:root {
  color-scheme: light;
  --app-paper: #f5f4ef;
  --app-surface: #fbfaf6;
  --app-panel: #fffefa;
  --app-ink: #222824;
  --app-muted: #687069;
  --app-line: #cfd3cc;
  --app-line-strong: #9fa79f;
  --app-accent: #245b49;
  --app-accent-dark: #173f32;
  --app-accent-soft: #e2ebe5;
  --app-blue: #2f6f88;
  --app-blue-soft: #dcebed;
  --app-orange: #a7642a;
  --app-orange-soft: #f5e8d9;
  --app-danger: #9b2f2f;
  --app-danger-soft: #f8e9e7;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html,
body {
  max-width: 100%;
  overflow-x: hidden;
}

button,
input {
  font: inherit;
}

a {
  color: inherit;
}

:focus-visible {
  outline: 3px solid var(--app-accent);
  outline-offset: 3px;
}

h2,
h3 {
  margin: 0;
  line-height: 1.4;
}

h2 {
  font-size: clamp(1.2rem, 2vw, 1.48rem);
}

h3 {
  font-size: 1rem;
}

p,
li,
dd,
span,
strong {
  overflow-wrap: anywhere;
}

.tool-shell,
.calculator-panel,
.visual-panel,
.input-row,
.result-metrics,
.evaluation-metrics,
.formula-list {
  min-width: 0;
}

.tool-shell {
  display: grid;
  grid-template-columns: minmax(0, 0.92fr) minmax(0, 1.08fr);
  border: 1px solid var(--app-line-strong);
  background: var(--app-surface);
}

.calculator-panel,
.visual-panel {
  padding: 24px;
}

.calculator-panel {
  border-right: 1px solid var(--app-line);
}

.visual-panel {
  background: var(--app-paper);
}

.section-heading {
  margin-bottom: 16px;
}

.section-kicker {
  margin: 0 0 5px;
  color: var(--app-accent);
  font-size: 0.78rem;
  font-weight: 780;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.values-fieldset {
  margin: 0;
  padding: 0;
  border: 0;
}

.values-fieldset > legend {
  margin-bottom: 10px;
  font-weight: 760;
}

.input-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 13px 12px;
}

.input-row {
  display: grid;
  align-content: start;
}

.input-row-time {
  grid-column: 1 / -1;
  padding-top: 13px;
  border-top: 1px solid var(--app-line);
}

.input-row label {
  margin-bottom: 5px;
  font-weight: 720;
}

.input-wrap {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  min-width: 0;
}

.input-wrap input {
  width: 100%;
  min-width: 0;
  min-height: 46px;
  padding: 9px 11px;
  border: 1px solid var(--app-line-strong);
  border-radius: 0;
  color: var(--app-ink);
  background: #fff;
  appearance: textfield;
}

.input-wrap input::-webkit-inner-spin-button,
.input-wrap input::-webkit-outer-spin-button {
  margin: 0;
  appearance: none;
}

.input-wrap input:focus {
  border-color: var(--app-accent);
  outline: 3px solid var(--app-accent-soft);
  outline-offset: 0;
}

.input-wrap input[aria-invalid="true"] {
  border-color: var(--app-danger);
  background: #fff8f8;
}

.unit {
  display: grid;
  min-width: 58px;
  place-items: center;
  padding: 0 10px;
  border: 1px solid var(--app-line-strong);
  border-left: 0;
  background: var(--app-paper);
  color: var(--app-muted);
  font-weight: 700;
}

.field-help,
.field-error {
  margin: 4px 0 0;
  font-size: 0.77rem;
  line-height: 1.5;
}

.field-help {
  color: var(--app-muted);
}

.field-error {
  min-height: 1.2em;
  color: var(--app-danger);
}

.form-error {
  margin: 14px 0 0;
  padding: 9px 11px;
  border-left: 4px solid var(--app-danger);
  background: var(--app-danger-soft);
  color: #762525;
  font-size: 0.86rem;
  font-weight: 700;
}

.form-error[hidden] {
  display: none;
}

.form-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 17px;
}

.button {
  min-height: 44px;
  padding: 8px 16px;
  border: 1px solid var(--app-accent);
  border-radius: 2px;
  cursor: pointer;
  font-weight: 760;
}

.button-primary {
  color: #fff;
  background: var(--app-accent);
}

.button-primary:hover {
  background: var(--app-accent-dark);
}

.button-secondary {
  color: var(--app-accent);
  background: var(--app-surface);
}

.button-secondary:hover {
  background: var(--app-accent-soft);
}

.result-box {
  margin-top: 21px;
  padding: 16px;
  border: 1px solid var(--app-accent);
  border-left-width: 4px;
  background: var(--app-accent-soft);
}

.result-box[data-state="error"] {
  border-color: var(--app-danger);
  background: var(--app-danger-soft);
}

.result-heading-row,
.visual-heading-row {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 12px;
}

.result-heading-row .section-kicker,
.visual-heading-row .section-kicker {
  margin-bottom: 3px;
}

.result-metrics,
.evaluation-metrics {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  margin: 15px 0 0;
  border-top: 1px solid rgba(36, 91, 73, 0.34);
  border-left: 1px solid rgba(36, 91, 73, 0.34);
}

.result-metrics > div,
.evaluation-metrics > div {
  min-width: 0;
  padding: 9px 10px;
  border-right: 1px solid rgba(36, 91, 73, 0.34);
  border-bottom: 1px solid rgba(36, 91, 73, 0.34);
  background: rgba(255, 255, 255, 0.38);
}

.result-metrics .metric-wide {
  grid-column: 1 / -1;
}

.result-metrics dt,
.evaluation-metrics dt {
  color: var(--app-muted);
  font-size: 0.75rem;
  font-weight: 720;
  line-height: 1.45;
}

.result-metrics dd,
.evaluation-metrics dd {
  margin: 3px 0 0;
  font-size: 0.94rem;
  font-weight: 760;
  line-height: 1.45;
  font-variant-numeric: tabular-nums;
}

.result-note,
.evaluation-summary {
  margin: 11px 0 0;
  color: #3f4c46;
  font-size: 0.85rem;
}

.evaluation-box {
  margin-top: 14px;
  padding: 15px 16px;
  border: 1px solid var(--app-blue);
  background: var(--app-blue-soft);
}

.evaluation-box[hidden] {
  display: none;
}

.evaluation-box .section-kicker {
  color: var(--app-blue);
}

.evaluation-metrics {
  border-color: rgba(47, 111, 136, 0.34);
}

.evaluation-metrics > div {
  border-color: rgba(47, 111, 136, 0.34);
}

.status-badge {
  flex: 0 0 auto;
  padding: 4px 8px;
  border: 1px solid var(--app-line-strong);
  background: var(--app-surface);
  color: var(--app-muted);
  font-size: 0.74rem;
  font-weight: 760;
  line-height: 1.4;
  white-space: nowrap;
}

.status-badge[data-state="ready"] {
  border-color: var(--app-accent);
  background: var(--app-accent-soft);
  color: var(--app-accent);
}

.visual-stage {
  display: grid;
  place-items: center;
  min-height: 350px;
  margin-top: 16px;
  padding: 10px;
  overflow: hidden;
  border: 1px solid var(--app-line);
  background: linear-gradient(180deg, #edf4f3 0%, #f8f4ec 100%);
}

.plot-figure {
  width: min(100%, 640px);
  margin: 0;
}

.plot-svg {
  display: block;
  width: 100%;
  height: auto;
  min-height: 270px;
  border: 1px solid var(--app-line-strong);
  background: #fffefa;
}

.plot-result[hidden],
.current-layer[hidden] {
  display: none;
}

.plot-grid {
  stroke: rgba(104, 112, 105, 0.18);
  stroke-width: 1;
  stroke-dasharray: 4 7;
}

.plot-axis,
.plot-ground {
  stroke: #758078;
  stroke-width: 1.5;
}

.plot-ground {
  stroke-width: 2;
}

.trajectory-path {
  fill: none;
  stroke: var(--app-accent);
  stroke-width: 3;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.plot-marker {
  stroke: #fff;
  stroke-width: 3;
}

.launch-point {
  fill: var(--app-ink);
}

.apex-point {
  fill: var(--app-orange);
}

.landing-point {
  fill: var(--app-accent);
}

.current-point {
  fill: var(--app-blue);
  stroke-width: 4;
}

.vector-line {
  fill: none;
  stroke-width: 3;
  stroke-linecap: round;
}

.velocity-line {
  stroke: var(--app-blue);
}

.gravity-line {
  stroke: var(--app-orange);
}

.plot-label,
.vector-label,
.axis-label,
.scale-label {
  paint-order: stroke;
  stroke: #fffefa;
  stroke-width: 5px;
  stroke-linejoin: round;
}

.plot-label {
  fill: var(--app-ink);
  font-size: 13px;
  font-weight: 750;
}

.vector-label {
  font-size: 12px;
  font-weight: 780;
}

.velocity-label {
  fill: var(--app-blue);
}

.gravity-label {
  fill: var(--app-orange);
}

.axis-label {
  fill: var(--app-ink);
  font-size: 13px;
  font-weight: 760;
}

.scale-label {
  fill: var(--app-muted);
  font-size: 11px;
}

.plot-figure figcaption,
.visual-description {
  margin: 10px 0 0;
  color: var(--app-muted);
  font-size: 0.78rem;
  line-height: 1.6;
}

.visual-description {
  color: var(--app-ink);
  font-size: 0.84rem;
}

.plot-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 15px;
  margin-top: 13px;
  color: var(--app-muted);
  font-size: 0.76rem;
}

.plot-legend > span {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.legend-line,
.legend-dot,
.legend-arrow {
  display: inline-block;
  flex: 0 0 auto;
}

.legend-line {
  width: 22px;
  height: 3px;
  background: var(--app-accent);
}

.legend-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--app-blue);
}

.legend-arrow {
  width: 18px;
  height: 3px;
  background: currentColor;
}

.legend-arrow-velocity {
  color: var(--app-blue);
}

.legend-arrow-gravity {
  color: var(--app-orange);
}

.content-section {
  margin-top: 34px;
  padding-top: 25px;
  border-top: 1px solid var(--app-line-strong);
}

.steps-list {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  margin: 0;
  padding: 0;
  border-block: 1px solid var(--app-line);
  list-style: none;
  counter-reset: steps;
}

.steps-list li {
  position: relative;
  min-width: 0;
  padding: 35px 12px 13px;
  border-right: 1px solid var(--app-line);
  counter-increment: steps;
  font-size: 0.86rem;
}

.steps-list li:last-child {
  border-right: 0;
}

.steps-list li::before {
  position: absolute;
  top: 7px;
  left: 12px;
  color: var(--app-accent);
  content: counter(steps, decimal-leading-zero);
  font-size: 0.75rem;
  font-weight: 800;
}

.formula-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  border-top: 1px solid var(--app-line);
  border-left: 1px solid var(--app-line);
}

.formula-list article {
  display: grid;
  gap: 4px;
  min-width: 0;
  padding: 13px 14px;
  border-right: 1px solid var(--app-line);
  border-bottom: 1px solid var(--app-line);
  background: var(--app-surface);
}

.formula-list article:last-child {
  grid-column: 1 / -1;
}

.formula-list strong {
  color: var(--app-accent);
  font-size: 0.98rem;
  font-variant-numeric: tabular-nums;
}

.formula-list span {
  color: var(--app-muted);
  font-size: 0.82rem;
}

.meaning-box,
.assumptions-box {
  margin-top: 15px;
  padding: 15px 17px;
  border: 1px solid var(--app-line);
  background: var(--app-surface);
}

.meaning-box {
  border-color: var(--app-accent);
  background: var(--app-accent-soft);
}

.meaning-box p {
  margin: 7px 0 0;
  color: #38413b;
  font-size: 0.86rem;
}

.assumptions-box ul {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 4px 24px;
  margin: 10px 0 0;
  padding-left: 1.2em;
  color: var(--app-muted);
  font-size: 0.84rem;
}

@media (max-width: 900px) {
  .tool-shell {
    grid-template-columns: 1fr;
  }

  .calculator-panel {
    border-right: 0;
    border-bottom: 1px solid var(--app-line);
  }
}

@media (max-width: 680px) {
  .calculator-panel,
  .visual-panel {
    padding: 18px;
  }

  .steps-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .steps-list li:nth-child(2) {
    border-right: 0;
  }

  .steps-list li:nth-child(-n + 2) {
    border-bottom: 1px solid var(--app-line);
  }

  .formula-list,
  .assumptions-box ul {
    grid-template-columns: 1fr;
  }

  .formula-list article:last-child {
    grid-column: auto;
  }
}

@media (max-width: 500px) {
  .calculator-panel,
  .visual-panel {
    padding: 15px;
  }

  .input-grid,
  .result-metrics,
  .evaluation-metrics {
    grid-template-columns: 1fr;
  }

  .input-row-time,
  .result-metrics .metric-wide {
    grid-column: auto;
  }

  .form-actions {
    display: grid;
    grid-template-columns: 1fr;
  }

  .form-actions .button {
    width: 100%;
  }

  .result-heading-row,
  .visual-heading-row {
    display: grid;
    gap: 8px;
  }

  .status-badge {
    justify-self: start;
  }

  .visual-stage {
    min-height: 280px;
    padding: 6px;
  }

  .plot-svg {
    min-height: 230px;
  }

  .plot-label {
    font-size: 20px;
    stroke-width: 6px;
  }

  .vector-label,
  .axis-label {
    font-size: 18px;
    stroke-width: 6px;
  }

  .scale-label {
    font-size: 15px;
    stroke-width: 6px;
  }

  .steps-list {
    grid-template-columns: 1fr;
  }

  .steps-list li,
  .steps-list li:nth-child(2) {
    border-right: 0;
    border-bottom: 1px solid var(--app-line);
  }

  .steps-list li:last-child {
    border-bottom: 0;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }
}