/* ── Magnetic Playground ───────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg:        #0d1117;
  --surface:   #161b27;
  --surface2:  #1f2535;
  --border:    #2a3050;
  --accent:    #f43f5e;
  --accent-lo: rgba(244,63,94,.22);
  --green:     #3ddc84;
  --red:       #ff5555;
  --gold:      #f5c842;
  --text:      #dde3f0;
  --text-dim:  #6b7a99;
  --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: 0 16px; }
#app { max-width: 1060px; margin: 0 auto; display: flex; flex-direction: column; gap: 14px; }

/* ── Header ────────────────────────────────────────────────────── */
header { text-align: center; padding: 4px 0; }
header h1 {
  font-size: 1.8rem; font-weight: 700;
  background: linear-gradient(120deg, #f43f5e 0%, #60a5fa 100%);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text;
}
.subtitle { color: var(--text-dim); font-size: 0.85rem; margin-top: 3px; }

/* ── Controls bar ──────────────────────────────────────────────── */
.controls-bar {
  display: flex; flex-wrap: wrap; align-items: center; gap: 14px;
  padding: 12px 16px;
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
}
.ctrl-group { display: flex; align-items: center; gap: 8px; }
.ctrl-label { font-size: 0.72rem; text-transform: uppercase; letter-spacing: .06em; color: var(--text-dim); white-space: nowrap; }

.pill-tabs { display: flex; background: var(--bg); border-radius: 8px; padding: 3px; gap: 2px; }
.pill {
  padding: 5px 13px; border: none; background: transparent; color: var(--text-dim);
  border-radius: 6px; cursor: pointer; font-size: 0.81rem;
  transition: background .18s, color .18s, box-shadow .18s;
}
.pill.active { background: var(--accent); color: #fff; box-shadow: 0 0 12px var(--accent-lo); }
.pill:hover:not(.active) { background: var(--surface2); color: var(--text); }

/* ── Canvas card ───────────────────────────────────────────────── */
.canvas-card {
  width: 100%; background: var(--surface);
  border: 1px solid var(--border); border-radius: var(--radius);
  padding: 8px; position: relative; overflow-x: clip;
}
/* touch-action none: drag-to-aim is the canvas's primary interaction, and
   its vertical component (setting the angle) must not scroll the page. */
.canvas-card canvas { display: block; width: 100%; height: auto; cursor: pointer; touch-action: none; }
.canvas-stage { position: relative; }

/* ── Buttons ───────────────────────────────────────────────────── */
.btn {
  padding: 8px 18px; border: none; border-radius: 8px; cursor: pointer;
  font-size: 0.84rem; font-weight: 600; transition: filter .18s, box-shadow .18s, opacity .18s;
}
.btn:disabled { opacity: 0.38; cursor: not-allowed; }
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:not(:disabled):hover { filter: brightness(1.12); box-shadow: 0 0 12px var(--accent-lo); }
.btn-ghost { background: var(--surface2); color: var(--text); border: 1px solid var(--border); }
.btn-ghost:hover { background: var(--border); }

/* ── Sim controls ─────────────────────────────────────────────── */
.sim-controls {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 14px 18px; display: flex; flex-direction: column; gap: 12px;
}
.sim-row { display: flex; align-items: center; gap: 14px; flex-wrap: wrap; }
.sim-slider-group { display: flex; align-items: center; gap: 10px; flex: 1; min-width: 200px; }
.sim-slider-label { font-size: 0.76rem; font-weight: 700; color: var(--text-dim); white-space: nowrap; min-width: 80px; }
.sim-slider {
  flex: 1; min-width: 0; -webkit-appearance: none; appearance: none; height: 6px;
  background: var(--surface2); border-radius: 3px; outline: none;
}
.sim-slider::-webkit-slider-thumb {
  -webkit-appearance: none; width: 18px; height: 18px;
  border-radius: 50%; background: var(--accent); cursor: pointer;
  box-shadow: 0 0 8px var(--accent-lo);
}
.sim-slider::-moz-range-thumb {
  width: 18px; height: 18px; border: none;
  border-radius: 50%; background: var(--accent); cursor: pointer;
}
.sim-slider-val {
  font-family: var(--mono); font-size: 0.9rem; font-weight: 700;
  color: var(--accent); min-width: 65px; text-align: right;
}

/* Aligned 2-column grid for the Simulate panel ------------------- */
/* Shared 80px label column so Angle/Velocity/Height/Gravity/Presets/Show line up */
.sim-controls .ctrl-label { min-width: 80px; }
/* Gravity occupies the right half (mirrors Velocity, identical flex to slider groups) */
.sim-row .sim-env { flex: 1; min-width: 200px; }
.sim-row .sim-env #gravity-tabs { margin-left: auto; }

.mass-presets { display: flex; gap: 6px; flex-wrap: wrap; }
.preset-btn {
  padding: 6px 14px; border: 2px solid var(--border); border-radius: 8px;
  background: var(--surface2); color: var(--text-dim); font-size: 0.78rem;
  font-weight: 700; cursor: pointer; transition: border-color .18s, color .18s, background .18s;
}
.preset-btn:hover { border-color: var(--accent); color: var(--text); }
.preset-btn.active { border-color: var(--accent); color: #fff; background: rgba(244,63,94,.18); }

.readout-row {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(130px, 1fr)); gap: 8px;
}
.readout-card {
  background: var(--bg); border: 1px solid var(--border); border-radius: 8px;
  padding: 8px 12px; text-align: center;
}
.readout-label { font-size: 0.62rem; text-transform: uppercase; letter-spacing: .07em; color: var(--text-dim); margin-bottom: 3px; }
.readout-val { font-family: var(--mono); font-size: 1.15rem; font-weight: 700; color: var(--accent); }
.readout-val.warn { color: var(--red); }
.readout-unit { font-size: 0.68rem; color: var(--text-dim); margin-left: 2px; }

.sim-toggles { display: flex; align-items: center; gap: 16px; flex-wrap: wrap; }
.sim-toggle { display: flex; align-items: center; gap: 6px; cursor: pointer; font-size: 0.78rem; color: var(--text-dim); }
.sim-toggle input[type="checkbox"] { accent-color: var(--accent); width: 16px; height: 16px; cursor: pointer; }
.sim-toggle.checked { color: var(--text); }

/* ── Explore mode ──────────────────────────────────────────────── */
.item-selector {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 14px 16px;
}
.is-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(155px, 1fr)); gap: 8px; margin-top: 10px; }
.is-btn {
  padding: 10px 14px; border: 2px solid var(--border); border-radius: 10px;
  background: var(--surface2); color: var(--text-dim); font-size: 0.82rem;
  font-weight: 600; cursor: pointer; text-align: left;
  transition: border-color .18s, color .18s, background .18s, box-shadow .18s;
}
.is-btn:hover { border-color: rgba(244,63,94,.45); color: var(--text); }
.is-btn.active { border-color: var(--accent); color: #fff; background: rgba(244,63,94,.15); box-shadow: 0 0 14px var(--accent-lo); }
.is-btn-name { display: block; font-size: 0.82rem; font-weight: 700; }
.is-btn-sym  { display: block; font-size: 0.68rem; color: var(--accent); margin-top: 2px; font-family: var(--mono); }

.item-info {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 16px 18px; display: flex; flex-direction: column; gap: 8px;
}
.ii-top { display: flex; align-items: center; gap: 12px; flex-wrap: wrap; }
.ii-name { font-size: 1.15rem; font-weight: 800; color: var(--text); }
.ii-cat-badge {
  font-size: 0.62rem; font-weight: 700; text-transform: uppercase;
  letter-spacing: .07em; padding: 3px 10px; border-radius: 20px;
  background: var(--accent-lo); color: var(--accent);
}
.ii-desc { font-size: 0.85rem; color: var(--text-dim); line-height: 1.65; }

/* Formula box */
.formula-box {
  background: var(--bg); border: 1px solid var(--border); border-radius: 8px;
  padding: 10px 14px; display: flex; align-items: center; gap: 16px; flex-wrap: wrap;
}
.fb-formula { font-family: var(--mono); font-size: 1.1rem; font-weight: 700; color: var(--accent); }
.fb-unit { font-size: 0.78rem; color: var(--text-dim); }

/* Example calculation */
.example-box {
  background: var(--surface2); border: 1px solid var(--border); border-radius: 8px;
  padding: 12px 14px;
}
.example-box h4 { font-size: 0.72rem; text-transform: uppercase; letter-spacing: .08em; color: var(--accent); margin-bottom: 8px; }
.example-box .ex-problem { font-size: 0.84rem; color: var(--text); margin-bottom: 8px; line-height: 1.6; }
.example-box .ex-step { font-size: 0.8rem; color: var(--text-dim); line-height: 1.6; padding: 2px 0; }
.example-box .ex-step strong { color: var(--green); font-family: var(--mono); }

/* ── Practice mode ─────────────────────────────────────────────── */
.practice-panel {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 16px 18px;
}
.pp-prompt { font-size: 0.92rem; font-weight: 600; color: var(--text); margin-bottom: 14px; line-height: 1.6; }
.pp-input-row { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.pp-input {
  flex: 1; min-width: 120px; max-width: 220px;
  padding: 10px 14px; border: 2px solid var(--border); border-radius: 8px;
  background: var(--bg); color: var(--text); font-family: var(--mono);
  font-size: 1rem; font-weight: 700; transition: border-color .18s;
}
.pp-input:focus { outline: none; border-color: var(--accent); }
.pp-unit { font-size: 0.88rem; color: var(--text-dim); font-weight: 600; }
.pp-bottom { display: flex; align-items: center; gap: 12px; flex-wrap: wrap; margin-top: 14px; }
.feedback { font-size: 0.88rem; font-weight: 600; }
.feedback.ok  { color: var(--green); }
.feedback.err { color: var(--red); }

.solution-panel {
  background: var(--surface2); border: 1px solid var(--border); border-radius: 8px;
  padding: 14px 16px; margin-top: 12px;
}
.solution-panel h4 { font-size: 0.72rem; text-transform: uppercase; letter-spacing: .08em; color: var(--accent); margin-bottom: 8px; }
.sol-step { font-size: 0.82rem; color: var(--text-dim); line-height: 1.7; padding: 2px 0; }
.sol-step strong { color: var(--green); font-family: var(--mono); }

.practice-bar {
  display: flex; align-items: center; gap: 12px; flex-wrap: wrap;
  padding: 12px 16px;
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
}
.pbar-score { font-size: 0.84rem; color: var(--text-dim); margin-left: auto; white-space: nowrap; }
.pbar-score span { color: var(--text); font-weight: 700; }

/* ── Quiz panels ───────────────────────────────────────────────── */
.question-panel {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 16px 18px;
}
.qp-prompt { font-size: 0.88rem; font-weight: 600; color: var(--text); margin-bottom: 12px; line-height: 1.6; }
.answer-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; }
.answer-btn {
  padding: 14px 16px; border: 2px solid var(--border); border-radius: 10px;
  background: var(--surface2); color: var(--text); font-size: 0.88rem;
  font-weight: 600; cursor: pointer; text-align: center;
  transition: border-color .18s, background .18s, color .18s, transform .12s;
}
.answer-btn:hover:not(.locked) { border-color: var(--accent); background: rgba(244,63,94,.06); }
.answer-btn.correct { border-color: var(--green); background: rgba(61,220,132,.12); color: var(--green); }
.answer-btn.wrong { border-color: var(--red); background: rgba(255,85,85,.08); color: var(--red); }
.answer-btn.locked { cursor: default; opacity: 0.6; }
.answer-btn.correct.locked { opacity: 1; }

.quiz-bar {
  display: flex; align-items: center; gap: 12px; flex-wrap: wrap;
  padding: 12px 16px;
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
}
.qbar-counter { display: flex; align-items: baseline; gap: 3px; background: var(--bg); border: 1px solid var(--border); border-radius: 8px; padding: 4px 12px; }
.qbar-q-label { font-size: 0.7rem; font-weight: 700; color: var(--accent); text-transform: uppercase; letter-spacing: .08em; }
.qbar-q-num { font-family: var(--mono); font-size: 1.3rem; font-weight: 700; color: var(--text); line-height: 1; }
.qbar-q-sep { font-size: 0.82rem; color: var(--text-dim); }
.qbar-q-total { font-family: var(--mono); font-size: 0.88rem; color: var(--text-dim); }
.quiz-feedback { font-size: 0.88rem; font-weight: 600; }
.quiz-feedback.ok  { color: var(--green); }
.quiz-feedback.err { color: var(--red); }

/* Quiz result */
.quiz-result {
  background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 20px 22px; display: flex; flex-direction: column; gap: 14px;
}
.qr-header { display: flex; align-items: flex-start; justify-content: space-between; }
.qr-title-wrap { display: flex; flex-direction: column; gap: 5px; }
.qr-title  { font-size: 1.1rem; font-weight: 700; color: var(--text); }
.qr-stars  { font-size: 1.2rem; letter-spacing: 3px; }
.qr-score-wrap { text-align: right; }
.qr-score { font-family: var(--mono); font-size: 2.2rem; font-weight: 700; line-height: 1; text-shadow: 0 0 14px currentColor; }
.qr-score.perfect { color: var(--gold); }
.qr-score.good { color: var(--green); }
.qr-score.poor { color: var(--red); }
.qr-verdict { font-size: 0.72rem; color: var(--text-dim); margin-top: 3px; }
.qr-rows { display: flex; flex-direction: column; gap: 7px; }
.qr-row {
  display: grid; grid-template-columns: 30px 1fr 26px; align-items: center; gap: 10px;
  background: var(--surface2); border: 1px solid var(--border); border-left-width: 3px;
  border-radius: 8px; padding: 9px 12px;
}
.qr-row.ok  { border-left-color: var(--green); }
.qr-row.err { border-left-color: var(--red); }
.qr-qnum { font-size: 0.72rem; font-weight: 700; color: var(--accent); }
.qr-detail { font-size: 0.78rem; color: var(--text-dim); }
.qr-detail strong { color: var(--text); }
.qr-mark { text-align: right; font-size: 1rem; font-weight: 700; }
.qr-row.ok .qr-mark { color: var(--green); }
.qr-row.err .qr-mark { color: var(--red); }

/* Quiz input row (for numeric quiz questions) */
.quiz-input-row { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; margin-bottom: 10px; }
.qi-input {
  flex: 1; min-width: 120px; max-width: 200px;
  padding: 10px 14px; border: 2px solid var(--border); border-radius: 8px;
  background: var(--bg); color: var(--text); font-family: var(--mono);
  font-size: 1rem; font-weight: 700; transition: border-color .18s;
}
.qi-input:focus { outline: none; border-color: var(--accent); }
.qi-unit { font-size: 0.84rem; color: var(--text-dim); font-weight: 600; }

/* ── Fire / Reset button row ──────────────────────────────────── */
.btn-fire-row {
  display: flex; align-items: center; gap: 8px; margin-left: auto;
}

/* ── Gravity selector spacing ─────────────────────────────────── */
#frame-tabs .pill {
  min-width: 52px; text-align: center;
}

/* ── Canvas overlay info box ──────────────────────────────────── */
.canvas-info-overlay {
  position: absolute; top: 8px; right: 8px;
  background: rgba(22,27,39,0.88); border: 1px solid var(--border);
  border-radius: 8px; padding: 8px 12px; pointer-events: none;
}

/* ── Responsive ────────────────────────────────────────────────── */
@media (max-width: 768px) {
  .answer-grid { grid-template-columns: 1fr 1fr; }
  .is-grid { grid-template-columns: repeat(auto-fill, minmax(130px, 1fr)); }
  .controls-bar { gap: 10px; }
  .readout-row { grid-template-columns: repeat(2, 1fr); }
  .sim-slider-group { min-width: 160px; }
}
@media (max-width: 500px) {
  header h1 { font-size: 1.4rem; }
  .subtitle  { font-size: 0.78rem; }
  .controls-bar { padding: 10px 12px; gap: 8px; }
  .pill { padding: 5px 10px; font-size: 0.76rem; }
  .answer-grid { grid-template-columns: 1fr; }
  .is-grid { grid-template-columns: 1fr 1fr; }
  .readout-row { grid-template-columns: 1fr 1fr; }
  /* Wrap so the stepper drops below the slider instead of overflowing */
  .sim-slider-group { min-width: 100%; flex-wrap: wrap; }
  .sim-slider { flex: 1 1 120px; }
  .sim-slider-group .stepper { margin-left: 90px; } /* align under slider (80px label + gap) */
  .preset-btn { padding: 5px 10px; font-size: 0.72rem; }
}

/* Touch devices: comfortable tap targets (audit E7) */
@media (pointer: coarse) {
  .step-btn { width: 40px; height: 40px; }
  .pill { min-height: 40px; }
  .ct-btn, .ct-toggle, .preset-btn { min-height: 44px; }
}

/* ═══ Stepper inputs ═════════════════════════════════════════════ */
.stepper {
  display: inline-flex; align-items: center; gap: 4px;
  background: var(--bg); border: 1px solid var(--border); border-radius: 8px;
  padding: 2px;
}
.step-btn {
  width: 26px; height: 26px; padding: 0;
  border: none; background: var(--surface2); color: var(--text);
  border-radius: 6px; cursor: pointer; font-size: 0.95rem; font-weight: 700;
  line-height: 1; display: inline-flex; align-items: center; justify-content: center;
  transition: background 0.15s, color 0.15s;
}
.step-btn:hover { background: var(--accent); color: #fff; }
.step-btn:focus-visible { outline: 2px solid var(--accent); outline-offset: 1px; }
.step-input {
  width: 56px; padding: 4px 6px;
  border: none; background: transparent; color: var(--accent);
  font-family: var(--mono); font-size: 0.88rem; font-weight: 700;
  text-align: center;
}
.step-input::-webkit-outer-spin-button,
.step-input::-webkit-inner-spin-button { -webkit-appearance: none; margin: 0; }
.step-input { -moz-appearance: textfield; }
.step-input:focus { outline: none; }
.step-unit { font-size: 0.74rem; color: var(--text-dim); padding-right: 6px; min-width: 28px; }

/* ═══ Feature toggles row ════════════════════════════════════════ */
.feature-toggles { gap: 16px 18px; }
.feature-toggles .sim-toggle { font-size: 0.78rem; }

/* ═══ Canvas display-controls (collapsible, extreme top-left) ════ */
.canvas-toggles {
  position: absolute; top: 8px; left: 8px; z-index: 4;
  background: rgba(13,17,30,0.82);
  -webkit-backdrop-filter: blur(3px); backdrop-filter: blur(3px);
  border: 1px solid rgba(139,157,195,0.22); border-radius: 9px;
  box-shadow: 0 4px 14px rgba(0,0,0,0.32);
}
.canvas-toggles > summary {
  list-style: none; cursor: pointer; user-select: none;
  display: flex; align-items: center; gap: 7px;
  padding: 6px 10px; white-space: nowrap;
  font-size: 0.66rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.05em;
  color: var(--text); border-radius: 9px;
  transition: background 0.12s, color 0.12s;
}
.canvas-toggles > summary::-webkit-details-marker { display: none; }
.canvas-toggles > summary::marker { content: ''; }
.canvas-toggles > summary:hover { background: rgba(244,63,94,0.10); color: var(--accent); }
.canvas-toggles .cvt-ico { flex-shrink: 0; color: var(--accent); }
.canvas-toggles .cvt-caret { margin-left: auto; padding-left: 4px; color: var(--text-dim); font-size: 0.7rem; transition: transform 0.2s; }
.canvas-toggles[open] > summary .cvt-caret { transform: rotate(180deg); color: var(--accent); }
.canvas-toggles[open] > summary { border-bottom: 1px solid rgba(139,157,195,0.18); border-radius: 9px 9px 0 0; }
.canvas-toggles .cvt-body { display: flex; flex-direction: column; gap: 5px; padding: 8px 11px 9px; }
.canvas-toggles .cvt-item {
  display: flex; align-items: center; gap: 6px;
  font-size: 0.72rem; color: var(--text-dim); cursor: pointer; white-space: nowrap;
  transition: color 0.12s;
}
.canvas-toggles .cvt-item:hover { color: var(--text); }
.canvas-toggles .cvt-item input[type="checkbox"] {
  accent-color: var(--accent); width: 14px; height: 14px; cursor: pointer; flex-shrink: 0;
}

/* ═══ Canvas hint banner ═════════════════════════════════════════ */
.canvas-hint {
  position: absolute; bottom: 14px; left: 50%; transform: translateX(-50%);
  background: rgba(245,200,66,0.95); color: #1a1a2e;
  padding: 6px 30px 6px 12px; border-radius: 20px;
  font-size: 0.78rem; font-weight: 600; box-shadow: 0 4px 12px rgba(0,0,0,0.35);
  z-index: 4; max-width: calc(100% - 40px);
}
.canvas-hint.hidden { display: none; }
.hint-close {
  position: absolute; right: 6px; top: 50%; transform: translateY(-50%);
  width: 20px; height: 20px; padding: 0;
  border: none; background: transparent; color: #1a1a2e;
  font-size: 1.1rem; line-height: 1; cursor: pointer; font-weight: 700;
}
.canvas-card canvas { cursor: crosshair; }

/* ═══ Canvas toolbar — chip-style action bar docked under canvas ══ */
.canvas-toolbar {
  display: flex; flex-wrap: nowrap; gap: 4px;
  margin-top: 8px; padding: 8px 6px;
  background: linear-gradient(180deg, rgba(30,38,66,0.35), rgba(20,26,46,0.25));
  border: 1px solid rgba(139,157,195,0.22);
  border-radius: 9px;
  box-shadow: inset 0 1px 0 rgba(255,255,255,0.03);
}
.canvas-toolbar .ct-btn {
  flex: 1 1 0;
  display: inline-flex; align-items: center; justify-content: center; gap: 5px;
  appearance: none;
  background: var(--surface2);
  border: 1px solid rgba(139,157,195,0.22);
  border-radius: 6px; color: var(--text);
  padding: 8px 8px; font-size: 0.75rem; font-weight: 600;
  letter-spacing: 0.02em; white-space: nowrap; min-width: 0; cursor: pointer;
  transition: background 0.12s ease, color 0.12s ease, border-color 0.12s ease, transform 0.1s ease;
}
.canvas-toolbar .ct-btn .ct-icon  { font-size: 0.9rem; line-height: 1; }
.canvas-toolbar .ct-btn .ct-label { overflow: hidden; text-overflow: ellipsis; }
.canvas-toolbar .ct-btn:hover:not(:disabled) {
  background: var(--accent-lo); border-color: rgba(244,63,94,0.55);
  color: var(--accent); transform: translateY(-1px);
}
.canvas-toolbar .ct-btn:active:not(:disabled) { transform: translateY(0); }
.canvas-toolbar .ct-btn:disabled {
  opacity: 0.40; cursor: not-allowed; background: var(--surface); color: var(--text-dim);
}
.canvas-toolbar .ct-btn:focus-visible { outline: 2px solid var(--gold); outline-offset: -1px; }

/* Air Resistance — chip-style toggle on the far left */
.canvas-toolbar .ct-toggle {
  flex: 1 1 0;
  display: inline-flex; align-items: center; justify-content: center; gap: 6px;
  background: var(--surface2);
  border: 1px solid rgba(139,157,195,0.22);
  border-radius: 6px; color: var(--text-dim);
  padding: 8px 8px; font-size: 0.75rem; font-weight: 600;
  white-space: nowrap; min-width: 0; cursor: pointer;
  transition: background 0.12s, color 0.12s, border-color 0.12s;
}
.canvas-toolbar .ct-toggle input[type="checkbox"] {
  accent-color: var(--accent); width: 15px; height: 15px; cursor: pointer; flex-shrink: 0;
}
.canvas-toolbar .ct-toggle:hover { border-color: rgba(244,63,94,0.45); color: var(--text); }
.canvas-toolbar .ct-toggle.checked {
  color: var(--accent); border-color: rgba(244,63,94,0.55); background: var(--accent-lo);
}
.canvas-toolbar .ct-toggle .ct-label { overflow: hidden; text-overflow: ellipsis; }
.canvas-toolbar .ct-toggle.disabled { opacity: 0.4; cursor: not-allowed; }
.canvas-toolbar .ct-toggle.disabled:hover { border-color: rgba(139,157,195,0.22); color: var(--text-dim); background: var(--surface2); }
.canvas-toolbar .ct-toggle.disabled input[type="checkbox"] { cursor: not-allowed; }

/* Wider chips for the long-label items so text isn't clipped */
.canvas-toolbar .ct-btn-calc { flex-grow: 1.7; }
.canvas-toolbar .ct-toggle  { flex-grow: 2.2; }

/* Show Calculations — gold-tinted highlight */
.canvas-toolbar .ct-btn-calc {
  background: linear-gradient(180deg, rgba(245,200,66,0.20), rgba(245,200,66,0.06));
  border-color: rgba(245,200,66,0.45); color: var(--gold); font-weight: 700;
}
.canvas-toolbar .ct-btn-calc:hover:not(:disabled) {
  background: linear-gradient(180deg, rgba(245,200,66,0.34), rgba(245,200,66,0.14));
  border-color: var(--gold); color: var(--gold);
}
/* Fire — primary action, green */
.canvas-toolbar .ct-btn-fire {
  background: linear-gradient(180deg, #f43f5e, #be123c);
  border-color: rgba(255,255,255,0.15); color: #fff; font-weight: 700;
}
.canvas-toolbar .ct-btn-fire:hover:not(:disabled) {
  filter: brightness(1.1); background: linear-gradient(180deg, #fda4af, #f43f5e);
  border-color: var(--accent); color: #fff;
}

/* ═══ Calculation modal ══════════════════════════════════════════ */
.calc-modal {
  display: none; position: fixed; inset: 0; z-index: 1200;
  background: rgba(0,0,0,0.72); backdrop-filter: blur(4px);
  align-items: flex-start; justify-content: center;
  padding: 24px 16px; overflow-y: auto;
}
.calc-modal.active { display: flex; }
.calc-modal-box {
  background: var(--surface); border: 1px solid rgba(139,157,195,0.25); border-radius: 12px;
  width: 100%; max-width: 760px;
  display: flex; flex-direction: column;
  box-shadow: 0 24px 64px rgba(0,0,0,0.6);
  max-height: calc(100vh - 48px); overflow: hidden;
}
.calc-modal-header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 14px 20px;
  border-bottom: 1px solid var(--border);
  background: var(--surface2); flex-shrink: 0;
}
.calc-modal-title { font-size: 1rem; font-weight: 800; color: var(--text); }
.calc-modal-close {
  width: 34px; height: 34px;
  border: 1px solid var(--border); border-radius: 8px;
  background: var(--bg); color: var(--text-dim);
  font-size: 1.4rem; line-height: 1; padding: 0;
  display: flex; align-items: center; justify-content: center; cursor: pointer;
  transition: border-color 0.15s, color 0.15s, background 0.15s;
}
.calc-modal-close:hover { border-color: var(--accent); color: var(--text); background: var(--surface2); }
.calc-modal-body { padding: 16px 20px; overflow-y: auto; display: flex; flex-direction: column; gap: 12px; }

.cs-inputs {
  background: rgba(244,63,94,0.08);
  border: 1px solid rgba(244,63,94,0.25); border-radius: 8px;
  padding: 12px 14px;
  display: flex; flex-direction: column; gap: 8px;
}
.cs-badge {
  display: inline-block; padding: 3px 12px; border-radius: 20px;
  background: rgba(244,63,94,0.22); color: var(--accent);
  font-size: 0.72rem; font-weight: 700;
  text-transform: uppercase; letter-spacing: 0.06em; align-self: flex-start;
}
.cs-given { display: flex; flex-wrap: wrap; gap: 6px 16px; }
.cs-given span { font-family: var(--mono); font-size: 0.82rem; color: var(--text); }
.cs-si-note { font-size: 0.72rem; color: var(--text-dim); margin: 0; }

.cs-step {
  background: var(--bg);
  border: 1px solid var(--border); border-radius: 8px;
  padding: 12px 14px;
  display: flex; flex-direction: column; gap: 6px;
}
.cs-step-hd { display: flex; align-items: baseline; gap: 8px; flex-wrap: wrap; }
.cs-num {
  font-size: 0.64rem; font-weight: 800;
  text-transform: uppercase; letter-spacing: 0.06em;
  color: var(--accent); background: rgba(244,63,94,0.18);
  padding: 2px 8px; border-radius: 20px; white-space: nowrap;
}
.cs-title { font-size: 0.9rem; font-weight: 700; color: var(--text); }
.cs-formula {
  font-size: 0.95rem; color: var(--text);
  background: var(--surface2); border-radius: 6px;
  padding: 8px 12px; border-left: 3px solid var(--accent);
}
.cs-calc   { font-family: var(--mono); font-size: 0.8rem; color: var(--text); white-space: pre-wrap; line-height: 1.7; }
.cs-result { font-size: 0.88rem; color: var(--text-dim); margin-top: 2px; }
.cs-result strong { font-family: var(--mono); font-size: 0.95rem; color: var(--green); }

/* ═══ Learning panels (collapsible) ══════════════════════════════ */
.learn-panels {
  margin-top: 4px; padding: 14px;
  background: linear-gradient(180deg, rgba(30,38,66,0.6), rgba(20,26,46,0.6));
  border: 1px solid rgba(139,157,195,0.2);
  border-radius: 12px;
}
.learn-head {
  display: flex; align-items: center; justify-content: space-between;
  gap: 12px; flex-wrap: wrap;
  padding-bottom: 10px;
  border-bottom: 1px solid rgba(139,157,195,0.18);
  margin-bottom: 12px;
}
.learn-head-title { font-size: 0.95rem; font-weight: 700; color: var(--text); letter-spacing: 0.01em; }
.learn-head-actions { display: flex; gap: 8px; }
.learn-toggle-all {
  padding: 5px 12px;
  background: rgba(244,63,94,0.12); border: 1px solid rgba(244,63,94,0.35);
  color: var(--accent); border-radius: 6px;
  font-size: 0.78rem; font-weight: 600; cursor: pointer;
  transition: background 0.15s, color 0.15s;
}
.learn-toggle-all:hover { background: rgba(244,63,94,0.25); color: var(--text); }
.learn-toggle-all:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

.learn-card {
  border: 1px solid rgba(139,157,195,0.18); border-radius: 10px;
  background: rgba(13,17,30,0.55);
  margin-bottom: 10px; overflow: hidden;
  transition: border-color 0.2s;
}
.learn-card:last-child { margin-bottom: 0; }
.learn-card[open] { border-color: rgba(244,63,94,0.35); }
.learn-card > summary {
  list-style: none; cursor: pointer;
  padding: 10px 14px;
  display: flex; align-items: center; gap: 10px; flex-wrap: wrap;
  font-size: 0.88rem; font-weight: 700; color: var(--text);
  user-select: none; transition: background 0.15s; position: relative;
}
.learn-card > summary::-webkit-details-marker { display: none; }
.learn-card > summary::marker { display: none; content: ''; }
.learn-card > summary:hover { background: rgba(244,63,94,0.08); }
.learn-card > summary::after {
  content: '\25BE'; margin-left: auto;
  color: var(--text-dim); font-size: 0.78rem;
  transition: transform 0.2s;
}
.learn-card[open] > summary::after { transform: rotate(180deg); color: var(--accent); }

.lp-badge {
  display: inline-flex; align-items: center; justify-content: center;
  width: 22px; height: 22px; border-radius: 6px;
  background: rgba(244,63,94,0.18); font-size: 0.9rem; flex-shrink: 0;
  color: var(--accent);
}
.lp-sub { color: var(--text-dim); font-weight: 500; font-size: 0.78rem; }
.learn-body { padding: 12px 14px 14px; }
.learn-body .eq-line { padding: 6px 0; border-bottom: 1px dashed rgba(139,157,195,0.15); overflow-x: auto; }
.learn-body .eq-line:last-child { border-bottom: none; }
.learn-body .eq-label { font-size: 0.74rem; color: var(--text-dim); margin-bottom: 4px; }
.learn-body .coach-tip {
  padding: 8px 12px; margin: 6px 0;
  background: rgba(244,63,94,0.08); border-left: 3px solid var(--accent);
  border-radius: 6px; font-size: 0.82rem; color: var(--text); line-height: 1.55;
}
.learn-body .coach-tip strong { color: var(--accent); }

/* ═══ Context menu ═══════════════════════════════════════════════ */
.ctx-menu {
  display: none; position: fixed; z-index: 1100;
  background: var(--surface); border: 1px solid var(--border); border-radius: 8px;
  box-shadow: 0 12px 32px rgba(0,0,0,0.6);
  padding: 4px; min-width: 180px;
}
.ctx-menu.active { display: flex; flex-direction: column; }
.ctx-item {
  padding: 8px 12px; border: none; background: transparent;
  color: var(--text); text-align: left; font-size: 0.84rem;
  cursor: pointer; border-radius: 6px;
}
.ctx-item:hover { background: var(--surface2); color: var(--accent); }

/* ═══ Featured snippet table ═════════════════════════════════════ */
.snippet-table {
  width: 100%; border-collapse: collapse; margin: 14px 0;
  background: var(--surface); border: 1px solid var(--border);
  border-radius: 8px; overflow: hidden;
}
.snippet-table th, .snippet-table td {
  padding: 8px 12px; text-align: left;
  font-size: 0.84rem; border-bottom: 1px solid var(--border);
}
.snippet-table th {
  background: var(--surface2); color: var(--accent);
  font-weight: 700; text-transform: uppercase; letter-spacing: 0.04em; font-size: 0.74rem;
}
.snippet-table td:nth-child(2) { font-family: var(--mono); color: var(--text); }
.snippet-table tbody tr:last-child td { border-bottom: none; }
.snippet-table tbody tr:hover { background: rgba(244,63,94,0.05); }

@media (max-width: 540px) {
  .canvas-toolbar { flex-wrap: wrap; }
  .canvas-toolbar .ct-btn,
  .canvas-toolbar .ct-toggle { flex: 1 1 28%; font-size: 0.72rem; padding: 8px 6px; min-height: 40px; }
}
@media (max-width: 500px) {
  .stepper .step-input { width: 44px; font-size: 0.82rem; }
  .step-btn { width: 24px; height: 24px; }
  .step-unit { font-size: 0.7rem; min-width: 22px; padding-right: 4px; }
  .feature-toggles { gap: 8px 12px; }
  .feature-toggles .sim-toggle { font-size: 0.72rem; }
  /* Compact the collapsible display controls on the short mobile canvas */
  .canvas-toggles > summary { padding: 5px 8px; font-size: 0.6rem; gap: 5px; }
  .canvas-toggles .cvt-body { padding: 6px 9px 7px; gap: 4px; }
  .canvas-toggles .cvt-item { font-size: 0.64rem; gap: 5px; }
  .canvas-toggles .cvt-item input[type="checkbox"] { width: 12px; height: 12px; }
  /* Hide the first-time tip on mobile — it can't fit clear of the toggles on a short canvas; the User Guide covers it */
  .canvas-hint { display: none; }
  .calc-modal { padding: 12px 8px; }
  .calc-modal-box { max-height: calc(100vh - 24px); }
  .calc-modal-body { padding: 12px 12px; }
  .cs-step { padding: 10px; }
  .learn-panels { padding: 10px; }
  .learn-card > summary { padding: 10px 12px; font-size: 0.82rem; }
  .lp-sub { display: none; }
  .learn-body { padding: 10px 12px 12px; }
  .learn-head-title { font-size: 0.85rem; }
  .learn-toggle-all { padding: 4px 10px; font-size: 0.72rem; }
  .snippet-table th, .snippet-table td { padding: 6px 8px; font-size: 0.76rem; }
}

/* 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 */


/* Slider hit area: the input itself is 24px tall and the visible 6px bar is its
   runnable track, so no padding trick is needed here. */

/* ═══ Mobile: collapse the canvas display-controls to an icon-only chip ═══
   On a short phone canvas the full "DISPLAY CONTROLS" bar sits across the top
   of the simulation and hides it. Below 768px the summary shrinks to a square
   icon button so the canvas stays readable; the label and caret come back the
   moment the panel is opened, because at that point the user has deliberately
   chosen to cover the canvas. The 44px minimum keeps the tap target within the
   project's touch-size rule. */
@media (max-width: 768px) {
  .canvas-toggles > summary {
    padding: 0; gap: 0;
    min-width: 44px; min-height: 44px;
    justify-content: center;
  }
  .canvas-toggles > summary .cvt-title,
  .canvas-toggles > summary .cvt-caret { display: none; }
  .canvas-toggles .cvt-ico { width: 18px; height: 18px; }

  .canvas-toggles[open] > summary {
    padding: 7px 10px; gap: 7px;
    min-height: 0; justify-content: flex-start;
  }
  .canvas-toggles[open] > summary .cvt-title { display: inline; }
  .canvas-toggles[open] > summary .cvt-caret { display: inline; margin-left: auto; padding-left: 4px; }
}

/* SI/Imperial toggle — first row of the control panel (moved out of the mode bar) */
.unit-row { display: flex; align-items: center; justify-content: flex-end; gap: 10px; flex-wrap: wrap; margin: 10px 0 6px; }
.unit-row .ctrl-group { margin: 0; }
/* In Simulate the toggle sits in the canvas toolbar, right after Reset. */
.unit-row.in-toolbar { margin: 0; }
.in-toolbar .ctrl-label { display: none; }
@media (max-width: 500px) { .unit-row { justify-content: flex-start; } }

/* ═══════════════════════════════════════════════════════════════════
   CENTRIPETAL FORCE — layout and components
   Canvas first (projectile-motion pattern), a four-step guide and key-reading
   tiles (galvanic-cell pattern), and the situation's controls in a column that
   sits BESIDE the canvas on wide screens and under it otherwise.
   ═══════════════════════════════════════════════════════════════════ */
#app { max-width: 1280px; }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; border: 0; }
.pill:disabled { opacity: 0.38; cursor: not-allowed; }
.pill:focus-visible, .chip:focus-visible, .btn:focus-visible, .situ-pill:focus-visible, .situ-group:focus-visible { outline: 2px solid var(--gold); outline-offset: 2px; }
.anchor-offset { display: block; position: relative; top: -12px; visibility: hidden; }
@keyframes pulse-ring { 0% { box-shadow: 0 0 0 0 rgba(244,63,94,.65); } 100% { box-shadow: 0 0 0 14px rgba(244,63,94,0); } }
.pulse-ring { animation: pulse-ring 1.1s ease-out 1; }
#sec-simulate { display: flex; flex-direction: column; gap: 12px; }

/* ── 1. the four-step guide: a progress rail, not a wall of text ── */
.lab-steps {
  list-style: none; margin: 0; padding: 4px; display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 4px;
  background: var(--surface); border: 1px solid var(--border); border-radius: 14px;
}
.lab-steps li { min-width: 0; }
.lab-steps button {
  width: 100%; height: 100%; display: flex; align-items: center; gap: 10px; padding: 7px 10px; min-height: 42px;
  border: 1px solid transparent; border-radius: 10px; background: transparent; color: var(--text-dim);
  font: 600 0.82rem var(--font); text-align: left; cursor: pointer; transition: background .15s, color .15s, border-color .15s;
}
.lab-steps button:hover { background: var(--surface2); color: var(--text); }
.ls-num { flex: 0 0 24px; height: 24px; border-radius: 50%; display: grid; place-items: center; font-size: 0.74rem; font-weight: 800; background: var(--surface2); color: var(--text-dim); border: 1px solid var(--border); }
.ls-txt { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.lab-steps button.current { background: rgba(244,63,94,.12); border-color: rgba(244,63,94,.45); color: var(--text); }
.lab-steps button.current .ls-num { background: var(--accent); border-color: var(--accent); color: #2a0710; box-shadow: 0 0 0 4px rgba(244,63,94,.18); }
.lab-steps button.done { color: var(--text); }
.lab-steps button.done .ls-num { background: rgba(61,220,132,.16); border-color: rgba(61,220,132,.5); color: var(--green); font-size: 0; }
.lab-steps button.done .ls-num::before { content: "\2713"; font-size: 0.8rem; }

/* ── 2. the workbench: canvas column + controls column ── */
.workbench { display: grid; grid-template-columns: minmax(0, 1fr); gap: 14px; align-items: start; }
@media (min-width: 1180px) {
  .workbench { grid-template-columns: minmax(0, 1fr) 340px; }
  .ctrl-col { position: sticky; top: 12px; max-height: calc(100vh - 24px); overflow-y: auto; overscroll-behavior: contain; scrollbar-width: thin; }
}
.bench-col { display: flex; flex-direction: column; gap: 10px; min-width: 0; }

/* the canvas card: picker on top, picture, toolbar docked underneath */
.canvas-card { padding: 0; border-radius: 16px; overflow: clip; box-shadow: 0 10px 30px rgba(0,0,0,.25); }
.canvas-stage { position: relative; padding: 8px 8px 0; }
.canvas-card canvas { cursor: default; touch-action: manipulation; border-radius: 10px; }

.situ-bar {
  display: flex; flex-direction: column; gap: 9px; padding: 10px 12px;
  background: linear-gradient(180deg, rgba(244,63,94,.09), rgba(244,63,94,0) 85%);
  border-bottom: 1px solid rgba(139,157,195,.16);
}
.situ-groups {
  display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 4px; width: 100%;
  background: var(--bg); border: 1px solid var(--border); padding: 4px; border-radius: 12px;
}
.situ-group {
  display: flex; align-items: center; justify-content: center; gap: 8px; min-width: 0;
  border: 1px solid transparent; background: transparent; color: var(--text-dim); font: 700 0.82rem var(--font); letter-spacing: .01em;
  padding: 8px 12px; border-radius: 9px; cursor: pointer; transition: background .15s, color .15s, border-color .15s;
}
.situ-group svg { width: 20px; height: 20px; flex: none; }
.sg-name { white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.sg-n { flex: none; min-width: 20px; height: 20px; padding: 0 6px; border-radius: 999px; display: inline-grid; place-items: center;
  font: 800 0.68rem var(--font); color: var(--text-dim); background: rgba(139,157,195,.14); }
.situ-group:hover { color: var(--text); background: rgba(139,157,195,.07); }
.situ-group.active { background: var(--surface2); color: #fff; border-color: rgba(244,63,94,.45); box-shadow: inset 0 -2px 0 var(--accent); }
.situ-group.active svg { color: var(--accent); }
.situ-group.active .sg-n { background: var(--accent); color: #1a0d12; }
/* situation tiles stretch to fill the row, however many the group holds */
.situ-pills { display: flex; gap: 8px; }
.situ-pills .situ-pill { flex: 1 1 0; }
.situ-pill {
  display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 6px; min-width: 0; min-height: 54px; padding: 10px 8px 9px; text-align: center;
  border-radius: 12px; border: 1px solid var(--border); background: var(--surface2); color: var(--text-dim);
  font: 600 0.84rem var(--font); cursor: pointer; transition: border-color .15s, color .15s, background .15s, transform .1s;
}
.sp-ico { flex: none; width: 36px; height: 36px; border-radius: 10px; display: grid; place-items: center;
  background: rgba(139,157,195,.10); border: 1px solid rgba(139,157,195,.18); transition: background .15s, color .15s; }
.sp-ico svg { width: 21px; height: 21px; }
.sp-txt { display: flex; flex-direction: column; align-items: center; gap: 2px; min-width: 0; }
.sp-name, .sp-hint { overflow-wrap: anywhere; }
.sp-name { font-weight: 700; color: inherit; line-height: 1.2; }
.sp-hint { font: 600 0.7rem var(--font); color: var(--text-dim); opacity: .85; line-height: 1.25; }
.situ-pill:hover { border-color: rgba(244,63,94,.55); color: var(--text); }
.situ-pill:hover .sp-ico { color: var(--accent); }
.situ-pill:active { transform: translateY(1px); }
.situ-pill.active { border-color: var(--accent); background: linear-gradient(180deg, rgba(244,63,94,.20), rgba(244,63,94,.08)); color: #fff; }
.situ-pill.active .sp-ico { background: var(--accent); border-color: var(--accent); color: #1a0d12; }
.situ-pill.active .sp-hint { color: #ffd0d8; opacity: 1; }
.situ-pill[hidden] { display: none; }

/* toolbar: projectile-motion's chips, with ONE primary action */
.canvas-toolbar { margin: 8px; flex-wrap: wrap; align-items: center; gap: 6px; padding: 7px; }
.canvas-toolbar .ct-btn { flex: 0 0 auto; padding: 8px 11px; }
.canvas-toolbar { gap: 5px; }
.canvas-toolbar .ct-btn-fire {
  flex: 1 1 108px; font-size: 0.86rem; padding: 9px 12px;
  background: linear-gradient(180deg, #f43f5e, #be123c); border-color: rgba(255,255,255,.18); color: #fff; font-weight: 800;
  box-shadow: 0 6px 18px rgba(225,29,72,.28);
}
.canvas-toolbar .ct-btn-fire:hover:not(:disabled) { filter: brightness(1.08); background: linear-gradient(180deg, #fda4af, #f43f5e); color: #fff; border-color: rgba(255,255,255,.3); }
.canvas-toolbar .ct-frame {
  flex: 0 0 auto; display: inline-flex; align-items: center; gap: 8px; padding: 8px 12px; cursor: pointer;
  background: var(--surface2); border: 1px solid rgba(139,157,195,.22); border-radius: 6px; color: var(--text-dim); font: 600 0.75rem var(--font);
}
.ct-frame .sw { width: 30px; height: 16px; border-radius: 999px; background: var(--bg); border: 1px solid var(--border); position: relative; flex: none; transition: background .15s, border-color .15s; }
.ct-frame .sw::after { content: ""; position: absolute; top: 2px; left: 2px; width: 10px; height: 10px; border-radius: 50%; background: #6b7a99; transition: transform .18s, background .15s; }
.ct-frame[aria-pressed="true"] { color: #ffd2c4; border-color: rgba(255,112,67,.6); background: rgba(255,112,67,.12); }
.ct-frame[aria-pressed="true"] .sw { background: rgba(255,112,67,.25); border-color: #ff7043; }
.ct-frame[aria-pressed="true"] .sw::after { transform: translateX(14px); background: #ff7043; }
.ct-frame:disabled { opacity: .45; cursor: not-allowed; }
.ct-frame:focus-visible { outline: 2px solid var(--gold); outline-offset: 1px; }
.ct-speed { display: inline-flex; }
/* the SI/Imperial switch lives in the toolbar right after Reset (moved out
   in Explore/Practice/Quiz, where the toolbar is hidden) */
.canvas-toolbar .unit-row { flex: 0 0 auto; }
.canvas-toolbar .unit-row .pill-tabs { min-height: 34px; }
.canvas-toolbar .unit-row .pill { padding: 6px 10px; font-size: 0.75rem; }
.speed-sel { min-height: 34px; padding: 5px 8px; border-radius: 6px; border: 1px solid rgba(139,157,195,.3); background: var(--surface2); color: var(--text); font: 600 0.75rem var(--font); }
.ct-more { position: relative; }
.ct-more > summary { list-style: none; }
.ct-more > summary::-webkit-details-marker { display: none; }
.act-menu {
  position: absolute; right: 0; bottom: calc(100% + 6px); z-index: 20; min-width: 210px; padding: 4px;
  display: flex; flex-direction: column; background: var(--surface); border: 1px solid var(--border); border-radius: 10px;
  box-shadow: 0 14px 34px rgba(0,0,0,.5);
}
.act-menu button { text-align: left; padding: 9px 12px; border: 0; background: transparent; color: var(--text); border-radius: 7px; font: 600 0.82rem var(--font); cursor: pointer; }
.act-menu button:hover { background: var(--surface2); color: var(--accent); }

/* status: one sentence that says what is happening, coloured by verdict */
.sim-status {
  margin: 0; padding: 10px 14px 10px 40px; position: relative; border-radius: 12px; background: var(--surface);
  border: 1px solid var(--border); font-size: 0.86rem; line-height: 1.45; color: var(--text); min-height: 1.4em;
}
.sim-status::before { content: "i"; position: absolute; left: 12px; top: 10px; width: 18px; height: 18px; border-radius: 50%; display: grid; place-items: center; font: 800 0.72rem var(--font); background: var(--surface2); color: var(--text-dim); }
.sim-status.ok { border-color: rgba(61,220,132,.35); }
.sim-status.ok::before { content: "\2713"; background: rgba(61,220,132,.18); color: var(--green); }
.sim-status.warn { border-color: rgba(245,200,66,.4); }
.sim-status.warn::before { content: "!"; background: rgba(245,200,66,.18); color: var(--gold); }
.sim-status.bad { border-color: rgba(255,85,85,.45); background: rgba(255,85,85,.06); }
.sim-status.bad::before { content: "!"; background: rgba(255,85,85,.2); color: var(--red); }

/* key readings: the situation's headline number is a full-width hero bar,
   the other five sit in one row beneath it */
.kpi-strip { display: grid; grid-template-columns: repeat(5, minmax(0, 1fr)); gap: 8px; }
.kpi { background: var(--surface); border: 1px solid var(--border); border-radius: 12px; padding: 9px 12px; display: flex; flex-direction: column; gap: 3px; min-width: 0; }
.kpi-l { font-size: 0.66rem; letter-spacing: .06em; text-transform: uppercase; color: var(--text-dim); font-weight: 700; line-height: 1.25; }
.kpi-v { font: 700 0.98rem var(--mono); color: var(--text); overflow-wrap: anywhere; }
.kpi.hero {
  grid-column: 1 / -1; flex-direction: row; align-items: center; justify-content: space-between; gap: 12px; padding: 11px 16px;
  background: linear-gradient(100deg, rgba(244,63,94,.18), rgba(244,63,94,.04) 70%); border-color: rgba(244,63,94,.5);
}
.kpi.hero .kpi-l { font-size: 0.74rem; color: #fecdd3; }
.kpi.hero .kpi-v { font-size: 1.5rem; color: #fff; text-shadow: 0 0 18px rgba(244,63,94,.45); text-align: right; }
.kpi.live .kpi-l::after { content: " \25CF live"; color: var(--green); letter-spacing: 0; text-transform: none; font-weight: 600; }
.kpi.warn { border-color: rgba(255,85,85,.55); background: rgba(255,85,85,.07); }
.kpi.warn .kpi-v { color: var(--red); }
.kpi.hero.warn { background: linear-gradient(100deg, rgba(255,85,85,.2), rgba(255,85,85,.04) 70%); }
@media (max-width: 860px) { .kpi-strip { grid-template-columns: repeat(3, minmax(0, 1fr)); } }

/* ── 3. the controls column ── */
.ctrl-col { background: var(--surface); border: 1px solid var(--border); border-radius: 16px; padding: 14px; display: flex; flex-direction: column; gap: 12px; }
.situ-now { display: flex; gap: 12px; align-items: flex-start; padding-bottom: 12px; border-bottom: 1px solid rgba(139,157,195,.16); }
.situ-now-ico { flex: 0 0 42px; height: 42px; border-radius: 12px; display: grid; place-items: center; color: var(--accent); background: rgba(244,63,94,.12); border: 1px solid rgba(244,63,94,.35); }
.situ-now-ico svg { width: 26px; height: 26px; }
.situ-now-txt { min-width: 0; }
.scen-title { display: block; font-size: 1rem; font-weight: 800; color: var(--text); margin-bottom: 3px; }
.sp-note { margin: 0; font-size: 0.8rem; line-height: 1.5; color: var(--text-dim); }
.param-set { display: flex; flex-direction: column; gap: 10px; }
.ctl { background: var(--bg); border: 1px solid var(--border); border-radius: 12px; padding: 10px 12px; display: flex; flex-direction: column; gap: 4px; transition: border-color .15s; }
.ctl:focus-within { border-color: rgba(244,63,94,.5); }
.ctl-head { display: flex; align-items: center; justify-content: space-between; gap: 8px; }
.ctl-name { font-size: 0.84rem; font-weight: 700; color: var(--text); }
.ctl .sim-slider { width: 100%; margin: 4px 0 0; }
.ctl-hint { margin: 0; font-size: 0.74rem; line-height: 1.4; color: var(--text-dim); }
.param-select { width: 100%; padding: 8px 10px; border-radius: 8px; border: 1px solid var(--border); background: var(--surface2); color: var(--text); font-size: 0.84rem; margin-top: 4px; }
.ctl .stepper { padding: 2px; }
.ctl .step-input { width: 64px; }
.step-unit { min-width: 34px; }
.sim-slider { height: 24px; background: transparent; border: none; }
.sim-slider::-webkit-slider-runnable-track { height: 6px; border-radius: 3px; border: 1px solid rgba(255,255,255,.1);
  background: linear-gradient(to right, var(--accent) 0, var(--accent) var(--pct, 0%), rgba(255,255,255,.12) var(--pct, 0%)); }
.sim-slider::-webkit-slider-thumb { margin-top: -7px; border: 2px solid rgba(255,255,255,.25); }
.sim-slider::-moz-range-track { height: 6px; border-radius: 3px; background: rgba(255,255,255,.12); border: 1px solid rgba(255,255,255,.1); }
.sim-slider::-moz-range-progress { height: 6px; border-radius: 3px; background: var(--accent); }
.chip-row { display: flex; align-items: center; gap: 6px; flex-wrap: wrap; margin-top: 4px; }
.chip-lbl { font-size: 0.66rem; text-transform: uppercase; letter-spacing: .06em; color: var(--text-dim); font-weight: 700; margin-right: 2px; }
.chip { padding: 4px 10px; border-radius: 16px; border: 1px solid var(--border); background: var(--surface2); color: var(--text-dim); font-size: 0.75rem; font-weight: 700; cursor: pointer; }
.chip em { font-style: normal; color: var(--accent); font-family: var(--mono); margin-left: 2px; }
.chip:hover { border-color: var(--accent); color: var(--text); }
.chip.active { border-color: var(--accent); color: #fff; background: rgba(244,63,94,.16); }
.try-this {
  font-size: 0.8rem; line-height: 1.55; color: var(--text); padding: 10px 12px; border-radius: 12px;
  background: rgba(245,200,66,.07); border: 1px dashed rgba(245,200,66,.45);
}
.try-this:empty { display: none; }
.try-k { display: inline-block; font-size: 0.66rem; font-weight: 800; letter-spacing: .07em; text-transform: uppercase; color: #1a1a2e; background: var(--gold); border-radius: 5px; padding: 1px 6px; margin-right: 4px; }
.try-this strong { color: var(--gold); }

/* stacked layout (below 1180): the controls sit in two columns under the canvas */
@media (min-width: 700px) and (max-width: 1179px) {
  .param-set { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

/* learning panels */
#lp-graph canvas { display: block; width: 100%; border-radius: 8px; }

/* ── Calculator card (the page's first answer) ── */
.calc-card {
  background: linear-gradient(180deg, rgba(244,63,94,0.08), rgba(22,27,39,0.9) 60%);
  border: 1px solid rgba(244,63,94,0.35); border-radius: var(--radius); padding: 14px 16px 16px;
}
.cc-head { display: flex; align-items: baseline; gap: 12px; flex-wrap: wrap; margin-bottom: 10px; }
.cc-title { font-size: 1.05rem; font-weight: 800; color: var(--text); margin: 0; }
.cc-sub { font-size: 0.8rem; color: var(--text-dim); }
.cc-solve-row { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; margin-bottom: 12px; }
.cc-grid { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 10px; }
.cc-field { display: flex; flex-direction: column; gap: 5px; background: var(--bg); border: 1px solid var(--border); border-radius: 10px; padding: 8px 10px; min-width: 0; }
.cc-field.solved { border-color: var(--accent); box-shadow: 0 0 0 1px var(--accent-lo) inset; background: rgba(244,63,94,0.08); }
.cc-lbl { font-size: 0.7rem; font-weight: 700; text-transform: uppercase; letter-spacing: .05em; color: var(--text-dim); display: flex; justify-content: space-between; gap: 6px; }
.cc-field.solved .cc-lbl::after { content: 'answer'; color: var(--accent); }
.cc-in-row { display: flex; align-items: center; gap: 6px; min-width: 0; }
.cc-in-row input {
  flex: 1; min-width: 0; width: 100%; padding: 7px 8px; border: 1px solid var(--border); border-radius: 7px;
  background: #0b0f17; color: var(--text); font-family: var(--mono); font-size: 0.95rem; font-weight: 700;
}
.cc-in-row input:focus { outline: none; border-color: var(--accent); }
.cc-in-row input[readonly] { background: transparent; border-color: transparent; color: var(--accent); }
.cc-unit { font-size: 0.78rem; color: var(--text-dim); font-weight: 600; white-space: nowrap; }
.cc-motion-sel { width: 100%; padding: 4px 6px; border-radius: 6px; border: 1px solid var(--border); background: var(--surface2); color: var(--text); font-size: 0.78rem; }
.cc-result { margin-top: 12px; }
.cc-main { display: flex; align-items: baseline; gap: 12px; flex-wrap: wrap; }
.cc-main-l { font-size: 0.82rem; color: var(--text-dim); font-weight: 700; }
.cc-main-v { font-family: var(--mono); font-size: 1.6rem; font-weight: 800; color: var(--accent); text-shadow: 0 0 14px var(--accent-lo); }
.cc-chips { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 8px; }
.cc-chips span { font-size: 0.76rem; color: var(--text-dim); background: var(--surface2); border: 1px solid var(--border); border-radius: 20px; padding: 3px 10px; }
.cc-chips b { color: var(--text); font-family: var(--mono); }
.cc-err { color: var(--gold); font-size: 0.85rem; font-weight: 600; }
.cc-steps { margin-top: 10px; }
.cc-steps .eq-line { padding: 6px 0; border-bottom: 1px dashed rgba(139,157,195,0.15); overflow-x: auto; }
.cc-note { font-size: 0.74rem; color: var(--text-dim); margin-top: 6px; }
.cc-foot { display: flex; align-items: center; gap: 12px; flex-wrap: wrap; margin-top: 10px; }
.cc-foot small { color: var(--text-dim); font-size: 0.75rem; }

/* ── Data Lab ── */
.lab-bar { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; margin-bottom: 10px; }
.lab-bar select { padding: 6px 8px; border-radius: 7px; border: 1px solid var(--border); background: var(--surface2); color: var(--text); font-size: 0.8rem; }
.lab-intro { font-size: 0.82rem; color: var(--text-dim); line-height: 1.55; margin-bottom: 10px; }
.lab-tbl { width: 100%; border-collapse: collapse; font-size: 0.78rem; margin-bottom: 10px; }
.lab-tbl th, .lab-tbl td { padding: 5px 8px; border-bottom: 1px solid var(--border); text-align: right; white-space: nowrap; }
.lab-tbl th:nth-child(2), .lab-tbl td:nth-child(2) { text-align: left; }
.lab-tbl th { color: var(--accent); font-size: 0.68rem; text-transform: uppercase; letter-spacing: .05em; }
.lab-tbl td { font-family: var(--mono); color: var(--text); }
.lab-empty { text-align: center !important; color: var(--text-dim) !important; font-family: var(--font) !important; white-space: normal !important; }
.lab-table-wrap { overflow-x: auto; max-height: 220px; overflow-y: auto; }
.lab-fit { font-size: 0.82rem; color: var(--text); margin-top: 8px; line-height: 1.5; }
#lab-canvas { display: block; width: 100%; border-radius: 8px; margin-top: 8px; }

/* ── Quiz key letters ── */
.ab-key { display: inline-block; min-width: 20px; color: var(--accent); font-family: var(--mono); font-weight: 800; }
.answer-btn { text-align: left; }
.rec-count { display: inline-block; min-width: 20px; margin-left: 4px; padding: 0 6px; border-radius: 999px; background: rgba(0,0,0,.25); font-size: 0.74rem; text-align: center; }

/* ── responsive ── */
@media (max-width: 900px) {
  .cc-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (max-width: 720px) {
  .lab-steps { grid-template-columns: 1fr 1fr; }
  .canvas-toolbar { margin: 6px; }
  .canvas-toolbar .ct-btn-fire { flex: 1 1 100%; min-height: 44px; }
  .canvas-toolbar .ct-btn, .canvas-toolbar .ct-frame, .speed-sel { min-height: 44px; }
  .canvas-toolbar .ct-btn, .canvas-toolbar .ct-frame, .ct-speed, .ct-more { flex: 1 1 calc(33% - 6px); justify-content: center; }
  .ct-more > summary { width: 100%; justify-content: center; }
  .canvas-toolbar .ct-btn.ct-btn-fire { flex: 1 1 100%; }
  .canvas-toolbar .unit-row { flex: 1 1 calc(33% - 6px); }
  .canvas-toolbar .unit-row .ctrl-group, .canvas-toolbar .unit-row .pill-tabs { width: 100%; height: 100%; }
  .canvas-toolbar .unit-row .pill { flex: 1 1 0; min-height: 44px; padding: 6px 4px; }
  .canvas-toolbar .ct-frame, .canvas-toolbar .ct-speed, .canvas-toolbar .ct-btn-calc, .canvas-toolbar .ct-more { flex: 1 1 calc(50% - 4px); }
  .speed-sel { width: 100%; }
}
@media (max-width: 500px) {
  .cc-grid { grid-template-columns: 1fr 1fr; gap: 8px; }
  .cc-main-v { font-size: 1.3rem; }
  .lab-steps .ls-txt { font-size: 0.74rem; white-space: normal; }
  .kpi-strip { grid-template-columns: 1fr 1fr; }
  .kpi-v { font-size: 0.9rem; }
  .kpi.hero .kpi-v { font-size: 1.2rem; }
  .ctl .step-input { width: 54px; }
  .canvas-stage { padding: 6px 6px 0; }
  .situ-bar { padding: 8px; }
}
@media (pointer: coarse) {
  .chip, .situ-group { min-height: 40px; }
  .cc-in-row input { min-height: 40px; }
}
@media (max-width: 560px) {
  .situ-group { flex-direction: column; gap: 3px; padding: 7px 4px; font-size: 0.72rem; }
  .sg-name { white-space: normal; text-align: center; line-height: 1.15; }
  .sg-n { display: none; }
  .situ-pills { display: grid; grid-template-columns: 1fr 1fr; gap: 6px; }
  .situ-pill[data-scen="shield"], .situ-pill[data-scen="particles"] { grid-column: span 2; }   /* the odd last tile of its group fills the row */
  .situ-pill { flex-direction: row; justify-content: flex-start; text-align: left; min-height: 50px; padding: 6px 8px 6px 6px; gap: 8px; font-size: 0.78rem; }
  .sp-txt { align-items: flex-start; }
  .sp-name, .sp-hint { white-space: normal; }
  .sp-ico { width: 30px; height: 30px; border-radius: 8px; }
  .sp-ico svg { width: 18px; height: 18px; }
  .sp-hint { font-size: 0.64rem; }
}

/* ═══ Magnetic Playground additions ═══════════════════════════════ */
header h1 { font-size: 1.7rem; }
.canvas-card canvas:focus-visible { outline: 2px solid var(--gold); outline-offset: 2px; }
/* station tools: small buttons above the controls */
.tool-row { display: flex; flex-wrap: wrap; gap: 6px; padding: 10px 0 2px; }
.tool-row[hidden] { display: none; }
.tool-btn {
  padding: 7px 11px; min-height: 34px; border-radius: 8px; border: 1px solid var(--border);
  background: var(--surface2); color: var(--text); font-size: 0.78rem; font-weight: 700; cursor: pointer;
  transition: border-color .15s, background .15s, color .15s;
}
.tool-btn:hover:not(:disabled) { border-color: var(--accent); background: var(--accent-lo); }
.tool-btn:active:not(:disabled) { background: var(--accent); color: #fff; }
.tool-btn:disabled { opacity: .4; cursor: not-allowed; }
.tool-btn:focus-visible { outline: 2px solid var(--gold); outline-offset: 2px; }
#param-rows .param-set { display: flex; flex-direction: column; gap: 8px; margin-top: 10px; }
.ctl[hidden] { display: none; }
.ctl-check { padding: 9px 12px; }
.chk { display: flex; align-items: flex-start; gap: 8px; font-size: 0.84rem; font-weight: 700; color: var(--text); cursor: pointer; line-height: 1.35; }
.chk input { accent-color: var(--accent); width: 18px; height: 18px; flex: 0 0 18px; margin-top: 1px; cursor: pointer; }
.ctl-val { font: 700 0.85rem var(--mono); color: var(--accent); white-space: nowrap; }
.sim-slider { height: 24px; background: transparent; }
.sim-slider::-webkit-slider-runnable-track { height: 6px; border-radius: 3px; background: linear-gradient(to right, var(--accent-lo) var(--pct, 50%), rgba(255,255,255,.12) var(--pct, 50%)); border: 1px solid rgba(255,255,255,.1); }
.sim-slider::-webkit-slider-thumb { margin-top: -7px; border: 2px solid rgba(255,255,255,.2); }
.sim-slider::-moz-range-track { height: 6px; border-radius: 3px; background: linear-gradient(to right, var(--accent-lo) var(--pct, 50%), rgba(255,255,255,.12) var(--pct, 50%)); border: none; }
/* grade-band badges */
.lvl-tag, .lvl-badge { display: inline-block; font-size: 0.66rem; font-weight: 800; letter-spacing: .04em; text-transform: uppercase; padding: 2px 8px; border-radius: 999px; vertical-align: middle; }
.lvl-tag { background: rgba(96,165,250,.14); color: #93c5fd; border: 1px solid rgba(96,165,250,.35); }
.lvl-badge.lvl-k5, .lvl-dot.lvl-k5 { background: rgba(61,220,132,.15); color: #6ee7a5; border: 1px solid rgba(61,220,132,.4); }
.lvl-badge.lvl-m8, .lvl-dot.lvl-m8 { background: rgba(245,200,66,.14); color: #fcd34d; border: 1px solid rgba(245,200,66,.4); }
.lvl-badge.lvl-h12, .lvl-dot.lvl-h12 { background: rgba(244,63,94,.14); color: #fda4af; border: 1px solid rgba(244,63,94,.4); }
.is-btn { position: relative; }
.lvl-dot { position: absolute; top: 7px; right: 7px; width: 9px; height: 9px; border-radius: 50%; padding: 0; }
.ii-top { flex-wrap: wrap; gap: 8px; }
#ex-go { margin-top: 12px; }
/* "the idea" cards under the canvas */
.read-card { padding: 10px 12px; border-radius: 10px; background: var(--bg); border: 1px solid var(--border); margin-bottom: 8px; }
.read-card:last-child { margin-bottom: 0; }
.rc-head { display: flex; align-items: center; justify-content: space-between; gap: 8px; margin-bottom: 6px; color: var(--text); font-size: 0.9rem; }
.rc-body { font-size: 0.84rem; line-height: 1.6; color: var(--text-dim); }
.rc-body strong { color: var(--text); }
.rc-formula { margin-top: 8px; font-family: var(--mono); font-size: 0.85rem; color: var(--accent); background: rgba(244,63,94,.07); border-left: 3px solid var(--accent); padding: 6px 10px; border-radius: 6px; }
/* practice: choice answers above the number box */
#pp-choices { margin: 10px 0; }
#pp-choices:empty { display: none; }
.pp-bottom { display: flex; align-items: center; gap: 12px; flex-wrap: wrap; }
#sec-practice, #sec-quiz, #sec-explore { display: flex; flex-direction: column; gap: 14px; }
.practice-bar { display: flex; align-items: center; flex-wrap: wrap; gap: 12px; }
.practice-panel .ctl-hint { margin-top: 10px; }
.canvas-hint { position: absolute; left: 50%; bottom: 12px; transform: translateX(-50%); max-width: min(520px, calc(100% - 24px)); }
@media (max-width: 768px) {
  header h1 { font-size: 1.35rem; }
  .tool-btn { min-height: 40px; }
}
@media (max-width: 500px) {
  header h1 { font-size: 1.2rem; }
  .tool-row { gap: 5px; }
  .tool-btn { flex: 1 1 calc(50% - 5px); }
}
#btn-action[hidden] { display: none !important; }

/* ═══ Magnet sandbox (2026-10-10) ═══════════════════════════════
   The tray sits inside the canvas card on its left edge; the bench is
   drawn to its right. Everything sandbox-only hangs off .sb-on. */
.view-row { display: flex; align-items: center; justify-content: space-between; gap: 10px; flex-wrap: wrap; }
.view-switch, .lvl-switch { display: flex; align-items: center; gap: 4px; background: var(--bg); border: 1px solid var(--border); border-radius: 10px; padding: 3px; }
.view-tab, .lvl-tab { border: 0; background: transparent; color: var(--text-dim); font: 700 0.82rem var(--font); padding: 7px 13px; border-radius: 8px; cursor: pointer; min-height: 34px; }
.view-tab:hover, .lvl-tab:hover { color: var(--text); background: var(--surface2); }
.view-tab.active { background: var(--accent); color: #fff; box-shadow: 0 0 12px var(--accent-lo); }
.lvl-tab.active { background: var(--surface2); color: #fff; box-shadow: inset 0 -2px 0 var(--accent); }
.lvl-label { font-size: 0.68rem; text-transform: uppercase; letter-spacing: .06em; color: var(--text-dim); padding: 0 6px; font-weight: 700; }
.view-tab:focus-visible, .lvl-tab:focus-visible, .sb-tab:focus-visible, .sb-tile:focus-visible, .sbq:focus-visible, .sbp-mbtn:focus-visible { outline: 2px solid var(--gold); outline-offset: 1px; }
.situ-pills[hidden] { display: none; }

.sb-tray, .sb-quick { display: none; }
.sb-on .sb-tray { display: flex; flex-direction: column; position: absolute; left: 12px; top: 12px; bottom: 6px; width: 100px; z-index: 3;
  background: rgba(13,17,30,0.9); border: 1px solid rgba(139,157,195,0.22); border-radius: 10px; overflow: hidden; }
.sb-tabs { display: grid; grid-template-columns: 1fr 1fr; gap: 2px; padding: 4px; border-bottom: 1px solid rgba(139,157,195,0.18); }
.sb-tab { display: flex; flex-direction: column; align-items: center; gap: 1px; border: 0; border-radius: 6px; background: transparent; color: var(--text-dim); font: 700 0.58rem var(--font); padding: 4px 1px; cursor: pointer; min-width: 0; }
.sb-tab span { max-width: 100%; overflow: hidden; text-overflow: clip; white-space: nowrap; }
.sb-tab svg { width: 16px; height: 16px; }
.sb-tab:hover { color: var(--text); background: var(--surface2); }
.sb-tab.active { color: #fff; background: rgba(244,63,94,0.22); box-shadow: inset 0 -2px 0 var(--accent); }
.sb-tiles { flex: 1; overflow-y: auto; overscroll-behavior: contain; scrollbar-width: thin; display: flex; flex-direction: column; gap: 4px; padding: 5px; }
.sb-tile { display: flex; flex-direction: column; align-items: center; gap: 1px; border: 1px solid rgba(139,157,195,0.18); border-radius: 8px; background: rgba(30,36,52,0.75); color: var(--text-dim); padding: 3px 2px 4px; cursor: grab; touch-action: none; }
.sb-tile:hover { border-color: rgba(244,63,94,0.55); color: var(--text); background: rgba(40,46,64,0.9); }
.sb-tile:active { cursor: grabbing; }
.sb-tile-ico { width: 64px; height: 44px; pointer-events: none; }
.sb-tile-lbl { font: 600 0.62rem var(--font); line-height: 1.15; text-align: center; pointer-events: none; }
.sb-on .canvas-toggles { left: 120px; }
.sb-on .sb-quick { display: flex; position: absolute; top: 12px; right: 14px; z-index: 4; gap: 4px; }
.sbq { width: 34px; height: 34px; border-radius: 8px; border: 1px solid rgba(139,157,195,0.25); background: rgba(13,17,30,0.82); color: var(--text); font-size: 1rem; cursor: pointer; display: grid; place-items: center; }
.sbq:hover { border-color: var(--accent); color: #fff; }
.sb-on .canvas-card canvas { touch-action: pan-y; }

.sb-panel { display: none; flex-direction: column; gap: 12px; }
.sb-on .sb-panel { display: flex; }
.sb-on .situ-now, .sb-on #tool-row, .sb-on #param-rows, .sb-on #try-this { display: none; }
.sbp-sec { display: flex; flex-direction: column; gap: 8px; padding-bottom: 12px; border-bottom: 1px solid rgba(139,157,195,.16); }
.sbp-sec:last-child { border-bottom: 0; padding-bottom: 0; }
.sbp-h { font-size: 0.95rem; font-weight: 800; color: var(--text); display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.sbp-badge { font: 700 0.7rem var(--mono); color: var(--gold); background: rgba(245,200,66,.12); border: 1px solid rgba(245,200,66,.35); border-radius: 999px; padding: 1px 8px; }
.sbp-top { display: flex; gap: 10px; align-items: center; }
.sbp-ico { width: 64px; height: 44px; flex: none; background: #1d2129; border-radius: 8px; border: 1px solid var(--border); }
.sbp-name { font-weight: 800; color: var(--text); font-size: 0.95rem; }
.sbp-sub { font-size: 0.78rem; color: var(--text-dim); line-height: 1.45; margin-top: 2px; }
.sbp-btns { display: flex; flex-wrap: wrap; gap: 5px; }
.sbp-btns .tool-btn { flex: 0 0 auto; }
.sbp-yes { color: var(--green); font-weight: 700; } .sbp-no { color: #ffa4a4; font-weight: 700; }
.sbp-n { color: #ff8a8d; } .sbp-s { color: #8db8ff; }
.sbp-lvl { font-size: 0.66rem; text-transform: uppercase; letter-spacing: .06em; color: var(--text-dim); font-weight: 700; margin-top: 4px; }
.sbp-mlist { display: flex; flex-direction: column; gap: 4px; }
.sbp-mbtn { display: flex; justify-content: space-between; align-items: center; gap: 8px; text-align: left; border: 1px solid var(--border); background: var(--bg); color: var(--text); border-radius: 8px; padding: 8px 10px; font: 600 0.8rem var(--font); cursor: pointer; min-height: 36px; }
.sbp-mbtn:hover { border-color: rgba(244,63,94,.55); background: rgba(244,63,94,.07); }
.sbp-mbtn.done { border-color: rgba(61,220,132,.35); }
.sbp-stars { color: var(--gold); letter-spacing: 1px; white-space: nowrap; }
.sbp-stars i { color: rgba(139,157,195,.35); font-style: normal; }
.sbp-reset { align-self: flex-start; margin-top: 4px; }
.sbp-mission { background: rgba(244,63,94,.06); border: 1px solid rgba(244,63,94,.35); border-radius: 12px; padding: 12px; }
.sbp-mission.done { background: rgba(61,220,132,.07); border-color: rgba(61,220,132,.45); }
.sbp-goal { font-size: 0.86rem; color: var(--text); line-height: 1.5; margin: 0; }
.sbp-hint { font-size: 0.8rem; color: var(--text-dim); margin: 0; line-height: 1.5; }
.sbp-win { font-weight: 800; color: var(--green); margin: 0; }
.sbp-why { font-size: 0.82rem; color: var(--text); margin: 0; line-height: 1.5; }
.sb-panel kbd { font: 700 0.7rem var(--mono); background: var(--bg); border: 1px solid var(--border); border-radius: 4px; padding: 0 4px; }

@media (max-width: 1024px) {
  .sb-on .sb-tray { width: 64px; }
  .sb-tab span, .sb-tile-lbl { display: none; }
  .sb-tabs { grid-template-columns: 1fr; }
  .sb-tab { min-height: 32px; justify-content: center; }
  .sb-tile-ico { width: 52px; height: 36px; }
  .sb-on .canvas-toggles { left: 84px; }
}
@media (pointer: coarse) {
  .sbq { width: 44px; height: 44px; }
  .sb-tab { min-height: 40px; }
  .sb-tile { min-height: 44px; }
  .view-tab, .lvl-tab { min-height: 44px; }
}
@media (max-width: 560px) {
  .view-tab, .lvl-tab { padding: 6px 9px; font-size: 0.76rem; }
  .lvl-label { display: none; }
}