/* Question tools: toolbar buttons, shared tool surface (drawer >= 1024px, sheet below), panels. Design: design/tools/01_toolbar.md */
.vh{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}

/* ---- toolbar ---- */
.q-tools{display:flex;gap:6px;align-items:center;flex-wrap:nowrap;margin-left:8px}
.q-head .q-id{margin-left:auto}
.tool-btn{position:relative;display:inline-grid;place-items:center;flex:none;width:44px;height:44px;border:1px solid var(--bp-line);border-radius:999px;background:var(--bp-neu-soft);color:var(--bp-ink-2);cursor:pointer;transition:transform var(--bp-t-press) var(--bp-ease)}
.tool-btn:active{transform:scale(.94)}
@media(hover:hover){.tool-btn:hover{background:var(--bp-paper-2)}}
.tool-btn[aria-pressed="true"],.tool-btn[aria-expanded="true"]{background:var(--bp-tint-soft);color:var(--bp-tint-ink);border-color:var(--bp-tint)}
.tool-btn.is-disabled{opacity:.45;cursor:not-allowed}
.tool-btn.is-disabled::before{content:"";position:absolute;left:11px;right:11px;top:50%;height:2px;background:currentColor;transform:rotate(-45deg);border-radius:2px}
.tool-btn .pad-dot{position:absolute;top:6px;right:6px;margin:0;width:8px;height:8px}
.tool-btn::after{content:attr(data-tip);position:absolute;bottom:calc(100% + 6px);left:50%;transform:translateX(-50%);padding:5px 9px;border-radius:8px;background:var(--bp-ink);color:var(--bp-paper);font:600 13px/1.2 var(--lg-font);white-space:nowrap;pointer-events:none;opacity:0;visibility:hidden;z-index:30}
@media(hover:hover){.tool-btn:hover::after{opacity:1;visibility:visible}}
.tool-btn:focus-visible::after{opacity:1;visibility:visible}
.tool-btn:not([data-tip])::after{display:none}
@media(max-width:560px){.q-tools{flex-basis:100%;justify-content:flex-end;margin:2px 0 0}.q-head .q-id{display:none}}
@media(min-width:561px) and (max-width:1023px){.q-head .q-id{margin-left:auto}}

/* ---- shared surface ---- */
.tool-host{position:fixed;z-index:70;display:flex;flex-direction:column;overflow:hidden;color:var(--bp-ink)}
.tool-host[hidden]{display:none}
.tool-host.opening{animation:bp-tool-in var(--bp-t-enter) var(--bp-ease)}
@keyframes bp-tool-in{from{opacity:0;transform:translateX(24px)}}
.tool-head{position:sticky;top:0;z-index:2;padding:4px 10px 6px;background:var(--bp-glass-menu);border-bottom:1px solid var(--bp-line)}
.tool-head-row{display:flex;align-items:center;gap:8px}
.tool-tabs{display:flex;gap:4px;padding:3px;border-radius:999px;background:var(--bp-paper-2);border:1px solid var(--bp-line);flex:1;min-width:0}
.tool-tabs button{flex:1;min-height:40px;border:0;border-radius:999px;background:none;color:var(--bp-ink-2);font:600 14px var(--lg-font);cursor:pointer;white-space:nowrap}
.tool-tabs button[aria-selected="true"]{background:var(--bp-paper);color:var(--bp-ink);box-shadow:var(--bp-shadow-1)}
.tool-close{flex:none;width:44px;height:44px;border:0;border-radius:50%;background:none;color:var(--bp-ink-2);display:grid;place-items:center;cursor:pointer}
.tool-body{flex:1;min-height:0;overflow:auto;overscroll-behavior:contain;padding:12px}
.tool-panel[hidden]{display:none}
.tool-grip{display:none;height:22px;align-items:center;justify-content:center;cursor:ns-resize;touch-action:none}
.tool-grip span{width:36px;height:5px;border-radius:3px;background:var(--bp-field-line);opacity:.6}
.tool-resize{display:none;position:absolute;left:0;top:0;bottom:0;width:12px;cursor:ew-resize;touch-action:none}
.tool-resize:hover,.tool-resize:focus-visible{background:var(--bp-tint-soft)}
.tool-loading{padding:12px}
/* drawer */
@media(min-width:1024px){
  .tool-host{top:calc(env(safe-area-inset-top,0px) + 84px);right:16px;bottom:16px;width:var(--tool-w,380px);border-radius:24px}
  .tool-resize{display:block}
  body.tools-drawer .wrap{width:min(1180px,calc(100% - 64px - var(--tool-w,380px) - 16px));margin-left:32px;margin-right:auto}
}
/* sheet */
@media(max-width:1023px){
  .tool-host{left:0;right:0;bottom:0;height:calc(var(--sheet-h,.55) * 100dvh);border-radius:24px 24px 0 0;padding-bottom:env(safe-area-inset-bottom,0px)}
  .tool-host.opening{animation-name:bp-sheet-in}
  .tool-grip{display:flex}
  .tool-body{padding:12px 16px}
  .tool-panel>*{max-width:560px;margin-left:auto;margin-right:auto}
  body.tools-sheet main{padding-bottom:calc(var(--sheet-h,.55) * 100dvh + 24px)}
  body.tools-sheet .kp-dock{display:none}
  body.tools-sheet .toast{bottom:calc(var(--sheet-h,.55) * 100dvh + 16px)}
  body.tools-sheet.kb-open .tool-host{height:56px;bottom:var(--kb-h,0px)}
  body.tools-sheet.kb-open .tool-body{display:none}
}
@keyframes bp-sheet-in{from{opacity:0;transform:translateY(24px)}}
/* calculator locked on a Non-calculator question */
.tool-panel{position:relative}
.calc-lock{position:absolute;inset:0;z-index:5;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:12px;text-align:center;padding:24px;background:var(--bp-paper);border-radius:16px;color:var(--bp-ink)}
.calc-locked .cz-device{pointer-events:none}
@media(forced-colors:active){.tool-btn{border:1px solid ButtonText}.tool-btn[aria-pressed="true"]{background:Highlight;color:HighlightText}.tool-host{border:1px solid CanvasText}}
@media(prefers-reduced-motion:reduce){.tool-host.opening{animation:none}}

/* ---- symbols ---- */
.sym-title{font:650 17px var(--lg-font-display);margin:0 0 10px}
.sym-search{display:block;width:100%;flex:none;margin-bottom:10px}
.sym-recent{margin-bottom:8px}.sym-recent .faint{margin-bottom:4px}
.sym-pills{display:flex;gap:6px;overflow-x:auto;scrollbar-width:none;padding:2px 0 10px;margin:0 -2px}
.sym-pills::-webkit-scrollbar{display:none}.sym-pills.dim{opacity:.5}
.sym-pill{flex:none;min-height:44px;padding:0 16px;border:0;border-radius:999px;background:var(--bp-neu-soft);color:var(--bp-ink-2);font:600 15px var(--lg-font);cursor:pointer;white-space:nowrap}
.sym-pill[aria-selected="true"]{background:var(--bp-primary);color:var(--bp-on-primary,#fff)}
.sym-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(48px,1fr));gap:6px}
.sym-key{position:relative;min-width:48px;min-height:48px;padding:0 4px;border:1px solid var(--bp-line);border-radius:12px;background:var(--bp-paper);color:var(--bp-ink);font-family:var(--math);cursor:pointer;display:grid;place-items:center;transition:transform var(--bp-t-press) var(--bp-ease)}
.sym-key:active{transform:scale(.94)}
@media(hover:hover){.sym-key:hover{background:var(--bp-paper-2)}.sym-key:hover::after{content:attr(data-tip);position:absolute;bottom:calc(100% + 6px);left:50%;transform:translateX(-50%);padding:5px 9px;border-radius:8px;background:var(--bp-ink);color:var(--bp-paper);font:600 13px/1.2 var(--lg-font);white-space:nowrap;pointer-events:none;z-index:40}}
.sym-box{opacity:.6}

/* ---- formula sheet ---- */
.formula-note{margin:0 0 10px;align-items:flex-start}
.fs-sect{border-top:1px solid var(--bp-line)}
.fs-sec{display:flex;align-items:center;gap:10px;width:100%;min-height:48px;padding:0 4px;border:0;background:none;color:var(--bp-ink);cursor:pointer;text-align:left;font:inherit}
.fs-sec .ic{transition:transform var(--bp-t-hover) var(--bp-ease)}.fs-sec[aria-expanded="true"] .ic{transform:rotate(180deg)}
.fs-row{display:grid;grid-template-columns:minmax(0,1fr) auto;gap:8px;align-items:start;padding:12px 4px;border-top:1px solid var(--bp-line)}
.fs-eq{font-size:1.1em;overflow-x:auto;padding:4px 0}
.fs-ins{padding:0;width:44px}

/* ---- calculator (.cz-*) ---- */
.cz-device{--cz-body:linear-gradient(180deg,#2A2D33,#1F2126);width:100%;max-width:356px;margin:0 auto;padding:8px;border-radius:26px;background:var(--cz-body);color:#F2F2F2;display:flex;flex-direction:column;gap:8px;box-shadow:0 12px 32px rgba(15,23,42,.28);outline:none;user-select:none;-webkit-user-select:none;touch-action:manipulation}
.cz-device:focus-visible{box-shadow:0 0 0 3px var(--bp-focus,#2563EB),0 12px 32px rgba(15,23,42,.28)}
.cz-lcd{position:relative;height:96px;padding:4px 10px 6px;border:6px solid #121418;border-radius:12px;background:#C8D5B9;color:#18221A;box-shadow:inset 0 2px 4px rgba(0,0,0,.25);font-family:ui-monospace,"SF Mono",Menlo,Consolas,monospace;font-variant-numeric:tabular-nums;display:flex;flex-direction:column;overflow:hidden}
.cz-ann{display:flex;gap:7px;height:14px;font:600 10px/14px var(--lg-font,system-ui);font-style:normal}
.cz-ann i{font-style:normal;opacity:.18}.cz-ann i.on{opacity:1}
.cz-expr{position:relative;flex:1;min-height:32px;overflow-x:auto;white-space:nowrap;scrollbar-width:none;font-size:20px;line-height:32px;display:flex;align-items:center}
.cz-expr::-webkit-scrollbar{display:none}
.cz-expr>.cz-slot,.cz-res>.cz-slot{display:inline-flex;align-items:center;white-space:nowrap}
.cz-res{min-height:34px;text-align:right;font-size:26px;line-height:34px;display:flex;justify-content:flex-end;align-items:center;overflow-x:auto;white-space:nowrap;scrollbar-width:none}
.cz-res.small{font-size:20px}
.cz-hint{height:13px;font:500 10px/13px var(--lg-font,system-ui);opacity:.75;white-space:nowrap;overflow:hidden}
.cz-err{font-weight:700}
.cz-slot{display:inline-flex;align-items:center}
.cz-f{display:inline-flex;flex-direction:column;align-items:center;vertical-align:middle;font-size:.82em;line-height:1.15;margin:0 .1em}
.cz-f>.d{border-top:1.5px solid currentColor;padding-top:1px}
.cz-sup{font-size:.7em;vertical-align:.65em;line-height:1;display:inline-flex}
.cz-sub{font-size:.7em;vertical-align:-.3em;display:inline-flex}
.cz-rad{display:inline-flex;align-items:stretch}
.cz-rt{display:inline-flex}.cz-rt svg{height:1.25em;width:.6em}
.cz-rad>.rad{border-top:1.5px solid currentColor;padding:0 .1em 0 .1em;display:inline-flex;align-items:center}
.cz-idx{font-size:.55em;align-self:flex-start}
.cz-abs{display:inline-flex;border-left:1.5px solid currentColor;border-right:1.5px solid currentColor;padding:0 .15em}
.cz-op{padding:0 .1em}.cz-fn{font-weight:600}
.cz-empty{display:inline-block;width:.55em;height:.85em;border:1px dashed currentColor;opacity:.55;border-radius:2px}
.cz-cur{display:inline-block;width:2px;height:1.1em;background:currentColor;margin:0 -1px;animation:cz-blink 1s steps(1) infinite}
.cz-device:not(:focus-within) .cz-cur{animation:none;opacity:.5}
@keyframes cz-blink{50%{opacity:0}}
.cz-mixed{display:inline-flex;align-items:center}
.cz-row{padding:2px 8px;font-size:15px;line-height:20px;border-radius:4px;cursor:pointer}
.cz-row.sel{background:#18221A;color:#C8D5B9}
.cz-lcd.is-menu .cz-expr{display:block;overflow:hidden;white-space:normal;font-size:15px;line-height:20px}
.cz-body{display:flex;flex-direction:column;gap:6px}
.cz-top{display:grid;grid-template-columns:44px 44px minmax(0,1fr) 44px 44px;grid-template-rows:repeat(3,44px);gap:6px;align-items:center}
.cz-brand{grid-area:1 / 4 / 2 / 6;display:flex;flex-direction:column;align-items:flex-end;justify-content:center;gap:4px;font:italic 600 11px var(--lg-font,system-ui);color:#cfcfcf}
.cz-solar{width:56px;height:8px;border-radius:2px;background:repeating-linear-gradient(90deg,#4a3b2a 0 6px,#2f2518 6px 8px)}
.cz-dpad{grid-area:1 / 3 / 4 / 4;position:relative;justify-self:center;width:132px;height:132px;border-radius:50%;background:#2A2D33;box-shadow:inset 0 0 0 1px rgba(255,255,255,.06)}
.cz-fn-grid{display:grid;grid-template-columns:repeat(6,minmax(0,1fr));gap:6px}
.cz-num-grid{display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:6px}
.cz-gap{min-height:44px}
.cz-key{position:relative;min-height:44px;min-width:44px;border:0;border-radius:10px;font:600 15px var(--lg-font,system-ui);cursor:pointer;display:flex;align-items:flex-end;justify-content:center;padding:0 2px 6px;box-shadow:0 2px 0 rgba(0,0,0,.35);transition:transform 80ms}
.cz-key:active,.cz-key.down{transform:translateY(1px) scale(.97)}
.cz-key:focus-visible{outline:2px solid #E0B54A;outline-offset:1px}
.cz-key.fn{background:#D9D4C7;color:#1B1C1F}
.cz-key.num{background:#EDE6D6;color:#1B1C1F;min-height:44px}
.cz-key.ctl{background:#EDE6D6;color:#9A3412;font-weight:800;min-height:44px}
.cz-key.exe{background:#EDE6D6;color:#1B1C1F;font-weight:800;min-height:44px}
.cz-key.top{background:#3A3D44;color:#F2F2F2;border-radius:999px;font-size:9px;letter-spacing:-.2px;align-items:center;padding:0}
.cz-key.shift{background:#3A3D44;color:#E0B54A;border-radius:999px;font-size:11px;align-items:center;padding:0}
.cz-key.top .cz-s{top:-1px}
.cz-s{position:absolute;top:2px;left:0;right:0;text-align:center;font:600 10px/12px var(--lg-font,system-ui);color:#B8860B}
.cz-key.top .cz-s,.cz-key.shift .cz-s{color:#E0B54A}
.cz-key.fn .cz-s,.cz-key.num .cz-s,.cz-key.ctl .cz-s,.cz-key.exe .cz-s{color:#8A6508}
.cz-lab.sm{font-size:12px}
.cz-key.dp{position:absolute;background:#3A3D44;color:#F2F2F2;border-radius:10px;align-items:center;padding:0;box-shadow:none;font-size:13px}
.dp-up{left:42px;top:0;width:48px;height:44px}.dp-down{left:42px;bottom:0;width:48px;height:44px}
.dp-left{left:0;top:42px;width:44px;height:48px}.dp-right{right:0;top:42px;width:44px;height:48px}
.cz-key.dp-ok{position:absolute;left:42px;top:42px;width:48px;height:48px;min-height:48px;border-radius:50%;background:#3A3D44;color:#F2F2F2;font-size:12px;align-items:center;padding:0}
.cz-foot{display:flex;align-items:center;gap:8px;max-width:356px;margin:8px auto 0}
.cz-model{flex:1;min-height:44px;border-radius:12px;border:1px solid var(--bp-line,rgba(0,0,0,.15));background:var(--bp-paper,#fff);color:var(--bp-ink,#111);padding:0 10px;font:inherit}
.cz-caption{max-width:356px;margin:4px auto 0;font-size:12px;line-height:16px}
.sr-only{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}
@media(prefers-reduced-motion:reduce){.cz-cur{animation:none}.cz-key{transition:none}}
@media(forced-colors:active){.cz-key{background:ButtonFace;color:ButtonText;border:1px solid ButtonText}.cz-lcd{background:Canvas;color:CanvasText}}