--ease),
    border-color var(--dur) var(--ease);
  border-bottom: 1px solid transparent;
}
.site-nav.is-scrolled {
  background: color-mix(in srgb, var(--color-bg) 78%, transparent);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom-color: var(--color-border);
}
.nav-inner {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 18px var(--gutter);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}
.brand { display: flex; align-items: baseline; gap: 10px; line-height: 1; }
.brand-en {
  font-weight: 800;
  font-size: 1.15rem;
  letter-spacing: 0.08em;
  background: var(--grad-accent);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
}
.brand-cn { font-size: 0.8rem; color: var(--color-muted); letter-spacing: 0.05em; }
.nav-right { display: flex; align-items: center; gap: 26px; }
.nav-links { display: flex; align-items: center; gap: 26px; }
.nav-link {
  position: relative;
  font-size: 0.9rem;
  letter-spacing: 0.12em;
  color: var(--color-muted);
  padding: 4px 0;
}
.nav-link:hover { color: var(--color-text); }
.nav-link::after {
  content: "";
  position: absolute;
  left: 50%;
  bottom: -4px;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--neon-2);
  box-shadow: 0 0 10px 2px rgba(255, 61, 119, 0.7);
  transform: translateX(-50%) scale(0);
  transition: transform var(--dur) var(--ease);
}
.nav-link:hover::after { transform: translateX(-50%) scale(1); }

.theme-toggle {
  background: none;
  border: 1px solid var(--color-border);
  border-radius: 999px;
  width: 38px;
  height: 38px;
  cursor: pointer;
  color: var(--color-text);
  font-size: 1rem;
  line-height: 1;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}
.theme-toggle:hover { border-color: var(--neon-2); color: var(--neon-2); box-shadow: var(--glow-sm); }
:root[data-theme="dark"] .icon-sun { display: none; }
:root[data-theme="light"] .icon-moon { display: none; }

/* 移动端汉堡按钮 */
.nav-menu-btn {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  background: none;
  border: none;
  cursor: pointer;
}
.nav-menu-btn span {
  display: block;
  height: 2px;
  width: 24px;
  margin: 0 auto;
  background: var(--color-text);
  transition: transform var(--dur) var(--ease), opacity var(--dur) var(--ease);
}
.nav-menu-btn[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-menu-btn[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav-menu-btn[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* 全屏移动菜单 */
.mobile-menu {
  position: fixed;
  inset: 0;
  z-index: 40;
  background: var(--color-bg);
  display: flex;
  align-items: center;
  padding: 0 var(--gutter);
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--dur) var(--ease), visibility var(--dur);
}
.mobile-menu.is-open { opacity: 1; visibility: visible; }
.mobile-menu-inner { display: flex; flex-direction: column; gap: 8px; width: 100%; }
.mobile-nav-link {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  padding: 12px 0;
  border-bottom: 1px solid var(--color-border);
  transition: color var(--dur) var(--ease);
}
.mobile-nav-link:hover { color: var(--neon-2); }
.mobile-menu-foot { margin-top: 32px; color: var(--color-muted); letter-spacing: 0.2em; font-size: 0.85rem; }

/* ---------- 页脚 ---------- */
.site-footer {
  border-top: 1px solid var(--color-border);
  margin-top: var(--space-section);
  padding: 64px 0 48px;
}
.footer-inner {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 var(--gutter);
  display: flex;
  flex-direction: column;
  gap: 20px;
}
.footer-brand {
  font-weight: 800;
  font-size: 1.2rem;
  letter-spacing: 0.08em;
  background: var(--grad-accent);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
}
.footer-slogan { color: var(--color-muted); letter-spacing: 0.2em; font-size: 0.85rem; }
.footer-links { display: flex; gap: 22px; }
.footer-link { color: var(--color-muted); font-size: 0.9rem; letter-spacing: 0.08em; transition: color var(--dur) var(--ease); }
.footer-link:hover { color: var(--neon-2); }
.footer-copy { color: var(--color-muted); font-size: 0.82rem; }

/* ---------- 首页区段时间轴快捷导航 ---------- */
.tl-nav {
  position: fixed;
  right: clamp(14px, 2.2vw, 36px);
  top: 50%;
  transform: translateY(-50%);
  z-index: 45;
  display: none;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.5s var(--ease);
}
@media (min-width: 1024px) {
  .tl-nav { display: block; }
}
.tl-nav.is-on { opacity: 1; pointer-events: auto; }
/* 串联节点的渐变竖线 */
.tl-nav::before {
  content: "";
  position: absolute;
  right: 5px;
  top: 14px;
  bottom: 14px;
  width: 2px;
  border-radius: 2px;
  background: linear-gradient(to bottom, var(--neon-1), var(--neon-2), var(--neon-3));
  opacity: 0.22;
}
.tl-item {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 12px;
  padding: 13px 0;
  color: var(--color-muted);
}
.tl-dot {
  position: relative;
  z-index: 1;
  flex: 0 0 auto;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  border: 2px solid var(--color-border-strong);
  background: var(--color-bg);
  transition: transform var(--dur) var(--ease), border-color var(--dur) var(--ease),
    background var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}
.tl-text {
  display: flex;
  align-items: baseline;
  gap: 8px;
  opacity: 0;
  transform: translateX(10px);
  transition: opacity var(--dur) var(--ease), transform var(--dur) var(--ease);
  pointer-events: none;
}
.tl-num {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--neon-2);
  font-weight: 700;
}
.tl-name { font-size: 0.78rem; letter-spacing: 0.14em; white-space: nowrap; }
.tl-item:hover .tl-text,
.tl-item.is-active .tl-text {
  opacity: 1;
  transform: none;
}
.tl-item:hover { color: var(--color-text); }
.tl-item.is-active { color: var(--color-text); }
.tl-item.is-active .tl-dot {
  border-color: transparent;
  background: var(--grad-accent);
  box-shadow: 0 0 0 4px var(--color-accent-soft), 0 0 14px 2px rgba(255, 61, 119, 0.6);
  transform: scale(1.2);
}