*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg: #0d1117;
  --surface: #161b27;
  --surface2: #1f2535;
  --border: #2a3050;
  --accent: #14b8a6;
  --accent-lo: rgba(20, 184, 166, .22);
  --accent-hi: #2dd4bf;
  --green: #3ddc84;
  --red: #ff5555;
  --gold: #f5c842;
  --text: #dde3f0;
  --text-dim: #8d99b8;
  --font: 'Segoe UI', system-ui, sans-serif;
  --mono: 'Courier New', monospace;
  --radius: 12px;
}

body {
  background: var(--bg); color: var(--text);
  font-family: var(--font);
  min-height: 100vh; padding: 16px;
  overflow-x: hidden;
}
#app { max-width: 1400px; margin: 0 auto; }

.skip-link { position: absolute; left: -9999px; }
.skip-link:focus { left: 16px; top: 16px; background: var(--accent); color: #04201c; padding: 8px 14px; border-radius: 8px; z-index: 100; }

.site-nav { padding: 6px 0 14px; }
.site-nav-back {
  color: var(--text-dim); text-decoration: none;
  font-size: 0.85rem; padding: 6px 10px; border-radius: 8px;
  transition: background .15s, color .15s;
}
.site-nav-back:hover { background: var(--surface2); color: var(--accent); }

header { text-align: center; padding: 8px 0 18px; }
header h1 {
  font-size: clamp(1.4rem, 3vw, 2.1rem); font-weight: 800;
  background: linear-gradient(120deg, var(--accent) 0%, #60a5fa 100%);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text; letter-spacing: -.02em;
}
.subtitle { color: var(--text-dim); margin-top: 4px; font-size: .92rem; }

/* ─── Controls bar / pill tabs ─── */
.controls-bar {
  display: flex; flex-wrap: wrap; gap: 10px; align-items: center;
  padding: 8px 12px; background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); margin-bottom: 12px;
}
.ctrl-group { display: flex; gap: 8px; align-items: center; flex-wrap: wrap; }
.ctrl-label { font-size: .72rem; font-weight: 700; color: var(--text-dim); text-transform: uppercase; letter-spacing: .05em; }
.pill-tabs {
  display: inline-flex; flex-wrap: wrap; gap: 2px;
  background: var(--bg); border: 1px solid var(--border);
  border-radius: 22px; padding: 3px;
}
.pill {
  border: none; background: transparent; color: var(--text-dim);
  padding: 10px 16px; border-radius: 999px;
  font-size: .82rem; font-weight: 600; cursor: pointer;
  transition: background .15s, color .15s; min-height: 44px;
}
.pill:hover:not(:disabled) { color: var(--text); }
.pill.active { background: var(--accent); color: #04201c; }
.pill:disabled { opacity: .35; cursor: not-allowed; }
.pill:focus-visible, .ptf-btn:focus-visible, .ov-btn:focus-visible, .pk-item:focus-visible, .btn:focus-visible, canvas:focus-visible {
  outline: 2px solid var(--accent-hi); outline-offset: 2px;
}

.btn {
  padding: 8px 16px; border: 1px solid var(--border);
  background: var(--surface2); color: var(--text);
  border-radius: 8px; font-size: .85rem; font-weight: 600;
  cursor: pointer; transition: all .15s;
  display: inline-flex; align-items: center; gap: 6px; min-height: 44px;
}
.btn:hover:not(:disabled) { background: var(--accent-lo); color: var(--accent-hi); border-color: var(--accent); }
.btn:disabled { opacity: .4; cursor: not-allowed; }
.btn-primary { background: var(--accent); color: #04201c; border-color: var(--accent); }
.btn-primary:hover:not(:disabled) { background: var(--accent-hi); color: #04201c; border-color: var(--accent-hi); }
.btn-ghost { background: transparent; }

/* ─── Layout ─── */
.sim-layout { display: grid; grid-template-columns: minmax(0, 1fr) 380px; gap: 14px; }

.canvas-card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 10px; overflow-x: clip;
}

.crystal-strip {
  display: flex; flex-wrap: wrap; align-items: center; gap: 8px 22px;
  padding: 6px 8px 10px;
}
.cs-id { flex: 1 1 220px; min-width: 0; }
.cs-name { font-size: 1.15rem; font-weight: 800; }
.cs-sub { font-size: .8rem; color: var(--text-dim); margin-top: 2px; }
.cs-z { display: flex; flex-direction: column; align-items: center; min-width: 78px; }
.cs-zv { font-size: 1.5rem; font-weight: 800; color: var(--accent-hi); line-height: 1.1; white-space: nowrap; }
.cs-zl { font-size: .66rem; text-transform: uppercase; letter-spacing: .05em; color: var(--text-dim); text-align: center; }

.canvas-wrap { position: relative; border-radius: 10px; overflow: hidden;
  background: radial-gradient(120% 120% at 50% 35%, #1b2236 0%, #10151f 70%); }
#cv { display: block; width: 100%; touch-action: pan-y; cursor: grab; }
#cv:active { cursor: grabbing; }

.canvas-tools { position: absolute; top: 8px; right: 8px; display: flex; gap: 6px; flex-wrap: wrap; justify-content: flex-end; }
.ov-btn {
  display: inline-flex; align-items: center; gap: 5px;
  padding: 6px 10px; min-height: 36px; border-radius: 8px;
  background: rgba(22, 27, 39, .86); color: var(--text-dim);
  border: 1px solid var(--border); font-size: .78rem; font-weight: 600; cursor: pointer;
}
.ov-btn:hover { color: var(--text); border-color: var(--accent); }
.ov-btn.active { color: #04201c; background: var(--accent); border-color: var(--accent); }

.share-controls[hidden], .hole-controls[hidden] { display: none; }
.caption-bar { padding: 10px 8px 4px; font-size: .88rem; line-height: 1.5; color: var(--text); min-height: 3.2em; }
.caption-bar b { color: var(--accent-hi); }
.caption-bar .sum { font-family: var(--mono); color: var(--gold); }
.share-controls, .hole-controls { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; padding: 6px 8px 2px; }

/* ─── Readouts ─── */
.readout-grid { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 8px; margin-top: 12px; }
.rd { background: var(--surface); border: 1px solid var(--border); border-radius: 10px; padding: 8px 10px; min-width: 0; }
.rd-l { font-size: .66rem; text-transform: uppercase; letter-spacing: .05em; color: var(--text-dim); }
.rd-v { font-size: .92rem; font-weight: 700; margin-top: 3px; overflow-wrap: anywhere; }
.rd-v small { font-weight: 500; color: var(--text-dim); }

.working { margin-top: 10px; background: var(--surface); border: 1px solid var(--border); border-radius: 10px; }
.working summary { cursor: pointer; padding: 10px 12px; font-weight: 700; font-size: .88rem; min-height: 44px; display: flex; align-items: center; }
.working-body { padding: 4px 14px 12px; font-family: var(--mono); font-size: .82rem; line-height: 1.8; color: var(--text); overflow-x: auto; }
.working-body .k { color: var(--text-dim); }

/* ─── Catalogue ─── */
.picker { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 12px; align-self: start; }
.picker-title { display: flex; justify-content: space-between; font-size: .75rem; font-weight: 700; text-transform: uppercase; letter-spacing: .05em; color: var(--text-dim); margin-bottom: 8px; }
.pt-filter { display: flex; gap: 2px; background: var(--bg); border: 1px solid var(--border); border-radius: 999px; padding: 3px; margin-bottom: 10px; }
.ptf-btn { flex: 1; border: none; background: transparent; color: var(--text-dim); padding: 8px 6px; border-radius: 999px; font-size: .8rem; font-weight: 700; cursor: pointer; min-height: 40px; }
.ptf-btn:hover { color: var(--text); }
.ptf-btn.active { background: var(--accent); color: #04201c; }

.pk-list { display: flex; flex-direction: column; gap: 4px; max-height: 640px; overflow-y: auto; padding-right: 2px; }
.pk-group { margin-top: 8px; font-size: .72rem; font-weight: 800; letter-spacing: .04em; text-transform: uppercase; color: var(--accent-hi); }
.pk-group small { color: var(--text-dim); font-weight: 600; text-transform: none; letter-spacing: 0; margin-left: 6px; }
.pk-items { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 4px; margin-top: 4px; }
.pk-item {
  display: flex; align-items: center; gap: 8px; text-align: left;
  background: var(--surface2); border: 1px solid var(--border); color: var(--text);
  border-radius: 8px; padding: 8px 10px; min-height: 44px; cursor: pointer; font-size: .82rem; font-weight: 600;
}
.pk-item:hover { border-color: var(--accent); }
.pk-item[aria-pressed="true"] { background: var(--accent-lo); border-color: var(--accent); color: #fff; }
.pk-dot { width: 14px; height: 14px; border-radius: 50%; flex: none; box-shadow: inset -2px -2px 3px rgba(0,0,0,.35); }
.pk-name { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.pk-item.wide { grid-column: 1 / -1; }

@media (max-width: 1080px) {
  .sim-layout { grid-template-columns: minmax(0, 1fr); }
  .readout-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .pk-list { max-height: none; }
  .pk-items { grid-template-columns: repeat(3, minmax(0, 1fr)); }
}
@media (max-width: 768px) {
  .pk-items { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .pill { padding: 10px 12px; }
}
@media (max-width: 500px) {
  body { padding: 10px; }
  .canvas-card { padding: 6px; }
  .ov-label { display: none; }
  .ov-btn { min-width: 44px; justify-content: center; }
  .cs-z { min-width: 64px; }
  .cs-zv { font-size: 1.2rem; }
}
@media (prefers-reduced-motion: reduce) { * { transition: none !important; } }

/* ─── Modes ─── */
.mode-section { display: none; }
.mode-section.active { display: block; }

.explore-tabs { display: flex; flex-wrap: wrap; gap: 4px; }
.explore-tab { border: 1px solid var(--border); background: var(--bg); color: var(--text-dim); padding: 10px 16px; border-radius: 999px; font-size: .85rem; font-weight: 700; cursor: pointer; min-height: 44px; }
.explore-tab:hover { color: var(--text); border-color: var(--accent); }
.explore-tab.active { background: var(--accent); color: #04201c; border-color: var(--accent); }
.explore-tab:focus-visible, .quiz-opt:focus-visible, #pr-in:focus-visible { outline: 2px solid var(--accent-hi); outline-offset: 2px; }
.explore-cards { display: grid; grid-template-columns: repeat(auto-fill, minmax(340px, 1fr)); gap: 12px; }
.explore-card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 16px; display: flex; flex-direction: column; gap: 10px; }
.explore-card h3 { font-size: 1rem; color: var(--accent-hi); }
.explore-card p { font-size: .9rem; line-height: 1.6; color: var(--text); }
.explore-card p b { color: #fff; }
.explore-card .btn { align-self: flex-start; margin-top: auto; }

.practice-card, .quiz-panel { max-width: 820px; margin: 0 auto; background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 18px; }
.practice-top, .quiz-progress { display: flex; justify-content: space-between; align-items: center; font-size: .85rem; color: var(--text-dim); margin-bottom: 10px; }
.practice-score { font-weight: 800; color: var(--accent-hi); }
.practice-q, .quiz-q { font-size: 1.05rem; line-height: 1.6; margin-bottom: 14px; }
.practice-row { display: flex; flex-wrap: wrap; gap: 10px; align-items: center; }
#pr-in { background: var(--bg); color: var(--text); border: 1px solid var(--border); border-radius: 8px; padding: 10px 12px; font-size: 1.05rem; min-height: 44px; width: 180px; font-family: var(--mono); }
.pr-unit { font-weight: 700; color: var(--text-dim); min-width: 40px; }
.practice-feedback { margin-top: 12px; padding: 0; border-radius: 8px; font-size: .92rem; line-height: 1.5; }
.practice-feedback.ok, .practice-feedback.err { padding: 10px 14px; }
.practice-feedback.ok { background: rgba(61,220,132,.12); color: var(--green); border: 1px solid var(--green); }
.practice-feedback.err { background: rgba(255,85,85,.12); color: var(--red); border: 1px solid var(--red); }
.practice-sol { margin-top: 12px; padding: 12px 14px; background: var(--bg); border: 1px solid var(--border); border-radius: 8px; font-family: var(--mono); font-size: .85rem; line-height: 1.9; }
.practice-sol[hidden] { display: none; }
.practice-actions { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 14px; }

.quiz-progress-bar { height: 6px; background: var(--bg); border-radius: 6px; margin-bottom: 16px; overflow: hidden; }
.quiz-progress-fill { height: 100%; background: var(--accent); width: 0; transition: width .25s; }
.quiz-options { display: grid; gap: 8px; }
.quiz-opt { text-align: left; background: var(--surface2); color: var(--text); border: 1px solid var(--border); border-radius: 10px; padding: 12px 14px; font-size: .95rem; cursor: pointer; min-height: 48px; line-height: 1.45; }
.quiz-opt:hover:not(:disabled) { border-color: var(--accent); background: var(--accent-lo); }
.quiz-opt.correct { border-color: var(--green); background: rgba(61,220,132,.14); }
.quiz-opt.wrong { border-color: var(--red); background: rgba(255,85,85,.14); }
.quiz-opt:disabled { cursor: default; }
.quiz-explain { margin-top: 12px; font-size: .9rem; line-height: 1.6; color: var(--text-dim); min-height: 1.2em; }
.quiz-explain b { color: var(--text); }
.quiz-next-row { margin-top: 14px; text-align: right; }
#quiz-next[hidden], #quiz-result[hidden] { display: none; }
.quiz-result-stars { text-align: center; font-size: 2.2rem; color: var(--gold); letter-spacing: 6px; margin: 10px 0; }
.quiz-result-score { text-align: center; font-size: 1.4rem; font-weight: 800; margin-bottom: 8px; }
@media (max-width: 500px) { .explore-cards { grid-template-columns: minmax(0, 1fr); } #pr-in { width: 100%; } }

/* ─── Article tables, FAQ, keys ─── */
.seo-article .byc-table { width: 100%; border-collapse: collapse; font-size: 13px; margin: 10px 0 16px; }
.seo-article .byc-table th { background: #1f2535; padding: 8px 12px; text-align: left; border: 1px solid #2a3050; }
.seo-article .byc-table td { padding: 8px 12px; border: 1px solid #2a3050; }
.seo-article .byc-table tbody tr:nth-child(even) { background: #161b27; }
.faq-item { margin: 0 0 12px; }
.faq-item h4 { font-size: .95rem; margin: 0 0 4px; color: var(--accent-hi); }
.faq-item p { margin: 0; }
kbd { background: var(--surface2); border: 1px solid var(--border); border-bottom-width: 2px; border-radius: 4px; padding: 1px 6px; font-family: var(--mono); font-size: .8em; }
.controls-bar .head-actions { margin-left: auto; }

/* INTERLINK-START  header quick-links */
.head-actions{display:flex;align-items:center;gap:8px;margin-left:auto;flex-wrap:wrap;justify-content:flex-end;}
.btn-link{display:inline-flex;align-items:center;gap:7px;padding:5px 12px;border-radius:8px;font-size:.82rem;font-weight:700;text-decoration:none;cursor:pointer;background:var(--surface2,#1f2535);color:var(--text,#dde3f0);border:1.5px solid var(--border,#2a3050);white-space:nowrap;transition:border-color .18s,background .18s,color .18s;}
.btn-link:hover{border-color:var(--accent,#4fc3f7);background:var(--accent-lo,rgba(79,195,247,.18));color:#fff;}
.btn-link img{width:20px;height:20px;border-radius:4px;flex:none;}
.btn-link .lbl{line-height:1;}
@media(max-width:560px){.btn-link .lbl{display:none;}.btn-link{padding:5px 9px;}}
/* INTERLINK-END */
.btn-guide { margin-left: auto; padding: 6px 14px; background: var(--gold); color: #1a1a2e; border: none; border-radius: 8px; font-size: .82rem; font-weight: 700; text-decoration: none; transition: filter .15s; min-height: 36px; display: inline-flex; align-items: center; }
.btn-guide:hover { filter: brightness(1.1); }

/* ─── Build mode (the game) ─── */
.mode-badge { font-size: .6rem; font-weight: 800; letter-spacing: .06em; background: var(--gold); color: #1a1a2e; border-radius: 4px; padding: 1px 5px; margin-left: 4px; vertical-align: 1px; }
.pill.active .mode-badge { background: #04201c; color: var(--gold); }
#bcv { display: block; width: 100%; touch-action: pan-y; cursor: grab; }
.lv-grid { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 6px; margin-bottom: 4px; }
.lv-btn { display: flex; flex-direction: column; align-items: center; justify-content: center; min-height: 52px; border: 1px solid var(--border); background: var(--surface2); color: var(--text); border-radius: 10px; cursor: pointer; padding: 4px; }
.lv-btn b { font-size: 1.05rem; }
.lv-btn span { font-size: .7rem; color: var(--gold); letter-spacing: 1px; }
.lv-btn:hover { border-color: var(--accent); }
.lv-btn.on { background: var(--accent-lo); border-color: var(--accent); }
.lv-btn:focus-visible, .b-pick:focus-visible, #b-a:focus-visible, #b-preset:focus-visible, #b-auto:focus-visible { outline: 2px solid var(--accent-hi); outline-offset: 2px; }
.b-sec { margin-top: 14px; }
.b-sec small { text-transform: none; letter-spacing: 0; font-weight: 500; }
.b-lat { width: 100%; }
.b-lat .pill { flex: 1; }
.b-brush { display: flex; gap: 6px; align-items: center; margin-bottom: 6px; }
.b-pick { display: inline-flex; align-items: center; gap: 4px; min-width: 56px; min-height: 44px; border: 1px solid var(--border); background: var(--surface2); color: var(--text); border-radius: 8px; cursor: pointer; font-weight: 700; padding: 0 10px; }
.b-pick[aria-pressed="true"] { border-color: var(--accent); background: var(--accent-lo); }
.b-brush select, #b-preset { flex: 1; min-width: 0; min-height: 44px; background: var(--bg); color: var(--text); border: 1px solid var(--border); border-radius: 8px; padding: 0 8px; font-size: .85rem; }
#b-preset { width: 100%; }
.b-check { display: flex; align-items: center; gap: 8px; font-size: .85rem; min-height: 36px; }
.b-range { display: flex; align-items: center; gap: 10px; }
.b-range input { flex: 1; min-width: 0; }
.b-range span { font-family: var(--mono); font-size: .8rem; min-width: 64px; text-align: right; }
.b-actions { display: flex; gap: 8px; margin: 14px 0 6px; flex-wrap: wrap; }
.b-preset-l { display: block; font-size: .78rem; color: var(--text-dim); margin: 12px 0 4px; }
@media (max-width: 500px) { .lv-grid { grid-template-columns: repeat(4, minmax(0, 1fr)); } }
.b-kb { margin-top: 12px; border: 1px solid var(--border); border-radius: 8px; background: var(--bg); }
.b-kb summary { cursor: pointer; padding: 10px 12px; font-size: .85rem; font-weight: 700; min-height: 44px; display: flex; align-items: center; }
.b-kb-note { font-size: .78rem; color: var(--text-dim); padding: 0 12px 8px; }
.b-sites { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 4px; padding: 0 8px 10px; }
.b-site { min-height: 44px; border: 1px solid var(--border); background: var(--surface2); color: var(--text); border-radius: 8px; font-size: .74rem; cursor: pointer; text-align: left; padding: 4px 8px; line-height: 1.25; }
.b-site[aria-pressed="true"] { border-color: var(--accent); background: var(--accent-lo); }
.b-site:focus-visible { outline: 2px solid var(--accent-hi); outline-offset: 2px; }
.b-site small { display: block; color: var(--text-dim); }