*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg: #f9f8f6;
  --ink: #1a1916;
  --ink-mid: #4a4845;
  --ink-light: #8a8785;
  --rule: #d8d5d0;
  --accent: #1e3a5f;
  --serif-ja: 'Shippori Mincho', 'Georgia', serif;
  --serif-latin: 'Cormorant Garamond', 'Georgia', serif;
  --sans: 'Noto Sans JP', sans-serif;
  --max: 800px;
  --side: clamp(1.5rem, 5vw, 4rem);
}

html { font-size: 16px; scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--ink);
  font-family: var(--serif-ja);
  font-weight: 400;
  line-height: 1.9;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

body.menu-open { overflow: hidden; }

a { color: inherit; text-decoration: none; }

/* ===== NAV ===== */
header {
  border-bottom: 1px solid var(--rule);
  position: sticky;
  top: 0;
  background: var(--bg);
  z-index: 200;
}

nav {
  max-width: calc(var(--max) + var(--side) * 2);
  margin: 0 auto;
  padding: 0 var(--side);
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.nav-logo-img {
  display: block;
  flex-shrink: 0;
  border-radius: 4px;
}

.nav-logo {
  font-family: var(--sans);
  font-weight: 300;
  font-size: 0.82rem;
  letter-spacing: 0.12em;
  color: var(--ink);
  display: flex;
  align-items: center;
  gap: 0.55rem;
}

nav ul { list-style: none; display: flex; gap: 2.5rem; }

nav ul a {
  font-family: var(--sans);
  font-weight: 300;
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  color: var(--ink-mid);
  transition: color 0.2s;
}

nav ul a:hover { color: var(--ink); }
nav ul a.current { color: var(--ink); }

/* ===== HAMBURGER BUTTON ===== */
.hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 5px;
  width: 36px;
  height: 36px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0;
  z-index: 300;
  position: relative;
}

.hamburger span {
  display: block;
  width: 22px;
  height: 1px;
  background: var(--ink);
  transition: transform 0.3s ease, opacity 0.3s ease;
  transform-origin: center;
}

/* 開いた状態: × に変形 */
.hamburger.is-open span:nth-child(1) { transform: translateY(6px) rotate(45deg); }
.hamburger.is-open span:nth-child(2) { opacity: 0; transform: scaleX(0); }
.hamburger.is-open span:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }

/* ===== MOBILE MENU OVERLAY ===== */
.mobile-menu {
  display: none;
  position: fixed;
  inset: 0;
  background: var(--bg);
  z-index: 150;
  flex-direction: column;
  justify-content: center;
  align-items: flex-start;
  padding: 0 var(--side);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.25s ease;
}

.mobile-menu.is-open {
  opacity: 1;
  pointer-events: auto;
}

.mobile-menu ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.mobile-menu ul a {
  font-family: var(--sans);
  font-weight: 300;
  font-size: 1.35rem;
  letter-spacing: 0.08em;
  color: var(--ink-mid);
  transition: color 0.2s;
}

.mobile-menu ul a:hover,
.mobile-menu ul a.current { color: var(--ink); }

.mobile-menu-footer {
  position: absolute;
  bottom: 2rem;
  left: var(--side);
  font-family: var(--serif-latin);
  font-style: italic;
  font-size: 0.75rem;
  color: var(--ink-light);
  opacity: 0.6;
  letter-spacing: 0.02em;
}

/* ===== LAYOUT ===== */
main {
  max-width: calc(var(--max) + var(--side) * 2);
  margin: 0 auto;
  padding: 0 var(--side);
}

section {
  padding: 5rem 0;
  border-bottom: 1px solid var(--rule);
}

section:last-of-type { border-bottom: none; }

/* ===== SECTION LABEL ===== */
.section-label {
  font-family: var(--sans);
  font-weight: 300;
  font-size: 0.72rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--ink-light);
  margin-bottom: 2.5rem;
}

/* ===== FOOTER ===== */
footer {
  border-top: 1px solid var(--rule);
  padding: 2rem var(--side);
  max-width: calc(var(--max) + var(--side) * 2);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
}

.footer-copy {
  font-family: var(--sans);
  font-weight: 300;
  font-size: 0.72rem;
  color: var(--ink-light);
  letter-spacing: 0.06em;
}

.footer-latin {
  font-family: var(--serif-latin);
  font-style: italic;
  font-size: 0.75rem;
  color: var(--ink-light);
  letter-spacing: 0.02em;
  opacity: 0.7;
}

.footer-links { display: flex; gap: 2rem; }

.footer-links a {
  font-family: var(--sans);
  font-weight: 300;
  font-size: 0.72rem;
  color: var(--ink-light);
  letter-spacing: 0.06em;
  transition: color 0.2s;
}

.footer-links a:hover { color: var(--ink); }

/* ===== EMAIL COPY FEEDBACK ===== */
.email-copied {
  opacity: 0.6 !important;
}

/* ===== RESPONSIVE ===== */
@media (max-width: 600px) {
  nav ul { display: none; }        /* デスクトップナビを隠す */
  .hamburger { display: flex; }    /* ハンバーガーを表示 */
  .mobile-menu { display: flex; }  /* オーバーレイを表示可能に */
}