/**
 * Fixed site header — shared across public pages.
 * Each page should define :root --nav-height, --primary-hover, --anniv-color,
 * --text-main, --bg-surface, --font-serif (optional: --ease-apple, --primary).
 */

.site-nav {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  min-height: var(--nav-height, 64px);
  padding: 10px 5%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
  z-index: 1000;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid rgba(0, 0, 0, 0.05);
  box-sizing: border-box;
}

.nav-logo-container {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  min-height: calc(var(--nav-height, 64px) - 20px);
  flex-shrink: 0;
}

.nav-logo-img {
  height: 36px;
  width: auto;
  object-fit: contain;
}

.nav-logo-text {
  font-family: var(--font-serif, serif);
  font-size: 1.3rem;
  font-weight: 800;
  color: var(--text-main, #1d1d1f);
  line-height: 1;
  transform: translateY(-2px);
}

.nav-links {
  display: flex;
  flex: 1;
  min-width: 0;
  flex-wrap: wrap;
  justify-content: flex-end;
  align-items: center;
  gap: 0.55rem 1.25rem;
  align-self: center;
}

.nav-links a {
  color: var(--text-main, #1d1d1f);
  text-decoration: none;
  font-size: 0.85rem;
  font-weight: 700;
  transition: color 0.2s;
  position: relative;
}

.nav-links a:hover {
  color: var(--primary-hover, #eab308);
}

.nav-links a.active {
  color: var(--primary-hover, #eab308);
}

.nav-links a.active::after {
  content: '';
  position: absolute;
  left: 0;
  right: 0;
  bottom: -6px;
  height: 2px;
  background: var(--primary-hover, #eab308);
  border-radius: 2px;
}

.nav-anniv-btn {
  color: #fff !important;
  background: var(--anniv-color, #ef4444);
  padding: 0.55rem 1.2rem;
  border-radius: 50px;
  font-size: 0.8rem !important;
  box-shadow: 0 4px 14px rgba(239, 68, 68, 0.3);
  display: none;
}

.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  z-index: 1100;
  padding: 10px;
  margin: 0;
  background: transparent;
  border: none;
  border-radius: 8px;
}

.hamburger span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--text-main, #1d1d1f);
  transition: transform 0.3s ease, opacity 0.3s ease;
}

@media (max-width: 860px) {
  .hamburger {
    display: flex;
  }

  .nav-links {
    position: fixed;
    top: 0;
    right: -100%;
    width: 82%;
    max-width: 340px;
    height: 100vh;
    height: 100dvh;
    background: var(--bg-surface, #ffffff);
    flex: none;
    flex-direction: column;
    flex-wrap: nowrap;
    justify-content: center;
    align-items: stretch;
    gap: 2.5rem;
    transition: right 0.4s var(--ease-apple, cubic-bezier(0.28, 0.11, 0.32, 1));
    box-shadow: -10px 0 30px rgba(0, 0, 0, 0.1);
    padding: 24px;
    box-sizing: border-box;
  }

  .nav-links a {
    font-size: 1.1rem;
    padding: 10px;
    text-align: center;
  }

  .nav-links.active {
    right: 0;
  }

  .hamburger.active span:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
  }

  .hamburger.active span:nth-child(2) {
    opacity: 0;
  }

  .hamburger.active span:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
  }
}

/* Dark navigation (e.g. 10周年記念ページ) */
body[data-nav-theme="dark"] .site-nav {
  background: rgba(5, 5, 5, 0.95);
  border-bottom-color: rgba(255, 255, 255, 0.1);
}

body[data-nav-theme="dark"] .nav-logo-text {
  color: var(--primary, #facc15);
}

body[data-nav-theme="dark"] .nav-links a {
  color: #f8fafc;
}

body[data-nav-theme="dark"] .nav-links a:hover,
body[data-nav-theme="dark"] .nav-links a.active {
  color: var(--primary, #facc15);
}

body[data-nav-theme="dark"] .nav-links a.active::after {
  background: var(--primary, #facc15);
}

body[data-nav-theme="dark"] .hamburger span {
  background: #f8fafc;
}

@media (max-width: 860px) {
  body[data-nav-theme="dark"] .nav-links {
    background: rgba(5, 5, 5, 0.98);
  }
}