/* DRVS — Dynamic Revealing Vector Search
   ui/reveal.css: the visual half of reverse semantic masking.

   Self-contained by design: every color, size, and timing is a --drvs-*
   custom property with a sensible default, so this file can be dropped onto
   any host page without inheriting or fighting that page's design tokens.
   To theme it, override the properties on :root (or any ancestor of the
   search root) — you should never need to edit or fork this file.

   Accessibility contract: tier state is NEVER communicated by color alone.
   Each row gets an opacity step AND a text label ("A｜精確：標題精確命中"),
   and each carries data-drvs-tier / data-drvs-score attributes for assistive
   tech and for your own CSS to hook. Opacity alone would fail anyone with
   low vision; color alone would fail anyone with a color vision deficiency. */

:root {
  --drvs-fg: #1c1b19;
  --drvs-fg-dim: #55524d;
  --drvs-fg-faint: #85807a;
  --drvs-bg: transparent;
  --drvs-surface: rgba(0, 0, 0, 0.02);
  --drvs-line: rgba(0, 0, 0, 0.16);
  --drvs-accent: #9a7b2f;
  --drvs-accent-contrast: #fffdf7;
  --drvs-notice: #2f6b63;
  --drvs-radius: 10px;
  --drvs-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;

  --drvs-tier-a-opacity: 1;
  --drvs-tier-b-opacity: 0.92;
  --drvs-tier-c-opacity: 0.62;
  --drvs-tier-d-opacity: 0.38;
  --drvs-hidden-opacity: 0.12;
  --drvs-transition: 180ms ease;
}

@media (prefers-color-scheme: dark) {
  :root {
    --drvs-fg: #e9e3d6;
    --drvs-fg-dim: #b3ab9c;
    --drvs-fg-faint: #857f74;
    --drvs-surface: rgba(233, 227, 214, 0.03);
    --drvs-line: rgba(233, 227, 214, 0.18);
    --drvs-accent: #c9a227;
    --drvs-accent-contrast: #14130f;
    --drvs-notice: #6fb3a8;
  }
}

/* ------------------------------------------------------------ control panel */

.drvs-panel {
  border: 1px solid var(--drvs-line);
  border-radius: var(--drvs-radius);
  padding: 1.1rem 1.3rem;
  background: var(--drvs-surface);
  color: var(--drvs-fg);
}

.drvs-row {
  display: flex;
  gap: 0.6rem;
  align-items: center;
  flex-wrap: wrap;
}

.drvs-input-wrap {
  position: relative;
  flex: 1 1 18rem;
  min-width: 12rem;
}

.drvs-input {
  width: 100%;
  font: inherit;
  font-size: 1.02rem;
  color: var(--drvs-fg);
  background: var(--drvs-bg);
  border: 1px solid var(--drvs-line);
  border-radius: calc(var(--drvs-radius) - 3px);
  padding: 0.65rem 2.4rem 0.65rem 0.9rem;
}

.drvs-input::placeholder { color: var(--drvs-fg-faint); }

.drvs-input:focus {
  outline: none;
  border-color: var(--drvs-accent);
}

/* Focus-visible outline is kept separate from the border recolor above so
   keyboard users still get a real focus ring even if a host overrides the
   accent color to something low-contrast. */
.drvs-input:focus-visible,
.drvs-mode-btn:focus-visible,
.drvs-reset-btn:focus-visible,
.drvs-clear:focus-visible {
  outline: 2px solid var(--drvs-accent);
  outline-offset: 2px;
}

.drvs-clear {
  position: absolute;
  right: 0.5rem;
  top: 50%;
  transform: translateY(-50%);
  background: none;
  border: none;
  color: var(--drvs-fg-faint);
  font-size: 1.1rem;
  line-height: 1;
  padding: 0.3rem 0.5rem;
  cursor: pointer;
  display: none;
}
.drvs-input-wrap.has-query .drvs-clear { display: block; }
.drvs-clear:hover { color: var(--drvs-fg); }

.drvs-mode-btn,
.drvs-reset-btn {
  font: inherit;
  font-size: 0.82rem;
  color: var(--drvs-fg-dim);
  background: transparent;
  border: 1px solid var(--drvs-line);
  border-radius: calc(var(--drvs-radius) - 3px);
  padding: 0.55rem 0.9rem;
  cursor: pointer;
  white-space: nowrap;
  transition: border-color var(--drvs-transition), color var(--drvs-transition);
}

.drvs-mode-btn[aria-pressed="true"] {
  color: var(--drvs-accent-contrast);
  background: var(--drvs-accent);
  border-color: var(--drvs-accent);
}

.drvs-mode-btn:hover,
.drvs-reset-btn:hover { border-color: var(--drvs-accent); }

.drvs-meta {
  margin-top: 0.65rem;
  font-family: var(--drvs-mono);
  font-size: 0.74rem;
  color: var(--drvs-fg-faint);
  letter-spacing: 0.02em;
  min-height: 1.1em;
}

.drvs-expansions {
  margin-top: 0.4rem;
  font-size: 0.76rem;
  line-height: 1.5;
  color: var(--drvs-accent);
  display: none;
}
.drvs-expansions.show { display: block; }

.drvs-banner {
  margin-top: 0.65rem;
  font-size: 0.82rem;
  line-height: 1.55;
  color: var(--drvs-notice);
  display: none;
}
.drvs-banner.show { display: block; }
.drvs-banner.low { color: var(--drvs-accent); }

/* --------------------------------------------------------- per-row reveal */

[data-drvs-tier="A"] { opacity: var(--drvs-tier-a-opacity); }
[data-drvs-tier="B"] { opacity: var(--drvs-tier-b-opacity); }
[data-drvs-tier="C"] { opacity: var(--drvs-tier-c-opacity); }
[data-drvs-tier="D"] { opacity: var(--drvs-tier-d-opacity); }

.drvs-hidden {
  opacity: var(--drvs-hidden-opacity);
  pointer-events: none;
}

/* Focus mode: masked rows leave the flow entirely. Reveal mode (the default)
   keeps them present but dimmed, which is the whole point of the technique —
   a reader can still see WHERE the matches sit within the original structure
   instead of getting a detached result list with no context. */
.drvs-focus .drvs-hidden { display: none; }
.drvs-focus .drvs-empty-group { display: none; }

.drvs-reason {
  font-family: var(--drvs-mono);
  font-size: 0.68rem;
  color: var(--drvs-accent);
  letter-spacing: 0.02em;
  margin-left: 0.55rem;
  white-space: nowrap;
}

/* A padding row has no reason of its own. It says so, and it says so in the
   muted voice — it must not look like a finding. */
.drvs-reason-padding {
  color: var(--drvs-fg-faint);
  font-style: italic;
}

/* Opacity is animated, but only for people who haven't asked for less motion.
   The reveal transition is the one piece of motion this package adds. */
@media (prefers-reduced-motion: no-preference) {
  [data-drvs-visible],
  .drvs-hidden {
    transition: opacity var(--drvs-transition);
  }
}

/* Forced-colors (Windows High Contrast) flattens opacity differences, so the
   tier signal has to come from something else there — the text label already
   present in every row carries it, and the masked rows get an explicit
   reduced-prominence treatment rather than silently looking identical. */
@media (forced-colors: active) {
  [data-drvs-tier] { opacity: 1; }
  .drvs-hidden { opacity: 1; }
  .drvs-mode-btn[aria-pressed="true"] { border-width: 3px; }
}

@media (max-width: 640px) {
  .drvs-row { flex-direction: column; align-items: stretch; }
  .drvs-mode-btn, .drvs-reset-btn { flex: 1; }
  .drvs-reason { white-space: normal; margin-left: 0; display: block; margin-top: 0.2rem; }
}