/* ========================================================================
   apple-shell.css — fixed nav + footer with Apple aesthetic
   Isolated namespace (--ash-* variables, .ash-* classes) to coexist with
   legacy style.css on inner pages without overriding their body styles.
======================================================================== */

:root {
  --ash-ink:        #1d1d1f;
  --ash-ink-2:      #424245;
  --ash-ink-3:      #6e6e73;
  --ash-ink-4:      #86868b;
  --ash-line:       #d2d2d7;
  --ash-line-2:     #e5e5e7;
  --ash-bg-2:       #f5f5f7;
  --ash-bg-3:       #fbfbfd;
  --ash-bg-deep:    #0d3b4d;
  --ash-bg-deep-2:  #1a5f7a;
  --ash-gold:       #c9a96e;
  --ash-max:        1280px;
  --ash-ease:       cubic-bezier(.4, 0, .2, 1);
}

body.ash-shell { padding-top: 52px; }
body.ash-shell { font-family: -apple-system, BlinkMacSystemFont, 'SF Pro Display', 'SF Pro Text', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', 'Helvetica Neue', sans-serif; }

/* Nav */
header.ash-nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 9000;
  height: 52px;
  background: rgba(255, 255, 255, 0);
  border-bottom: 1px solid transparent;
  transition: background .25s var(--ash-ease), border-color .25s var(--ash-ease);
}
header.ash-nav.scrolled, header.ash-nav.solid {
  background: rgba(251, 251, 253, .82);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid rgba(0,0,0,.08);
}
.ash-nav-inner {
  max-width: var(--ash-max);
  margin: 0 auto;
  padding: 0 max(20px, 4vw);
  height: 100%;
  display: flex; align-items: center; justify-content: space-between;
}
.ash-nav-brand {
  display: flex; align-items: center; gap: 10px;
  font-size: 1.02rem; font-weight: 600; letter-spacing: -.005em; color: var(--ash-ink) !important;
  text-decoration: none !important;
}
.ash-nav-brand .ash-mark {
  width: 28px; height: 28px; border-radius: 7px;
  background: linear-gradient(135deg, var(--ash-bg-deep), var(--ash-bg-deep-2));
  color: var(--ash-gold);
  font-weight: 700; font-size: .82rem;
  display: flex; align-items: center; justify-content: center;
}
.ash-nav-brand .ash-mark::before { content: 'B'; }
.ash-nav-brand .ash-sub { color: var(--ash-ink-3); font-weight: 400; font-size: .82rem; margin-left: 4px; letter-spacing: .04em; }
.ash-nav-links { display: flex; align-items: center; gap: 2px; }
.ash-nav-links a {
  font-size: .82rem; font-weight: 400; color: var(--ash-ink-2) !important;
  padding: 6px 12px; border-radius: 6px;
  text-decoration: none !important;
  transition: color .15s ease;
}
.ash-nav-links a:hover { color: var(--ash-ink) !important; }
.ash-nav-links a.ash-active { color: var(--ash-ink) !important; font-weight: 500; }
.ash-nav-lang { display: flex; gap: 6px; margin-left: 18px; padding-left: 18px; border-left: 1px solid var(--ash-line-2); }
.ash-nav-lang a { font-size: .78rem; padding: 4px 8px; color: var(--ash-ink-3) !important; border-radius: 4px; }
.ash-nav-lang a:hover { color: var(--ash-ink) !important; }
.ash-nav-lang a.ash-active { color: var(--ash-ink) !important; font-weight: 500; }

.ash-nav-toggle { display: none; }
.ash-nav-drawer { display: none; }
@media (max-width: 880px) {
  .ash-nav-links { display: none; }
  .ash-nav-toggle {
    display: flex; flex-direction: column; gap: 4px; padding: 6px;
    cursor: pointer; background: none; border: 0;
  }
  .ash-nav-toggle span { width: 22px; height: 1.5px; background: var(--ash-ink); transition: transform .2s ease; }
  .ash-nav-drawer {
    position: fixed; top: 52px; left: 0; right: 0;
    background: rgba(251,251,253,.97); backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--ash-line-2);
    padding: 18px max(20px, 4vw);
  }
  .ash-nav-drawer.ash-open { display: block; }
  .ash-nav-drawer a {
    display: block; padding: 12px 0; font-size: 1.02rem;
    color: var(--ash-ink) !important; border-bottom: 1px solid var(--ash-line-2);
    text-decoration: none !important;
  }
  .ash-nav-drawer .ash-lang-row { display: flex; gap: 14px; padding: 12px 0; }
  .ash-nav-drawer .ash-lang-row a { display: inline; border: none; color: var(--ash-ink-3) !important; font-size: .9rem; }
  .ash-nav-drawer .ash-lang-row a.ash-active { color: var(--ash-ink) !important; font-weight: 500; }
}

/* Footer */
footer.ash-footer {
  background: var(--ash-bg-2);
  color: var(--ash-ink-3);
  padding: 64px 0 28px;
  font-size: .85rem;
  margin-top: 60px;
}
.ash-footer-inner {
  max-width: var(--ash-max);
  margin: 0 auto;
  padding: 0 max(20px, 5vw);
  display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 32px;
}
.ash-footer .ash-col h4 {
  font-size: .82rem; color: var(--ash-ink); margin-bottom: 14px;
  letter-spacing: -.005em; font-weight: 600;
}
.ash-footer .ash-col a {
  display: block; padding: 4px 0; color: var(--ash-ink-3) !important;
  text-decoration: none !important;
}
.ash-footer .ash-col a:hover { color: var(--ash-ink) !important; }
.ash-footer .ash-col p { margin-bottom: 8px; line-height: 1.55; }
.ash-footer .ash-brand-col p { max-width: 280px; }
.ash-footer-legal {
  max-width: var(--ash-max);
  margin: 48px auto 0;
  padding: 24px max(20px, 5vw) 0;
  border-top: 1px solid var(--ash-line-2);
  display: flex; justify-content: space-between; flex-wrap: wrap; gap: 8px;
  font-size: .78rem; color: var(--ash-ink-4);
}
.ash-footer-legal a { color: var(--ash-ink-4) !important; text-decoration: none !important; }
.ash-footer-legal a:hover { color: var(--ash-ink-3) !important; }
@media (max-width: 880px) { .ash-footer-inner { grid-template-columns: 1fr 1fr; } }
@media (max-width: 560px) { .ash-footer-inner { grid-template-columns: 1fr; } }