/* Shared navigation shell for the standalone calculator pages. */
.f2-site-nav {
  position: sticky;
  top: 0;
  z-index: 300;
  background: rgba(255, 255, 255, .97);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid #E2E8F0;
  box-shadow: 0 1px 3px rgba(0, 0, 0, .08);
}
.f2-site-inner {
  max-width: 1280px;
  min-height: 60px;
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  gap: 16px;
}
.f2-site-logo { display: flex; align-items: center; gap: 10px; text-decoration: none; flex-shrink: 0; }
.f2-site-logomark { width: 34px; height: 34px; display: grid; place-items: center; border-radius: 8px; background: linear-gradient(135deg, #1B4FD8, #0891B2); color: #fff; font-size: 13px; font-weight: 900; }
.f2-site-logoname { color: #0D2137; font-size: 17px; font-weight: 800; letter-spacing: 0; }
.f2-site-logoname span { color: #1B4FD8; }
.f2-site-links { display: flex; flex: 1; align-items: center; gap: 4px; min-width: 0; }
.f2-site-links a { padding: 6px 11px; border-radius: 6px; color: #374151; font-size: 13px; font-weight: 500; text-decoration: none; white-space: nowrap; }
.f2-site-links a:hover, .f2-site-links a.active { background: #EEF2FF; color: #1B4FD8; }
.f2-site-links a.active { font-weight: 700; }
.f2-site-auth { display: flex; align-items: center; gap: 8px; flex-shrink: 0; }
.f2-auth-link, .f2-auth-button { display: inline-flex; align-items: center; justify-content: center; min-height: 34px; padding: 7px 13px; border-radius: 7px; font: 600 12px/1 Inter, system-ui, sans-serif; text-decoration: none; cursor: pointer; }
.f2-auth-link { border: 1.5px solid #CBD5E1; color: #374151; background: #fff; }
.f2-auth-link:hover { border-color: #1B4FD8; color: #1B4FD8; background: #EEF2FF; }
.f2-auth-button { border: 1.5px solid #1B4FD8; color: #fff; background: #1B4FD8; }
.f2-auth-button:hover { background: #1541B5; border-color: #1541B5; }
.f2-menu-toggle { display: none; width: 38px; height: 38px; align-items: center; justify-content: center; border: 1.5px solid #CBD5E1; border-radius: 7px; background: #fff; color: #374151; cursor: pointer; flex-shrink: 0; }
.f2-menu-toggle span, .f2-menu-toggle::before, .f2-menu-toggle::after { content: ''; display: block; width: 18px; height: 2px; margin: 3px 0; border-radius: 2px; background: currentColor; }
.f2-mobile-overlay { display: none; position: fixed; inset: 0; z-index: 498; background: rgba(0, 0, 0, .45); }
.f2-mobile-overlay.open { display: block; }
.f2-mobile-menu { position: fixed; top: 0; right: -300px; bottom: 0; z-index: 499; width: min(280px, 84vw); padding: 14px 12px; overflow-y: auto; background: #fff; box-shadow: -4px 0 32px rgba(0, 0, 0, .15); transition: right .2s ease; }
.f2-mobile-menu.open { right: 0; }
.f2-mobile-head { display: flex; align-items: center; justify-content: space-between; padding: 3px 8px 14px; border-bottom: 1px solid #E2E8F0; }
.f2-mobile-close { width: 32px; height: 32px; border: 1px solid #CBD5E1; border-radius: 7px; background: #F4F6FA; color: #374151; font-size: 20px; line-height: 1; cursor: pointer; }
.f2-mobile-links { padding: 12px 0; }
.f2-mobile-links a { display: block; margin-bottom: 2px; padding: 11px 12px; border-radius: 7px; color: #374151; font-size: 14px; font-weight: 600; text-decoration: none; }
.f2-mobile-links a:hover, .f2-mobile-links a.active { background: #EEF2FF; color: #1B4FD8; }
.f2-mobile-auth { padding-top: 12px; border-top: 1px solid #E2E8F0; }
.f2-mobile-auth .f2-auth-link, .f2-mobile-auth .f2-auth-button { width: 100%; margin-bottom: 8px; }

@media (max-width: 1080px) {
  .f2-site-links, .f2-site-auth { display: none; }
  .f2-menu-toggle { display: inline-flex; margin-left: auto; }
}
@media (max-width: 600px) {
  .f2-site-inner { min-height: 56px; padding: 0 14px; gap: 8px; }
  .f2-site-logomark { width: 32px; height: 32px; }
  .f2-site-logoname { font-size: 16px; }
}