/* Number Systems (computer-science/number-base-converter.php). The page chrome is the one-screen
   layout in /css/resource.css. On a laptop or desktop: binary, denary and hexadecimal side by side,
   each with its working underneath (scrolling inside its panel). On smaller screens they stack and
   the page scrolls. Theme tokens only. */

.ns{flex:1;min-height:0;display:grid;grid-template-columns:minmax(0,1.2fr) minmax(0,1fr) minmax(0,1fr);gap:14px;align-items:stretch}
.ns-col{display:flex;flex-direction:column;min-height:0;padding:14px 16px 12px}
.ns-head{display:flex;align-items:baseline;justify-content:space-between;gap:10px;margin-bottom:10px;flex:none}
.ns-head h2{margin:0;font:700 15px/1.2 var(--font-display);color:var(--ink);letter-spacing:normal;text-transform:none}
.ns-base{font:500 11.5px/1 var(--font-mono);color:var(--muted);margin-left:6px}
.ns-range{font-size:11.5px;color:var(--muted);white-space:nowrap}

/* typed values */
.ns-input{flex:none;width:100%;font:600 26px/1.2 var(--font-mono);letter-spacing:.04em;color:var(--ink);background:var(--paper);border:1.5px solid var(--line-strong);border-radius:6px;padding:8px 12px}
.ns-input:focus{outline:none;border-color:var(--focus);box-shadow:0 0 0 3px var(--hint-tint)}
.ns-input.err{border-color:var(--bad);box-shadow:0 0 0 3px var(--bad-tint)}
.ns-err{flex:none;margin:4px 0 0;min-height:1.2em;font-size:12px;line-height:1.2;color:var(--bad)}

/* the bits: one row per byte, each bit a column (place value, switch, digit, what it adds) */
.ns-bits{flex:none;display:flex;flex-direction:column;gap:10px;margin:2px 0 8px}
.ns-byte{display:grid;grid-template-columns:repeat(4,minmax(0,1fr)) 10px repeat(4,minmax(0,1fr));align-items:start}
.ns-byte .gap{align-self:stretch;margin:2px 4px;border-left:1px dashed var(--line-strong)}
.ns-bit{display:flex;flex-direction:column;align-items:center;gap:5px;min-width:0}
.ns-place{font:500 11px/1 var(--font-mono);color:var(--muted);white-space:nowrap}
.ns-bit.sign .ns-place{color:var(--accent-b-deep);font-weight:700}
.ns-digit{font:700 17px/1 var(--font-mono);color:var(--ink)}
.ns-adds{font:500 11px/1 var(--font-mono);color:var(--ink-soft);white-space:nowrap}
.ns-adds.zero{color:var(--line-strong)}
.ns-bit.sign .ns-adds:not(.zero){color:var(--accent-b-deep);font-weight:700}

/* a switch: the knob slides across when the bit changes (tap, click, swipe or Space) */
.ns-switch{position:relative;width:40px;height:22px;border-radius:999px;border:1.5px solid var(--line-strong);background:var(--line);padding:0;cursor:pointer;touch-action:pan-y;transition:background .2s ease,border-color .2s ease}
.ns-switch .knob{position:absolute;top:2px;left:2px;width:15px;height:15px;border-radius:50%;background:var(--panel);box-shadow:0 1px 2px color-mix(in srgb, var(--screen-bg) 30%, transparent);transition:transform .22s cubic-bezier(.3,.7,.2,1)}
.ns-switch[aria-checked="true"]{background:var(--accent);border-color:var(--accent)}
.ns-switch[aria-checked="true"] .knob{transform:translateX(18px);background:var(--on-accent)}
.ns-switch:focus-visible{outline:2px solid var(--focus);outline-offset:2px}
.ns-bit.sign .ns-switch[aria-checked="true"]{background:var(--accent-b-deep);border-color:var(--accent-b-deep)}

/* the working */
.ns-work{flex:1;min-height:0;overflow:auto;margin-top:6px;padding-top:10px;border-top:1px solid var(--line);font-size:13.5px;color:var(--ink-soft)}
.ns-work h3{margin:0 0 6px;font:700 11px/1.2 var(--font-display);text-transform:uppercase;letter-spacing:.07em;color:var(--muted)}
.ns-work h3:not(:first-child){margin-top:14px}
.ns-sum{font:500 14px/1.6 var(--font-mono);color:var(--ink-soft);word-break:break-word}
.ns-sum b{color:var(--accent);font-size:17px}
.ns-sum .neg{color:var(--accent-b-deep);font-weight:700}
.ns-note{margin:6px 0 0;font-size:12.5px;line-height:1.45;color:var(--muted)}
.ns-ladder{width:100%;border-collapse:collapse;font:500 13.5px/1.2 var(--font-mono)}
.ns-ladder td{padding:4px 6px;border-bottom:1px solid var(--line);color:var(--ink-soft)}
.ns-ladder td.r{text-align:right;white-space:nowrap;color:var(--muted);font-family:var(--font-body);font-size:12px}
.ns-ladder td.r b{font:700 15px/1 var(--font-mono);color:var(--accent);margin-left:6px}
.ns-pattern{font:600 15px/1.5 var(--font-mono);letter-spacing:.08em;color:var(--ink)}
.ns-pattern .grp{display:inline-block;margin-right:.6em}
.ns-pattern .ch{color:var(--accent-b-deep)}
.ns-step{display:flex;gap:8px;align-items:flex-start;margin:6px 0}
.ns-step .n{flex:none;width:20px;height:20px;border-radius:50%;background:var(--active-tint);color:var(--active);font:700 11px/20px var(--font-body);text-align:center}
.ns-nibbles{display:grid;grid-template-columns:repeat(auto-fill,minmax(140px,1fr));gap:8px}
.ns-nib{background:var(--paper);border:1px solid var(--line);border-radius:6px;padding:8px 10px}
.ns-nib .bits{font:600 15px/1.2 var(--font-mono);letter-spacing:.12em;color:var(--ink)}
.ns-nib .sum{font:500 11.5px/1.3 var(--font-mono);color:var(--muted);margin-top:3px}
.ns-nib .hex{font:700 22px/1 var(--font-mono);color:var(--accent-b-deep);margin-top:5px}

/* the questions (js/challenges.js) fill the same space */
.ns-quiz{flex:1;min-height:0}
.ns-q-val{display:inline-block;font:700 1.05em/1.2 var(--font-mono);letter-spacing:.06em;color:var(--accent-deep);background:var(--accent-tint);border-radius:4px;padding:1px 8px;margin:0 2px}
.ns-quiz .cq-opt > span:first-child{font-family:var(--font-mono);font-size:18px;letter-spacing:.04em}

/* fade the working in when it changes (not the switches) */
.ns-work > *{animation:ns-in .25s ease both}
@keyframes ns-in{from{opacity:0;transform:translateY(3px)}to{opacity:1;transform:none}}
@media (prefers-reduced-motion:reduce){.ns-work > *{animation:none}.ns-switch,.ns-switch .knob{transition:none}}

/* ---------- smaller screens: stack, and let the page scroll ---------- */
@media (max-width:900px),(max-height:560px){
  .ns{grid-template-columns:1fr;flex:none}
  .ns-work{flex:none;overflow:visible}
}
@media (max-width:420px){
  .ns-col{padding:12px}
  .ns-switch{width:34px;height:20px}
  .ns-switch .knob{width:13px;height:13px}
  .ns-switch[aria-checked="true"] .knob{transform:translateX(14px)}
  .ns-place,.ns-adds{font-size:10px}
  .ns-input{font-size:22px}
}