@import url('https://fonts.googleapis.com/css2?family=Spectral:ital,wght@0,400;0,500;0,600;0,700;1,400&family=IBM+Plex+Sans:wght@400;500;600;700&family=IBM+Plex+Mono:wght@400;500&display=swap');

:root {
  /* UI Vault Design System — built in Claude Design 2026-09-17.
     projects/ui-vault/_import/tokens/*.css is the source of truth. */
  --gray-950: #0b0d10; --gray-900: #12151a; --gray-800: #1a1e24; --gray-700: #262b33;
  --gray-600: #363c46; --gray-500: #565d69; --gray-400: #7c828c; --gray-300: #9aa1ab;
  --gray-200: #c7cad0; --gray-100: #e7e9ec; --gray-50: #f4f5f6;
  --bg-canvas: var(--gray-950); --bg-surface: var(--gray-900); --bg-elevated: var(--gray-800);
  --border-subtle: var(--gray-700); --border-strong: var(--gray-600);
  --text-primary: var(--gray-50); --text-secondary: var(--gray-300); --text-tertiary: var(--gray-400);
  --accent: #4A9FE8; --accent-strong: #78BCF3; --accent-ink: #04121F; --accent-wash: rgba(74, 159, 232, .14);
  --cat-blue: #4A9FE8; --cat-green: #5FBF7A; --cat-orange: #E8934A; --cat-violet: #9C8CF0; --cat-neutral: #C9C7C0;

  --font-display: "Spectral", Georgia, serif;
  --font-body: "IBM Plex Sans", -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, monospace;

  --space-2: 8px; --space-3: 12px; --space-4: 16px; --space-5: 24px; --space-6: 32px;

  --radius-sm: 12px; --radius-md: 18px; --radius-lg: 24px; --radius-round: 999px;
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, .45);
  --shadow-md: 0 12px 32px rgba(0, 0, 0, .5);

  --dur-fast: 120ms; --dur-med: 220ms;
  --ease-standard: cubic-bezier(.16, 1, .3, 1);
  --ease-snap: cubic-bezier(.34, 1.56, .64, 1);

  /* Category hues reuse the system's own cat-* tokens, not invented ones.
     Element: neutral (foundational). Interaction: accent (the system's own rule —
     accent marks anything interactive). Motion: violet. Style: orange. */
  --cat-element: var(--cat-neutral);
  --cat-interaction: var(--cat-blue);
  --cat-motion: var(--cat-violet);
  --cat-style: var(--cat-orange);
  --sidebar-w: 252px;

  color-scheme: dark;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0; background: var(--bg-canvas); color: var(--text-primary);
  font-family: var(--font-body); font-size: 15px; line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }
::selection { background: var(--accent-wash); color: var(--text-primary); }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; border-radius: 2px; }
h1, h2, h3, p { margin: 0; }

::-webkit-scrollbar { width: 12px; height: 12px; }
::-webkit-scrollbar-track { background: var(--bg-canvas); }
::-webkit-scrollbar-thumb { background: var(--gray-700); border: 3px solid var(--bg-canvas); border-radius: var(--radius-round); }
::-webkit-scrollbar-thumb:hover { background: var(--gray-600); }
* { scrollbar-color: var(--gray-700) var(--bg-canvas); scrollbar-width: thin; }

button { font-family: inherit; border: none; background: none; color: inherit; }

.app { display: grid; grid-template-columns: var(--sidebar-w) 1fr; min-height: 100vh; }

/* ---- sidebar ---- */
.sidebar {
  background: var(--bg-surface);
  border-right: 1px solid var(--border-subtle);
  padding: 26px 18px 20px;
  display: flex; flex-direction: column; gap: 26px;
  position: sticky; top: 0; height: 100vh; overflow-y: auto;
}
.brand { display: flex; flex-direction: column; gap: 2px; padding: 0 8px; }
.brand b { font-family: var(--font-display); font-weight: 700; font-size: 21px; }
.brand span { font-size: 11px; letter-spacing: .14em; text-transform: uppercase; color: var(--text-tertiary); }

.nav-group { display: flex; flex-direction: column; gap: 2px; }
.nav-label { font-size: 10.5px; font-weight: 600; letter-spacing: .16em; text-transform: uppercase; color: var(--text-tertiary); padding: 0 8px 8px; }
.nav-item {
  display: flex; align-items: center; justify-content: space-between; gap: 8px;
  width: 100%; border: 0; background: transparent; cursor: pointer;
  font: inherit; font-size: 14px; color: var(--text-secondary);
  padding: 8px 10px; border-radius: var(--radius-sm); text-align: left;
  border-left: 2px solid transparent;
}
.nav-item:hover { background: var(--bg-elevated); color: var(--text-primary); }
.nav-item[aria-pressed="true"] { background: var(--bg-elevated); color: var(--text-primary); font-weight: 600; border-left-color: var(--accent); box-shadow: var(--shadow-sm); }
.nav-item .n { font-size: 12px; font-weight: 500; color: var(--text-tertiary); font-variant-numeric: tabular-nums; }

.nav-accordion summary {
  cursor: pointer; list-style: none; display: flex; align-items: center; justify-content: space-between;
  font-size: 10.5px; font-weight: 600; letter-spacing: .1em; text-transform: uppercase;
  color: var(--text-tertiary); padding: 8px 10px; border-radius: var(--radius-sm);
}
.nav-accordion summary::-webkit-details-marker { display: none; }
.nav-accordion summary::after { content: "\25B8"; font-size: 10px; transition: transform 120ms ease; }
.nav-accordion[open] summary::after { transform: rotate(90deg); }
.nav-accordion summary:hover { background: var(--bg-elevated); color: var(--text-primary); }
.nav-accordion .nav-item { padding-left: 20px; }

.ext { display: flex; align-items: center; gap: 6px; padding: 8px 10px; border-radius: var(--radius-sm); font-size: 14px; color: var(--text-secondary); }
.ext svg { color: var(--text-tertiary); }
.ext:hover { background: var(--bg-elevated); color: var(--accent-strong); }
.ext:hover svg { color: var(--accent-strong); }

.sidebar-foot { margin-top: auto; padding: 12px 8px 0; font-size: 12px; color: var(--text-tertiary); }
.sidebar-foot a { border-bottom: 1px solid var(--border-subtle); }
.sidebar-foot a:hover { border-color: var(--accent-strong); color: var(--accent-strong); }

/* ---- main ---- */
main { padding: 24px 32px 60px; min-width: 0; }
.toolbar { display: flex; gap: 12px; align-items: center; }
.search { position: relative; flex: 1; min-width: 0; }
.search svg { position: absolute; left: 13px; top: 50%; transform: translateY(-50%); pointer-events: none; }
.search input {
  width: 100%; height: 42px; padding: 0 14px 0 38px;
  border: 1px solid var(--border-subtle); border-radius: var(--radius-sm); background: var(--bg-elevated);
  font: inherit; font-size: 14.5px; color: var(--text-primary); outline: none;
}
.search input::placeholder { color: var(--text-tertiary); }
.search input:focus { border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-wash); }

select {
  height: 42px; padding: 0 34px 0 14px; border: 1px solid var(--border-subtle); border-radius: var(--radius-sm);
  background: var(--bg-elevated) url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" width="10" height="6"><path d="M0 0l5 6 5-6z" fill="%237c828c"/></svg>') no-repeat right 14px center;
  font: inherit; font-size: 13.5px; color: var(--text-secondary); appearance: none; -webkit-appearance: none; cursor: pointer;
}

.btn {
  display: inline-flex; align-items: center; gap: 8px; justify-content: center;
  height: 42px; padding: 0 18px; flex-shrink: 0;
  font-family: var(--font-body); font-weight: 600; font-size: 14px; cursor: pointer;
  border: 1px solid transparent; border-radius: var(--radius-sm); white-space: nowrap;
  background: var(--accent); color: var(--accent-ink);
  transition: transform var(--dur-fast) var(--ease-snap), background var(--dur-fast) var(--ease-standard);
}
.btn:hover { background: var(--accent-strong); transform: translateY(-1px); }

.icon-btn {
  width: 34px; height: 34px; border-radius: var(--radius-round);
  border: 1px solid var(--border-subtle); background: var(--bg-elevated); color: var(--text-secondary);
  display: inline-flex; align-items: center; justify-content: center; cursor: pointer; flex-shrink: 0;
  transition: transform var(--dur-fast) var(--ease-snap), background var(--dur-fast) var(--ease-standard);
}
.icon-btn:hover { transform: scale(1.1); background: var(--bg-elevated); color: var(--text-primary); }

.results-head { display: flex; align-items: baseline; gap: 10px; margin: 28px 0 14px; }
.results-head h2 { font-size: 15px; font-weight: 600; letter-spacing: -.01em; font-family: var(--font-body); }
.results-head .count { font-size: 13px; color: var(--text-tertiary); font-variant-numeric: tabular-nums; }

.grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; }
@media (min-width: 1400px) { .grid { grid-template-columns: repeat(4, 1fr); } }
@media (max-width: 700px) { .grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 460px) { .grid { grid-template-columns: 1fr; } }

/* ---- card ---- */
.card {
  display: flex; flex-direction: column;
  background: var(--bg-surface); border: 1px solid var(--border-subtle); border-radius: var(--radius-sm);
  overflow: hidden; --tc: var(--cat-motion);
  transition: transform var(--dur-fast) var(--ease-standard), box-shadow var(--dur-med) var(--ease-standard), border-color var(--dur-med) var(--ease-standard);
  animation: cardIn .32s var(--ease-standard) both;
}
.card:hover { transform: translateY(-2px); box-shadow: var(--shadow-md); border-color: var(--border-strong); }
@keyframes cardIn { from { opacity: 0; transform: translateY(8px); } }

.card-thumb {
  position: relative; aspect-ratio: 16 / 10; overflow: hidden;
  background: color-mix(in srgb, var(--tc) 12%, var(--bg-surface));
  border-bottom: 1px solid color-mix(in srgb, var(--tc) 24%, var(--border-subtle));
}
.card-thumb img { width: 100%; height: 100%; object-fit: cover; object-position: top center; display: block; opacity: 0; transition: opacity .3s ease; }
.card-thumb img.loaded { opacity: 1; }
.card-cat {
  position: absolute; top: 9px; left: 9px; z-index: 1;
  font-size: 9.5px; font-weight: 600; letter-spacing: .11em; text-transform: uppercase;
  color: var(--accent-ink); background: var(--tc); padding: 3px 7px; border-radius: 5px;
  box-shadow: 0 1px 3px rgba(0, 0, 0, .3);
}
.card-actions {
  position: absolute; top: 6px; right: 6px; z-index: 1;
  display: flex; gap: 5px;
}
.card-action {
  width: 28px; height: 28px;
  opacity: 0; transform: translateY(-4px);
  transition: opacity var(--dur-fast) var(--ease-snap), transform var(--dur-fast) var(--ease-snap), background var(--dur-fast) var(--ease-standard);
}
.card:hover .card-action, .card-action.is-active { opacity: 1; transform: translateY(0); }
.card-action svg { width: 13px; height: 13px; }
.card-action.is-active { background: var(--accent-wash); color: var(--accent); border-color: var(--accent); }

.card-body { padding: 14px; flex: 1; display: flex; flex-direction: column; gap: 8px; }
.card-title { font-family: var(--font-display); font-weight: 600; font-size: 16px; line-height: 1.2; color: var(--text-primary); }
.card-note { font-size: 13px; line-height: 1.45; color: var(--text-secondary); }
.card-tags { display: flex; flex-wrap: wrap; gap: 5px; margin-top: auto; padding-top: 4px; }
.card-tags span { font-size: 10.5px; font-family: var(--font-mono); color: var(--text-tertiary); background: var(--bg-elevated); border-radius: 5px; padding: 2px 7px; }

.card-foot { display: flex; align-items: center; justify-content: space-between; padding: 10px 14px; border-top: 1px solid var(--border-subtle); font-size: 12px; color: var(--text-tertiary); }
.card-foot .src { letter-spacing: .04em; text-transform: uppercase; }
.card-foot svg { width: 14px; height: 14px; color: var(--text-tertiary); transition: transform var(--dur-fast) var(--ease-standard); }
.card:hover .card-foot svg { transform: translateX(3px); color: var(--text-primary); }

.empty { grid-column: 1 / -1; padding: 64px 0; text-align: center; color: var(--text-tertiary); }
.empty button {
  margin-top: 12px; border: 1px solid var(--accent); background: transparent; color: var(--accent-strong);
  padding: 8px 16px; font: inherit; font-weight: 500; border-radius: var(--radius-sm); cursor: pointer;
}
.empty button:hover { background: var(--accent); color: var(--accent-ink); }

/* ---- Add reference modal ---- */
.modal-overlay[hidden] { display: none; }
.modal-overlay {
  position: fixed; inset: 0; background: rgba(6, 7, 9, .72); backdrop-filter: blur(6px); z-index: 100;
  display: flex; align-items: center; justify-content: center; padding: var(--space-5);
  animation: overlay-in var(--dur-med) var(--ease-standard);
}
@keyframes overlay-in { from { opacity: 0; } to { opacity: 1; } }
.modal {
  background: var(--bg-surface); border: 1px solid var(--border-subtle); border-radius: var(--radius-lg);
  width: 100%; max-width: 440px; box-sizing: border-box; padding: var(--space-6);
  animation: modal-in var(--dur-med) var(--ease-standard);
}
@keyframes modal-in { from { opacity: 0; transform: translateY(8px) scale(.98); } to { opacity: 1; transform: none; } }
.modal__header { display: flex; justify-content: space-between; align-items: center; margin-bottom: var(--space-5); }
.modal__title { font-family: var(--font-display); font-size: 22px; font-weight: 600; }

.field { display: flex; flex-direction: column; gap: var(--space-4); }
.field__label { font-family: var(--font-body); font-size: 11.5px; font-weight: 600; color: var(--text-tertiary); margin-bottom: 6px; text-transform: uppercase; letter-spacing: .04em; }
.field__label .is-guess { color: var(--accent-strong); text-transform: none; letter-spacing: 0; font-weight: 400; }

/* ---- responsive ---- */
@media (max-width: 860px) {
  .app { grid-template-columns: 1fr; }
  .sidebar { position: static; height: auto; flex-direction: row; flex-wrap: wrap; gap: 14px 24px; border-right: 0; border-bottom: 1px solid var(--border-subtle); overflow: visible; }
  .brand { flex-basis: 100%; flex-direction: row; align-items: baseline; gap: 10px; }
  .nav-group { flex-direction: row; flex-wrap: wrap; align-items: center; gap: 6px; }
  .nav-label { padding: 0; }
  .nav-item { width: auto; border-left: 0; border: 1px solid var(--border-subtle); border-radius: var(--radius-round); padding: 6px 12px; }
  .nav-item[aria-pressed="true"] { border-color: var(--accent); box-shadow: none; }
  .nav-item .n { display: none; }
  .sidebar-foot { margin: 0; flex-basis: 100%; }
  main { padding: 20px; }
  .toolbar { flex-wrap: wrap; }
  .btn { width: 100%; order: 3; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: .01ms !important; transition-duration: .01ms !important; }
}