/* Benchtop Calculator page. Tokens, the top bar (.gn/.sn) and shared blocks come from benchtop/css/frame.css (homepage look,
   2026-10-17); buttons, inputs and the solver rows start from benchtop/css/app.css and are restyled at the end of this file. */
body.calc-page { min-height: 100vh; display: flex; flex-direction: column; background: var(--bg); }

.calc-main { flex: 1; width: 100%; max-width: 1240px; margin: 0 auto; padding: 24px max(16px, env(safe-area-inset-right, 0px)) 40px max(16px, env(safe-area-inset-left, 0px)); }
.calc-hero .lede { margin: 6px 0 16px; max-width: 70ch; }
.calc-modes { display: inline-flex; gap: 4px; padding: 4px; border: 1px solid var(--line); border-radius: 12px; background: var(--surface); margin-bottom: 18px; }
.calc-modes button { display: inline-flex; align-items: center; gap: 8px; border: 0; background: none; padding: 9px 16px; border-radius: 9px; font-size: 15px; font-weight: 600; color: var(--muted); }
.calc-modes button svg { width: 18px; height: 18px; fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
.calc-modes button[aria-pressed="true"] { background: var(--accent); color: var(--accent-ink); }
.calc-h2 { margin: 0 0 10px; font: 700 20px/1.2 var(--font-display); }

/* one formula */
.calc-one { display: grid; grid-template-columns: 300px minmax(0, 1fr); gap: 16px; align-items: start; }
.calc-lawlist { position: sticky; top: 76px; max-height: calc(100vh - 96px); overflow-y: auto; overscroll-behavior: contain; }
.calc-lawlist .input { margin-bottom: 6px; }
.calc-list-h { margin: 14px 0 4px; text-transform: uppercase; letter-spacing: .06em; font-size: 11.5px; }
.calc-lawitems { display: flex; flex-direction: column; gap: 2px; }
.calc-lawitem { display: flex; flex-direction: column; gap: 2px; text-align: left; border: 1px solid transparent; background: none; border-radius: 8px; padding: 7px 9px; color: var(--ink); font: inherit; }
.calc-lawitem:hover { background: var(--surface-2); }
.calc-lawitem.on { border-color: var(--accent); background: var(--accent-soft); }
.calc-lawitem.above { opacity: .82; }
.calc-lawitem .nm { font-size: 14px; font-weight: 500; }
.calc-lawitem .f { font-size: 14px; color: var(--muted); }
.calc-solver .sv-formula { font-size: 26px; }
.calc-solver .sv-formula > span { display: inline-block; }
.cw-warn { color: var(--ink); border-left: 3px solid var(--warn); padding-left: 8px; }

/* multi-step */
.calc-multi { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1.15fr); gap: 16px; align-items: start; }
.calc-inputs { display: flex; flex-direction: column; gap: 10px; }
.calc-inputs .calc-h2 { margin: 6px 0 0; }
.calc-ex { display: flex; flex-direction: column; gap: 4px; padding-bottom: 10px; border-bottom: 1px solid var(--line); }
.calc-ex select { width: 100%; }
.kn-rows { display: flex; flex-direction: column; gap: 6px; }
.kn-row { display: grid; grid-template-columns: 40px minmax(0, 1.5fr) minmax(0, 1fr) auto 30px; gap: 6px 8px; align-items: center; padding: 6px 8px; border: 1px solid var(--line); border-radius: 8px; background: var(--surface-2); }
.kn-sym { font: 600 17px/1 var(--font-body); text-align: center; }
.kn-row select.kn-q { min-width: 0; width: 100%; }
.kn-del { border: 1px solid var(--line); background: var(--surface); border-radius: 6px; width: 30px; height: 30px; font-size: 18px; line-height: 1; color: var(--muted); }
.kn-del:hover { color: var(--bad); border-color: var(--bad); }
.kn-err { grid-column: 2 / -1; font-size: 13px; }
.kn-err:empty { display: none; }
.kn-add { display: flex; flex-wrap: wrap; align-items: center; gap: 6px; }
.kn-target { display: flex; flex-wrap: wrap; align-items: center; gap: 8px; }
.kn-target #tg-q { flex: 1 1 260px; min-width: 0; }
.calc-assume { margin-top: 4px; font-size: 14px; }
.calc-result { position: sticky; top: 76px; max-height: calc(100vh - 96px); overflow-y: auto; overscroll-behavior: contain; display: flex; flex-direction: column; gap: 10px; border-top: 3px solid var(--accent); }
.calc-empty { margin: 4px 0; }
.calc-hints { display: flex; flex-wrap: wrap; gap: 6px; }
.calc-hints .chip { white-space: normal; text-align: left; }

.chain-flow { display: flex; flex-wrap: wrap; align-items: center; gap: 6px; padding: 10px 12px; border: 1px dashed var(--line-strong); border-radius: 10px; font-size: 16px; }
.cf-given { color: var(--muted); font-weight: 500; }
.cf-arrow { color: var(--faint); }
.cf-q { padding: 3px 10px; border-radius: 999px; border: 1px solid var(--line-strong); background: var(--surface); font-weight: 600; }
.cf-q.bridge { border-style: dashed; }
.cf-q.target { background: var(--accent); border-color: var(--accent); color: var(--accent-ink); }

.cw-steps { list-style: none; margin: 10px 0 0; padding: 0; display: flex; flex-direction: column; gap: 10px; }
.cw-step { border: 1px solid var(--line); border-radius: 10px; padding: 10px 12px; background: var(--surface-2); }
.cw-step.bridge { border-style: dashed; }
.cw-step.last { border-color: var(--accent); }
.cw-head { display: flex; flex-wrap: wrap; align-items: baseline; gap: 4px 10px; margin-bottom: 6px; }
.cw-n { font: 700 12px/1 var(--font-mono); text-transform: uppercase; letter-spacing: .06em; color: var(--accent); }
.cw-what { font-weight: 600; font-size: 16px; }
.cw-note { margin: 0 0 6px; }
.cw-step .steps { margin: 0; }
.cw-final { margin-top: 10px; }
.badge.assume { background: color-mix(in oklab, var(--warn) 22%, var(--surface)); color: var(--ink); border-color: var(--warn); }
.badge.link { background: var(--surface); }
.calc-working .steps li { grid-template-columns: 120px 1fr; }

.calc-foot { text-align: center; padding: 18px 16px 28px; font-size: 13px; color: var(--muted); border-top: 1px solid var(--line); }
.calc-foot a { color: var(--muted); }

@media (max-width: 900px) {
  .calc-one, .calc-multi { grid-template-columns: 1fr; }
  .calc-lawlist, .calc-result { position: static; max-height: none; }
  .calc-lawlist { max-height: 340px; overflow-y: auto; overscroll-behavior: auto; }
  .calc-result { overscroll-behavior: auto; }
}
@media (max-width: 640px) {
  .kn-row { grid-template-columns: 34px minmax(0, 1fr) auto; }
  .kn-row .kn-q { grid-column: 2; }
  .kn-row .kn-del { grid-column: 3; grid-row: 1; justify-self: end; }
  .kn-row .kn-v { grid-column: 1 / 3; }
  .kn-row .kn-u, .kn-row .sv-unit-fixed { grid-column: 3; }
  .kn-err { grid-column: 1 / -1; }
  .calc-modes { display: flex; }
  .calc-modes button { flex: 1; justify-content: center; padding: 9px 8px; }
  .calc-working .steps li { grid-template-columns: 1fr; gap: 4px; }
  .calc-working .steps .k { justify-self: start; padding: 4px 8px; }
}


/* ================= homepage-style restyle (2026-10-17) ================= */
/* top bar: Benchtop's .gn + .sn, with the grade / language / theme tools this page draws into #calc-tools */
.calc-page .gn-tools .seg { padding: 2px; }
.calc-page .gn-tools .seg button { padding: 3px 9px; font-size: 11.5px; font-weight: 600; }
.calc-pill { display: inline-grid; place-items: center; height: 26px; padding: 0 10px; border: 0; border-radius: 999px; background: var(--seg-bg); color: var(--ink); font-size: 11.5px; font-weight: 600; -webkit-tap-highlight-color: transparent; }
.calc-pill.icon { width: 32px; height: 32px; padding: 0; background: none; }
.calc-pill.icon:hover { background: var(--seg-bg); }
.calc-pill svg { width: 17px; height: 17px; fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; }
.tool-back { display: inline-flex; flex: none; align-items: center; gap: 4px; padding: 6px 13px 6px 8px; border-radius: 999px; background: var(--seg-bg); color: var(--ink); font-size: 13px; font-weight: 500; text-decoration: none; -webkit-tap-highlight-color: transparent; }
.tool-back:hover { background: color-mix(in oklab, var(--seg-bg), var(--ink) 8%); }
.tool-back svg { width: 16px; height: 16px; fill: none; stroke: currentColor; stroke-width: 2.2; stroke-linecap: round; stroke-linejoin: round; }
.tool-back .short { display: none; }

/* page */
.calc-main { padding-top: 28px; }
.calc-hero .lede { margin: 10px 0 20px; }
.calc-modes { gap: 0; padding: 3px; border: 0; border-radius: 999px; background: var(--seg-bg); margin-bottom: 22px; }
.calc-modes button { padding: 8px 18px; border-radius: 999px; font-weight: 500; -webkit-tap-highlight-color: transparent; }
.calc-modes button[aria-pressed="true"] { background: var(--seg-on); color: var(--ink); box-shadow: 0 1px 3px rgba(0, 0, 0, .12); }
.calc-h2 { margin: 0 0 12px; font: 600 21px/1.2 var(--font-display); letter-spacing: -.01em; }
.calc-page .panel-card { padding: 22px; border-radius: 24px; }
.calc-one { gap: 20px; }
.calc-lawlist { top: calc(var(--snav) + 16px); max-height: calc(100vh - var(--snav) - 32px); padding: 18px 14px; }
.calc-lawlist .input { border: 0; background: var(--surface); box-shadow: inset 0 0 0 1px var(--line); }
.calc-list-h { margin: 16px 4px 6px; text-transform: none; letter-spacing: 0; font-size: 12px; font-weight: 600; }
.calc-lawitem { border: 0; border-radius: 12px; padding: 8px 10px; }
.calc-lawitem:hover { background: color-mix(in oklab, var(--surface-2), var(--ink) 5%); }
.calc-lawitem.on { border: 0; background: var(--surface); box-shadow: inset 0 0 0 1.5px var(--accent); }

/* the solver card, the same as the calculator on Benchtop's topic pages (benchtop/css/pages/physics.css) */
.calc-solver, .calc-result { background: var(--surface); box-shadow: var(--shadow); }
.calc-solver .solver { gap: 14px; }
.calc-solver .sv-laws .chip { padding: 6px 12px; font-size: 13px; white-space: normal; text-align: left; }
/* solver.js makes .sv-formula a flex row, which split "E<sub>k</sub>" into "E k": keep it one inline line */
.calc-solver .sv-formula { display: block; font: 600 26px/1.35 var(--font-body); }
.calc-solver .sv-formula > .lvl-tag { margin-left: 8px; }
.calc-solver .sv-tools .btn, .calc-solver .sv-work .btn { min-height: 32px; padding: 6px 14px; border: 0; border-radius: 999px; background: var(--seg-bg); color: var(--ink); font-size: 13px; font-weight: 500; }
.calc-solver .sv-tools .btn:hover, .calc-solver .sv-work .btn:hover { background: color-mix(in oklab, var(--seg-bg), var(--ink) 8%); }
.calc-solver .sv-rows { gap: 8px; }
.calc-solver .sv-row { grid-template-columns: 56px 48px minmax(0, 1fr) 170px 120px; gap: 8px 10px; padding: 10px 12px; border: 0; border-radius: 16px; background: var(--surface-2); }
.calc-solver .sv-row.unknown { background: var(--accent-soft); box-shadow: inset 0 0 0 1.5px var(--accent); }
.calc-solver .sv-name { font-size: 14px; line-height: 1.3; }
.calc-solver .sv-presets { grid-column: 3 / -1; }
.calc-solver .sv-find { height: 30px; padding: 0; border: 0; border-radius: 999px; background: var(--surface); color: var(--muted); font: 600 12px/1 var(--font-body); cursor: pointer; box-shadow: inset 0 0 0 1px var(--line); -webkit-tap-highlight-color: transparent; }
.calc-solver .sv-find:hover { color: var(--ink); }
.calc-solver .sv-find[aria-pressed="true"] { background: var(--accent); color: var(--accent-ink); font-size: 15px; box-shadow: none; }
.calc-solver .sv-sym { font-size: 19px; }
.calc-solver .sv-in { height: 40px; padding: 0 12px; border: 1.5px dashed transparent; border-radius: 10px; background: var(--surface); color: var(--ink); font: 500 16px var(--font-mono); box-shadow: inset 0 0 0 1px var(--line); }
.calc-solver .sv-in:focus { border-color: transparent; outline: none; box-shadow: inset 0 0 0 2px var(--accent); }
.calc-solver .sv-in:disabled { border-color: var(--line-strong); background: transparent; box-shadow: none; }
.calc-solver .sv-unit { height: 40px; padding: 0 8px; border: 0; border-radius: 10px; background: var(--surface); color: var(--ink); font-size: 14px; box-shadow: inset 0 0 0 1px var(--line); }
.calc-solver .sv-unit-fixed { font-size: 14px; }
.calc-solver .mini { padding: 3px 10px; border: 0; border-radius: 999px; background: var(--surface); color: var(--muted); box-shadow: inset 0 0 0 1px var(--line); }
.calc-solver .mini:hover { color: var(--ink); box-shadow: inset 0 0 0 1px var(--line-strong); }
.calc-solver .sv-answer { gap: 4px; padding: 14px 16px; border: 0; border-radius: 16px; background: var(--accent-soft); }
.calc-solver .sv-ans-v { font-size: 24px; }
.calc-solver .sv-work summary { color: var(--ink); font-size: 14px; }
.calc-page .err { padding: 10px 14px; border-radius: 12px; background: var(--bad-soft); color: var(--bad); font-size: 14px; }

/* multi-step */
.calc-multi { gap: 20px; }
.calc-ex select, .kn-target select, .kn-row select, .kn-row input { border-radius: 10px; }
.kn-row { border: 0; border-radius: 14px; background: var(--surface); padding: 8px 10px; }
.kn-del { border: 0; border-radius: 999px; background: var(--seg-bg); }
.kn-del:hover { background: var(--bad-soft); color: var(--bad); }
.calc-result { top: calc(var(--snav) + 16px); max-height: calc(100vh - var(--snav) - 32px); border-top: 0; }
.chain-flow { border: 0; border-radius: 14px; background: var(--surface-2); }
.cf-q { border: 0; background: var(--surface); box-shadow: inset 0 0 0 1px var(--line); }
.cf-q.bridge { box-shadow: inset 0 0 0 1px var(--line-strong); }
.cf-q.target { background: var(--accent); color: var(--accent-ink); box-shadow: none; }
.cw-step { border: 0; border-radius: 16px; background: var(--surface-2); padding: 12px 14px; }
.cw-step.bridge { border: 0; box-shadow: inset 0 0 0 1px var(--line-strong); }
.cw-step.last { border: 0; box-shadow: inset 0 0 0 1.5px var(--accent); }
.cw-n { font: 600 12px/1 var(--font-body); text-transform: none; letter-spacing: 0; }
.calc-foot { border-top: 0; }

@media (max-width: 1100px) {
  .calc-solver .sv-row { grid-template-columns: 52px 40px minmax(0, 1fr); }
  .calc-solver .sv-name { grid-column: 3; }
  .calc-solver .sv-in { grid-column: 1 / 3; }
  .calc-solver .sv-unit, .calc-solver .sv-unit-fixed { grid-column: 3; justify-self: start; }
  .calc-solver .sv-presets { grid-column: 1 / -1; }
}
@media (max-width: 734px) {
  .calc-page .gn-brand span { display: none; }
  .calc-page .gn-row { gap: 12px; }
  .calc-page .gn-tools { gap: 6px; }
  .calc-page .gn-tools .seg button { padding: 3px 7px; }
  .tool-back .long { display: none; }
  .tool-back .short { display: inline; }
  .calc-main { padding-top: 20px; }
  .calc-page .panel-card { padding: 16px 14px; border-radius: 20px; }
  .calc-solver .sv-in, .calc-solver .sv-unit { height: 42px; font-size: 16px; }
  .calc-solver .sv-formula { font-size: 23px; }
}