/* =====================
   共通ナビゲーション
===================== */
.site-nav {
  position: absolute;
  top: 0; left: 0;
  width: 100%;
  z-index: 10;
  padding: 1.2rem 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.site-nav .logo { display: inline-block; text-decoration: none; line-height: 0; }
.site-nav .logo img {
  height: 28px; width: auto;
  filter: brightness(0) invert(1) drop-shadow(0 1px 4px rgba(0,0,0,0.3));
}

.site-nav .nav-links { display: flex; align-items: center; gap: 1.5rem; }

.site-nav .nav-link {
  font-size: 0.8rem;
  color: rgba(255,255,255,0.85);
  text-decoration: none;
  letter-spacing: 0.05em;
}
.site-nav .nav-link:hover { color: #fff; }

.site-nav .nav-link--active {
  color: #fff;
  border-bottom: 1px solid rgba(255,255,255,0.5);
  padding-bottom: 2px;
}

.site-nav .nav-link--account {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
}

/* ハンバーガーボタン（デスクトップでは非表示） */
.nav-hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 32px;
  height: 32px;
  padding: 4px;
  background: none;
  border: none;
  cursor: pointer;
  flex-shrink: 0;
}
.nav-hamburger span {
  display: block;
  width: 100%;
  height: 2px;
  background: #fff;
  border-radius: 2px;
  transition: transform 0.22s, opacity 0.22s;
}
.nav-hamburger.is-open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-hamburger.is-open span:nth-child(2) { opacity: 0; }
.nav-hamburger.is-open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* モバイル */
@media (max-width: 640px) {
  .nav-hamburger { display: flex; }

  .site-nav .nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    gap: 0;
    background: rgba(25, 20, 15, 0.93);
    padding: 0.5rem 2rem 1.2rem;
  }
  .site-nav .nav-links.is-open { display: flex; }

  .site-nav .nav-link {
    font-size: 0.9rem;
    padding: 0.75rem 0;
    border-bottom: 1px solid rgba(255,255,255,0.1);
    color: rgba(255,255,255,0.88);
  }
  .site-nav .nav-link:last-child { border-bottom: none; }

  .site-nav .nav-link--active {
    border-bottom: 1px solid rgba(255,255,255,0.1);
    padding-bottom: 0.75rem;
  }
  .site-nav .nav-link--active:last-child { border-bottom: none; }

  .site-nav .nav-link--account { gap: 0.4rem; }
}