:root {
  --celtic-shell-width: 290px;
  --celtic-shell-top: 72px;
  --celtic-shell-bg: rgba(7, 16, 24, 0.94);
  --celtic-shell-panel: rgba(14, 25, 34, 0.92);
  --celtic-shell-line: rgba(127, 160, 180, 0.18);
  --celtic-shell-text: #eef7f7;
  --celtic-shell-muted: #9eb8be;
  --celtic-shell-accent: #7af0b8;
  --celtic-shell-accent-2: #49d7d9;
  --celtic-shell-warm: #ffd166;
  --celtic-shell-danger: #ff7b7b;
  --celtic-shell-shadow: 0 18px 45px rgba(0, 0, 0, 0.22);
  --celtic-shell-mono: "IBM Plex Mono", monospace;
  --celtic-shell-sans: "Sora", sans-serif;
}

html:has(body[data-celtic-shell="true"]),
body[data-celtic-shell="true"] {
  min-height: 100%;
}

body[data-celtic-shell="true"] {
  padding-left: calc(var(--celtic-shell-width) + 22px);
  font-family: var(--celtic-shell-sans);
}

.celtic-shell-sidebar {
  position: fixed;
  inset: 0 auto 0 0;
  width: var(--celtic-shell-width);
  padding: 18px 16px 16px;
  background:
    radial-gradient(circle at top left, rgba(122, 240, 184, 0.14), transparent 34%),
    linear-gradient(180deg, rgba(6, 16, 24, 0.98) 0%, rgba(10, 20, 29, 0.98) 100%);
  border-right: 1px solid var(--celtic-shell-line);
  box-shadow: var(--celtic-shell-shadow);
  z-index: 60;
  overflow-y: auto;
}

.celtic-shell-mobilebar {
  display: none;
}

.celtic-shell-brand {
  padding: 14px;
  border-radius: 22px;
  background: var(--celtic-shell-panel);
  border: 1px solid var(--celtic-shell-line);
}

.celtic-shell-overline,
.celtic-shell-section-label,
.celtic-shell-item-desc,
.celtic-shell-meta {
  font-family: var(--celtic-shell-mono);
}

.celtic-shell-overline {
  color: var(--celtic-shell-muted);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-size: 11px;
}

.celtic-shell-brand h1 {
  margin: 8px 0 6px;
  color: var(--celtic-shell-text);
  font-size: 22px;
  line-height: 1.1;
}

.celtic-shell-brand p {
  margin: 0;
  color: var(--celtic-shell-muted);
  font-size: 12px;
  line-height: 1.55;
}

.celtic-shell-feature {
  margin-top: 12px;
  padding: 10px 12px;
  border-radius: 16px;
  background: rgba(11, 20, 28, 0.72);
  border: 1px solid var(--celtic-shell-line);
}

.celtic-shell-feature strong {
  display: block;
  color: var(--celtic-shell-text);
  font-size: 13px;
}

.celtic-shell-feature span {
  display: block;
  margin-top: 5px;
  color: var(--celtic-shell-muted);
  font-size: 12px;
  line-height: 1.45;
}

.celtic-shell-nav {
  margin-top: 16px;
  display: grid;
  gap: 14px;
}

.celtic-shell-section {
  display: grid;
  gap: 8px;
}

.celtic-shell-section-label {
  color: var(--celtic-shell-muted);
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  padding: 0 4px;
}

.celtic-shell-item {
  display: block;
  padding: 12px 12px 11px;
  border-radius: 16px;
  border: 1px solid var(--celtic-shell-line);
  background: rgba(11, 20, 28, 0.64);
  color: var(--celtic-shell-text);
  text-decoration: none;
  transition: transform 140ms ease, border-color 140ms ease, background-color 140ms ease, box-shadow 140ms ease;
}

.celtic-shell-item:hover {
  transform: translateY(-1px);
  border-color: rgba(122, 240, 184, 0.32);
  background: rgba(14, 27, 36, 0.82);
}

.celtic-shell-item.active {
  border-color: rgba(122, 240, 184, 0.34);
  background: linear-gradient(135deg, rgba(122, 240, 184, 0.16), rgba(73, 215, 217, 0.12));
  box-shadow: 0 0 0 1px rgba(122, 240, 184, 0.08);
}

.celtic-shell-item-title {
  display: block;
  font-size: 14px;
  font-weight: 600;
  line-height: 1.25;
}

.celtic-shell-item-desc {
  display: block;
  margin-top: 6px;
  color: var(--celtic-shell-muted);
  font-size: 11px;
  line-height: 1.45;
}

.celtic-shell-meta {
  margin-top: 14px;
  padding: 12px;
  border-radius: 16px;
  background: rgba(11, 20, 28, 0.72);
  border: 1px solid var(--celtic-shell-line);
  color: var(--celtic-shell-muted);
  font-size: 11px;
  line-height: 1.6;
}

.celtic-shell-meta strong {
  color: var(--celtic-shell-accent);
}

.celtic-shell-backdrop {
  display: none;
}

body[data-celtic-shell="true"] .celtic-shell-page-title-fix {
  font-family: var(--celtic-shell-sans);
}

@media (max-width: 980px) {
  body[data-celtic-shell="true"] {
    padding-left: 0;
    padding-top: var(--celtic-shell-top);
  }

  .celtic-shell-mobilebar {
    position: fixed;
    inset: 0 0 auto 0;
    height: var(--celtic-shell-top);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    padding: 14px 16px;
    background: rgba(7, 16, 24, 0.94);
    border-bottom: 1px solid var(--celtic-shell-line);
    backdrop-filter: blur(12px);
    z-index: 70;
  }

  .celtic-shell-mobilebar strong {
    display: block;
    color: var(--celtic-shell-text);
    font-size: 15px;
  }

  .celtic-shell-mobilebar span {
    display: block;
    margin-top: 2px;
    color: var(--celtic-shell-muted);
    font: 500 11px var(--celtic-shell-mono);
  }

  .celtic-shell-toggle {
    appearance: none;
    border: 1px solid var(--celtic-shell-line);
    background: rgba(11, 20, 28, 0.76);
    color: var(--celtic-shell-text);
    border-radius: 12px;
    padding: 10px 12px;
    font: 600 12px var(--celtic-shell-mono);
    cursor: pointer;
  }

  .celtic-shell-sidebar {
    transform: translateX(-105%);
    transition: transform 180ms ease;
    z-index: 80;
  }

  body.celtic-shell-open .celtic-shell-sidebar {
    transform: translateX(0);
  }

  .celtic-shell-backdrop {
    position: fixed;
    inset: 0;
    background: rgba(3, 8, 12, 0.55);
    z-index: 75;
  }

  body.celtic-shell-open .celtic-shell-backdrop {
    display: block;
  }
}