/* NAV */
.nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: var(--z-nav);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
  padding: 1.1rem clamp(1.25rem, 3vw, 2.5rem);
  border-bottom: 1px solid transparent;
  transition: padding 0.3s;
}
.nav::before {
  content: "";
  position: absolute;
  inset: 0;
  background: rgba(10, 10, 15, 0.45);
  backdrop-filter: blur(14px) saturate(140%);
  -webkit-backdrop-filter: blur(14px) saturate(140%);
  border-bottom: 1px solid transparent;
  transition: background 0.3s, border-color 0.3s;
  z-index: -1;
}
.nav.is-stuck::before {
  background: rgba(10, 10, 15, 0.78);
  border-bottom-color: var(--line);
}
.nav.is-stuck { padding-block: 0.75rem; }
.nav > * { position: relative; z-index: 1; }
.nav__brand { display: flex; align-items: center; gap: 0.7rem; }
.nav__logo { width: 38px; height: auto; }
.nav__brand-text { display: flex; flex-direction: column; line-height: 1; gap: 2px; }
.nav__brand-cn {
  font-family: var(--font-cn);
  font-weight: 700;
  font-size: 0.95rem;
  letter-spacing: 0.05em;
  color: var(--fg);
}
.nav__brand-en {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  letter-spacing: 0.32em;
  color: var(--fg-3);
  text-transform: uppercase;
}
.nav__menu { display: flex; gap: 2.2rem; }
.nav__menu a {
  font-size: 0.9rem;
  color: var(--fg-2);
  font-weight: 500;
  position: relative;
  padding: 0.4rem 0;
  transition: color 0.2s;
}
.nav__menu a:hover { color: var(--fg); }
.nav__menu a::after {
  content: "";
  position: absolute;
  left: 50%; bottom: 0;
  height: 1px; width: 0;
  background: var(--accent-grad);
  transition: width 0.3s var(--ease-out), left 0.3s var(--ease-out);
}
.nav__menu a:hover::after { width: 100%; left: 0; }
.nav__cta {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.55rem 1.05rem;
  border-radius: var(--r-full);
  border: 1px solid var(--line-2);
  background: var(--bg-card);
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--fg);
  transition: all 0.25s var(--ease-out);
}
.nav__cta:hover {
  background: var(--accent-grad);
  border-color: transparent;
  color: #0A0A0F;
  transform: translateY(-1px);
  box-shadow: 0 8px 24px -8px rgba(255, 107, 31, 0.6);
}
.nav__burger {
  display: none;
  width: 40px; height: 40px;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 5px;
  border: 1px solid var(--line);
  border-radius: 8px;
}
.nav__burger span { display: block; width: 18px; height: 1.5px; background: var(--fg); transition: transform 0.3s, opacity 0.3s; }
.nav__burger[aria-expanded="true"] span:first-child { transform: translateY(3px) rotate(45deg); }
.nav__burger[aria-expanded="true"] span:last-child { transform: translateY(-4px) rotate(-45deg); }

@media (max-width: 960px) {
  .nav__menu {
    display: flex;
    flex-direction: column;
    gap: 0;
    position: fixed;
    top: 0; right: 0; bottom: 0; left: 0;
    background: rgba(8, 8, 12, 0.98);
    backdrop-filter: blur(24px) saturate(140%);
    -webkit-backdrop-filter: blur(24px) saturate(140%);
    padding: 6rem 1.5rem 2rem;
    z-index: 95;
    align-items: stretch;
    justify-content: flex-start;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-12px);
    transition: opacity 0.3s var(--ease-out), transform 0.3s var(--ease-out), visibility 0.3s;
    overflow-y: auto;
  }
  .nav__menu.is-open {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
  }
  .nav__menu a {
    padding: 1.4rem 0;
    font-size: 1.5rem;
    font-weight: 500;
    color: var(--fg);
    border-bottom: 1px solid var(--line);
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
  }
  .nav__menu a::before {
    content: "→";
    font-family: var(--font-mono);
    color: var(--accent-2);
    opacity: 0;
    transform: translateX(-8px);
    transition: opacity 0.3s, transform 0.3s;
  }
  .nav__menu a:hover::before {
    opacity: 1;
    transform: translateX(0);
  }
  .nav__menu a::after { display: none; }
  .nav__cta { display: none; }
  .nav__burger { display: flex; position: relative; z-index: 110; }
  body.menu-open { overflow: hidden; }
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.85rem 1.5rem;
  border-radius: var(--r-md);
  font-weight: 600;
  font-size: 0.95rem;
  font-family: var(--font-cn);
  transition: all 0.25s var(--ease-out);
  white-space: nowrap;
  position: relative;
  overflow: hidden;
}
.btn--primary {
  background: var(--accent-grad);
  color: #0A0A0F;
  border: 1px solid transparent;
  box-shadow: 0 0 0 0 rgba(255,107,31,0);
}
.btn--primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 28px -8px rgba(255, 107, 31, 0.55);
}
.btn--primary::before {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(120deg, transparent 30%, rgba(255,255,255,0.4), transparent 70%);
  transform: translateX(-100%);
  transition: transform 0.7s var(--ease-out);
}
.btn--primary:hover::before { transform: translateX(100%); }
.btn--ghost {
  background: transparent;
  border: 1px solid var(--line-2);
  color: var(--fg);
}
.btn--ghost:hover {
  background: var(--bg-card-hover);
  border-color: var(--accent-2);
  color: var(--accent-3);
}
.btn--sm { padding: 0.6rem 1.1rem; font-size: 0.85rem; }

/* Dot indicator */
.dot {
  display: inline-block;
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 4px rgba(255,107,31,0.2);
  animation: pulse 2s ease-in-out infinite;
}
@keyframes pulse {
  0%, 100% { box-shadow: 0 0 0 4px rgba(255,107,31,0.2); }
  50% { box-shadow: 0 0 0 8px rgba(255,107,31,0); }
}

/* Bullet */
.bullet {
  display: inline-block;
  width: 4px; height: 4px;
  border-radius: 50%;
  background: var(--accent);
  margin-right: 0.7rem;
  vertical-align: middle;
  flex-shrink: 0;
}