/* ===================================================
   QuantumLab Beginner — dark futuristic theme
   =================================================== */

:root{
  --bg:#0a0e1a;
  --bg-2:#070a13;
  --surface:#141b2d;
  --surface-2:#1b2238;
  --border:#262e47;
  --accent:#7c3aed;
  --accent-2:#06b6d4;
  --accent-3:#ec4899;
  --text:#e6e8ef;
  --muted:#8b93a7;
  --success:#10b981;
  --danger:#ef4444;
  --warn:#f59e0b;
  --grad:linear-gradient(135deg,#7c3aed 0%,#06b6d4 100%);
  --grad-2:linear-gradient(135deg,#ec4899 0%,#7c3aed 100%);
  --shadow:0 10px 30px rgba(0,0,0,.45);
  --radius:14px;
}

*{box-sizing:border-box}
html,body{margin:0;padding:0}
body{
  font-family:'Inter',system-ui,-apple-system,Segoe UI,Roboto,sans-serif;
  background:
    radial-gradient(1200px 600px at 80% -10%,rgba(124,58,237,.18),transparent 60%),
    radial-gradient(1000px 500px at -10% 30%,rgba(6,182,212,.14),transparent 60%),
    var(--bg);
  color:var(--text);
  line-height:1.55;
  min-height:100vh;
}

a{color:var(--accent-2);text-decoration:none}
h1,h2,h3,h4{margin:0 0 .5em;letter-spacing:-.01em}
p{margin:.4em 0}
.muted{color:var(--muted);font-size:.92rem}

/* ===================== HERO ===================== */
.hero{
  position:sticky;top:0;z-index:50;
  background:rgba(10,14,26,.85);
  backdrop-filter:blur(12px);
  border-bottom:1px solid var(--border);
}
.hero-inner{
  max-width:1400px;margin:0 auto;
  display:flex;align-items:center;gap:24px;
  padding:14px 24px;
}
.logo{display:flex;align-items:center;gap:14px;flex:1;min-width:0}
.logo h1{font-size:1.25rem;background:var(--grad);-webkit-background-clip:text;background-clip:text;color:transparent}
.tagline{margin:0;font-size:.85rem;color:var(--muted)}
.logo-orb{
  width:42px;height:42px;border-radius:50%;
  background:var(--grad);
  box-shadow:0 0 24px rgba(124,58,237,.6),inset 0 0 18px rgba(255,255,255,.18);
  animation:orbPulse 4s ease-in-out infinite;
  flex-shrink:0;
}
@keyframes orbPulse{50%{box-shadow:0 0 36px rgba(6,182,212,.7),inset 0 0 18px rgba(255,255,255,.25)}}

.overall-progress{flex:1;max-width:320px}
.progress-label{display:flex;justify-content:space-between;font-size:.8rem;color:var(--muted);margin-bottom:6px}
.progress-track{height:8px;background:var(--surface-2);border-radius:99px;overflow:hidden;border:1px solid var(--border)}
.progress-fill{height:100%;width:0%;background:var(--grad);transition:width .6s ease;border-radius:99px}

#menu-toggle{
  display:none;background:transparent;border:1px solid var(--border);color:var(--text);
  font-size:1.4rem;width:42px;height:42px;border-radius:10px;cursor:pointer
}

/* ===================== LAYOUT ===================== */
.layout{
  max-width:1400px;margin:0 auto;
  display:grid;
  grid-template-columns:240px 1fr 280px;
  gap:24px;padding:24px;
}

.sidebar{
  position:sticky;top:88px;align-self:start;
  background:var(--surface);border:1px solid var(--border);
  border-radius:var(--radius);padding:18px;
  max-height:calc(100vh - 110px);overflow:auto;
}
.sidebar h2{font-size:.78rem;text-transform:uppercase;color:var(--muted);letter-spacing:.12em;margin-top:14px}
.sidebar h2:first-child{margin-top:0}
.nav-list{list-style:none;padding:0;margin:0 0 8px}
.nav-list a{
  display:flex;align-items:center;justify-content:space-between;
  padding:9px 12px;margin:4px 0;border-radius:9px;
  color:var(--text);font-size:.92rem;
  transition:background .2s,transform .2s;
}
.nav-list a:hover{background:var(--surface-2);transform:translateX(2px)}
.nav-list a.active{background:linear-gradient(135deg,rgba(124,58,237,.25),rgba(6,182,212,.18));border:1px solid rgba(124,58,237,.4)}
.nav-list a.done::after{content:"✓";color:var(--success);font-weight:700;margin-left:8px}
.nav-list a.locked{opacity:.45;pointer-events:none}

.ghost-btn{
  width:100%;margin-top:14px;
  background:transparent;color:var(--muted);
  border:1px solid var(--border);border-radius:10px;
  padding:9px;cursor:pointer;font-size:.85rem;
  transition:.2s;
}
.ghost-btn:hover{color:var(--danger);border-color:var(--danger)}

/* ===================== CONTENT ===================== */
.content{min-width:0}
.module{display:none;animation:fadeIn .4s ease}
.module.active{display:block}
@keyframes fadeIn{from{opacity:0;transform:translateY(8px)}to{opacity:1;transform:translateY(0)}}

.card{
  background:linear-gradient(180deg,var(--surface),var(--surface-2));
  border:1px solid var(--border);
  border-radius:var(--radius);
  padding:22px;margin-bottom:20px;
  box-shadow:var(--shadow);
}
.card.lesson h2{
  font-size:1.7rem;
  background:var(--grad);-webkit-background-clip:text;background-clip:text;color:transparent
}
.card.try-it{border-color:rgba(6,182,212,.3)}
.card.try-it h3{color:var(--accent-2)}
.card.quiz{border-color:rgba(124,58,237,.3)}

/* ===================== RIGHT PANEL ===================== */
.right-panel{
  position:sticky;top:88px;align-self:start;
  max-height:calc(100vh - 110px);overflow:auto;
  display:flex;flex-direction:column;gap:16px;
}
.right-panel .card{margin-bottom:0;padding:16px}
.right-panel h3{font-size:.95rem;color:var(--muted);text-transform:uppercase;letter-spacing:.08em}
.score-line{font-size:1.15rem}
.score-line b{color:var(--accent-2)}

/* badges */
.badges{display:grid;grid-template-columns:repeat(4,1fr);gap:8px}
.badge{
  aspect-ratio:1;display:flex;align-items:center;justify-content:center;
  background:var(--surface-2);border:1px solid var(--border);border-radius:10px;
  font-size:1.2rem;opacity:.35;transition:.3s;
}
.badge.earned{
  opacity:1;background:var(--grad);border-color:transparent;
  animation:badgePop .5s ease;
  box-shadow:0 4px 16px rgba(124,58,237,.5)
}
@keyframes badgePop{0%{transform:scale(0)}70%{transform:scale(1.2)}100%{transform:scale(1)}}

.quick-glossary{font-size:.88rem;display:flex;flex-direction:column;gap:8px;max-height:240px;overflow:auto}
.quick-glossary div b{color:var(--accent-2)}

/* ===================== BUTTONS ===================== */
.primary-btn{
  background:var(--grad);color:#fff;
  border:none;border-radius:10px;
  padding:10px 18px;font-weight:600;font-size:.92rem;cursor:pointer;
  transition:transform .15s,box-shadow .2s;
}
.primary-btn:hover{transform:translateY(-1px);box-shadow:0 6px 20px rgba(124,58,237,.45)}
.primary-btn:disabled{opacity:.45;cursor:not-allowed}
.row-buttons{display:flex;gap:10px;flex-wrap:wrap;margin:12px 0}
.row-buttons .ghost-btn{width:auto;margin:0}

/* ===================== TERMS / TOOLTIPS ===================== */
.term{
  border-bottom:1px dashed var(--accent-2);
  cursor:help;color:var(--accent-2);
  position:relative;
}
.term:hover::after{
  content:attr(data-tip);
  position:absolute;left:0;bottom:120%;
  background:var(--bg-2);color:var(--text);
  padding:8px 12px;border-radius:8px;
  border:1px solid var(--border);
  font-size:.82rem;width:240px;z-index:20;
  box-shadow:var(--shadow);
}

/* ===================== BLOCH ===================== */
.bloch-wrap{display:grid;grid-template-columns:200px 1fr;gap:24px;align-items:center}
.bloch{
  position:relative;width:200px;height:200px;
  background:radial-gradient(circle at 50% 50%,rgba(6,182,212,.06),transparent 70%);
}
.bloch-circle{
  position:absolute;inset:0;border-radius:50%;
  border:2px solid rgba(124,58,237,.4);
  box-shadow:inset 0 0 30px rgba(124,58,237,.15);
}
.bloch-axis-z{position:absolute;left:50%;top:0;bottom:0;width:1px;background:rgba(255,255,255,.15)}
.bloch-axis-x{position:absolute;top:50%;left:0;right:0;height:1px;background:rgba(255,255,255,.15)}
.bloch-arrow{
  position:absolute;left:50%;top:50%;
  width:4px;height:90px;
  background:var(--grad);
  transform-origin:bottom center;
  transform:translate(-50%,-100%) rotate(0deg);
  border-radius:4px;
  transition:transform .8s cubic-bezier(.34,1.56,.64,1);
  box-shadow:0 0 18px rgba(124,58,237,.6);
}
.bloch-arrow::after{
  content:"";position:absolute;top:-10px;left:50%;transform:translateX(-50%);
  border:6px solid transparent;border-bottom-color:#06b6d4;
}
.bloch-arrow.spin{animation:spinAround 4s linear infinite}
@keyframes spinAround{
  0%  {transform:translate(-50%,-100%) rotate(-90deg)}
  50% {transform:translate(-50%,-100%) rotate(90deg)}
  100%{transform:translate(-50%,-100%) rotate(270deg)}
}
.bloch-label{position:absolute;left:50%;transform:translateX(-50%);font-size:.85rem;color:var(--muted)}
.bloch-label.top{top:-22px}
.bloch-label.bottom{bottom:-22px}

.bloch-controls{display:flex;flex-direction:column;gap:8px}
.state-btn{
  background:var(--surface-2);color:var(--text);
  border:1px solid var(--border);border-radius:10px;
  padding:10px;cursor:pointer;font-size:.92rem;text-align:left;
  transition:.2s;
}
.state-btn:hover{border-color:var(--accent-2);background:var(--surface)}
.state-btn.active{border-color:var(--accent);box-shadow:0 0 0 2px rgba(124,58,237,.3)}

/* ===================== 3D BLOCH SPHERE ===================== */
.bloch-row{
  display:grid;grid-template-columns:340px 1fr;gap:24px;align-items:center;
}
@media(max-width:850px){.bloch-row{grid-template-columns:1fr;justify-items:center}}

.bloch-stage{
  width:320px;height:320px;perspective:900px;margin:0 auto;
  user-select:none;
}
.bloch-cube{
  width:100%;height:100%;position:relative;
  transform-style:preserve-3d;
  transform:rotateX(-22deg) rotateY(-30deg);
  cursor:grab;
  transition:transform .15s ease;
}
.bloch-cube:active{cursor:grabbing;transition:none}

/* Wireframe great circles */
.bloch-cube .ring{
  position:absolute;left:50%;top:50%;
  width:240px;height:240px;
  margin:-120px 0 0 -120px;
  border:1px solid rgba(124,58,237,.45);
  border-radius:50%;
  box-shadow:0 0 30px rgba(124,58,237,.08) inset;
  transform-style:preserve-3d;
  pointer-events:none;
}
.bloch-cube .ring.equator{transform:rotateX(90deg)}
.bloch-cube .ring.meridian-x{}                       /* faces camera */
.bloch-cube .ring.meridian-y{transform:rotateY(90deg)}

/* Axes — three faint lines through the origin */
.bloch-cube .b-axis{
  position:absolute;left:50%;top:50%;
  background:rgba(255,255,255,.18);
  pointer-events:none;
}
.bloch-cube .b-axis.ax{
  width:280px;height:1px;margin:0 0 0 -140px;
}
.bloch-cube .b-axis.az{
  width:1px;height:280px;margin:-140px 0 0 0;
}
.bloch-cube .b-axis.ay{
  width:280px;height:1px;margin:0 0 0 -140px;
  transform:rotateY(90deg);
}

/* Axis labels */
.bloch-cube .b-lbl{
  position:absolute;left:50%;top:50%;
  width:auto;
  font-family:'STIX Two Math','Cambria Math','Times New Roman',serif;
  font-size:.92rem;color:var(--accent-2);
  background:rgba(10,14,26,.7);
  padding:1px 6px;border-radius:4px;
  pointer-events:none;
  white-space:nowrap;
}
.bloch-cube .b-lbl.pos-z{transform:translate3d(-50%, -150px, 0)}
.bloch-cube .b-lbl.neg-z{transform:translate3d(-50%, 138px, 0)}
.bloch-cube .b-lbl.pos-x{transform:translate3d(140px, -50%, 0)}
.bloch-cube .b-lbl.neg-x{transform:translate3d(-180px, -50%, 0)}
.bloch-cube .b-lbl.pos-y{transform:translate3d(-50%, -50%, 140px)}
.bloch-cube .b-lbl.neg-y{transform:translate3d(-50%, -50%, -140px)}

/* State vector — a thin line from origin */
.bloch-cube .bloch-vec{
  position:absolute;left:50%;top:50%;
  width:120px;height:3px;
  background:linear-gradient(90deg,rgba(124,58,237,.1),var(--accent));
  border-radius:2px;
  transform-origin:0 50%;
  margin-top:-1.5px;
  box-shadow:0 0 12px rgba(124,58,237,.6);
  pointer-events:none;
  transition:transform .35s cubic-bezier(.34,1.4,.64,1);
}
.bloch-cube .bloch-tip{
  position:absolute;left:50%;top:50%;
  width:14px;height:14px;border-radius:50%;
  background:var(--accent);
  margin:-7px 0 0 -7px;
  box-shadow:0 0 18px var(--accent), inset 0 0 6px rgba(255,255,255,.5);
  pointer-events:none;
  transition:transform .35s cubic-bezier(.34,1.4,.64,1);
}

.bloch-controls{display:flex;flex-direction:column;gap:6px}
.bloch-controls label{font-size:.92rem;margin-top:8px}
.bloch-gate-row{display:flex;gap:6px;flex-wrap:wrap;align-items:center;margin-top:8px}
.bloch-gate-row .muted{font-size:.85rem;margin-right:4px}
.bloch-gate{
  background:var(--surface-2);border:1px solid var(--border);color:var(--text);
  border-radius:8px;padding:6px 12px;cursor:pointer;
  font-family:'JetBrains Mono',monospace;font-size:.88rem;font-weight:600;
  transition:.15s;
}
.bloch-gate:hover{border-color:var(--accent-2);transform:translateY(-1px)}
.bloch-gate:active{transform:translateY(0)}
.bloch-view-row{font-size:.8rem;color:var(--muted);margin-top:8px}

/* ===================== SLIDERS / PROBS ===================== */
.slider{
  -webkit-appearance:none;appearance:none;
  width:100%;height:6px;border-radius:99px;
  background:linear-gradient(90deg,var(--accent),var(--accent-2));
  outline:none;margin:10px 0;
}
.slider::-webkit-slider-thumb{
  -webkit-appearance:none;appearance:none;
  width:18px;height:18px;border-radius:50%;
  background:#fff;border:2px solid var(--accent);cursor:pointer;
  box-shadow:0 2px 10px rgba(0,0,0,.4);
}
.slider::-moz-range-thumb{
  width:18px;height:18px;border-radius:50%;
  background:#fff;border:2px solid var(--accent);cursor:pointer;
}

.prob-row{display:grid;grid-template-columns:1fr 1fr;gap:16px;margin:14px 0}
.prob-block{background:var(--surface-2);padding:12px;border-radius:10px;border:1px solid var(--border)}
.prob-label{font-size:.88rem;color:var(--muted);margin-bottom:6px}
.prob-bar{height:14px;background:var(--bg-2);border-radius:99px;overflow:hidden;margin-bottom:6px}
.prob-fill{height:100%;width:50%;border-radius:99px;transition:width .35s ease}
.prob-fill.p0{background:linear-gradient(90deg,var(--accent-2),#22d3ee)}
.prob-fill.p1{background:linear-gradient(90deg,var(--accent-3),var(--accent))}

#sp-wave,#m-chart,#c-canvas{width:100%;display:block;background:var(--bg-2);border-radius:10px;margin-top:12px;border:1px solid var(--border)}

/* ===================== ENTANGLEMENT ===================== */
.bell-pair{display:flex;align-items:center;justify-content:center;gap:0;margin:18px 0}
.qbox{
  width:120px;text-align:center;padding:18px;border-radius:14px;
  background:var(--surface-2);border:1px solid var(--border);
  transition:.3s;
}
.qbox.measured{border-color:var(--accent-2);box-shadow:0 0 24px rgba(6,182,212,.35)}
.qlabel{font-size:.85rem;color:var(--muted)}
.qval{font-size:2.4rem;font-weight:700;background:var(--grad);-webkit-background-clip:text;background-clip:text;color:transparent;margin-top:6px}
.link-line{
  flex:1;max-width:160px;height:2px;
  background:repeating-linear-gradient(90deg,var(--accent) 0 8px,transparent 8px 16px);
  position:relative;
}
.link-line::before{
  content:"⚛";position:absolute;left:50%;top:-12px;transform:translateX(-50%);
  font-size:1.4rem;background:var(--bg);padding:0 6px;
}

/* ===================== DIRAC BOX ===================== */
.dirac-box{
  margin:12px 0;padding:14px 16px;border-radius:10px;
  background:linear-gradient(180deg,rgba(124,58,237,.10),rgba(6,182,212,.06));
  border:1px solid var(--border);
  font-family:'STIX Two Math','Cambria Math','Latin Modern Math','Times New Roman',Georgia,serif;
  text-align:center;line-height:1.9;
}
.dirac-box .label{
  display:block;font-size:.7rem;text-transform:uppercase;letter-spacing:.12em;
  color:var(--muted);margin-bottom:6px;
  font-family:'Inter',system-ui,sans-serif;
}
.dirac-box .eq{font-size:1.3rem}
.dirac-box .alpha{color:#22d3ee}
.dirac-box .beta{color:#f472b6}
.dirac-box .ket{color:var(--text)}
.dirac-box .approx{
  display:block;font-size:.92rem;color:var(--muted);margin-top:6px;
  font-family:'STIX Two Math','Cambria Math','Times New Roman',serif;
}

/* Proper inline fraction — vertically centred on the math axis. */
.frac{
  display:inline-block;
  vertical-align:middle;
  font-size:.7em;
  line-height:1;
  margin:0 .25em;
  text-align:center;
  position:relative;
  top:-0.05em;
}
.frac .num{
  display:block;
  padding:0 .35em .1em;
  border-bottom:1.2px solid currentColor;
  line-height:1.1;
}
.frac .den{
  display:block;
  padding:.1em .35em 0;
  line-height:1.1;
}

/* In tight contexts (amplitude column rows) keep fractions even tighter. */
.sv-row .sv-amp .frac{font-size:.78em;top:0}

/* ===================== HISTORY OF QM TIMELINE ===================== */
.qm-timeline{
  position:relative;padding:8px 0 8px 64px;
}
.qm-timeline::before{
  content:"";position:absolute;left:24px;top:14px;bottom:14px;width:3px;
  background:linear-gradient(180deg,var(--accent) 0%,var(--accent-2) 50%,var(--accent-3) 100%);
  border-radius:99px;opacity:.7;
}
.qm-event{
  position:relative;margin-bottom:18px;
  padding:14px 18px;
  background:var(--surface-2);
  border:1px solid var(--border);border-radius:10px;
  transition:transform .2s,border-color .2s;
}
.qm-event:hover{
  transform:translateX(3px);
  border-color:var(--accent-2);
}
.qm-event::before{
  content:"";position:absolute;left:-46px;top:18px;
  width:18px;height:18px;border-radius:50%;
  background:var(--accent);
  border:3px solid var(--bg);
  box-shadow:0 0 14px var(--accent),0 0 0 4px rgba(124,58,237,.18);
  z-index:2;
}
.qm-event h4{
  font-size:1.05rem;color:var(--text);margin:0 0 4px;
  display:inline-block;
}
.qm-year{
  display:inline-block;
  font-family:'JetBrains Mono',monospace;font-weight:700;
  background:linear-gradient(135deg,rgba(124,58,237,.18),rgba(6,182,212,.14));
  color:var(--accent-2);
  padding:4px 10px;border-radius:6px;
  margin-right:10px;font-size:.95rem;
  border:1px solid rgba(6,182,212,.25);
  vertical-align:middle;line-height:1.1;text-align:center;
}
.qm-year small{
  display:block;font-size:.65rem;font-weight:500;opacity:.75;
  letter-spacing:.04em;margin-top:1px;
}
.qm-people{
  font-size:.82rem;color:var(--accent-3);margin:2px 0 8px;
  font-style:italic;
}
.qm-event p{font-size:.92rem;line-height:1.6;color:var(--text)}
.qm-formula{
  display:inline-block;margin-top:8px;
  padding:6px 12px;border-radius:6px;
  background:var(--bg-2);border:1px solid var(--border);
  font-family:'STIX Two Math','Cambria Math','Times New Roman',serif;
  font-size:1.02rem;color:var(--text);
}
.qm-formula sub, .qm-formula sup{font-size:.75em}
@media(max-width:600px){
  .qm-timeline{padding-left:42px}
  .qm-timeline::before{left:14px}
  .qm-event::before{left:-32px;width:14px;height:14px}
}

/* ===================== MATH / POSTULATES (LaTeX-like) ===================== */
.math-row{
  display:flex;flex-wrap:wrap;gap:14px;align-items:center;
  margin:8px 0;justify-content:center;
}
/* Display-mode formula block — centered, serif, proper sub/sup. */
.math-formula{
  display:block;
  background:var(--bg-2);border:1px solid var(--border);border-radius:8px;
  padding:14px 20px;margin:12px 0;
  font-family:'STIX Two Math','Cambria Math','Latin Modern Math','Times New Roman',Georgia,serif;
  font-size:1.2rem;line-height:1.85;color:var(--text);
  text-align:center;
  letter-spacing:.005em;
  overflow-x:auto;
}
.math-formula sub{
  font-size:.72em;vertical-align:-0.35em;
  margin-left:-.04em;font-style:normal;
}
.math-formula sup{
  font-size:.72em;vertical-align:0.55em;font-style:normal;
}
.math-formula b{color:var(--accent-2);font-weight:600;font-style:normal}
.math-formula i{font-style:italic}
.math-formula .op{font-style:normal;margin:0 .15em}        /* operators (+, =, ·) keep upright spacing */
.math-formula .var{font-style:italic}                       /* explicit italic variables when needed */
.math-formula .matrix{vertical-align:middle;margin:0 .2em;font-size:.95em}
.math-formula .matrix .grid span{font-style:italic}

/* Inline-mode formula (flows with prose, no big block) */
.math-inline{
  font-family:'STIX Two Math','Cambria Math','Times New Roman',Georgia,serif;
  font-size:1.05em;color:var(--text);
}
.math-inline sub{font-size:.72em;vertical-align:-0.3em}
.math-inline sup{font-size:.72em;vertical-align:0.5em}

.math-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(260px,1fr));gap:12px;margin:8px 0}
.math-cell{
  background:var(--surface-2);border:1px solid var(--border);border-radius:10px;
  padding:14px;
}
.math-cell-h{
  font-size:.7rem;text-transform:uppercase;letter-spacing:.1em;color:var(--muted);
  margin-bottom:6px;
}
.math-cell .math-formula{margin:0;font-size:1.05rem;padding:10px 14px}

/* ===================== QUANTUM PARADOXES ===================== */
.paradox-tabs{display:flex;gap:6px;flex-wrap:wrap;margin-bottom:14px}
.pdx-tab{
  background:var(--surface-2);border:1px solid var(--border);color:var(--text);
  padding:8px 14px;border-radius:9px;cursor:pointer;font-family:inherit;font-size:.88rem;
  transition:.2s;
}
.pdx-tab:hover{border-color:var(--accent-2)}
.pdx-tab.active{background:var(--grad);border-color:transparent;color:#fff}
.pdx-panel{padding:6px 0}
.pdx-panel.hidden{display:none}
.pdx-panel h4{font-size:1.1rem;color:var(--accent-2);margin-bottom:8px}

/* — Schrödinger's Cat — */
.cat-stage{display:grid;grid-template-columns:220px 1fr;gap:20px;align-items:center;margin:14px 0}
@media(max-width:700px){.cat-stage{grid-template-columns:1fr;justify-items:center}}
.cat-box{
  width:220px;height:220px;border-radius:14px;
  background:linear-gradient(135deg,#0e1424,#1a2240);
  border:2px solid var(--accent);position:relative;overflow:hidden;
  display:flex;flex-direction:column;align-items:center;justify-content:center;
  box-shadow:0 0 30px rgba(124,58,237,.18) inset;
  transition:.4s;
}
.cat-box.opened{border-color:var(--accent-2)}
.cat-vis{position:relative;width:120px;height:120px;display:flex;align-items:center;justify-content:center}
.cat-icon{position:absolute;font-size:5rem;transition:opacity .5s}
.cat-box.closed .cat-icon{animation:catShimmer 2s ease-in-out infinite}
.cat-box.closed .cat-icon.dead{animation-delay:1s}
.cat-box.opened .cat-icon{opacity:0}
.cat-box.opened.alive .cat-icon.alive{opacity:1}
.cat-box.opened.dead  .cat-icon.dead {opacity:1}
.cat-label{font-family:'JetBrains Mono',monospace;font-size:.78rem;color:var(--muted);
  margin-top:10px;text-align:center;padding:0 6px;line-height:1.3}
@keyframes catShimmer{0%,100%{opacity:.25}50%{opacity:1}}

/* — Wigner's Friend — */
.wig-stage{
  display:grid;grid-template-columns:1fr auto 1fr;gap:10px;align-items:stretch;
  margin:14px 0;
}
@media(max-width:700px){.wig-stage{grid-template-columns:1fr;}.wig-divider{transform:rotate(90deg);padding:6px 0}}
.wig-actor{
  background:var(--surface-2);border:1px solid var(--border);border-radius:12px;
  padding:14px;text-align:center;
}
.wig-actor.measured{border-color:var(--accent);box-shadow:0 0 16px rgba(124,58,237,.25)}
.wig-icon{font-size:2.4rem}
.wig-name{font-weight:600;margin:6px 0}
.wig-state{
  font-family:'JetBrains Mono',monospace;font-size:.85rem;color:var(--accent-2);
  background:var(--bg-2);padding:8px;border-radius:8px;border:1px solid var(--border);
  min-height:40px;display:flex;align-items:center;justify-content:center;
}
.wig-divider{
  display:flex;align-items:center;justify-content:center;
  font-size:.85rem;color:var(--muted);background:var(--bg-2);
  border-radius:8px;border:1px dashed var(--border);padding:0 14px;
}

/* — Frauchiger–Renner — */
.frauch-chain{
  display:flex;align-items:center;flex-wrap:wrap;gap:8px;margin:14px 0;
  background:var(--surface-2);padding:14px;border-radius:10px;border:1px solid var(--border);
  justify-content:center;
}
.fc-actor{
  background:var(--bg-2);border:1px solid var(--accent);border-radius:10px;
  padding:10px 14px;font-weight:600;text-align:center;font-size:.9rem;
}
.fc-actor small{display:block;color:var(--muted);font-weight:400;font-size:.72rem;margin-top:2px}
.fc-arrow{color:var(--muted);font-size:.85rem;font-style:italic}

.paradox-svg{
  width:100%;max-width:760px;display:block;margin:14px auto;
  background:var(--bg-2);border:1px solid var(--border);border-radius:10px;
  padding:6px;
}
.paradox-svg text{font-family:'Inter',system-ui,sans-serif}

/* — Double-Slit (Wave-Particle Duality) — */
.ds-detector-overlay{opacity:.25;transition:opacity .3s}
.ds-detector-overlay.active{opacity:1;filter:drop-shadow(0 0 6px rgba(245,158,11,.6))}
#ds-screen{
  width:100%;display:block;background:var(--bg-2);border-radius:10px;
  border:1px solid var(--border);margin-top:8px;
}

/* — Quantum Eraser — */
.er-controls{display:flex;gap:10px;flex-wrap:wrap;align-items:center;margin:10px 0}
.er-toggle{
  display:inline-flex;align-items:center;gap:6px;cursor:pointer;
  background:var(--surface-2);border:1px solid var(--border);
  padding:8px 14px;border-radius:9px;font-size:.9rem;
}
.er-toggle input{accent-color:var(--accent);width:14px;height:14px}
#er-screen,#zeno-canvas{
  width:100%;display:block;background:var(--bg-2);border-radius:10px;
  border:1px solid var(--border);margin-top:8px;
}

/* — Delayed-choice — */
.dl-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;margin:12px 0}
@media(max-width:700px){.dl-grid{grid-template-columns:1fr}}
.dl-panel{
  background:var(--surface-2);border:1px solid var(--border);border-radius:10px;padding:10px;
}
.dl-panel h5{font-size:.78rem;text-transform:uppercase;letter-spacing:.1em;color:var(--muted);margin:0 0 6px}
.dl-canvas{width:100%;height:80px;background:var(--bg-2);border-radius:6px;border:1px solid var(--border)}

/* — Quantum Zeno — */
.zeno-controls{display:flex;gap:14px;flex-wrap:wrap;align-items:center;margin:12px 0}
.zeno-controls > label{flex:1;min-width:240px}

/* ===================== QFT DEMO ===================== */
.qft-controls{display:flex;flex-wrap:wrap;gap:10px;align-items:center;margin:10px 0}
.qft-inputs{display:inline-flex;gap:6px;flex-wrap:wrap}
.qft-input{
  background:var(--surface-2);border:1px solid var(--border);color:var(--text);
  padding:6px 12px;border-radius:8px;cursor:pointer;
  font-family:'STIX Two Math','Cambria Math','Times New Roman',serif;font-size:.95rem;
  transition:.15s;
}
.qft-input:hover{border-color:var(--accent-2)}
.qft-input.active{background:var(--grad);border-color:transparent;color:#fff}

.qft-results{
  display:flex;gap:6px;padding:14px;background:var(--bg-2);
  border:1px solid var(--border);border-radius:10px;margin-top:10px;overflow-x:auto;
}
.qft-bin{
  flex:1;min-width:50px;display:flex;flex-direction:column;align-items:center;gap:6px;
}
.qft-clock{
  width:38px;height:38px;border-radius:50%;
  border:1.5px solid var(--accent-2);position:relative;
  background:var(--bg-2);
}
.qft-clock::before{
  content:"";position:absolute;left:50%;top:50%;
  width:5px;height:5px;border-radius:50%;background:var(--accent-2);
  transform:translate(-50%,-50%);
}
.qft-clock-arm{
  position:absolute;left:50%;top:50%;
  width:14px;height:2px;background:var(--accent);
  transform-origin:left center;
  transform:translate(0,-50%) rotate(0deg);
  border-radius:2px;
  transition:transform .4s ease;
}
.qft-bar{
  width:28px;height:90px;background:var(--surface-2);
  border:1px solid var(--border);border-radius:4px;
  display:flex;align-items:flex-end;overflow:hidden;
}
.qft-bar-fill{width:100%;background:var(--grad);border-radius:0 0 4px 4px;transition:height .4s}
.qft-label{
  font-family:'STIX Two Math','Cambria Math','Times New Roman',serif;
  font-size:.85rem;color:var(--muted);
}
.qft-phase{
  font-family:'JetBrains Mono',monospace;font-size:.7rem;color:var(--accent-3);
  min-height:.85rem;
}

/* mc-cross used by SWAP renderings */
.mc-cross{font-size:1.3rem;font-weight:700;color:var(--accent);line-height:1}

/* Algorithm explainer card — placed before the mini-circuit diagram. */
.algo-explainer{
  background:var(--surface-2);
  border:1px solid var(--border);
  border-left:3px solid var(--accent-2);
  border-radius:8px;
  padding:12px 16px;margin:10px 0 14px;
  font-size:.92rem;line-height:1.6;
}
.algo-explainer p{margin:6px 0}
.algo-explainer p:first-child{margin-top:0}
.algo-explainer p:last-child{margin-bottom:0}
.algo-explainer .label{
  display:inline-block;font-size:.7rem;text-transform:uppercase;letter-spacing:.1em;
  color:var(--accent-2);font-weight:700;margin-right:6px;
}
.algo-explainer ul{margin:4px 0 6px 20px;padding:0}
.algo-explainer ul li{margin:2px 0}
.algo-meta{
  display:inline-flex;gap:8px;flex-wrap:wrap;font-size:.78rem;margin-top:8px;
}
.algo-meta span{
  background:var(--bg-2);border:1px solid var(--border);
  padding:3px 9px;border-radius:99px;color:var(--muted);
}
.algo-meta span b{color:var(--accent-3)}

/* ===================== MINI CIRCUIT DIAGRAM (algorithms) ===================== */
.mini-circuit{
  background:var(--bg-2);border:1px solid var(--border);border-radius:10px;
  padding:12px 14px;margin:10px 0 14px;overflow-x:auto;
}
.mc-grid{
  display:grid;grid-auto-rows:42px;
  grid-template-columns:auto repeat(var(--cols), 64px) 1fr;
  position:relative;align-items:center;
}
.mc-rowlabel{
  display:flex;align-items:center;justify-content:flex-end;
  font-family:'JetBrains Mono',monospace;font-size:.82rem;color:var(--muted);
  padding-right:12px;white-space:nowrap;
}
.mc-wirebg{
  align-self:center;height:2px;background:var(--border);
  margin:0 -2px;
}
.mc-cell{
  display:flex;align-items:center;justify-content:center;
  position:relative;z-index:2;
}
.mc-spangate{align-self:stretch;padding:5px 4px}
.mc-spangate .mc-gate{
  display:flex;align-items:center;justify-content:center;
  width:auto;flex:1;font-size:.78rem;
}
.mc-gate{
  background:var(--grad);color:#fff;font-weight:700;font-size:.78rem;
  padding:5px 8px;border-radius:6px;min-width:30px;text-align:center;
  font-family:'JetBrains Mono',monospace;
  box-shadow:0 2px 6px rgba(124,58,237,.35);
}
.mc-gate.rot{background:var(--grad-2)}
.mc-gate.meas{background:linear-gradient(135deg,#10b981,#06b6d4)}
.mc-gate.oracle{background:linear-gradient(135deg,#7c3aed,#a78bfa)}
.mc-gate.diff{background:linear-gradient(135deg,#f59e0b,#fb923c)}
.mc-gate.qft{background:linear-gradient(135deg,#06b6d4,#3b82f6)}
.mc-gate.cond{background:linear-gradient(135deg,#64748b,#94a3b8);font-style:italic}
.mc-ctrl{width:14px;height:14px;border-radius:50%;background:var(--accent);box-shadow:0 0 8px var(--accent)}
.mc-targ{
  width:26px;height:26px;border-radius:50%;border:2px solid var(--accent);
  display:flex;align-items:center;justify-content:center;background:var(--bg-2);
  font-weight:700;color:var(--accent);font-size:.85rem;
}
.mc-vline{
  width:2px;background:var(--accent);justify-self:center;
  align-self:stretch;z-index:1;
}
.mc-caption{font-size:.78rem;color:var(--muted);margin-top:8px;font-style:italic}

/* ===================== BB84 (Quantum Cryptography) ===================== */
.bb-controls{display:flex;flex-wrap:wrap;gap:18px;align-items:center;margin-bottom:10px}
.bb-controls > div{flex:1;min-width:220px}
.bb-eve-toggle{
  display:inline-flex;align-items:center;gap:8px;cursor:pointer;
  background:var(--surface-2);border:1px solid var(--border);
  padding:8px 14px;border-radius:9px;font-size:.92rem;
}
.bb-eve-toggle input{accent-color:var(--accent-3);width:16px;height:16px}

/* Quantum Cryptography tabs */
.qc-tabs{display:flex;gap:6px;flex-wrap:wrap;margin-bottom:14px}
.qc-tab{
  background:var(--surface-2);border:1px solid var(--border);color:var(--text);
  padding:8px 16px;border-radius:9px;cursor:pointer;font-family:inherit;font-size:.92rem;
  transition:.2s;
}
.qc-tab:hover{border-color:var(--accent-2)}
.qc-tab.active{background:var(--grad);border-color:transparent;color:#fff}
.qc-panel{padding:6px 0}
.qc-panel.hidden{display:none}
.qc-panel h4{font-size:1.15rem;color:var(--accent-2);margin:6px 0 10px}
.qc-panel h5{font-size:.95rem;margin:14px 0 6px}
.qc-panel ul, .qc-panel ol{padding-left:22px;line-height:1.6}
.qc-panel li{margin:4px 0}

/* Reference tables inside the QC panels */
.qc-table-wrap{overflow-x:auto;margin:8px 0}
.qc-table{
  width:100%;border-collapse:collapse;font-size:.88rem;
  background:var(--surface-2);border:1px solid var(--border);border-radius:8px;overflow:hidden;
}
.qc-table th, .qc-table td{
  padding:8px 12px;text-align:left;border-bottom:1px solid var(--border);
}
.qc-table thead th{
  background:var(--bg-2);color:var(--accent-2);
  font-size:.78rem;text-transform:uppercase;letter-spacing:.06em;font-weight:600;
}
.qc-table tbody tr:last-child td{border-bottom:none}
.qc-table tbody tr:hover{background:rgba(124,58,237,.06)}

.bb-table{
  background:var(--bg-2);border:1px solid var(--border);border-radius:10px;
  padding:8px;margin-top:14px;overflow-x:auto;
}
.bb-row{
  display:grid;gap:8px;align-items:center;padding:6px 8px;border-radius:6px;
  font-family:'JetBrains Mono',monospace;font-size:.85rem;
}
.bb-row.hdr{
  font-family:inherit;font-size:.7rem;text-transform:uppercase;letter-spacing:.08em;
  color:var(--muted);background:transparent;padding-bottom:8px;border-bottom:1px solid var(--border);
}
.bb-row.match{background:rgba(16,185,129,.08)}
.bb-row.discard{opacity:.5}
.bb-row.error{background:rgba(239,68,68,.12)}
.bb-cell{text-align:center}
.bb-cell.idx{color:var(--muted)}
.bb-cell.basis{display:inline-flex;align-items:center;justify-content:center;
  background:var(--surface-2);border:1px solid var(--border);border-radius:6px;
  padding:2px 0;font-weight:700;color:var(--accent-2);min-width:30px;margin:0 auto;
}
.bb-cell.basis.x{color:var(--accent-3)}
.bb-cell.qubit{
  display:inline-flex;align-items:center;justify-content:center;
  background:var(--surface-2);border:1px solid var(--border);border-radius:6px;
  padding:2px 6px;font-weight:700;color:var(--accent);
  min-width:48px;margin:0 auto;
}
.bb-cell.bit{font-weight:700;color:var(--text)}
.bb-cell.tag{font-size:.7rem;text-transform:uppercase;letter-spacing:.06em;color:var(--muted)}
.bb-cell.tag.kept{color:var(--success)}
.bb-cell.tag.err{color:var(--danger);font-weight:700}

.bb-summary{
  margin-top:14px;padding:14px;border-radius:10px;
  background:var(--surface-2);border:1px solid var(--border);
  display:none;
}
.bb-summary.show{display:block}
.bb-summary h4{margin:0 0 10px;color:var(--accent-2)}
.bb-summary .bb-stat{display:grid;grid-template-columns:auto 1fr auto;gap:10px;align-items:center;font-size:.9rem;margin:6px 0}
.bb-summary .bb-stat-bar{height:10px;background:var(--bg-2);border-radius:99px;overflow:hidden;border:1px solid var(--border)}
.bb-summary .bb-stat-fill{height:100%;width:0;border-radius:99px;transition:.4s}
.bb-summary .bb-stat-fill.good{background:var(--success)}
.bb-summary .bb-stat-fill.bad{background:var(--danger)}
.bb-key{
  margin-top:12px;padding:10px 12px;background:var(--bg-2);border-radius:8px;
  font-family:'JetBrains Mono',monospace;letter-spacing:.18em;font-size:1rem;
  color:var(--accent-2);border:1px solid var(--border);
  word-break:break-all;
}
.bb-verdict{margin-top:12px;font-weight:600;padding:10px;border-radius:8px;text-align:center}
.bb-verdict.safe{background:rgba(16,185,129,.15);color:var(--success);border:1px solid var(--success)}
.bb-verdict.danger{background:rgba(239,68,68,.15);color:var(--danger);border:1px solid var(--danger)}
.bb-verdict.warn{background:rgba(245,158,11,.15);color:var(--warn);border:1px solid var(--warn)}

/* ===================== NOISE CHANNEL ===================== */
.n-ctrl-row{display:grid;grid-template-columns:1fr 1fr;gap:18px;margin:8px 0 4px}
@media(max-width:700px){.n-ctrl-row{grid-template-columns:1fr}}
.n-channel-wrap{
  display:flex;align-items:center;gap:6px;margin:14px 0 10px;
  background:var(--bg-2);border:1px solid var(--border);border-radius:10px;padding:14px;
  overflow-x:auto;
}
.n-end{
  flex-shrink:0;width:48px;height:48px;border-radius:10px;
  display:flex;align-items:center;justify-content:center;font-weight:700;font-family:'JetBrains Mono',monospace;
  border:1px solid var(--border);
}
.n-end.in{background:var(--surface-2);color:var(--accent-2)}
.n-end.out{background:var(--surface-2);color:var(--muted);font-size:1.05rem}
.n-end.out.good{border-color:var(--success);color:var(--success);box-shadow:0 0 16px rgba(16,185,129,.35)}
.n-end.out.bad{border-color:var(--danger);color:var(--danger);box-shadow:0 0 16px rgba(239,68,68,.35)}
.n-channel{display:flex;align-items:center;gap:4px;flex:1}
.n-seg{
  flex:1;min-width:14px;height:32px;border-radius:6px;
  background:var(--surface-2);border:1px solid var(--border);
  display:flex;align-items:center;justify-content:center;
  font-size:.85rem;color:var(--muted);position:relative;
  transition:.25s;
}
.n-seg.flipped{background:rgba(239,68,68,.25);border-color:var(--danger);color:#fca5a5;animation:flipPop .4s}
@keyframes flipPop{0%{transform:scale(.5)}60%{transform:scale(1.25)}100%{transform:scale(1)}}
.n-stats{margin-top:8px}

/* ===================== QUANTUM ERROR CORRECTION ===================== */
.qec-controls{display:flex;flex-wrap:wrap;gap:18px;align-items:center;justify-content:space-between;margin-bottom:12px}
.qec-noise-ctrl{flex:1;min-width:240px}
.qec-bit{
  background:var(--surface-2);border:1px solid var(--border);color:var(--text);
  border-radius:9px;padding:6px 14px;cursor:pointer;font-family:'JetBrains Mono',monospace;
  margin-left:6px;font-size:.95rem;transition:.2s;
}
.qec-bit:hover{border-color:var(--accent-2)}
.qec-bit.active{background:var(--grad);border-color:transparent;color:#fff}

.qec-stage{
  background:var(--bg-2);border:1px solid var(--border);border-radius:12px;
  padding:14px;margin-bottom:14px;
}
.qec-section-title{
  font-size:.78rem;text-transform:uppercase;letter-spacing:.1em;color:var(--muted);
  margin-bottom:10px;text-align:center;
}
.qec-channel{display:flex;flex-direction:column;gap:8px;margin-bottom:14px}
.qec-row{
  display:grid;grid-template-columns:auto 60px 1fr 60px;gap:10px;align-items:center;
  background:var(--surface-2);padding:8px 12px;border-radius:8px;border:1px solid var(--border);
}
.qec-row .qec-label{color:var(--muted);font-family:'JetBrains Mono',monospace;font-size:.85rem}
.qec-row .qec-state{
  font-family:'JetBrains Mono',monospace;font-weight:700;font-size:1rem;text-align:center;
  padding:4px 8px;border-radius:6px;background:var(--bg-2);border:1px solid var(--border);
}
.qec-row .qec-state.err{color:var(--danger);border-color:var(--danger)}
.qec-row .qec-state.in{color:var(--accent-2)}
.qec-row .qec-track{
  position:relative;height:24px;border-radius:99px;
  background:linear-gradient(90deg,var(--surface-2),rgba(124,58,237,.18),var(--surface-2));
  display:flex;align-items:center;justify-content:center;font-size:.85rem;color:var(--muted);
}
.qec-row .qec-track.flip{background:linear-gradient(90deg,var(--surface-2),rgba(239,68,68,.35),var(--surface-2));color:#fca5a5;font-weight:600;animation:flipPop .4s}

.qec-decode-row{
  text-align:center;padding:10px;background:var(--surface-2);border-radius:8px;
  border:1px solid var(--border);font-family:'JetBrains Mono',monospace;font-size:.95rem;
}
.qec-decoded{display:inline-block;padding:4px 12px;border-radius:6px;font-weight:700;margin-left:6px}
.qec-decoded.ok{background:rgba(16,185,129,.18);color:var(--success);border:1px solid var(--success)}
.qec-decoded.err{background:rgba(239,68,68,.18);color:var(--danger);border:1px solid var(--danger)}

.qec-msg{margin:10px 0 0;padding:10px;border-radius:8px;background:var(--surface-2);font-size:.9rem;border:1px solid var(--border)}

.qec-stats{display:flex;flex-direction:column;gap:8px;margin-top:8px;padding:14px;background:var(--bg-2);border-radius:10px;border:1px solid var(--border)}
.qec-stat-row{display:grid;grid-template-columns:200px 1fr 80px;gap:10px;align-items:center;font-size:.88rem}
.qec-stat-bar{height:14px;background:var(--surface-2);border:1px solid var(--border);border-radius:99px;overflow:hidden}
.qec-stat-fill{height:100%;width:0;border-radius:99px;transition:.5s ease}
.qec-stat-fill.bare{background:linear-gradient(90deg,var(--accent-3),var(--danger))}
.qec-stat-fill.code{background:linear-gradient(90deg,var(--success),var(--accent-2))}
.qec-stat-val{text-align:right;font-family:'JetBrains Mono',monospace;font-weight:700;color:var(--accent-2)}
@media(max-width:700px){.qec-stat-row{grid-template-columns:1fr;text-align:left}.qec-stat-val{text-align:left}}

/* ===================== PHASE KICKBACK ===================== */
.kb-targets{display:flex;gap:8px;flex-wrap:wrap;margin:8px 0 16px}
.kb-target{
  background:var(--surface-2);border:1px solid var(--border);color:var(--text);
  border-radius:9px;padding:8px 14px;cursor:pointer;font-family:inherit;
  font-size:.92rem;transition:.2s;
}
.kb-target:hover{border-color:var(--accent-2)}
.kb-target.active{background:var(--grad);border-color:transparent;color:#fff}
.kb-grid{
  display:grid;grid-template-columns:1fr auto 1fr;gap:16px;align-items:stretch;margin:12px 0;
}
.kb-stage{
  background:var(--surface-2);border:1px solid var(--border);
  border-radius:12px;padding:14px;
}
.kb-stage-title{font-size:.7rem;text-transform:uppercase;letter-spacing:.12em;color:var(--muted);margin-bottom:8px}
.kb-tensor{
  font-family:'STIX Two Math','Cambria Math','Times New Roman',Georgia,serif;
  font-size:1.25rem;text-align:center;line-height:1.7;
  background:var(--bg-2);padding:12px 14px;border-radius:8px;border:1px solid var(--border);
  margin-bottom:10px;color:var(--text);
}
.kb-arrow{
  display:flex;align-items:center;justify-content:center;
  font-family:'JetBrains Mono',monospace;font-weight:700;color:var(--accent);
  font-size:1.05rem;
  padding:0 4px;
}
.kb-verdict{
  margin-top:8px;padding:12px 14px;border-radius:10px;text-align:center;font-weight:600;
  background:var(--bg-2);border:1px solid var(--border);
}
.kb-verdict.kick{background:rgba(124,58,237,.15);border-color:var(--accent);color:#c4b5fd}
.kb-verdict.entangle{background:rgba(6,182,212,.12);border-color:var(--accent-2);color:#67e8f9}
.kb-verdict.identity{background:rgba(16,185,129,.12);border-color:var(--success);color:#6ee7b7}

@media (max-width:700px){
  .kb-grid{grid-template-columns:1fr}
  .kb-arrow{transform:rotate(90deg);padding:6px 0}
}

/* ===================== BELL / CHSH ===================== */
.bell-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:12px;margin:14px 0}
.bell-cell{background:var(--surface-2);border:1px solid var(--border);border-radius:10px;padding:12px}
.bell-cell-label{font-family:'JetBrains Mono',monospace;color:var(--muted);font-size:.85rem;margin-bottom:6px}
.bell-cell-bar{position:relative;height:14px;background:var(--bg-2);border:1px solid var(--border);border-radius:99px;margin:6px 0}
.bell-cell-bar::before{content:"";position:absolute;left:50%;top:-3px;bottom:-3px;width:2px;background:var(--border);z-index:1}
.bell-bar-fill{position:absolute;top:0;bottom:0;width:0;border-radius:99px;transition:.45s ease}
.bell-bar-fill.pos{background:linear-gradient(90deg,var(--accent-2),#22d3ee)}
.bell-bar-fill.neg{background:linear-gradient(90deg,var(--accent-3),var(--accent))}
.bell-cell-stats{font-size:.85rem;font-family:'JetBrains Mono',monospace}
.bell-cell-stats b{color:var(--accent-2)}

.bell-meter-wrap{margin-top:14px;background:var(--surface-2);padding:14px 16px;border-radius:10px;border:1px solid var(--border)}
.bell-S-display{
  text-align:center;font-family:'JetBrains Mono',monospace;font-size:.92rem;
  margin-bottom:14px;color:var(--muted);
}
.bell-S-display span{color:var(--accent-2);font-weight:700;font-size:1.1rem}
.bell-meter-track{
  position:relative;height:18px;border-radius:99px;overflow:visible;
  background:linear-gradient(90deg,
    rgba(16,185,129,.45) 0%, rgba(16,185,129,.45) 50%,
    rgba(245,158,11,.55) 50%, rgba(245,158,11,.55) 70.7%,
    rgba(239,68,68,.5) 70.7%, rgba(239,68,68,.5) 100%);
  border:1px solid var(--border);
}
.bell-meter-needle{
  position:absolute;top:-5px;width:4px;height:28px;border-radius:2px;
  background:#fff;left:0%;transform:translateX(-50%);
  transition:left .55s cubic-bezier(.34,1.2,.64,1);
  box-shadow:0 0 14px rgba(255,255,255,.65);
}
.bell-meter-marks{position:relative;height:32px;font-size:.72rem;color:var(--muted);margin-top:6px}
.bell-meter-marks span{position:absolute;transform:translateX(-50%);text-align:center;font-family:'JetBrains Mono',monospace;font-weight:600;color:var(--text)}
.bell-meter-marks span small{display:block;color:var(--muted);font-size:.62rem;font-weight:400;letter-spacing:.05em;margin-top:2px}
.bell-verdict{margin-top:14px;text-align:center;font-weight:600;padding:8px 12px;border-radius:8px;background:var(--bg-2);border:1px solid var(--border)}
.bell-verdict.classical{color:var(--success);border-color:rgba(16,185,129,.4)}
.bell-verdict.quantum{color:var(--warn);border-color:rgba(245,158,11,.5)}
.bell-verdict.over{color:var(--danger);border-color:rgba(239,68,68,.5)}

/* ===================== STATE VECTOR PANEL ===================== */
.state-vector{
  margin-top:18px;padding:16px;border-radius:12px;
  background:linear-gradient(180deg,rgba(124,58,237,.08),rgba(6,182,212,.05));
  border:1px solid var(--border);
}
.sv-title{font-size:.75rem;text-transform:uppercase;letter-spacing:.12em;color:var(--muted);margin-bottom:8px}
.sv-formula{
  font-family:'STIX Two Math','Cambria Math','Latin Modern Math','Times New Roman',Georgia,serif;
  font-size:1.25rem;line-height:1.7;
  background:var(--bg-2);padding:14px 16px;border-radius:8px;
  border:1px solid var(--border);text-align:center;
  color:var(--text);
}
.sv-amps{display:grid;gap:6px;margin-top:12px}
.sv-row{display:grid;grid-template-columns:60px 1fr 80px;gap:10px;align-items:center;
  font-family:'STIX Two Math','Cambria Math','Times New Roman',serif;font-size:1rem}
.sv-row .sv-label{color:var(--muted)}
.sv-row .sv-bar{height:10px;background:var(--bg-2);border:1px solid var(--border);border-radius:99px;overflow:hidden}
.sv-row .sv-bar div{height:100%;width:0;background:var(--grad);transition:width .5s ease;border-radius:99px}
.sv-row.zero .sv-bar div{background:var(--surface-2)}
.sv-row .sv-amp{color:var(--accent-2);text-align:right}
.sv-note{font-size:.85rem;margin-top:10px}

/* ===================== GATES REFERENCE ===================== */
.gates-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:14px;margin-top:8px}
.gate-card{
  background:var(--surface-2);border:1px solid var(--border);
  border-radius:12px;padding:16px;display:flex;flex-direction:column;gap:12px;
  transition:transform .2s,border-color .2s;
}
.gate-card:hover{transform:translateY(-3px);border-color:var(--accent)}
.gate-head{display:flex;align-items:center;gap:14px}
.gate-symbol{
  width:50px;height:50px;border-radius:10px;
  background:var(--grad);display:flex;align-items:center;justify-content:center;
  font-weight:700;color:#fff;font-size:1rem;font-family:'JetBrains Mono',monospace;
  flex-shrink:0;box-shadow:0 4px 14px rgba(124,58,237,.4);
}
.gate-symbol.rot{background:var(--grad-2)}
.gate-symbol.two{width:auto;padding:0 14px;font-size:.85rem}
.gate-name{font-weight:600;font-size:1rem}
.gate-name small{display:block;color:var(--muted);font-weight:400;font-size:.78rem;margin-top:2px}
.gate-expl{font-size:.88rem;color:var(--muted);line-height:1.55}
.gate-effect{
  font-size:.82rem;color:var(--accent-2);
  font-family:'JetBrains Mono',monospace;
  background:var(--bg-2);padding:8px 10px;border-radius:8px;border:1px solid var(--border);
  word-break:break-word;
}

/* matrix with brackets */
.matrix{
  display:inline-flex;align-items:stretch;align-self:center;
  font-family:'JetBrains Mono',monospace;font-size:.92rem;color:var(--text);
}
.matrix .br{
  width:8px;border:2px solid var(--text);
}
.matrix .br.l{border-right:none;border-radius:6px 0 0 6px}
.matrix .br.r{border-left:none;border-radius:0 6px 6px 0}
.matrix .grid{
  display:grid;gap:4px 14px;padding:8px 12px;
}
.matrix .grid span{text-align:center;color:var(--accent-2);min-width:32px}

/* ===================== MEASUREMENT CHART ===================== */
.dot{display:inline-block;width:10px;height:10px;border-radius:50%;vertical-align:middle;margin-right:4px}
.dot.c0{background:var(--accent-2)}
.dot.c1{background:var(--accent-3)}

/* ===================== CIRCUITS ===================== */
.circuit-toolbar{display:flex;gap:14px;flex-wrap:wrap;margin-bottom:12px;align-items:flex-start}
.gate-palette{display:flex;gap:8px;flex-wrap:wrap;flex:1}
.gate-btn{
  background:var(--surface-2);border:1px solid var(--border);color:var(--text);
  border-radius:10px;padding:8px 12px;cursor:pointer;
  display:flex;flex-direction:column;align-items:center;font-weight:700;
  font-family:inherit;transition:.2s;min-width:58px;font-size:.92rem;
}
.gate-btn small{font-weight:400;color:var(--muted);font-size:.65rem;margin-top:2px;letter-spacing:.02em}
.gate-btn:hover{border-color:var(--accent);transform:translateY(-2px)}
.gate-btn.active{background:var(--grad);border-color:transparent;color:#fff}
.gate-btn.active small{color:rgba(255,255,255,.85)}
.gate-btn[draggable="true"]{cursor:grab}
.gate-btn:active{cursor:grabbing}

.qwire.drag-over .cells::before{
  background:var(--accent-2);
  box-shadow:0 0 14px var(--accent-2);
  height:3px;
}
.qwire.drag-over{
  background:rgba(6,182,212,.10);border-radius:8px;
  outline:1px dashed var(--accent-2);
  outline-offset:-2px;
}

.qubit-controls{display:flex;gap:6px;align-items:center;background:var(--surface-2);padding:6px 10px;border-radius:10px;border:1px solid var(--border)}
.qubit-controls button{
  background:var(--bg-2);border:1px solid var(--border);color:var(--text);
  border-radius:8px;padding:4px 12px;cursor:pointer;font-size:1rem;font-weight:700;
}
.qubit-controls button:hover{border-color:var(--accent);color:var(--accent-2)}
#qcount-label{font-size:.85rem}

.circuit-canvas{
  background:var(--bg-2);border:1px solid var(--border);border-radius:10px;
  padding:14px 14px 14px 0;margin-top:6px;overflow-x:auto;
}
.qwire{display:flex;align-items:center;height:52px;gap:0}
.qwire .wire-label{color:var(--muted);font-family:'JetBrains Mono',monospace;width:46px;flex-shrink:0;text-align:center;font-size:.85rem}
.qwire .cells{display:flex;flex:1;align-items:center;position:relative;min-height:52px}
.qwire .cells::before{
  content:"";position:absolute;left:0;right:0;top:50%;height:2px;background:var(--border);z-index:0;
}
.qwire .cell{
  width:62px;height:52px;display:flex;align-items:center;justify-content:center;
  flex-shrink:0;position:relative;z-index:1;
}
.cell.tail{flex:1;min-width:62px;color:var(--muted);font-size:1.2rem;cursor:default}
.cell.tail.armed{cursor:crosshair;color:var(--accent-2)}
.cell.tail.armed::after{
  content:"+ drop or click";font-size:.75rem;color:var(--accent-2);
  border:1px dashed var(--accent-2);border-radius:6px;padding:3px 8px;
  background:rgba(6,182,212,.08);
}
.cell .gate-box{
  background:var(--grad);color:#fff;font-weight:700;
  display:flex;flex-direction:column;align-items:center;justify-content:center;
  padding:5px 7px;border-radius:7px;
  min-width:42px;line-height:1.1;
  font-size:.82rem;cursor:pointer;
  text-align:center;
  box-shadow:0 2px 8px rgba(124,58,237,.4);
  font-family:'JetBrains Mono',monospace;
  animation:fadeIn .25s;
}
.cell .gate-box .gate-name{
  font-size:.88rem;font-weight:700;line-height:1.1;
  letter-spacing:.02em;
}
.cell .gate-box .gate-angle{
  font-size:.66rem;font-weight:500;line-height:1;
  margin-top:2px;opacity:.92;letter-spacing:.01em;
  font-family:'STIX Two Math','Cambria Math','Times New Roman',serif;
  white-space:nowrap;
}
.cell .gate-box.rot{
  background:var(--grad-2);
  padding:4px 8px;
  min-width:50px;
  box-shadow:0 2px 8px rgba(236,72,153,.4);
}
.cell .gate-box.meas{background:linear-gradient(135deg,#10b981,#06b6d4)}
.cell.gate-cell:hover .gate-box{background:var(--danger);box-shadow:0 2px 12px rgba(239,68,68,.5)}
.cell .ctrl-dot{
  width:14px;height:14px;border-radius:50%;background:var(--accent);
  box-shadow:0 0 12px var(--accent);cursor:pointer;
}
.cell.ctrl:hover .ctrl-dot,.cell.target:hover .xor{opacity:.5}
.cell .xor{
  width:32px;height:32px;border-radius:50%;
  border:2px solid var(--accent);
  color:var(--accent);display:flex;align-items:center;justify-content:center;
  font-weight:700;background:var(--bg-2);font-size:1.1rem;cursor:pointer;
}
.cell .swap-x{
  width:24px;height:24px;display:flex;align-items:center;justify-content:center;
  font-weight:700;font-size:1.4rem;color:var(--accent);cursor:pointer;
  text-shadow:0 0 8px rgba(124,58,237,.6);
}
.cell.cnot-line::after{
  content:"";position:absolute;left:50%;top:0;bottom:0;width:2px;background:var(--accent);
  transform:translateX(-50%);z-index:0;
}
.cell.barrier-cell{position:relative}
.cell.barrier-cell::after{
  content:"";position:absolute;left:50%;top:-4px;bottom:-4px;width:0;
  border-left:2px dashed var(--accent-2);transform:translateX(-50%);z-index:2;
}
.output-box{
  margin-top:14px;padding:14px;
  background:var(--bg-2);border:1px solid var(--border);border-radius:10px;
  font-family:'JetBrains Mono',monospace;font-size:.88rem;white-space:pre-wrap;
  max-height:240px;overflow:auto;
}

/* Probability chart (IBM-Composer-style bar chart) */
.cir-result{
  margin-top:14px;background:var(--bg-2);
  border:1px solid var(--border);border-radius:10px;
  padding:14px 14px 8px;
}
.cir-result-head{
  display:flex;justify-content:space-between;align-items:baseline;
  padding:0 4px 6px;border-bottom:1px solid var(--border);margin-bottom:10px;
}
.cir-result-title{
  font-size:.78rem;text-transform:uppercase;letter-spacing:.1em;color:var(--muted);
}
.cir-result-sub{
  font-family:'STIX Two Math','Cambria Math','Times New Roman',serif;
  font-size:.95rem;color:var(--accent-2);
}
#cir-chart{
  width:100%;display:block;height:260px;
}
.cir-measured{
  margin-top:8px;padding:8px 12px;border-radius:6px;text-align:center;
  font-family:'JetBrains Mono',monospace;font-size:.92rem;
  background:rgba(16,185,129,.10);border:1px solid var(--success);
  color:var(--success);
}
.cir-measured.empty{display:none}
.cir-numeric{
  margin-top:8px;font-size:.85rem;color:var(--muted);
}
.cir-numeric summary{cursor:pointer;padding:6px 0;user-select:none}
.cir-numeric summary:hover{color:var(--accent-2)}
.cir-numeric .output-box{margin-top:6px}
.story-steps{display:flex;flex-direction:column;gap:8px;margin-top:12px}
.story-steps .tele-step{
  background:var(--surface-2);padding:10px 14px;border-radius:8px;
  border-left:3px solid var(--accent);font-size:.9rem;
  animation:fadeIn .35s;
}
.story-steps .tele-step.last{border-left-color:var(--success);background:rgba(16,185,129,.1)}

/* ===================== CONTROL VERDICT ===================== */
.verdict{
  margin-top:12px;padding:12px;border-radius:10px;text-align:center;font-weight:600;
  background:var(--surface-2);border:1px solid var(--border);
}
.verdict.ok{background:rgba(16,185,129,.15);border-color:var(--success);color:var(--success)}
.verdict.under{background:rgba(245,158,11,.15);border-color:var(--warn);color:var(--warn)}
.verdict.over{background:rgba(239,68,68,.15);border-color:var(--danger);color:var(--danger)}

/* ===================== ALGORITHMS ===================== */
.tabs{display:flex;gap:6px;margin-bottom:12px;flex-wrap:wrap}
.tab-btn{
  background:var(--surface-2);border:1px solid var(--border);color:var(--text);
  padding:8px 14px;border-radius:8px;cursor:pointer;font-size:.88rem;
}
.tab-btn.active{background:var(--grad);border-color:transparent}
.tab-panel.hidden{display:none}
.coin{
  width:100px;height:100px;border-radius:50%;
  background:var(--grad);display:flex;align-items:center;justify-content:center;
  font-size:2.4rem;font-weight:800;color:#fff;
  margin:14px 0;box-shadow:0 6px 20px rgba(124,58,237,.4);
  transition:transform .4s;
}
.coin.flipping{animation:coinFlip .8s ease}
@keyframes coinFlip{50%{transform:rotateY(540deg) scale(.7)}100%{transform:rotateY(1080deg)}}
.grover-row{display:grid;grid-template-columns:repeat(4,1fr);gap:10px;margin:14px 0}
.grover-box{
  aspect-ratio:1;display:flex;align-items:center;justify-content:center;
  background:var(--surface-2);border:1px solid var(--border);border-radius:10px;
  font-size:1.5rem;transition:.3s;
}
.grover-box.target{background:var(--grad);border-color:transparent;animation:badgePop .5s}

/* ===================== QUIZ ===================== */
.quiz-body .q-text{font-weight:600;margin:6px 0 10px}
.choice{
  display:block;width:100%;text-align:left;
  background:var(--surface-2);border:1px solid var(--border);color:var(--text);
  padding:10px 14px;border-radius:9px;margin:6px 0;cursor:pointer;
  transition:.2s;font-family:inherit;font-size:.92rem;
}
.choice:hover:not(:disabled){border-color:var(--accent-2);transform:translateX(2px)}
.choice.correct{background:rgba(16,185,129,.18);border-color:var(--success)}
.choice.wrong{background:rgba(239,68,68,.18);border-color:var(--danger)}
.choice:disabled{cursor:default}
.feedback{margin-top:10px;padding:10px;border-radius:8px;background:var(--bg-2);border:1px solid var(--border);font-size:.9rem}
.quiz-result{padding:14px;border-radius:10px;margin-top:8px;text-align:center;font-weight:600}
.quiz-result.pass{background:rgba(16,185,129,.18);color:var(--success);border:1px solid var(--success)}
.quiz-result.fail{background:rgba(239,68,68,.18);color:var(--danger);border:1px solid var(--danger)}

/* ===================== GLOSSARY / FAQ ===================== */
.glossary-list{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:12px}
.glossary-list .g-item{background:var(--surface-2);padding:12px;border-radius:10px;border:1px solid var(--border)}
.glossary-list .g-item b{color:var(--accent-2)}
details{background:var(--surface-2);border:1px solid var(--border);border-radius:10px;padding:10px 14px;margin:8px 0}
details summary{cursor:pointer;font-weight:600}
details[open] summary{color:var(--accent-2)}

/* ===================== TOAST ===================== */
.toast{
  position:fixed;bottom:24px;left:50%;transform:translateX(-50%) translateY(120%);
  background:var(--bg-2);border:1px solid var(--accent);
  padding:12px 22px;border-radius:99px;
  box-shadow:var(--shadow);
  transition:transform .4s ease;z-index:100;
}
.toast.show{transform:translateX(-50%) translateY(0)}

/* ===================== FOOTER ===================== */
footer{
  text-align:center;padding:30px 24px;color:var(--muted);font-size:.85rem;
  border-top:1px solid var(--border);margin-top:40px;
}

/* ===================== RESPONSIVE ===================== */
@media (max-width:1200px){
  .layout{grid-template-columns:220px 1fr}
  .right-panel{grid-column:1 / -1;position:static;flex-direction:row;flex-wrap:wrap;max-height:none}
  .right-panel .card{flex:1;min-width:200px}
}
@media (max-width:900px){
  .layout{grid-template-columns:1fr;padding:16px}
  .sidebar{position:fixed;left:-280px;top:0;bottom:0;width:260px;z-index:60;transition:left .3s;border-radius:0;max-height:100vh}
  .sidebar.open{left:0}
  #menu-toggle{display:flex;align-items:center;justify-content:center}
  .right-panel{flex-direction:column}
  .bloch-wrap{grid-template-columns:1fr;justify-items:center}
  .prob-row{grid-template-columns:1fr}
  .overall-progress{display:none}
}