mathew/frontend/app/assets/css/_calculator.scss

@use 'mixins' as *;

// ---------- Graphing calculator (/calculator) ----------

// desktop: the plane owns the space beside the sidebar the way the link
// map does — a full surface with the function dock and the zoom buttons
// floating over it. (The page transition only fades, so no transform
// steals the fixed positioning.)
.calc-stage {
  position: fixed;
  inset: 0 0 0 var(--sidebar-w);
  transition: left 0.22s ease;
  z-index: 1;
  background: var(--bg);
}

// the plane fills the stage
.plot-wrap {
  position: absolute;
  inset: 0;
  overflow: hidden;
  background: var(--surface);
}

.plot-canvas {
  display: block;
  width: 100%;
  height: 100%;
  touch-action: none; // the plane owns drags and pinches, not the page
}

// the function dock, pinned to the plane's left edge
.calc-dock {
  position: absolute;
  top: 0;
  left: 0;
  bottom: 0;
  z-index: 2;
  display: flex;
  flex-direction: column;
  width: clamp(260px, 24vw, 320px);
  padding: 18px 16px;
  border-right: 1px solid var(--border);
  background: color-mix(in srgb, var(--bg-elev) 92%, transparent);
  backdrop-filter: blur(12px);
  box-shadow: var(--shadow-lg);
  overflow-y: auto;
}

.calc-dock-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  margin: 0 0 14px;
}

.calc-dock-title {
  @include eyebrow(0.74rem, 750, 0.09em);
  margin: 0;
}

.calc-rows {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.calc-row {
  display: flex;
  align-items: center;
  gap: 8px;
}

// the curve's hue; a press hands it on to the next one in the palette
.calc-swatch {
  flex: none;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  border: 2px solid color-mix(in srgb, var(--text) 12%, transparent);
  transition: transform 0.15s;

  &:hover { transform: scale(1.2); }
}

.calc-input-box {
  flex: 1;
  display: flex;
  align-items: center;
  min-width: 0;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--surface);
  transition: border-color 0.15s, box-shadow 0.15s;

  &:focus-within {
    border-color: var(--accent);
    box-shadow: var(--ring);
  }

  .calc-item.invalid & {
    border-color: color-mix(in srgb, var(--danger) 55%, transparent);
  }
}

// the "y =" the field answers to, set like the math it introduces
.calc-y {
  flex: none;
  padding: 0 2px 0 10px;
  color: var(--faint);
  font: italic 0.95rem/1 'Computer Modern', Georgia, serif;
}

// only a field that reads as a function wears the "y =" gutter; everything
// else — a relation, point, slider, or unfinished text — is bare, and the
// input takes back the room the gutter stood in
.calc-input-box.bare .calc-input {
  padding-left: 10px;
}

.calc-input {
  flex: 1;
  min-width: 0;
  padding: 9px 10px 9px 6px;
  border: 0;
  outline: none;
  background: transparent;
  color: var(--text);
  font: 0.95rem/1.2 'Computer Modern', Georgia, serif;

  &.input-error { color: var(--danger); }
}

// The typeset echo of the field's text (Desmos' way): while the reader
// types, the formula sets on its own line under the text; once the field
// rests, it takes the text's place beside the "y =" gutter, so the dock
// reads as mathematics. A click wakes the text again (the box is a label);
// the input only steps out of sight, never out of the tab order — and
// Tab waking it draws the text back. An expression that does not read
// carries no echo, so it stays plain text and red, as ever.
.calc-typeset {
  display: none;
  color: var(--text);

  .katex { font-size: 1rem; }
}

.calc-input-box.typeset {
  flex-wrap: wrap;

  .calc-typeset { display: block; }

  // typing: the echo takes a line of its own, under the field
  &:focus-within .calc-typeset {
    flex: 0 0 100%;
    padding: 0 10px 8px;
  }

  // at rest: the field folds away and the formula stands in its place
  &:not(:focus-within) {
    .calc-input {
      flex: none;
      width: 0;
      min-width: 0;
      padding: 0;
      opacity: 0;
    }

    .calc-typeset {
      flex: 1;
      min-width: 0;
      padding: 8px 10px;
      overflow-x: auto;
    }
  }
}

// A row that declared a variable ("k", "k = 3"). Once the reader stops
// editing it, the field folds away to nothing — the name and value now live
// in the slider laid in its place (see .calc-vars.is-inline). The input stays
// mounted and focusable (never display:none), so the slider's name can be a
// label that wakes it back to edit the declaration; a focused field stands
// open as any other. This is how a made variable reads as just a slider, not
// a "k = 3" box above a slider.
.calc-input-box.var-decl:not(:focus-within) {
  flex: 0 0 0;
  min-width: 0;
  overflow: hidden;
  border-color: transparent;
  background: transparent;

  .calc-input {
    width: 0;
    min-width: 0;
    padding: 0;
  }
}

// while the declaration's text is awake, its inline slider steps aside — the
// field is the whole row again
.calc-input-box.var-decl:focus-within ~ .calc-vars.is-inline {
  display: none;
}

.calc-remove:hover {
  color: var(--danger);
  background: color-mix(in srgb, var(--danger) 10%, transparent);
}

.calc-error {
  display: block;
  margin: 5px 2px 1px;
  color: var(--danger);
  font-size: 0.78rem;
}

.calc-add { margin-top: 12px; }

// free variables ("k", "a", "radius") — each slider hangs just under the
// row that claims it. The name sets like the maths it names; the drag does
// the rough work, the field the fine
.calc-vars {
  display: flex;
  flex-direction: column;
  gap: 4px;
  margin: 5px 0 2px;
  padding: 0;
  list-style: none;
}

.calc-var {
  display: flex;
  align-items: center;
  gap: 8px;
}

.calc-var-name {
  flex: none;
  min-width: 1.5ch;
  color: var(--text);
  font: italic 0.98rem/1 'Computer Modern', Georgia, serif;
}

// the name of a made variable is the door back to its declaration: it is a
// label for the folded field, so clicking it wakes "k = 3" to be edited
.calc-var-name.editable {
  padding: 1px 2px;
  border-radius: 4px;
  cursor: text;

  &:hover { background: var(--surface-2); }
}

// a made variable's slider laid in the row in place of its field: no hanging
// margin, the drag takes the room the field used to hold
.calc-vars.is-inline {
  flex: 1;
  min-width: 0;
  margin: 0;
  gap: 0;
}

.calc-var-range {
  flex: 1;
  min-width: 0;
  accent-color: var(--accent);
}

.calc-var-number {
  flex: none;
  width: 58px;
  min-width: 0;
  padding: 3px 6px;
  border: 1px solid var(--border);
  border-radius: 7px;
  background: var(--bg-elev);
  color: var(--text);
  font: 0.8rem/1.3 'Computer Modern', Georgia, serif;
  font-variant-numeric: tabular-nums;

  // no spinners on the slider's little twin — the drag is the spinner
  -moz-appearance: textfield;
  appearance: textfield;

  &::-webkit-outer-spin-button,
  &::-webkit-inner-spin-button {
    -webkit-appearance: none;
    appearance: none;
    margin: 0;
  }

  &:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: var(--ring);
  }
}

// the fold: the dock slides out to the left, under the app sidebar, and a
// quiet card takes its place at the plane's top-left corner
.calc-dock-enter-active,
.calc-dock-leave-active { transition: transform 0.22s ease; }

.calc-dock-enter-from,
.calc-dock-leave-to { transform: translateX(-105%); }

.calc-dock-open {
  position: absolute;
  top: 10px;
  left: 12px;
  z-index: 2;
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 7px 12px;
  border: 1px solid var(--border);
  border-radius: 11px;
  background: color-mix(in srgb, var(--bg-elev) 84%, transparent);
  backdrop-filter: blur(10px);
  box-shadow: var(--shadow-sm);
  color: var(--muted);
  font-size: 0.84rem;
  font-weight: 650;
  white-space: nowrap;
  transition: color 0.15s, background-color 0.15s;

  &:hover { color: var(--text); background: var(--surface-2); }
}

// the button row floating on the plane's top-right corner — clear of the dock
.plot-toolbar {
  position: absolute;
  top: 10px;
  right: 12px;
  z-index: 2;
  display: flex;
  gap: 2px;
  padding: 4px;
  border: 1px solid var(--border);
  border-radius: 11px;
  background: color-mix(in srgb, var(--bg-elev) 84%, transparent);
  backdrop-filter: blur(10px);
  box-shadow: var(--shadow-sm);
}

// the 3D scene hangs its toolbar from a wrapper so the configuration
// card can fold out under it: the wrapper takes the corner, the row
// keeps its look on the hinge
.plot-tools {
  position: absolute;
  top: 10px;
  right: 12px;
  z-index: 2;

  .plot-toolbar { position: static; }

  // the configuration button while its card is open, the graph menu's way
  .panel-icon-btn.open { color: var(--text); background: var(--surface-2); }
}

// the configuration card: the space the surfaces stand in — each edge
// editable, the height by default the surfaces' own, the mesh's fineness
.plot-config {
  @include dropdown-panel($z: 20, $overflow: visible);
  right: 0;
  min-width: 250px;
  padding: 10px 12px;
}

.plot-config-row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 18px;
  padding: 3px 0;
}

.plot-config-axis {
  color: var(--muted);
  font: italic 13px 'Computer Modern', Georgia, serif;
}

.plot-config-label {
  color: var(--muted);
  font-size: 0.8rem;
  font-weight: 600;
}

.plot-config-value {
  color: var(--text);
  font: 0.82rem/1.3 'Computer Modern', Georgia, serif;
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}

.plot-config-bounds {
  display: flex;
  align-items: center;
  gap: 6px;
}

.plot-config-dots {
  color: var(--faint);
}

.plot-config-input {
  width: 68px;
  min-width: 0;
  padding: 4px 7px;
  border: 1px solid var(--border);
  border-radius: 7px;
  background: var(--surface);
  color: var(--text);
  font: 0.82rem/1.2 'Computer Modern', Georgia, serif;
  font-variant-numeric: tabular-nums;

  &:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: var(--ring);
  }
}

// the switch that decides whose height z answers to: the surfaces' or
// the reader's own two bounds
.plot-config-toggle {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  width: 100%;
  margin-top: 7px;
  padding: 7px 0 5px;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.74rem;
  line-height: 1.35;
  text-align: left;

  &:hover { color: var(--text); }
}

.plot-config-switch {
  position: relative;
  flex: none;
  width: 32px;
  height: 18px;
  border-radius: 999px;
  background: var(--border-strong);
  transition: background-color 0.15s;

  .knob {
    position: absolute;
    top: 2px;
    left: 2px;
    width: 14px;
    height: 14px;
    border-radius: 50%;
    background: var(--bg-elev);
    box-shadow: var(--shadow-sm);
    transition: transform 0.15s ease;
  }

  &.on {
    background: var(--accent);

    .knob { transform: translateX(14px); }
  }
}

// where the cursor stands, bottom-right so the dock never covers it
.plot-readout {
  position: absolute;
  bottom: 10px;
  right: 12px;
  padding: 4px 10px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: color-mix(in srgb, var(--bg-elev) 84%, transparent);
  backdrop-filter: blur(10px);
  color: var(--muted);
  font: 0.78rem/1.3 'Computer Modern', Georgia, serif;
  font-variant-numeric: tabular-nums;
  pointer-events: none;
}

// the top bar is in the flow here, so the calculator folds into panels of
// the page: the dock first, then the plane as its own card
@media (max-width: 900px) {
  .calc-stage {
    position: static;
    inset: auto;
    display: flex;
    flex-direction: column;
    background: transparent;
  }

  .calc-dock {
    position: static;
    order: 1;
    width: auto;
    margin-bottom: 16px;
    border: 1px solid var(--border);
    border-radius: 14px;
    background: var(--bg-elev);
    backdrop-filter: none;
    box-shadow: var(--shadow-sm);
    overflow: visible;
  }

  .plot-wrap {
    position: static;
    order: 2;
    width: 100%;
    height: min(66dvh, 560px);
    border: 1px solid var(--border);
    border-radius: 14px;
  }

  .plot-toolbar { top: 8px; right: 8px; }

  .plot-tools { top: 8px; right: 8px; }

  // during the fold the dock lifts out of the flow, so the plane takes the
  // width back at once rather than after the slide
  .calc-dock-leave-active { position: absolute; left: 0; right: 0; }
}

// ---------- Laid on a page of the book (ToolPane) ----------
// A pane of the book is a full surface again, at any screen width: the plane
// fills the page and the input dock pins to its edge as on the desktop, and
// the fold above — panels of the plain /calculator page — does not reach
// into the pane.

.pane-stage .calc-stage {
  position: absolute;
  inset: 0;
  display: block;
  background: var(--bg);
}

.pane-stage .plot-wrap {
  position: absolute;
  width: auto;
  height: auto;
  border: 0;
  border-radius: 0;
}

.pane-stage .calc-dock {
  position: absolute;
  top: 0;
  left: 0;
  bottom: 0;
  width: clamp(260px, 24vw, 320px);
  margin: 0;
  border: 0;
  border-right: 1px solid var(--border);
  border-radius: 0;
  background: color-mix(in srgb, var(--bg-elev) 92%, transparent);
  backdrop-filter: blur(12px);
  box-shadow: var(--shadow-lg);
  overflow-y: auto;
}