.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  padding: 14px 28px;
  z-index: 300;
  background: rgba(28, 42, 22, 0.80);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--rule);
  color: var(--ink);
}

.nav .issue {
  font-family: "JetBrains Mono", monospace;
  font-size: 10px;
  letter-spacing: 0.2em;
}

.nav .issue b {
  background: var(--hot);
  color: #fff;
  padding: 2px 6px;
  margin-right: 6px;
  letter-spacing: 0.15em;
}

.nav .brand {
  font-family: "Archivo Black", sans-serif;
  font-size: 22px;
  letter-spacing: -0.02em;
}

.nav .brand em {
  color: var(--hot);
  font-style: normal;
}

.nav-right {
  justify-self: end;
  display: flex;
  gap: 14px;
  align-items: center;
}

.nav-links {
  display: flex;
  gap: 18px;
  font-family: "JetBrains Mono", monospace;
  font-size: 10px;
  letter-spacing: 0.15em;
  font-weight: 500;
}

.nav-links a {
  padding: 4px 0;
  border-bottom: 1px solid transparent;
  transition: border-color 0.2s, color 0.2s;
}

.nav-links a:hover,
.nav-links a.current {
  border-color: var(--hot);
  color: var(--hot);
}

.nav-cta {
  font-family: "Oswald", sans-serif;
  font-size: 11px;
  letter-spacing: 0.2em;
  font-weight: 500;
  background: var(--ink);
  color: var(--paper);
  padding: 8px 14px;
  border: 1px solid var(--ink);
  transition: background 0.2s, color 0.2s, border-color 0.2s;
}

.nav-cta:hover {
  background: var(--hot);
  border-color: var(--hot);
  color: var(--paper);
}

.nav-toggle {
  display: none;
  width: 42px;
  height: 42px;
  border: 1px solid var(--rule);
  background: rgba(18, 27, 15, 0.35);
  color: var(--ink);
  align-items: center;
  justify-content: center;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
}

.nav-toggle span {
  display: block;
  width: 18px;
  height: 1px;
  background: currentColor;
  transition: transform 0.2s, opacity 0.2s;
}

.mobile-section-indicator {
  display: none;
}

@media (max-width: 1000px) {
  .nav-links {
    display: none;
  }
}

@media (max-width: 640px) {
  .nav {
    padding: 12px 16px;
    grid-template-columns: 1fr auto;
  }

  .nav .issue {
    display: none;
  }

  .nav .brand {
    justify-self: start;
    grid-column: 1;
    grid-row: 1;
  }

  .nav-toggle {
    display: inline-flex;
    grid-column: 2;
    grid-row: 1;
    justify-self: end;
  }

  .nav.open .nav-toggle span:nth-child(1) {
    transform: translateY(6px) rotate(45deg);
  }

  .nav.open .nav-toggle span:nth-child(2) {
    opacity: 0;
  }

  .nav.open .nav-toggle span:nth-child(3) {
    transform: translateY(-6px) rotate(-45deg);
  }

  .nav-right {
    display: none;
    grid-column: 1 / -1;
    grid-row: 2;
    justify-self: stretch;
    width: 100%;
    padding-top: 14px;
    border-top: 1px solid var(--rule);
    margin-top: 12px;
  }

  .nav.open .nav-right {
    display: grid;
    gap: 14px;
  }

  .nav.open .nav-links {
    display: grid;
    gap: 0;
    font-size: 12px;
    letter-spacing: 0.16em;
  }

  .nav-links a {
    padding: 12px 0;
    border-bottom: 1px solid var(--rule);
  }

  .nav-cta {
    display: inline-flex;
    justify-content: center;
    align-items: center;
    min-height: 44px;
    width: 100%;
  }

  .mobile-section-indicator {
    position: fixed;
    top: 70px;
    left: 16px;
    right: 16px;
    z-index: 240;
    display: flex;
    align-items: center;
    gap: 10px;
    min-height: 34px;
    padding: 7px 10px;
    border: 1px solid var(--rule);
    background: rgba(28, 42, 22, 0.82);
    color: var(--ink);
    backdrop-filter: blur(12px);
    opacity: 0;
    transform: translateY(-8px);
    pointer-events: none;
    transition: opacity 0.2s, transform 0.2s;
  }

  .mobile-section-indicator.is-visible {
    opacity: 1;
    transform: translateY(0);
  }

  .nav.open + .mobile-section-indicator {
    opacity: 0;
  }

  .mobile-section-num {
    flex: 0 0 auto;
    font-family: "JetBrains Mono", monospace;
    font-size: 10px;
    letter-spacing: 0.12em;
    color: var(--hot);
  }

  .mobile-section-title {
    min-width: 0;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    font-family: "M PLUS 1p", "Noto Sans JP", sans-serif;
    font-size: 12px;
    font-weight: 800;
    letter-spacing: 0;
  }
}