/* ============================================================
   How a Quantum Computer Works — additions to style.css
   ============================================================ */

.quantum { --q0: var(--accent); --q1: var(--amber); --neg: var(--rose); }

/* the brand mark turns into a tiny sphere on this page */
.quantum .brand-mark { border-radius: 50%; border-color: var(--violet);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--violet) 14%, transparent); }
.quantum .brand-mark::after { border-radius: 50%; background: var(--violet); }
.quantum .eyebrow, .quantum .kicker-n, .quantum .lede-sub { color: var(--violet); }
.quantum .callout { border-left-color: var(--violet); }

/* ── bit vs qubit ────────────────────────────────────────── */
.cmp { margin: 2.2rem 0 0; border: 1px solid var(--line); border-radius: var(--radius);
  overflow: hidden; background: var(--surface); box-shadow: var(--shadow); }
.cmp-row { display: grid; grid-template-columns: 118px minmax(0, .8fr) minmax(0, 1.4fr);
  border-top: 1px solid var(--line-soft); }
.cmp-row:first-child { border-top: 0; }
.cmp-row > span { padding: .62rem .9rem; font-size: .9rem; color: var(--dim); }
.cmp-row > span:first-child { font-family: var(--mono); font-size: .72rem; letter-spacing: .08em;
  text-transform: uppercase; color: var(--dimmer); align-self: center; }
.cmp-row > span:last-child { color: var(--text); }
.cmp-head { background: var(--surface-2); }
.cmp-head > span { font-family: var(--mono); font-size: .74rem !important; letter-spacing: .1em;
  text-transform: uppercase; color: var(--dim) !important; }
.cmp-head > span:last-child { color: var(--violet) !important; }
@media (max-width: 620px) {
  .cmp-row { grid-template-columns: 1fr 1fr; }
  .cmp-row > span:first-child { grid-column: 1 / -1; padding-bottom: 0; }
  .cmp-head > span:first-child { display: none; }
}

/* ── shared bits ─────────────────────────────────────────── */
.gate-btns { display: flex; flex-wrap: wrap; gap: .4rem; }
.gate-btn {
  font-family: var(--mono); font-size: .95rem; font-weight: 700; min-width: 42px; height: 38px;
  padding: 0 .6rem; border-radius: 9px; cursor: pointer; color: var(--text);
  background: var(--surface-2); border: 1px solid var(--line); transition: .15s;
}
.gate-btn:hover:not(:disabled) { border-color: var(--violet); color: var(--violet); }
.gate-btn:disabled { opacity: .4; cursor: not-allowed; }
.gate-btn.wide { font-family: var(--sans); font-size: .8rem; font-weight: 560; color: var(--dim); }

.amp-line { font-family: var(--mono); font-size: .92rem; color: var(--text); line-height: 1.5;
  padding: .55rem .75rem; border-radius: 9px; background: var(--surface-2);
  border: 1px solid var(--line-soft); overflow-x: auto; white-space: nowrap; }
.amp-line .ket { color: var(--violet); }
.amp-line .op { color: var(--dimmer); padding: 0 .3rem; }

.sub-label { font-family: var(--mono); font-size: .68rem; letter-spacing: .12em; text-transform: uppercase;
  color: var(--dimmer); margin: 0; }

.probbar { display: flex; height: 26px; border-radius: 7px; overflow: hidden;
  border: 1px solid var(--line-soft); background: var(--surface-2); }
.probbar > span { display: flex; align-items: center; min-width: 0; font-family: var(--mono);
  font-size: .72rem; white-space: nowrap; overflow: hidden; transition: flex-basis .35s ease; }
.probbar em { font-style: normal; padding: 0 .5rem; }
.probbar .p0 { background: color-mix(in srgb, var(--q0) 26%, transparent); color: var(--q0); }
.probbar .p1 { background: color-mix(in srgb, var(--q1) 26%, transparent); color: var(--q1);
  justify-content: flex-end; }

/* circle notation */
.circles { display: flex; flex-wrap: wrap; gap: .5rem .35rem; justify-content: center; }
.circ { display: grid; justify-items: center; gap: .1rem; width: 70px; }
.circ svg { width: 58px; height: 58px; }
.circ-k { font-family: var(--mono); font-size: .78rem; color: var(--violet); }
.circ-p { font-family: var(--mono); font-size: .68rem; color: var(--dimmer); font-variant-numeric: tabular-nums; }
.circles.small .circ { width: 58px; }
.circles.small .circ svg { width: 46px; height: 46px; }

.minis { display: flex; gap: .6rem; justify-content: center; flex-wrap: wrap; }
.mini { display: grid; justify-items: center; gap: .15rem; width: 104px; }
.mini svg { width: 96px; height: 96px; }
.mini-cap { font-family: var(--mono); font-size: .7rem; color: var(--dim); text-align: center; line-height: 1.3; min-height: 2.6em; }
.mini-cap em { color: var(--rose); font-style: normal; }
.lab-state .minis { gap: .2rem; }
.lab-state .mini { width: 94px; }
.lab-state .mini svg { width: 88px; height: 88px; }

.bloch { cursor: grab; touch-action: pan-y; user-select: none; -webkit-user-select: none; }
.bloch.dragging { cursor: grabbing; }

/* ── 1. qubit ────────────────────────────────────────────── */
.qubit-demo { display: grid; grid-template-columns: minmax(0, 300px) minmax(0, 1fr); gap: 1.2rem;
  padding: 1.1rem; align-items: start; }
@media (max-width: 700px) { .qubit-demo { grid-template-columns: 1fr; justify-items: stretch; }
  .qubit-demo .bloch-holder { max-width: 300px; margin: 0 auto; width: 100%; } }
.q-side { display: grid; gap: .8rem; min-width: 0; }
.q-history { font-family: var(--mono); font-size: .76rem; color: var(--dimmer); min-height: 1.4em;
  overflow-x: auto; white-space: nowrap; }
.q-history b { color: var(--violet); font-weight: 600; }
.q-hint { font-size: .76rem; color: var(--dimmer); margin: 0; }

/* ── 2. measure ──────────────────────────────────────────── */
.measure-demo { display: grid; grid-template-columns: minmax(0, 250px) minmax(0, 1fr); gap: 1.2rem;
  padding: 1.1rem; align-items: start; }
@media (max-width: 700px) { .measure-demo { grid-template-columns: 1fr; }
  .measure-demo .bloch-holder { max-width: 250px; margin: 0 auto; width: 100%; } }
.m-side { display: grid; gap: .8rem; min-width: 0; }
.m-result { display: flex; align-items: center; gap: 1rem; padding: .6rem .8rem; border-radius: 10px;
  background: var(--surface-2); border: 1px solid var(--line-soft); min-height: 76px; }
.m-digit { font-family: var(--mono); font-size: 2.6rem; font-weight: 700; line-height: 1; width: 1.4em;
  text-align: center; color: var(--dimmer); }
.m-digit.is0 { color: var(--q0); text-shadow: 0 0 22px color-mix(in srgb, var(--q0) 45%, transparent); }
.m-digit.is1 { color: var(--q1); text-shadow: 0 0 22px color-mix(in srgb, var(--q1) 45%, transparent); }
.m-note { font-size: .84rem; color: var(--dim); line-height: 1.45; }
.m-btns { display: flex; flex-wrap: wrap; gap: .45rem; }
.hist2 { display: grid; gap: .35rem; }
.hist2-row { display: grid; grid-template-columns: 22px minmax(0, 1fr) 64px; gap: .5rem; align-items: center;
  font-family: var(--mono); font-size: .76rem; color: var(--dim); }
.hist2-track { position: relative; height: 20px; border-radius: 5px; background: var(--surface-2);
  border: 1px solid var(--line-soft); }
.hist2-fill { position: absolute; inset: 0 auto 0 0; width: 0; border-radius: 4px; transition: width .4s ease; }
.hist2-exp { position: absolute; top: -3px; bottom: -3px; width: 2px; background: var(--text); opacity: .55;
  transition: left .3s ease; }
.m-est { font-size: .82rem; color: var(--dim); margin: 0; }
.m-est b { color: var(--text); font-family: var(--mono); }

.slider-row { display: grid; gap: .3rem; }
.slider-row input[type=range] { width: 100%; accent-color: var(--violet); }

/* ── 3. interference ─────────────────────────────────────── */
.interf { padding: 1rem; display: grid; gap: 1rem; }
.interf-trees { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 1rem; }
.interf-lower { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)) minmax(0, 1.3fr); gap: 1rem; }
@media (max-width: 820px) {
  .interf-trees { grid-template-columns: 1fr; }
  .interf-lower { grid-template-columns: 1fr 1fr; }
  .interf-lower .fringe-box { grid-column: 1 / -1; }
}
.fig { background: var(--surface-2); border: 1px solid var(--line-soft); border-radius: 10px;
  padding: .6rem .6rem .5rem; display: grid; gap: .3rem; min-width: 0; }
.fig h5 { margin: 0; font-family: var(--mono); font-size: .72rem; font-weight: 500; letter-spacing: .05em;
  color: var(--dim); }
.fig-note { margin: 0; font-size: .76rem; color: var(--dimmer); line-height: 1.45; }
.interf-ctl { display: grid; grid-template-columns: auto minmax(0, 1fr) auto; gap: .8rem; align-items: center; }
.interf-ctl label { font-family: var(--mono); font-size: .72rem; color: var(--dimmer); letter-spacing: .08em;
  text-transform: uppercase; }
.interf-ctl input[type=range] { width: 100%; accent-color: var(--violet); }
.interf-ctl output { font-family: var(--mono); font-size: .9rem; color: var(--violet); min-width: 4.2em; text-align: right; }
.chip-btn { font-family: var(--mono); font-size: .74rem; padding: .28rem .6rem; border-radius: 999px;
  cursor: pointer; background: var(--surface); color: var(--dim); border: 1px solid var(--line); }
.chip-btn:hover { color: var(--text); border-color: var(--violet); }
.chip-btn.on { color: var(--violet); border-color: var(--violet);
  background: color-mix(in srgb, var(--violet) 12%, var(--surface)); }

/* ── 4. entanglement ─────────────────────────────────────── */
.ent { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: 1.1rem; padding: 1.1rem; }
@media (max-width: 760px) { .ent { grid-template-columns: 1fr; } }
.ent-left, .ent-right { display: grid; gap: .8rem; align-content: start; min-width: 0; }
.ent-verdict { font-size: .86rem; color: var(--dim); padding: .55rem .75rem; border-radius: 9px;
  background: var(--surface-2); border: 1px solid var(--line-soft); line-height: 1.45; }
.ent-verdict b { color: var(--text); }
.ent-verdict.tangled b { color: var(--violet); }
.meter { height: 8px; border-radius: 99px; background: var(--surface-2); border: 1px solid var(--line-soft); overflow: hidden; }
.meter > span { display: block; height: 100%; width: 0; background: linear-gradient(90deg, var(--accent), var(--violet));
  transition: width .35s ease; }
.corr { display: grid; grid-template-columns: 72px repeat(2, minmax(0, 1fr)); gap: 3px; font-family: var(--mono);
  font-size: .8rem; }
.corr > span { padding: .45rem .3rem; text-align: center; border-radius: 6px; background: var(--surface-2);
  color: var(--dim); border: 1px solid var(--line-soft); }
.corr > span.h { background: transparent; border-color: transparent; color: var(--dimmer); font-size: .7rem; }
.corr > span.hot { color: var(--text); border-color: color-mix(in srgb, var(--violet) 50%, transparent);
  background: color-mix(in srgb, var(--violet) 14%, var(--surface-2)); }
.corr small { display: block; font-size: .66rem; color: var(--dimmer); }

.growth { padding: 1.1rem; display: grid; gap: .9rem; }
.growth-ctl { display: grid; grid-template-columns: auto minmax(0, 1fr) auto; gap: .8rem; align-items: center; }
.growth-ctl label { font-family: var(--mono); font-size: .72rem; color: var(--dimmer); letter-spacing: .08em; text-transform: uppercase; }
.growth-ctl input { width: 100%; accent-color: var(--violet); }
.growth-n { font-family: var(--mono); font-size: 1.5rem; font-weight: 700; color: var(--violet); min-width: 3.6em; text-align: right; }
.growth-out { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: .6rem; }
@media (max-width: 620px) { .growth-out { grid-template-columns: 1fr; } }
.stat { background: var(--surface-2); border: 1px solid var(--line-soft); border-radius: 10px; padding: .6rem .75rem; min-width: 0; }
.stat span { display: block; font-family: var(--mono); font-size: .66rem; letter-spacing: .1em; text-transform: uppercase; color: var(--dimmer); }
.stat b { display: block; font-family: var(--mono); font-size: 1.05rem; color: var(--text); margin-top: .15rem;
  overflow-wrap: anywhere; }
.growth-say { margin: 0; font-size: .92rem; color: var(--dim); }
.growth-say strong { color: var(--text); }
.growth-ticks { display: flex; flex-wrap: wrap; gap: .35rem; }

/* ── 5. lab ──────────────────────────────────────────────── */
.lab { display: grid; gap: 1rem; grid-template-columns: minmax(0, 1fr) 340px;
  grid-template-areas: "circuit state" "shots state"; align-items: start; position: relative; }
.lab > * { min-width: 0; }
@media (max-width: 1020px) { .lab { grid-template-columns: minmax(0, 1fr); grid-template-areas: "circuit" "state" "shots"; } }
.lab-circuit { grid-area: circuit; }
.lab-state { grid-area: state; }
.lab-shots { grid-area: shots; }
.lab .panel { margin: 0; }
.lab-bar { display: flex; flex-wrap: wrap; gap: .5rem; align-items: center; padding: .7rem 1rem;
  border-bottom: 1px solid var(--line-soft); background: var(--surface-2); }
.lab-bar select { font: inherit; font-size: .8rem; background: var(--surface); color: var(--text);
  border: 1px solid var(--line); border-radius: 8px; padding: .3rem .5rem; }
.lab-bar .grow { flex: 1; }
.lab-scroll { overflow-x: auto; padding: .6rem .4rem .2rem; }
.lab-scroll svg { width: 100%; height: auto; min-width: 560px; }
.lab-step { display: grid; grid-template-columns: auto minmax(0, 1fr) auto auto; gap: .6rem; align-items: center;
  padding: .5rem 1rem .8rem; }
.lab-step input { width: 100%; accent-color: var(--violet); }
.lab-step output { font-family: var(--mono); font-size: .76rem; color: var(--dim); white-space: nowrap; }
.cell-hit { cursor: pointer; }
.cell-hit:hover rect.cell-bg { fill: color-mix(in srgb, var(--violet) 12%, transparent); }
.cell-hit:focus { outline: none; }
.cell-hit:focus-visible rect.cell-bg { stroke: var(--violet); stroke-width: 2; }

.picker {
  position: absolute; z-index: 20; display: grid; grid-template-columns: repeat(4, 44px); gap: .3rem;
  padding: .5rem; border-radius: 12px; background: var(--surface); border: 1px solid var(--violet);
  box-shadow: 0 18px 40px rgba(0, 0, 0, .45);
}
.picker .gate-btn { min-width: 0; width: 44px; height: 40px; padding: 0; }
.picker .gate-btn.cur { border-color: var(--violet); color: var(--violet);
  background: color-mix(in srgb, var(--violet) 14%, var(--surface-2)); }
.picker-title { grid-column: 1 / -1; font-family: var(--mono); font-size: .68rem; color: var(--dimmer); letter-spacing: .06em; }
.picker .clear { grid-column: span 2; width: auto; font-family: var(--sans); font-size: .76rem; font-weight: 560; }
.picker .ctrl-btn { font-size: 1.2rem; }

.lab-state .panel-body, .lab-shots .panel-body { padding: .9rem; display: grid; gap: .8rem; }
.lab-shots .panel-body { grid-template-columns: minmax(0, 1fr); }
.shots-ctl { display: flex; flex-wrap: wrap; align-items: center; gap: .6rem; }
.shots-ctl label { font-family: var(--mono); font-size: .72rem; color: var(--dimmer); }
.shots-ctl input[type=range] { width: 140px; accent-color: var(--rose); }
.shots-ctl output { font-family: var(--mono); font-size: .76rem; color: var(--rose); min-width: 3em; }
.hist8 { display: grid; grid-template-columns: repeat(8, minmax(0, 1fr)); gap: .35rem; align-items: end; height: 150px;
  padding-top: .4rem; }
.hist8 .hb { position: relative; height: 100%; display: flex; align-items: flex-end; justify-content: center; }
.hist8 .hb-ghost { position: absolute; left: 12%; right: 12%; bottom: 0; border: 1.5px dashed var(--dimmer); border-bottom: 0;
  border-radius: 4px 4px 0 0; opacity: .7; transition: height .3s ease; }
.hist8 .hb-fill { position: relative; width: 64%; border-radius: 4px 4px 0 0; background: var(--violet);
  transition: height .45s ease; min-height: 0; }
.hist8 .hb-fill.odd { background: var(--rose); }
.hist8-labels { display: grid; grid-template-columns: repeat(8, minmax(0, 1fr)); gap: .35rem; }
.hist8-labels span { font-family: var(--mono); font-size: .68rem; color: var(--dim); text-align: center; }
.hist8-labels small { display: block; color: var(--dimmer); font-size: .62rem; font-variant-numeric: tabular-nums; }
.shots-note { margin: 0; font-size: .8rem; color: var(--dimmer); }

/* ── 6. grover ───────────────────────────────────────────── */
.grover { padding: 1rem 1.1rem 1.2rem; display: grid; gap: 1rem; }
.gv-top { display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: .8rem; align-items: center; }
@media (max-width: 620px) { .gv-top { grid-template-columns: 1fr; } }
.gv-btns { display: flex; flex-wrap: wrap; gap: .45rem; }
.gv-k { font-family: var(--mono); font-size: .8rem; color: var(--dim); text-align: right; }
.gv-k b { color: var(--violet); font-size: 1.1rem; }
.gv-stage { position: relative; height: 220px; border-radius: 10px; background: var(--surface-2);
  border: 1px solid var(--line-soft); padding: 10px 8px; }
.gv-bars { position: absolute; inset: 10px 70px 10px 8px; display: flex; gap: 2px; }
.gv-bar { position: relative; flex: 1 1 0; min-width: 0; cursor: pointer; border-radius: 3px; }
.gv-bar:hover { background: color-mix(in srgb, var(--violet) 8%, transparent); }
.gv-bar > i { position: absolute; left: 12%; right: 12%; border-radius: 2px; background: var(--accent);
  transition: top .5s cubic-bezier(.3,.8,.3,1), height .5s cubic-bezier(.3,.8,.3,1), background .3s; }
.gv-bar.neg > i { background: var(--rose); }
.gv-bar.mark > i { background: var(--amber); box-shadow: 0 0 14px color-mix(in srgb, var(--amber) 50%, transparent); }
.gv-bar.mark.neg > i { background: var(--rose); box-shadow: 0 0 14px color-mix(in srgb, var(--rose) 50%, transparent); }
.gv-axis { position: absolute; left: 0; right: 0; top: 50%; height: 1px; background: var(--line); pointer-events: none; }
.gv-mean { position: absolute; left: 0; right: 0; height: 0; border-top: 1.5px dashed var(--violet);
  transition: top .5s cubic-bezier(.3,.8,.3,1); pointer-events: none; }
.gv-mean span { position: absolute; right: -64px; top: -.72em; font-family: var(--mono); font-size: .66rem; color: var(--violet);
  background: var(--surface-2); padding: 0 .3rem; border-radius: 4px; }
.gv-say { margin: 0; font-size: .88rem; color: var(--dim); min-height: 2.9em; line-height: 1.55; }
.gv-say b { color: var(--text); }
.gv-lower { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1.2fr); gap: 1rem; align-items: start; }
@media (max-width: 760px) { .gv-lower { grid-template-columns: 1fr; } }
.gv-stats { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: .5rem; }

/* ── 7. hardware ─────────────────────────────────────────── */
.plats { display: grid; grid-template-columns: repeat(auto-fit, minmax(230px, 1fr)); gap: .9rem; margin: 0 0 1.8rem; }
.plat { background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius); padding: 1rem 1.05rem;
  box-shadow: var(--shadow); }
.plat h4 { color: var(--violet); font-family: var(--mono); font-size: .8rem; letter-spacing: .06em; text-transform: uppercase; }
.plat p { margin: 0 0 .45rem; font-size: .86rem; color: var(--dim); line-height: 1.5; }
.plat p:last-child { margin-bottom: 0; }
.plat b { color: var(--text); font-weight: 600; }

.budget { padding: 1rem 1.1rem 1.2rem; display: grid; gap: .8rem; }
.budget-ctl { display: grid; grid-template-columns: auto minmax(0, 1fr) auto; gap: .8rem; align-items: center; }
.budget-ctl label { font-family: var(--mono); font-size: .72rem; color: var(--dimmer); letter-spacing: .06em; text-transform: uppercase; }
.budget-ctl input { width: 100%; accent-color: var(--rose); }
.budget-ctl output { font-family: var(--mono); font-size: .95rem; color: var(--rose); min-width: 5.5em; text-align: right; }
.budget-say { margin: 0; font-size: .9rem; color: var(--dim); }
.budget-say b { color: var(--text); font-family: var(--mono); }

.sc { padding: 1rem 1.1rem 1.2rem; display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 250px); gap: 1.1rem; align-items: center; }
@media (max-width: 720px) { .sc { grid-template-columns: 1fr; } }
.sc-fig { display: grid; place-items: center; min-width: 0; }
.sc-fig svg { width: auto; max-width: 100%; height: auto; }
.sc-side { display: grid; gap: .7rem; }
.sc-say { margin: 0; font-size: .86rem; color: var(--dim); line-height: 1.5; }
.sc-say b { color: var(--text); }
.sc-legend { display: grid; gap: .3rem; font-size: .76rem; color: var(--dimmer); font-family: var(--mono); }
.sc-legend span { display: flex; align-items: center; gap: .45rem; }
.sw { width: 12px; height: 12px; border-radius: 3px; display: inline-block; flex: none; }
.data-q { cursor: pointer; }
.data-q:focus { outline: none; }
.data-q:focus-visible circle.dq { stroke: var(--violet); stroke-width: 3; }

/* ── 8. uses ─────────────────────────────────────────────── */
.uses { display: grid; grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); gap: .9rem; }
.use { position: relative; background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 1rem 1.05rem; box-shadow: var(--shadow); border-top: 3px solid var(--line); }
.use h4 { margin: .35rem 0 .45rem; }
.use p { margin: 0; font-size: .86rem; color: var(--dim); line-height: 1.55; }
.use-tag { font-family: var(--mono); font-size: .66rem; letter-spacing: .1em; text-transform: uppercase;
  padding: .12rem .45rem; border-radius: 5px; border: 1px solid; }
.use-yes { border-top-color: var(--accent); }
.use-yes .use-tag { color: var(--accent); border-color: color-mix(in srgb, var(--accent) 45%, transparent); }
.use-maybe { border-top-color: var(--amber); }
.use-maybe .use-tag { color: var(--amber); border-color: color-mix(in srgb, var(--amber) 45%, transparent); }
.use-no { border-top-color: var(--rose); }
.use-no .use-tag { color: var(--rose); border-color: color-mix(in srgb, var(--rose) 45%, transparent); }

@media (prefers-reduced-motion: reduce) {
  .gv-bar > i, .gv-mean, .hist8 .hb-fill, .hist8 .hb-ghost, .hist2-fill, .meter > span, .probbar > span { transition: none; }
}