:root {
  --color-bg: #0C1524;
  --color-card: #18233C;
  --color-accent: #FFC300;
  --color-text: #F0F4F8;
  --color-muted: #A0AEC0;
  --color-line: #2D3748;
  --color-input: #080E1A;
  --color-error: #f87171;
  --color-ok: #4ade80;
  --color-warn: #fbbf24;
  --shadow: 0 10px 24px rgba(0, 0, 0, 0.28);
  --radius: 12px;
  --font: "Inter", system-ui, -apple-system, "Segoe UI", sans-serif;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  --header-h: 56px;
}

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

html { scroll-behavior: smooth; }

body {
  margin: 0;
  min-height: 100vh;
  font-family: var(--font);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.55;
}

a { color: var(--color-accent); text-decoration: none; }
a:hover { text-decoration: underline; }
a:focus-visible, button:focus-visible, input:focus-visible, textarea:focus-visible, select:focus-visible, summary:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

.skip-link {
  position: absolute;
  left: 12px;
  top: -40px;
  background: var(--color-accent);
  color: var(--color-bg);
  padding: 0.4rem 0.7rem;
  border-radius: 6px;
  z-index: 100;
  font-weight: 700;
}
.skip-link:focus { top: 12px; }

.wrap {
  max-width: 1100px;
  margin: 0 auto;
  padding: 1.25rem 1.25rem 2.5rem;
}

.wrap-wide { max-width: 1280px; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  min-height: var(--header-h);
  background: linear-gradient(135deg, rgba(24, 35, 60, 0.96), rgba(255, 195, 0, 0.05));
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--color-line);
}

.site-header-inner {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0.55rem 1.25rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  justify-content: space-between;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.55rem;
  color: var(--color-text);
  font-weight: 800;
  letter-spacing: -0.03em;
  text-decoration: none;
  flex-shrink: 0;
}
.brand:hover { text-decoration: none; color: var(--color-accent); }
.brand-mark {
  width: 28px;
  height: 28px;
  display: block;
}
.brand-name { font-size: 0.95rem; }
.brand-name span { color: var(--color-accent); }

.site-nav {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-wrap: wrap;
  justify-content: flex-end;
}

.nav-link, .nav-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  border: 1px solid var(--color-line);
  background: var(--color-card);
  color: var(--color-text);
  border-radius: 8px;
  padding: 0.35rem 0.7rem;
  font-size: 0.78rem;
  font-weight: 700;
  cursor: pointer;
  text-decoration: none;
}
.nav-link:hover, .nav-btn:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
  text-decoration: none;
}

.nav-menu { position: relative; }
.nav-menu summary { list-style: none; }
.nav-menu summary::-webkit-details-marker { display: none; }
.nav-panel {
  position: absolute;
  right: 0;
  top: calc(100% + 8px);
  width: min(720px, calc(100vw - 1.5rem));
  background: var(--color-card);
  border: 1px solid var(--color-line);
  border-radius: 12px;
  box-shadow: var(--shadow);
  padding: 0.9rem;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 0.85rem;
  max-height: min(70vh, 520px);
  overflow: auto;
}
.nav-group h3 {
  margin: 0 0 0.4rem;
  font-size: 0.68rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-accent);
}
.nav-group a {
  display: block;
  color: var(--color-muted);
  font-size: 0.78rem;
  font-weight: 600;
  padding: 0.18rem 0;
  text-decoration: none;
}
.nav-group a:hover, .nav-group a[aria-current="page"] {
  color: var(--color-text);
}
.nav-group a[aria-current="page"] { color: var(--color-accent); }

.page-main { padding-top: 0.5rem; }
.page-title {
  margin: 0 0 0.35rem;
  font-size: clamp(1.4rem, 3vw, 1.85rem);
  letter-spacing: -0.03em;
}
.page-lead {
  margin: 0 0 1.25rem;
  color: var(--color-muted);
  max-width: 62ch;
}

.section-title {
  position: relative;
  font-size: 1.15rem;
  font-weight: 700;
  margin: 2rem 0 1rem;
  padding-left: 0.85rem;
  color: var(--color-accent);
}
.section-title::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.15rem;
  bottom: 0.15rem;
  width: 4px;
  background: var(--color-accent);
  border-radius: 2px;
}

.hero h1 {
  margin: 0 0 0.35rem;
  font-size: clamp(2rem, 6vw, 3.1rem);
  letter-spacing: -0.045em;
  font-weight: 900;
}
.hero p {
  margin: 0 0 1.1rem;
  color: var(--color-muted);
  font-size: 1.05rem;
  max-width: 52ch;
}
.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  align-items: center;
  margin-bottom: 2rem;
}

.socials { display: flex; gap: 0.7rem; }
.socials a {
  color: var(--color-text);
  font-weight: 700;
  font-size: 0.85rem;
}
.socials a:hover { color: var(--color-accent); text-decoration: none; }

.tool-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 0.85rem;
}

.tool-card {
  background: var(--color-card);
  border: 1px solid var(--color-line);
  border-radius: 16px;
  padding: 1.15rem 1.2rem;
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  color: var(--color-text);
  text-decoration: none;
  min-height: 132px;
  transition: transform 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;
}
.tool-card:hover {
  transform: translateY(-4px);
  border-color: var(--color-accent);
  box-shadow: var(--shadow);
  text-decoration: none;
}
.tool-card h3 {
  margin: 0;
  font-size: 1.02rem;
}
.tool-card p {
  margin: 0;
  color: var(--color-muted);
  font-size: 0.8rem;
}
.tool-card .icon {
  width: 28px;
  height: 28px;
  color: var(--color-accent);
  margin-bottom: 0.15rem;
}

.card {
  background: var(--color-card);
  border: 1px solid var(--color-line);
  border-radius: var(--radius);
  padding: 1.15rem;
}

.toolbar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  align-items: center;
  margin-bottom: 0.85rem;
}

.btn, button.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  border-radius: 8px;
  padding: 0.5rem 0.9rem;
  font-weight: 700;
  font-size: 0.8rem;
  border: 1px solid transparent;
  cursor: pointer;
  font-family: inherit;
  text-decoration: none;
}
.btn:hover { text-decoration: none; }
.btn-gold {
  background: var(--color-accent);
  color: var(--color-bg);
  border-color: var(--color-accent);
}
.btn-gold:hover { filter: brightness(1.08); }
.btn-ghost {
  background: transparent;
  color: var(--color-muted);
  border-color: var(--color-line);
}
.btn-ghost:hover { color: var(--color-accent); border-color: var(--color-accent); }
.btn-danger {
  background: transparent;
  color: var(--color-error);
  border-color: rgba(248, 113, 113, 0.35);
}

label, .label {
  display: block;
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-muted);
  margin-bottom: 0.4rem;
}

input[type="text"], input[type="number"], input[type="search"], input[type="url"],
input[type="email"], input[type="datetime-local"], select, textarea {
  width: 100%;
  background: var(--color-input);
  color: var(--color-text);
  border: 1px solid var(--color-line);
  border-radius: 10px;
  padding: 0.7rem 0.8rem;
  font-family: var(--mono);
  font-size: 0.85rem;
}
textarea {
  min-height: 180px;
  resize: vertical;
  line-height: 1.5;
}
input:focus, select:focus, textarea:focus {
  outline: none;
  border-color: var(--color-accent);
}

.pane-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}
.pane-grid.stack-mobile { align-items: stretch; }

.status {
  min-height: 1.3rem;
  font-size: 0.8rem;
  color: var(--color-muted);
  margin: 0.4rem 0 0.8rem;
}
.status.ok { color: var(--color-ok); }
.status.err { color: var(--color-error); }

.muted { color: var(--color-muted); }
.mono { font-family: var(--mono); }
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}

.site-footer {
  border-top: 1px solid var(--color-line);
  color: var(--color-muted);
  font-size: 0.72rem;
  font-family: var(--mono);
  letter-spacing: 0.04em;
  padding: 1.25rem;
  text-align: center;
}

.swatch {
  width: 100%;
  height: 88px;
  border-radius: 10px;
  border: 1px solid var(--color-line);
}

.badge {
  display: inline-block;
  padding: 0.28rem 0.65rem;
  margin: 0.15rem;
  font-size: 0.72rem;
  font-weight: 600;
  border-radius: 999px;
  background: rgba(255, 195, 0, 0.1);
  color: var(--color-accent);
  border: 1px solid rgba(255, 195, 0, 0.3);
}

.diff-added { background: rgba(34, 197, 94, 0.18); color: #4ade80; }
.diff-removed { background: rgba(239, 68, 68, 0.18); color: #f87171; }
.diff-same { opacity: 0.55; }

.preview-box, pre.out {
  background: var(--color-input);
  border: 1px solid var(--color-line);
  border-radius: 10px;
  padding: 0.9rem;
  overflow: auto;
  font-family: var(--mono);
  font-size: 0.8rem;
  white-space: pre-wrap;
  word-break: break-word;
}

.kvs { display: grid; grid-template-columns: 140px 1fr; gap: 0.35rem 0.75rem; font-size: 0.85rem; }
.kvs dt { color: var(--color-muted); }

.match-hit { background: rgba(255, 195, 0, 0.28); color: var(--color-text); border-radius: 3px; }

body[data-tool="draw"],
body[data-tool="collab"] { overflow: hidden; }
body[data-tool="draw"] .wrap,
body[data-tool="collab"] .wrap {
  height: calc(100vh - var(--header-h) - 8px);
  max-height: calc(100vh - var(--header-h) - 8px);
}
body[data-tool="draw"] .site-footer,
body[data-tool="collab"] .site-footer { display: none; }

@media (max-width: 800px) {
  .pane-grid { grid-template-columns: 1fr; }
  .nav-panel { left: auto; right: 0; }
  .hero h1 { font-size: 2rem; }
  .kvs { grid-template-columns: 1fr; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    transition: none !important;
    animation: none !important;
  }
}


/* --- AI book pages (Skillbook / Promptbook) --- */
.book-toolbar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.65rem;
  align-items: flex-end;
  margin-bottom: 1rem;
}
.book-toolbar .search-field {
  flex: 1 1 220px;
  min-width: 180px;
}
.book-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin: 0 0 1.1rem;
}
.chip {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  border: 1px solid var(--color-line);
  background: var(--color-card);
  color: var(--color-muted);
  border-radius: 999px;
  padding: 0.32rem 0.7rem;
  font-size: 0.72rem;
  font-weight: 700;
  cursor: pointer;
  font-family: inherit;
}
.chip:hover { color: var(--color-accent); border-color: var(--color-accent); }
.chip.is-active {
  background: rgba(255, 195, 0, 0.12);
  color: var(--color-accent);
  border-color: rgba(255, 195, 0, 0.45);
}
.book-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 0.9rem;
}
.book-card {
  background: var(--color-card);
  border: 1px solid var(--color-line);
  border-radius: 16px;
  padding: 1.1rem 1.15rem 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.55rem;
  min-height: 220px;
  transition: border-color 0.2s ease, box-shadow 0.2s ease, transform 0.2s ease;
}
.book-card:hover {
  border-color: rgba(255, 195, 0, 0.55);
  box-shadow: var(--shadow);
  transform: translateY(-2px);
}
.book-card h3 {
  margin: 0;
  font-size: 1.02rem;
  letter-spacing: -0.02em;
}
.book-when {
  margin: 0;
  color: var(--color-muted);
  font-size: 0.82rem;
}
.book-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
}
.tool-pill {
  display: inline-block;
  padding: 0.2rem 0.55rem;
  font-size: 0.68rem;
  font-weight: 700;
  border-radius: 999px;
  border: 1px solid var(--color-line);
  color: var(--color-muted);
  background: rgba(8, 14, 26, 0.55);
}
.tool-pill.copilot { border-color: rgba(255, 195, 0, 0.35); color: var(--color-accent); }
.tool-pill.claude-code { border-color: rgba(74, 222, 128, 0.35); color: var(--color-ok); }
.tool-pill.codex { border-color: rgba(96, 165, 250, 0.4); color: #60a5fa; }
.tool-pill.all { border-color: rgba(255, 195, 0, 0.45); color: var(--color-accent); }
.book-card-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  margin-top: auto;
  padding-top: 0.35rem;
}
.book-detail {
  margin-top: 1.25rem;
}
.book-detail[hidden] { display: none !important; }
.book-detail .format-notes {
  margin: 0 0 0.85rem;
  color: var(--color-muted);
  font-size: 0.82rem;
}
.book-body {
  background: var(--color-input);
  border: 1px solid var(--color-line);
  border-radius: 12px;
  padding: 1rem 1.05rem;
  font-family: var(--mono);
  font-size: 0.78rem;
  line-height: 1.55;
  white-space: pre-wrap;
  word-break: break-word;
  max-height: min(55vh, 520px);
  overflow: auto;
}
.btn-copy.is-copied {
  background: rgba(74, 222, 128, 0.15);
  border-color: rgba(74, 222, 128, 0.45);
  color: var(--color-ok);
}
.hub-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 0.9rem;
  margin-top: 1rem;
}
.empty-state {
  color: var(--color-muted);
  padding: 1.5rem 0.25rem;
  font-size: 0.9rem;
}
.ai-card-accent {
  border-color: rgba(255, 195, 0, 0.35);
}