.header { position: absolute; top: 0; left: 0; width: 100%; height: 0; }

.header__mark {
  position: fixed;
  top: 12px;
  left: 12px;
  margin-left: var(--nav-w);
  z-index: 80;
  display: block;
  width: 50px;
  height: 50px;
  color: var(--accent);
  background: var(--bg);
  border-radius: 50%;
}
.header__mark path, .header__mark circle { stroke-width: 1; }

.header__tel {
  position: fixed;
  top: 13px;
  right: calc(var(--side-w) + 15px);
  z-index: 80;
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 6px 0 3px;
  font-size: 11px;
  letter-spacing: 1.5px;
  color: var(--accent);
  transition: opacity .5s ease;
}
.header__tel:hover { opacity: .6; }

.header__button {
  display: none;
  position: fixed;
  top: 0;
  right: 0;
  z-index: 90;
  width: 60px;
  height: 60px;
  padding: 11px 0 0;
  border: 0;
  border-radius: 0;
  background: var(--dark);
  color: var(--on-dark);
  text-align: center;
  cursor: pointer;
  transition: opacity .5s ease;
}
.header__button:hover { opacity: .6; }
.header__bars { position: relative; display: inline-block; width: 34px; height: 18px; }
.header__bars span { position: absolute; left: 0; width: 100%; height: 1px; background: currentColor; transition: all .4s; }
.header__bars span:nth-child(1) { top: 0; }
.header__bars span:nth-child(2) { top: 50%; }
.header__bars span:nth-child(3) { bottom: 0; }
.header__button-txt { display: block; margin-top: 2px; font-family: var(--font-min); font-size: 10px; letter-spacing: .1em; line-height: 1.6; }
.is-menu-open .header__bars span:nth-child(1) { top: -4.5px; transform: translateY(12px) rotate(-45deg); }
.is-menu-open .header__bars span:nth-child(2) { opacity: 0; }
.is-menu-open .header__bars span:nth-child(3) { bottom: -1px; transform: translateY(-11px) rotate(45deg); }

/* 左の固定メニュー（スマホは全画面で開く） */
.gnav {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 70;
  width: var(--nav-w);
  height: 100%;
  background: var(--dark);
  color: var(--on-dark);
}
.gnav__inner { position: relative; width: 100%; height: 100%; }
.gnav__inner > * { position: absolute; left: 50%; transform: translate(-50%, -50%); }
.gnav__logo {
  top: 35%;
  writing-mode: vertical-rl;
  white-space: nowrap;
  font-family: var(--font-min);
  font-size: 24px;
  letter-spacing: 10px;
  line-height: 1.25;
}
.gnav__logo-sub { font-size: 14px; letter-spacing: 6px; margin-bottom: 12px; }
.gnav__main { bottom: 12vh; white-space: nowrap; }
.gnav__main li + li { margin-top: 18px; }
.gnav__main a { display: block; font-size: 14px; letter-spacing: 1.6px; line-height: 1.8; transition: opacity .5s ease; }
.gnav__sub { bottom: 6vh; display: flex; gap: 17px; }
.gnav__sub a { display: block; transition: opacity .5s ease; }
.gnav__main a:hover, .gnav__sub a:hover { opacity: .6; }

@media (max-width: 1025px) {
  .header__tel { right: 15px; }
}
@media (max-width: 620px) {
  .header__mark { margin-left: 0; }
  .header__tel { right: 80px; }
  .header__button { display: block; }
  .gnav { width: 100%; opacity: 0; visibility: hidden; }
  .is-menu-open .gnav { visibility: visible; opacity: .95; animation: fade-in-menu .8s ease-in-out both; }
  .is-menu-open .header__tel { color: var(--on-dark); }
  .gnav__main { bottom: auto; top: 62%; text-align: center; }
  .gnav__sub { bottom: 6%; }
}
@keyframes fade-in-menu { from { opacity: 0; } to { opacity: .95; } }