/* ============================================================
   导航栏 · is-navbar（v3 · 深蓝透明 → 深蓝毛玻璃）
   Logo 白色 / 导航文字浅灰白 / 滚动后深蓝半透明 + 毛玻璃
   ============================================================ */

is-navbar {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 100;
  display: block;
  height: var(--nav-h);
  background: transparent;
  border-bottom: 1px solid transparent;
  transition: background-color var(--dur) var(--ease), height var(--dur) var(--ease),
              border-color var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}

is-navbar.is-scrolled {
  height: var(--nav-h-scrolled);
  background: rgba(4, 27, 58, 0.78);
  -webkit-backdrop-filter: blur(16px) saturate(1.3);
  backdrop-filter: blur(16px) saturate(1.3);
  border-bottom-color: var(--color-line-soft);
  box-shadow: 0 10px 30px -18px rgba(2, 19, 38, 0.9);
}

.nav { height: 100%; display: flex; align-items: center; justify-content: space-between; gap: 2rem; }

/* —— 品牌（白色 Logo） —— */
.brand { display: inline-flex; align-items: center; gap: 0.75rem; color: var(--color-heading); }
.brand__mark { width: 38px; height: 38px; flex: none; object-fit: contain; border-radius: 6px; }
.brand__name { display: flex; flex-direction: column; line-height: 1.25; }
.brand__cn { font-size: 1.0625rem; font-weight: 700; letter-spacing: 0.06em; color: var(--color-heading); }
.brand__en {
  font-size: 0.5rem; font-weight: 600; letter-spacing: 0.24em; text-transform: uppercase;
  color: var(--color-text-muted); margin-top: 0.15rem;
}

/* —— 桌面链接（浅灰白） —— */
.nav__links { display: flex; align-items: center; gap: clamp(1.25rem, 2.2vw, 2.5rem); }
.nav__link {
  position: relative;
  display: inline-block;
  padding: 0.4rem 0.05rem;
  font-size: 0.9375rem;
  font-weight: 500;
  letter-spacing: 0.02em;
  color: var(--color-text-muted);
  transition: color var(--dur) var(--ease);
}
.nav__link::after {
  content: "";
  position: absolute;
  left: 0; bottom: 0;
  width: 100%; height: 1px;
  background: var(--color-accent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--dur) var(--ease);
}
.nav__link:hover, .nav__link[aria-current="page"] { color: var(--color-heading); }
.nav__link:hover::after, .nav__link[aria-current="page"]::after { transform: scaleX(1); }

.nav__cta { margin-left: 0.5rem; min-height: 40px; padding: 0 1.25rem; font-size: 0.8125rem; }

/* —— 移动端 —— */
.nav__toggle {
  display: none;
  width: 42px; height: 42px;
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.25);
  border-radius: var(--radius-s);
  color: var(--color-heading);
  align-items: center;
  justify-content: center;
  transition: background-color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}
.nav__toggle svg { width: 20px; height: 20px; }

.menu {
  position: fixed;
  inset: 0;
  z-index: 99;
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 5.5rem 1.75rem 3rem;
  background:
    radial-gradient(70% 50% at 85% 8%, rgba(10, 61, 115, 0.5), transparent 70%),
    var(--color-ink);
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--dur) var(--ease), visibility var(--dur);
}
.menu.is-open { opacity: 1; visibility: visible; }

.menu__list { border-top: 1px solid var(--color-line-soft); }
.menu__item { border-bottom: 1px solid var(--color-line-soft); }
.menu__link {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  padding: 1rem 0.25rem;
  color: var(--color-heading);
  font-size: 1.25rem;
  font-weight: 600;
  letter-spacing: 0.06em;
}
.menu__link small { font-size: 0.625rem; font-weight: 600; letter-spacing: 0.2em; text-transform: uppercase; color: var(--color-accent); }
.menu__link[aria-current="page"] { color: var(--color-accent); }

.menu__foot { margin-top: 2rem; font-size: 0.6875rem; letter-spacing: 0.18em; color: var(--color-text-faint); }

@media (max-width: 1024px) {
  .nav__links, .nav__cta { display: none; }
  .nav__toggle { display: inline-flex; }
}

/* —— 账号入口 —— */
.nav__account {
  display: inline-flex;
  align-items: center;
  min-height: 38px;
  padding: 0 1.125rem;
  border: 1px solid rgba(255, 255, 255, 0.35);
  border-radius: var(--radius-btn);
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--color-on-dark);
  transition: border-color var(--dur) var(--ease), color var(--dur) var(--ease), background-color var(--dur) var(--ease);
}
.nav__account:hover { border-color: var(--color-accent); color: var(--color-accent); background: rgba(201, 162, 39, 0.06); }
is-navbar.is-scrolled .nav__account { border-color: rgba(10, 22, 40, 0.25); color: var(--color-heading); }
is-navbar.is-scrolled .nav__account:hover { border-color: var(--color-accent); color: var(--color-accent); }
.menu__account {
  display: block;
  margin-top: 1.5rem;
  padding: 0.875rem 1rem;
  border: 1px solid rgba(255, 255, 255, 0.25);
  border-radius: var(--radius-m);
  text-align: center;
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--color-on-dark);
  transition: border-color var(--dur) var(--ease), color var(--dur) var(--ease);
}
.menu__account:hover { border-color: var(--color-accent); color: var(--color-accent); }

/* —— 导航栏售后客服 —— */
.nav__qq {
  flex: none;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  color: var(--color-accent);
  white-space: nowrap;
}
.menu__qq {
  padding: 0.875rem 1.25rem;
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--color-accent);
  border-top: 1px solid var(--color-line-soft);
}