@font-face {
  font-family: CalcMath;
  src: url("vendor/fonts/KaTeX_Main-Regular.woff2");
}
* {
  box-sizing: border-box;
}
:root {
  color-scheme: light;
  --bg: #f6f7f4;
  --card: #fff;
  --ink: #17372f;
  --muted: #75847c;
  --line: #e1e7e0;
  --soft: #f0f4ef;
  --accent: #0b5d4b;
  --gold: #d9b26a;
  --shadow: 0 12px 45px #153d2510;
}
html[data-theme="dark"] {
  color-scheme: dark;
  --bg: #111c19;
  --card: #1a2823;
  --ink: #e8f0e9;
  --muted: #a3b4a9;
  --line: #34483d;
  --soft: #23382e;
  --accent: #79c7a9;
  --shadow: 0 12px 45px #0002;
}
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font:
    15px/1.7 system-ui,
    -apple-system,
    "Segoe UI",
    sans-serif;
}
button,
input,
select,
textarea {
  font: inherit;
}
button,
a,
input,
select,
textarea {
  outline-offset: 4px;
}
button {
  cursor: pointer;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--card);
  color: var(--ink);
  padding: 8px 13px;
  transition:
    background 0.15s,
    transform 0.15s;
}
button:hover {
  background: var(--soft);
}
button:active {
  transform: scale(0.97);
}
button:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}
a {
  color: var(--accent);
  text-decoration: none;
}
.app {
  max-width: 1280px;
  margin: auto;
  padding: 0 36px;
}
header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  padding: 26px 0;
  border-bottom: 1px solid var(--line);
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  font-weight: 750;
  font-size: 19px;
}
.brandmark {
  display: grid;
  place-items: center;
  width: 38px;
  height: 42px;
  background: #0b5d4b;
  color: #d9b26a;
  border-radius: 12px;
  font:
    28px CalcMath,
    serif;
}
.brand small {
  font: 10px system-ui;
  letter-spacing: 2px;
  color: var(--muted);
  margin-inline-start: 12px;
}
.tools {
  display: flex;
  gap: 7px;
}
.tools button {
  font-size: 12px;
}
.intro {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 15px;
  padding: 39px 0 27px;
}
.eyebrow {
  font-size: 11px;
  color: var(--accent);
  font-weight: 650;
  letter-spacing: 1px;
  margin: 0 0 9px;
}
h1 {
  font-size: clamp(25px, 3vw, 37px);
  letter-spacing: -1.2px;
  line-height: 1.4;
  margin: 0 0 9px;
  font-weight: 650;
}
.subtitle {
  color: var(--muted);
  margin: 0;
  font-size: 14px;
}
.status {
  white-space: nowrap;
  color: var(--accent);
  font-size: 10px;
  letter-spacing: 1px;
  border: 1px solid var(--line);
  border-radius: 30px;
  padding: 7px 12px;
}
nav {
  display: flex;
  gap: 5px;
  overflow-x: auto;
  padding-bottom: 14px;
  margin-bottom: 8px;
  scrollbar-width: thin;
}
nav button {
  white-space: nowrap;
  border-color: transparent;
  background: transparent;
  color: var(--muted);
  font-size: 13px;
  padding: 9px 15px;
}
nav button.active {
  background: #0b5d4b;
  color: #fff;
  box-shadow: 0 3px 8px #0b5d4b20;
}
.workspace {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 280px;
  gap: 22px;
  align-items: start;
}
.panel,
.side-card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 20px;
  padding: 24px;
  box-shadow: var(--shadow);
  min-width: 0;
}
.panel-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  margin-bottom: 18px;
}
h2 {
  font-size: 16px;
  margin: 0;
  font-weight: 650;
}
.precision {
  color: var(--muted);
  font-size: 10px;
  letter-spacing: 1px;
}
.side-card .panel-top button {
  border: 0;
  padding: 0;
  font-size: 11px;
  color: var(--muted);
}
.side-card {
  padding: 20px;
  margin-bottom: 18px;
}
.note {
  background: #e9efe6;
  box-shadow: none;
  color: #1c4938;
  border-color: #dce6d6;
}
.note-icon {
  font-size: 28px;
  color: #947a3d;
}
.note h3 {
  font-size: 20px;
  margin: 6px 0;
}
.note p {
  font-size: 13px;
  color: #5d735e;
}
.note small {
  font-size: 10px;
}
kbd {
  border: 1px solid #cad5c5;
  border-radius: 5px;
  font-size: 10px;
  padding: 3px 6px;
  background: #ffffff80;
}
.field {
  display: flex;
  flex-direction: column;
  gap: 5px;
  min-width: 0;
  font-size: 12px;
  color: var(--muted);
}
.field input,
.field select,
.field textarea {
  width: 100%;
  background: var(--soft);
  border: 1px solid var(--line);
  border-radius: 10px;
  color: var(--ink);
  padding: 10px 12px;
  direction: ltr;
  text-align: left;
  min-width: 0;
}
.field textarea {
  min-height: 90px;
  font-family: ui-monospace, monospace;
}
.field .expression {
  font:
    25px/1.6 CalcMath,
    system-ui;
  padding: 18px;
  min-height: 82px;
  background: var(--card);
}
.row {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  margin-bottom: 14px;
}
.row > .field {
  flex: 1;
  min-width: 90px;
}
.toolbar {
  display: flex;
  flex-wrap: wrap;
  gap: 7px;
  align-items: center;
  margin-bottom: 12px;
}
.toolbar select {
  border: 1px solid var(--line);
  background: var(--soft);
  color: var(--ink);
  padding: 5px 8px;
  border-radius: 7px;
  font-size: 11px;
}
.toolbar label {
  font-size: 11px;
  color: var(--muted);
}
.keyboard {
  display: grid;
  grid-template-columns: repeat(6, minmax(0, 1fr));
  gap: 7px;
  direction: ltr;
  margin: 15px 0;
}
.keyboard button {
  height: 43px;
  background: var(--soft);
  border: 0;
  font-size: 16px;
  border-radius: 9px;
  font-family: CalcMath, system-ui;
}
.keyboard button.num {
  background: var(--card);
  border: 1px solid var(--line);
  font-size: 20px;
}
.keyboard button.equals,
.primary {
  background: #0b5d4b;
  color: #fff;
  border: 0;
}
.keyboard button.op {
  color: var(--accent);
}
.primary {
  padding: 11px 23px;
  min-height: 44px;
}
.primary:hover {
  background: #137b62;
  color: #fff;
}
.result {
  margin-top: 20px;
  padding: 18px;
  border: 1px solid var(--line);
  background: var(--soft);
  border-radius: 13px;
  min-width: 0;
}
.result-label {
  display: flex;
  justify-content: space-between;
  font-size: 10px;
  letter-spacing: 1px;
  color: var(--muted);
}
#result {
  direction: ltr;
  text-align: end;
  font:
    24px/1.7 CalcMath,
    ui-monospace,
    monospace;
  white-space: pre-wrap;
  overflow-wrap: anywhere;
  margin: 12px 0;
  color: var(--ink);
  max-height: 360px;
  overflow: auto;
}
#result.error {
  color: #d04e44;
  font: 14px/1.7 system-ui;
}
#pretty {
  direction: ltr;
  text-align: end;
  overflow-x: auto;
  font-size: 18px;
  padding-top: 8px;
}
#steps {
  font:
    13px/1.8 ui-monospace,
    monospace;
  direction: ltr;
  white-space: pre-wrap;
  overflow-wrap: anywhere;
}
.result-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  border-top: 1px solid var(--line);
  padding-top: 12px;
}
.result-actions button,
.result-actions select {
  font-size: 10px;
  padding: 5px 8px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--card);
  color: var(--muted);
}
#history {
  max-height: 430px;
  overflow: auto;
}
.history-item {
  display: block;
  width: 100%;
  text-align: start;
  border: 0;
  border-bottom: 1px solid var(--line);
  border-radius: 0;
  padding: 12px 0;
  background: transparent;
}
.history-item small {
  display: block;
  color: var(--muted);
  direction: ltr;
  text-align: end;
  overflow-wrap: anywhere;
}
.history-item strong {
  display: block;
  font:
    18px/1.6 CalcMath,
    monospace;
  direction: ltr;
  text-align: end;
  overflow-wrap: anywhere;
}
.empty {
  font-size: 12px;
  text-align: center;
  padding: 27px 0;
  color: var(--muted);
}
footer {
  display: flex;
  justify-content: space-between;
  gap: 10px;
  padding: 28px 0;
  color: var(--muted);
  font-size: 11px;
}
.hint {
  font-size: 11px;
  color: var(--muted);
  margin: 8px 0;
}
.library {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 9px;
}
.library button {
  text-align: start;
  font-size: 12px;
}
.library code {
  display: block;
  direction: ltr;
  font-size: 11px;
  color: var(--muted);
  overflow-wrap: anywhere;
}
.table-wrap {
  overflow: auto;
  max-height: 340px;
}
table {
  border-collapse: collapse;
  width: 100%;
  direction: ltr;
  font-size: 12px;
}
td,
th {
  padding: 7px 12px;
  border-bottom: 1px solid var(--line);
  text-align: center;
}
#plot {
  overflow: hidden;
  margin-top: 15px;
  border-radius: 12px;
}
#plot svg {
  max-width: 100%;
  background: #fff;
}
#exam-settings {
  border: 1px solid var(--gold);
  border-radius: 12px;
  background: #d9b26a18;
  padding: 12px;
  margin-bottom: 15px;
  display: flex;
  gap: 15px;
  flex-wrap: wrap;
  font-size: 12px;
}
#exam-settings[hidden] {
  display: none;
}
.exam-active {
  border-color: var(--gold) !important;
  color: var(--gold) !important;
}
.toast {
  position: fixed;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%);
  padding: 10px 22px;
  border-radius: 10px;
  background: #0b5d4b;
  color: white;
  z-index: 5;
  font-size: 13px;
}
@media (max-width: 850px) {
  .workspace {
    grid-template-columns: minmax(0, 1fr);
  }
  aside {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
  }
  .status {
    display: none;
  }
  .intro {
    padding-top: 27px;
  }
}
@media (max-width: 520px) {
  .app {
    padding: 0 16px;
  }
  header {
    padding: 16px 0;
    gap: 7px;
    align-items: start;
  }
  .brand {
    font-size: 14px;
    gap: 7px;
  }
  .brand small {
    display: none;
  }
  .brandmark {
    width: 30px;
    height: 34px;
    font-size: 24px;
  }
  .tools {
    gap: 4px;
    flex-wrap: wrap;
    justify-content: end;
    max-width: 165px;
  }
  .tools button {
    font-size: 10px;
    padding: 5px 8px;
  }
  h1 {
    font-size: 27px;
  }
  .subtitle {
    font-size: 12px;
  }
  .eyebrow {
    font-size: 10px;
  }
  .intro {
    padding: 25px 0 19px;
  }
  nav {
    margin-inline: -5px;
  }
  nav button {
    padding: 8px 11px;
    font-size: 12px;
  }
  .panel {
    padding: 16px;
    border-radius: 16px;
  }
  .keyboard {
    gap: 5px;
  }
  .keyboard button {
    height: 43px;
    font-size: 14px;
    padding: 3px;
  }
  .keyboard button.num {
    font-size: 19px;
  }
  .row {
    gap: 7px;
  }
  .precision {
    font-size: 8px;
  }
  aside {
    display: block;
  }
  .note {
    display: none;
  }
  footer {
    font-size: 9px;
    flex-wrap: wrap;
  }
  #result {
    font-size: 22px;
  }
  .result {
    padding: 13px;
  }
  .library {
    grid-template-columns: 1fr;
  }
}
/* Round 2: compact calculator, a persistent mode rail and visual editors. */
.mode-strip {
  position: sticky;
  top: 0;
  z-index: 20;
  display: flex;
  align-items: center;
  background: var(--bg);
  border-bottom: 1px solid var(--line);
  margin-bottom: 12px;
  padding-top: 6px;
  gap: 4px;
}
.mode-strip nav {
  flex: 1;
  min-width: 0;
  margin: 0;
  padding: 4px 0 10px;
  scrollbar-width: thin;
}
.mode-strip > button {
  flex-shrink: 0;
  width: 32px;
  padding: 0;
  font-size: 26px;
  color: var(--accent);
  background: var(--soft);
}
.calculator-mode {
  display: flex;
  flex-direction: column;
}
.calculator-mode > .panel-top {
  order: 0;
}
.calculator-mode #mode-content {
  display: contents;
}
.calculator-mode .toolbar {
  order: 1;
}
.calculator-mode #mode-content > .field,
.calculator-mode #natural-slot {
  order: 2;
}
.calculator-mode .result {
  order: 3;
}
.calculator-mode .keyboard {
  order: 4;
}
.calculator-mode .hint {
  order: 5;
}
.calculator-mode #plot {
  order: 6;
}
.calculator-mode .toolbar > .field {
  flex-direction: row;
  align-items: center;
  font-size: 10px;
  gap: 4px;
}
.calculator-mode .toolbar > .field select {
  padding: 4px;
}
.calculator-mode .result {
  margin-top: 10px;
  margin-bottom: 0;
}
.calculator-mode .result #steps:empty {
  display: none;
}
#live-preview {
  direction: ltr;
  text-align: end;
  font:
    18px/1.5 CalcMath,
    monospace;
  color: var(--muted);
  min-height: 27px;
}
#live-preview:empty {
  display: none;
}
.calculator-mode #result {
  margin: 4px 0;
  font-size: 30px;
  line-height: 1.35;
}
.calculator-mode #pretty {
  font-size: 15px;
  padding: 0;
}
.calculator-mode .result-label {
  font-size: 9px;
}
.calculator-mode .result-actions {
  padding-top: 6px;
  margin-top: 8px;
}
.calculator-mode .keyboard {
  margin: 12px 0 0;
}
.calculator-mode .keyboard .equals {
  font-size: 24px;
}
.field[hidden],
#natural-slot[hidden] {
  display: none !important;
}
math-field {
  display: block;
  direction: ltr;
  background: var(--soft);
  color: var(--ink);
  border: 1px solid var(--line);
  border-radius: 10px;
  min-height: 56px;
  font-size: 26px;
  padding: 8px;
}
math-field::part(virtual-keyboard-toggle) {
  display: none;
}
.matrix-editor {
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 12px;
  margin: 12px 0;
}
.matrix-editor h3 {
  margin: 0 0 8px;
  font-size: 14px;
}
.matrix-grid {
  display: grid;
  gap: 6px;
  direction: ltr;
}
.matrix-grid input,
.data-grid input {
  min-width: 0;
  width: 100%;
  text-align: center;
  background: var(--soft);
  color: var(--ink);
  border: 1px solid var(--line);
  padding: 8px 2px;
  border-radius: 6px;
  font-size: 14px;
}
.data-editor {
  margin: 12px 0;
}
.data-grid td {
  padding: 4px;
}
.data-grid th {
  font-size: 10px;
}
.data-grid button {
  padding: 2px 6px;
}
.data-editor .table-wrap {
  max-height: 290px;
  margin: 10px 0;
}
.library-search {
  margin-bottom: 14px;
}
.formula-work {
  border: 1px solid var(--gold);
  padding: 16px;
  border-radius: 12px;
  margin: 14px 0;
}
.formula-work h3 {
  margin-top: 0;
}
.formula-work code {
  display: block;
  direction: ltr;
  overflow-wrap: anywhere;
}
.formula-work .row {
  margin-top: 10px;
}
.library small {
  display: block;
  color: var(--muted);
}
.graph-tools {
  display: flex;
  gap: 7px;
  flex-wrap: wrap;
  margin: 12px 0;
}
.analysis-points button {
  font-size: 11px;
  margin: 4px;
}
.graph-selected {
  color: var(--accent);
  font-size: 12px;
  direction: ltr;
}
.stats-inference {
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 12px;
  margin-top: 18px;
}
.stats-inference summary {
  cursor: pointer;
  font-weight: 600;
}
dialog {
  background: var(--card);
  color: var(--ink);
  border: 1px solid var(--line);
  border-radius: 18px;
  max-width: calc(100% - 30px);
  width: 430px;
  padding: 24px;
}
dialog::backdrop {
  background: #001e1977;
}
dialog dl {
  display: grid;
  grid-template-columns: 120px 1fr;
  gap: 12px;
  font-size: 13px;
}
dialog dt {
  direction: ltr;
  font-family: monospace;
}
dialog dd {
  margin: 0;
  color: var(--muted);
}
#close-shortcuts {
  float: inline-end;
}
@media (max-width: 600px) {
  .app {
    padding: 0 10px;
  }
  header {
    padding: 9px 0;
    align-items: center;
    min-height: 50px;
  }
  .brand {
    font-size: 13px;
  }
  .brandmark {
    height: 29px;
    width: 27px;
    font-size: 22px;
  }
  .brand small {
    display: none;
  }
  .tools {
    max-width: none;
    gap: 3px;
  }
  .tools button {
    min-height: 29px;
    padding: 4px 7px;
    font-size: 10px;
  }
  #theme {
    font-size: 19px;
    line-height: 1;
    min-width: 29px;
  }
  .intro {
    display: none;
  }
  .mode-strip {
    padding-top: 3px;
    margin-bottom: 7px;
  }
  .mode-strip nav button {
    font-size: 11px;
    padding: 7px 10px;
  }
  .mode-strip nav {
    padding-bottom: 6px;
  }
  .panel {
    padding: 12px;
    border-radius: 14px;
  }
  .calculator-mode > .panel-top {
    margin-bottom: 7px;
  }
  .calculator-mode h2 {
    font-size: 13px;
  }
  .calculator-mode .toolbar {
    margin-bottom: 6px;
    gap: 5px;
  }
  .calculator-mode .field > span {
    font-size: 10px;
  }
  .calculator-mode .field .expression {
    min-height: 49px;
    padding: 8px 11px;
    font-size: 23px;
  }
  .calculator-mode .result {
    padding: 10px;
    margin-top: 7px;
  }
  .calculator-mode #result {
    font-size: 29px;
  }
  .calculator-mode .keyboard {
    gap: 4px;
    margin-top: 9px;
  }
  .calculator-mode .keyboard button {
    height: 37px;
    padding: 2px;
    font-size: 13px;
  }
  .calculator-mode .keyboard button.num {
    font-size: 18px;
  }
  .calculator-mode .hint {
    font-size: 9px;
    margin: 6px 0 0;
  }
  .workspace {
    gap: 12px;
  }
  .matrix-grid {
    gap: 4px;
  }
  .matrix-editor {
    padding: 8px;
  }
  .matrix-grid input {
    padding: 8px 0;
    font-size: 12px;
  }
  .library {
    grid-template-columns: 1fr;
  }
  .result-actions button,
  .result-actions select {
    font-size: 9px;
  }
  .calculator-mode .result-actions {
    padding-top: 4px;
    margin-top: 5px;
  }
  .mode-strip > button {
    font-size: 22px;
    width: 25px;
  }
  .calculator-mode .precision {
    font-size: 8px;
  }
}
@media (max-height: 740px) and (max-width: 600px) {
  .calculator-mode .keyboard button {
    height: 32px;
  }
  .calculator-mode .hint {
    display: none;
  }
  .calculator-mode .result-actions {
    margin-top: 3px;
  }
  .calculator-mode .panel-top {
    margin-bottom: 3px;
  }
}
/* Presentation precision is independent of the stored 64-digit value. */
.calculator-mode #result{white-space:pre;overflow-wrap:normal;word-break:normal;max-height:2.8em;overflow:auto;line-height:1.35}
#decimal-result{color:var(--muted);text-align:end;white-space:pre;overflow:hidden;font:14px/1.6 CalcMath,monospace}
.numeric-controls{display:flex;gap:6px;margin-top:6px;justify-content:flex-end}.numeric-controls button{font-size:10px;padding:4px 8px;min-height:26px}
.numeric-controls[hidden],#decimal-result[hidden],#full-precision[hidden]{display:none}
#full-precision{border-top:1px solid var(--line);margin-top:8px;padding-top:6px;color:var(--muted);font-size:10px}
#full-value{font:13px/1.8 ui-monospace,monospace;white-space:pre;overflow-x:auto;margin:4px 0;max-height:3.6em}