/* CSA2 Attention Studio — light academic sheet */
:root {
  --paper: #f6f8fa;
  --paper-2: #eef2f6;
  --ink: #1f2733;
  --ink-2: #4a5666;
  --ink-3: #77839a;
  --line: #d4dce6;
  --line-strong: #b8c3d2;
  --current: #2f9e77;
  --reuse-kv: #d8a62a;
  --topk: #e0654c;
  --mainq: #3b6fd4;
  --swa: #8f7ad6;
  --card: #ffffff;
  --shadow: 0 1px 2px rgba(24, 38, 62, .08), 0 8px 24px rgba(24, 38, 62, .06);
  --radius: 10px;
  --font: "Manrope", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans CJK SC", system-ui, sans-serif;
}
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; height: 100%; }
body {
  font-family: var(--font);
  background: var(--paper);
  color: var(--ink);
  font-size: 15px;
  line-height: 1.55;
  overflow: hidden;
}
.skip-link {
  position: absolute; left: 8px; top: -48px; z-index: 50;
  background: var(--ink); color: #fff; padding: 6px 12px; border-radius: 6px;
  transition: top .15s ease;
}
.skip-link:focus { top: 8px; }
.topbar {
  height: 56px; display: flex; align-items: center; justify-content: space-between;
  padding: 0 20px; border-bottom: 1px solid var(--line); background: var(--card);
}
.brand { display: flex; align-items: center; gap: 12px; }
.brand-mark {
  width: 22px; height: 22px; border-radius: 5px;
  background: linear-gradient(135deg, var(--mainq) 0 34%, var(--current) 34% 67%, var(--reuse-kv) 67% 100%);
}
.topbar h1 { font-size: 16px; margin: 0; font-weight: 600; letter-spacing: .01em; }
.subtitle { margin: 0; font-size: 12px; color: var(--ink-3); }
.top-actions { display: flex; gap: 6px; }
.lang-btn {
  font: inherit; font-size: 13px; padding: 6px 14px; cursor: pointer;
  border: 1px solid var(--line-strong); background: var(--paper); color: var(--ink-2);
  border-radius: 999px;
}
.lang-btn.is-active { background: var(--ink); border-color: var(--ink); color: #fff; }
.layout { display: flex; height: calc(100% - 56px); }
.stage { position: relative; flex: 1; min-width: 0; }
.canvas-host { position: absolute; inset: 0; }
.canvas-host canvas { display: block; width: 100% !important; height: 100% !important; }
.legend {
  position: absolute; left: 16px; bottom: 16px; z-index: 5;
  background: rgba(255, 255, 255, .92); border: 1px solid var(--line);
  border-radius: var(--radius); padding: 10px 12px; box-shadow: var(--shadow);
  max-width: 248px;
}
.legend-title { font-size: 11px; color: var(--ink-3); margin-bottom: 6px; letter-spacing: .06em; }
.legend ul { list-style: none; margin: 0; padding: 0; display: grid; gap: 5px; }
.legend li { display: flex; align-items: center; gap: 8px; font-size: 12.5px; color: var(--ink-2); }
.swatch { width: 12px; height: 12px; border-radius: 3px; flex: none; border: 1px solid rgba(24,38,62,.14); }
.sw-current { background: #2f9e77; }
.sw-reuse-kv { background: #e7c563; }
.sw-topk { background: #e0654c; }
.sw-mainq { background: #3b6fd4; }
.sw-swa { background: #b9a8ec; }
.hint {
  position: absolute; right: 16px; bottom: 16px; z-index: 5; margin: 0;
  font-size: 12px; color: var(--ink-3); background: rgba(255,255,255,.85);
  padding: 5px 10px; border-radius: 999px; border: 1px solid var(--line);
}
.panel {
  width: 372px; flex: none; overflow-y: auto;
  border-left: 1px solid var(--line); background: var(--card);
  padding: 16px; display: flex; flex-direction: column; gap: 16px;
}
.group { flex-shrink: 0; display: flex; flex-direction: column; gap: 9px; }
.group.grow { flex: 0 0 auto; min-height: auto; }
.panel h2 {
  font-size: 12px; letter-spacing: .08em; color: var(--ink-3);
  margin: 0; font-weight: 600; text-transform: none;
}
.panel h3 { font-size: 12px; color: var(--ink-3); margin: 4px 0 0; font-weight: 600; }
.seg { display: flex; gap: 6px; }
.seg-btn {
  flex: 1; font: inherit; font-size: 13.5px; font-weight: 600; cursor: pointer;
  padding: 9px 0; border-radius: 8px; border: 1px solid var(--line-strong);
  background: var(--paper); color: var(--ink-2);
}
.seg-btn.is-active { background: var(--ink); border-color: var(--ink); color: #fff; }
.mode-meta { margin: 0; font-size: 12.5px; color: var(--ink-2); }
.row { display: flex; gap: 8px; }
.btn {
  font: inherit; font-size: 13.5px; cursor: pointer; padding: 8px 16px;
  border-radius: 8px; border: 1px solid var(--line-strong);
  background: var(--paper); color: var(--ink);
}
.btn.primary { background: var(--mainq); border-color: var(--mainq); color: #fff; }
.btn.is-active { background: var(--ink); border-color: var(--ink); color: #fff; }
.stages { display: grid; gap: 6px; }
.stage-btn {
  font: inherit; font-size: 12.5px; text-align: left; cursor: pointer;
  padding: 8px 10px; border-radius: 8px; border: 1px solid var(--line);
  background: var(--card); color: var(--ink-2); display: flex; gap: 8px; align-items: baseline;
}
.stage-btn .idx { color: var(--ink-3); font-size: 11px; min-width: 18px; }
.stage-btn.is-active { border-color: var(--mainq); background: #eef6f2; color: var(--ink); }
.explanation { margin: 0; font-size: 13.5px; color: var(--ink); line-height: 1.6; }
.provenance, .impl { margin: 0; font-size: 12.5px; color: var(--ink-2); line-height: 1.6; }
.provenance code, .impl code {
  font-family: ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;
  font-size: 11.5px; background: var(--paper-2); padding: 1px 5px; border-radius: 4px;
}
.tip {
  position: fixed; left: 50%; bottom: 22px; transform: translateX(-50%); z-index: 40;
  background: var(--ink); color: #fff; font-size: 13px; padding: 9px 16px;
  border-radius: 999px; box-shadow: var(--shadow); max-width: 70vw; text-align: center;
}
.noscript { padding: 24px; font-size: 14px; }
button:focus-visible, [tabindex]:focus-visible {
  outline: 2px solid var(--mainq); outline-offset: 2px;
}

@media (max-width: 900px) {
  body { overflow: auto; }
  .layout { flex-direction: column; height: auto; }
  .stage { height: 58vh; min-height: 420px; width: 100%; }
  .panel { width: 100%; border-left: none; border-top: 1px solid var(--line); }
  .legend { max-width: 210px; padding: 8px 10px; }
  .hint { display: none; }
}
@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; animation: none !important; }
}