:root {
  color-scheme: light;
  --bg: #f3fbff;
  --panel: rgba(255, 255, 255, 0.92);
  --border: rgba(38, 114, 142, 0.24);
  --text: #0f2a34;
  --muted: #4d7484;
  --accent: #0f7f9d;
  --error: #c13131;
  --shadow: 0 18px 44px rgba(14, 61, 79, 0.2);
  --page-radial: rgba(104, 191, 219, 0.3);
  --page-gradient: linear-gradient(160deg, #f5fcff 0%, #e4f5ff 45%, #d9eef9 100%);
  --header-gloss: rgba(255, 255, 255, 0.55);
  --history-track: rgba(190, 222, 236, 0.65);
  --history-track-border: rgba(121, 178, 199, 0.35);
  --history-thumb: linear-gradient(180deg, rgba(44, 152, 186, 0.72), rgba(25, 109, 137, 0.72));
  --history-thumb-hover: linear-gradient(180deg, rgba(44, 152, 186, 0.9), rgba(25, 109, 137, 0.9));
  --history-thumb-border: rgba(224, 243, 251, 0.9);
  --input-border: rgba(38, 114, 142, 0.2);
  --mode-border: rgba(38, 114, 142, 0.3);
  --mode-bg: rgba(255, 255, 255, 0.84);
  --keypad-border: rgba(38, 114, 142, 0.28);
  --keypad-bg: rgba(255, 255, 255, 0.7);
  --keypad-primary-border: rgba(15, 127, 157, 0.5);
  --keypad-primary-bg: rgba(15, 127, 157, 0.14);
  --keypad-sticky-bg: linear-gradient(180deg, rgba(243, 251, 255, 0) 0%, rgba(243, 251, 255, 0.88) 22%, rgba(243, 251, 255, 0.98) 100%);
}

@media (prefers-color-scheme: dark) {
  :root {
    color-scheme: dark;
    --bg: #071014;
    --panel: rgba(9, 24, 31, 0.92);
    --border: rgba(117, 196, 173, 0.28);
    --text: #e7fff7;
    --muted: #8fb8ac;
    --accent: #7dffcf;
    --error: #ff8f8f;
    --shadow: 0 24px 60px rgba(0, 0, 0, 0.45);
    --page-radial: rgba(39, 95, 79, 0.45);
    --page-gradient: linear-gradient(160deg, #020608 0%, #071014 45%, #0b171c 100%);
    --header-gloss: rgba(255, 255, 255, 0.02);
    --history-track: rgba(12, 29, 36, 0.65);
    --history-track-border: rgba(117, 196, 173, 0.16);
    --history-thumb: linear-gradient(180deg, rgba(125, 255, 207, 0.72), rgba(77, 200, 163, 0.72));
    --history-thumb-hover: linear-gradient(180deg, rgba(125, 255, 207, 0.9), rgba(77, 200, 163, 0.9));
    --history-thumb-border: rgba(12, 29, 36, 0.72);
    --input-border: rgba(117, 196, 173, 0.14);
    --mode-border: rgba(117, 196, 173, 0.28);
    --mode-bg: rgba(0, 0, 0, 0.2);
    --keypad-border: rgba(117, 196, 173, 0.24);
    --keypad-bg: rgba(0, 0, 0, 0.12);
    --keypad-primary-border: rgba(125, 255, 207, 0.55);
    --keypad-primary-bg: rgba(125, 255, 207, 0.12);
    --keypad-sticky-bg: linear-gradient(180deg, rgba(7, 16, 20, 0) 0%, rgba(7, 16, 20, 0.88) 22%, rgba(7, 16, 20, 0.98) 100%);
  }
}

* {
  box-sizing: border-box;
}

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
}

/* iOS Safari zooms focused inputs when font-size < 16px. */
input,
textarea,
select,
button {
  font-size: 14px;
}

body {
  margin: 0;
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 24px;
  overflow: hidden;
  background:
    radial-gradient(circle at top, var(--page-radial), transparent 32%),
    var(--page-gradient);
  color: var(--text);
  font-family: "SFMono-Regular", "Consolas", "Liberation Mono", monospace;
}

.keyboard-open .app-footer {
  display: none;
}

.terminal {
  width: calc(100vw - 48px);
  height: 84vh;
  min-height: 230px;
  display: flex;
  flex-direction: column;
  border: 1px solid var(--border);
  border-radius: 18px;
  overflow: hidden;
  background: var(--panel);
  box-shadow: var(--shadow);
  backdrop-filter: blur(16px);
}

.terminal-header {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 14px 18px;
  border-bottom: 1px solid var(--border);
  background: var(--header-gloss);
}

.terminal-title {
  margin-left: 8px;
  font-size: 0.95rem;
  color: var(--muted);
  letter-spacing: 0.04em;
}

.terminal-meta {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
  padding: 6px 18px 10px;
  color: var(--muted);
  font-size: 0.72rem;
  letter-spacing: 0.02em;
  border-bottom: 1px solid var(--input-border);
}

.mode-label {
  color: var(--muted);
}

.mode-select {
  border: 1px solid var(--mode-border);
  border-radius: 8px;
  background: var(--mode-bg);
  color: var(--text);
  font: inherit;
  padding: 2px 8px;
}

.terminal-body {
  display: flex;
  flex-direction: column;
  flex: 1;
  min-height: 0;
  padding: 20px;
  gap: 18px;
  overflow: hidden;
}

.history {
  flex: 1;
  min-height: 0;
  overflow-y: auto;
  overflow-x: hidden;
  -webkit-overflow-scrolling: touch;
  overscroll-behavior: contain;
  touch-action: pan-y;
  white-space: pre-wrap;
  word-break: break-word;
}

.history-content {
  min-height: 100%;
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
}

/* Desktop scrollbar theming for the history pane. */
@media (hover: hover) and (pointer: fine) {
  .history {
    scrollbar-width: thin;
    scrollbar-color: color-mix(in srgb, var(--accent) 60%, transparent) var(--history-track);
  }

  .history::-webkit-scrollbar {
    width: 12px;
  }

  .history::-webkit-scrollbar-track {
    background: var(--history-track);
    border-left: 1px solid var(--history-track-border);
  }

  .history::-webkit-scrollbar-thumb {
    background: var(--history-thumb);
    border: 2px solid var(--history-thumb-border);
    border-radius: 999px;
  }

  .history::-webkit-scrollbar-thumb:hover {
    background: var(--history-thumb-hover);
  }
}

.entry {
  margin-bottom: 16px;
  animation: fade-in 160ms ease-out;
}

.prompt {
  color: var(--accent);
  user-select: none;
}

.inline-comment {
  color: #2b6f3c;
  font-family: "Segoe UI", "Helvetica Neue", Helvetica, Arial, sans-serif;
  font-weight: 700;
  font-size: 0.92em;
}

.result {
  padding-left: 26px;
  color: var(--text);
}

.result.error {
  color: var(--error);
}

.result.plot-result {
  padding-top: 8px;
  padding-right: 8px;
}

.points-plot {
  display: block;
  width: min(100%, 720px);
  height: auto;
  color: var(--text);
}

.points-plot .plot-background {
  fill: var(--panel);
}

.points-plot .plot-axes {
  fill: none;
  stroke: var(--muted);
  stroke-width: 1;
}

.points-plot .plot-axis-arrows {
  fill: var(--muted);
  font-family: inherit;
  font-size: 18px;
  font-weight: 700;
}

.points-plot .plot-points {
  fill: var(--accent);
  stroke: color-mix(in srgb, var(--accent) 65%, var(--text));
  stroke-width: 1.5;
}

.points-plot .plot-ticks {
  fill: var(--muted);
  stroke: var(--muted);
  stroke-width: 1;
}

.points-plot .plot-ticks text,
.points-plot .plot-axis-names {
  fill: var(--muted);
  stroke: none;
  font-family: inherit;
  font-size: 13px;
}

.points-plot .plot-axis-names {
  font-size: 15px;
  font-weight: 700;
}

.input-row {
  position: relative;
  display: flex;
  align-items: center;
  gap: 10px;
  padding-top: 8px;
  border-top: 1px solid var(--input-border);
  flex: 0 0 auto;
}

.completion-list {
  position: absolute;
  z-index: 10;
  left: 26px;
  right: 0;
  bottom: calc(100% + 5px);
  max-height: min(280px, 42vh);
  overflow-y: auto;
  border: 1px solid var(--input-border);
  border-radius: 10px;
  background: var(--panel);
  box-shadow: 0 12px 30px rgba(0, 0, 0, 0.2);
}

.completion-list[hidden] {
  display: none;
}

.completion-option {
  display: grid;
  grid-template-columns: minmax(max-content, auto) 1fr;
  gap: 14px;
  width: 100%;
  padding: 8px 10px;
  border: 0;
  background: transparent;
  color: var(--text);
  font: inherit;
  text-align: left;
  cursor: pointer;
}

.completion-option:hover,
.completion-option[aria-selected="true"] {
  background: color-mix(in srgb, var(--accent) 14%, transparent);
}

.completion-signature {
  color: var(--accent);
  white-space: nowrap;
}

.completion-description {
  overflow: hidden;
  color: var(--muted);
  text-overflow: ellipsis;
  white-space: nowrap;
}

.keypad {
  display: none;
  flex: 0 0 auto;
  --keypad-btn-min-width: 56px;
  --keypad-gap: 10px;
  gap: var(--keypad-gap);
}

.keypad[data-force-visible="true"] {
  display: flex !important;
  flex-wrap: wrap;
  visibility: visible;
}

.keypad-mode-toggle {
  width: 100%;
  display: none;
  align-items: center;
  gap: 8px;
  color: var(--muted);
  margin-bottom: 2px;
}

.keypad-btn {
  border: 1px solid var(--keypad-border);
  background: var(--keypad-bg);
  color: var(--text);
  font: inherit;
  min-width: var(--keypad-btn-min-width);
  border-radius: 14px;
  padding: 12px 14px;
  line-height: 1;
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
}

.keypad-btn:active {
  transform: translateY(1px);
}

.keypad-btn.primary {
  border-color: var(--keypad-primary-border);
  background: var(--keypad-primary-bg);
  color: var(--accent);
  min-width: calc(var(--keypad-btn-min-width) * 2 + var(--keypad-gap));
}

.expression-input {
  flex: 1;
  border: 0;
  outline: none;
  background: transparent;
  color: var(--text);
  font: inherit;
  font-size: 16px;
  caret-color: var(--accent);
}

.app-footer {
  position: fixed;
  bottom: 10px;
  left: 50%;
  transform: translateX(-50%);
  font-size: 0.72rem;
  letter-spacing: 0.04em;
  color: var(--muted);
  opacity: 0.88;
}

@keyframes fade-in {
  from {
    opacity: 0;
    transform: translateY(6px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}


/* Touch-first sizing (e.g. iPhones) even if the CSS viewport width is large. */
@media (pointer: coarse) and (hover: none) and (max-width: 900px) {
  :root {
    --touch-font: 48px;
    --footer-space: 44px;
  }

  body {
    padding: 0;
    display: flex;
    flex-direction: column;
    justify-content: flex-start;
    align-items: stretch;
  }

  .terminal {
    position: fixed;
    left: 6px;
    right: 6px;
    top: calc(6px + var(--vvt, 0px));
    bottom: auto;
    width: auto;
    height: var(--term-h, calc(100dvh - 56px));
    min-height: 0;
    border-radius: 20px;
  }

  .terminal-header {
    padding: 22px 22px 18px;
  }

  .terminal-title {
    font-size: 1.55rem;
  }

  .terminal-body {
    padding: 36px 30px;
    gap: 36px;
  }

  .terminal-meta {
    padding: 8px 22px 14px;
    font-size: 1rem;
  }

  .mode-select {
    border-radius: 12px;
    padding: 6px 12px;
  }

  .history {
    font-size: var(--touch-font);
    line-height: 1.7;
  }

  .entry {
    margin-bottom: 22px;
  }

  .input-row {
    gap: 22px;
    padding-top: 22px;
    padding-bottom: 18px;
  }

  .keypad {
    display: flex;
    flex-wrap: wrap;
    --keypad-btn-min-width: 96px;
    --keypad-gap: 14px;
    gap: var(--keypad-gap);
    padding-bottom: 14px;
  }

  .keypad[data-force-visible="true"] {
    display: flex !important;
    flex-wrap: wrap;
    gap: var(--keypad-gap);
    margin-top: auto;
    padding-bottom: max(14px, env(safe-area-inset-bottom));
  }

  .keyboard-open .keypad[data-force-visible="true"] {
    position: sticky;
    bottom: 0;
    z-index: 2;
    background: var(--keypad-sticky-bg);
  }

  .keypad-mode-toggle {
    display: flex;
    margin-bottom: 8px;
    font-size: 1rem;
  }

  .keypad-btn {
    min-height: 72px;
    padding: 18px 18px;
    border-radius: 22px;
    font-size: 34px;
  }

  .prompt {
    font-size: 3rem;
    line-height: 1.2;
  }

  .result {
    padding-left: 52px;
  }

  .expression-input {
    font-size: var(--touch-font);
    line-height: 1.3;
    padding: 22px 0;
  }

  .app-footer {
    bottom: calc(8px + env(safe-area-inset-bottom));
  }
}


html.touch-layout {
  --touch-font: 48px;
  --footer-space: 44px;
}

html.touch-layout body {
  padding: 0;
  display: flex;
  flex-direction: column;
  justify-content: flex-start;
  align-items: stretch;
}

html.touch-layout .terminal {
  position: fixed;
  left: 6px;
  right: 6px;
  top: calc(6px + var(--vvt, 0px));
  bottom: auto;
  width: auto;
  height: var(--term-h, calc(100dvh - 56px));
  min-height: 0;
  border-radius: 20px;
}

html.touch-layout .terminal-header {
  padding: 22px 22px 18px;
}

html.touch-layout .terminal-title {
  font-size: 1.55rem;
}

html.touch-layout .terminal-body {
  padding: 36px 30px;
  gap: 36px;
}

html.touch-layout .terminal-meta {
  padding: 8px 22px 14px;
  font-size: 1rem;
}

html.touch-layout .mode-select {
  border-radius: 12px;
  padding: 6px 12px;
}

html.touch-layout .history {
  font-size: var(--touch-font);
  line-height: 1.7;
}

html.touch-layout .entry {
  margin-bottom: 22px;
}

html.touch-layout .input-row {
  gap: 22px;
  padding-top: 22px;
  padding-bottom: 18px;
}

html.touch-layout .keypad {
  display: flex;
  flex-wrap: wrap;
  --keypad-btn-min-width: 96px;
  --keypad-gap: 14px;
  gap: var(--keypad-gap);
  padding-bottom: 14px;
}

html.touch-layout .keypad[data-force-visible="true"] {
  display: flex !important;
  flex-wrap: wrap;
  gap: var(--keypad-gap);
  margin-top: auto;
  padding-bottom: max(14px, env(safe-area-inset-bottom));
}

html.touch-layout.keyboard-open .keypad[data-force-visible="true"] {
  position: sticky;
  bottom: 0;
  z-index: 2;
  background: var(--keypad-sticky-bg);
}

html.touch-layout .keypad-mode-toggle {
  display: flex;
  margin-bottom: 8px;
  font-size: 1rem;
}

html.touch-layout .keypad-btn {
  min-height: 72px;
  padding: 18px 18px;
  border-radius: 22px;
  font-size: 34px;
}

html.touch-layout .prompt {
  font-size: 3rem;
  line-height: 1.2;
}

html.touch-layout .result {
  padding-left: 52px;
}

html.touch-layout .expression-input {
  font-size: var(--touch-font);
  line-height: 1.3;
  padding: 22px 0;
}

html.touch-layout .completion-list {
  left: 52px;
  max-height: 36vh;
  border-radius: 18px;
}

html.touch-layout .completion-option {
  grid-template-columns: 1fr;
  gap: 4px;
  padding: 14px 18px;
  font-size: 24px;
}

html.touch-layout .completion-description {
  font-size: 18px;
}

html.touch-layout .app-footer {
  bottom: calc(8px + env(safe-area-inset-bottom));
}