:root {
  color-scheme: light;
  font-family:
    Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI",
    sans-serif;
  color: #17202a;
  background: #f4f6f7;
  --accent: #276b78;
  --accent-dark: #184954;
  --border: #bcc8cc;
  --danger: #a12622;
  --paper: #ffffff;
  --muted: #53646b;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  line-height: 1.55;
}

a {
  color: var(--accent-dark);
}

button,
input,
select,
textarea {
  font: inherit;
}

button,
summary {
  cursor: pointer;
}

button {
  min-height: 2.75rem;
  border: 2px solid var(--accent);
  border-radius: 0.45rem;
  padding: 0.55rem 0.9rem;
  color: #fff;
  background: var(--accent);
  font-weight: 700;
}

button.secondary {
  color: var(--accent-dark);
  background: #fff;
}

button:disabled {
  cursor: not-allowed;
  opacity: 0.55;
}

:focus-visible {
  outline: 3px solid #e69f00;
  outline-offset: 3px;
}

.skip-link {
  position: fixed;
  z-index: 10;
  top: 0.5rem;
  left: 0.5rem;
  transform: translateY(-200%);
  padding: 0.65rem;
  color: #fff;
  background: #17202a;
}

.skip-link:focus {
  transform: none;
}

.site-header,
.app-shell,
footer {
  width: min(92rem, calc(100% - 2rem));
  margin-inline: auto;
}

.site-header {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(18rem, 24rem);
  gap: 2rem;
  align-items: center;
  padding-block: 2.5rem 1.5rem;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  margin-bottom: 0.4rem;
  font-size: clamp(2rem, 5vw, 3.4rem);
  line-height: 1.05;
}

.eyebrow {
  margin-bottom: 0.45rem;
  color: var(--accent-dark);
  font-size: 0.82rem;
  font-weight: 800;
  letter-spacing: 0.11em;
  text-transform: uppercase;
}

.runtime-card,
.controls,
.results,
footer section {
  border: 1px solid var(--border);
  border-radius: 0.8rem;
  background: var(--paper);
  box-shadow: 0 0.25rem 1rem rgb(23 32 42 / 7%);
}

.runtime-card {
  padding: 1rem 1.2rem;
}

.runtime-card h2 {
  margin-bottom: 0.35rem;
  font-size: 1rem;
}

[data-state="error"] {
  color: var(--danger);
}

.version-text {
  color: var(--muted);
  font-size: 0.82rem;
}

.app-shell {
  display: grid;
  grid-template-columns: minmax(18rem, 25rem) minmax(0, 1fr);
  gap: 1.25rem;
  align-items: start;
  padding-block: 1rem 2rem;
}

.controls,
.results {
  min-width: 0;
  padding: clamp(1rem, 3vw, 1.6rem);
}

.controls {
  position: sticky;
  top: 1rem;
}

.scope-note,
.empty-state,
details {
  color: var(--muted);
}

.field {
  display: grid;
  gap: 0.35rem;
  margin-block: 1rem;
}

label,
.field-label,
legend {
  font-weight: 750;
}

input[type="text"],
input[type="number"],
select,
textarea {
  width: 100%;
  min-height: 2.75rem;
  border: 2px solid var(--border);
  border-radius: 0.4rem;
  padding: 0.55rem 0.65rem;
  background: #fff;
}

input[aria-invalid="true"] {
  border-color: var(--danger);
}

input[type="checkbox"],
input[type="radio"] {
  width: 1.1rem;
  height: 1.1rem;
  accent-color: var(--accent-dark);
}

input:disabled,
select:disabled,
textarea:disabled {
  color: var(--muted);
  background: #edf1f2;
}

fieldset {
  margin: 0 0 1.2rem;
  border: 1px solid var(--border);
  border-radius: 0.6rem;
  padding: 0.8rem 1rem;
}

legend {
  padding-inline: 0.35rem;
}

small {
  color: var(--muted);
}

.choice-group {
  display: grid;
  gap: 0.45rem;
  margin-block: 1rem;
}

.choice-group label,
.check-row {
  display: flex;
  gap: 0.55rem;
  align-items: flex-start;
  font-weight: 600;
}

.two-column {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.8rem;
}

.guardrail-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 7.5rem;
  gap: 0.8rem;
  align-items: center;
  margin-block: 0.75rem;
}

.guardrail-row label {
  display: flex;
  gap: 0.55rem;
  align-items: center;
}

details {
  margin-block: 1.2rem;
  border-block: 1px solid var(--border);
  padding-block: 0.8rem;
}

summary {
  color: var(--accent-dark);
  font-weight: 750;
}

.actions,
.export-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.65rem;
}

.error-summary {
  border-left: 0.35rem solid var(--danger);
  padding: 0.8rem 1rem;
  background: #fff0ef;
}

.error-summary h3 {
  margin-bottom: 0.35rem;
  font-size: 1rem;
}

.error-summary ul {
  margin-block: 0;
}

.result-summary {
  border-left: 0.35rem solid var(--accent);
  padding: 0.8rem 1rem;
  background: #edf6f7;
  font-size: 1.08rem;
  font-weight: 650;
}

.conditioning {
  color: var(--accent-dark);
  font-weight: 700;
}

.joint-card {
  margin-block: 1rem;
  border: 2px solid var(--accent);
  border-radius: 0.7rem;
  padding: 1rem;
  background: #f7fbfc;
}

.joint-card[data-status="infeasible"] {
  border-color: var(--danger);
  background: #fff5f4;
}

.metric-grid {
  display: grid;
  grid-template-columns: minmax(12rem, 1fr) minmax(8rem, 1fr);
  gap: 0.35rem 1rem;
}

.metric-grid dt {
  font-weight: 750;
}

.metric-grid dd {
  margin: 0;
}

.plot {
  width: 100%;
  min-height: 34rem;
}

.table-wrap {
  max-width: 100%;
  margin-block: 1rem;
  overflow-x: auto;
}

table {
  width: 100%;
  border-collapse: collapse;
}

caption {
  margin-bottom: 0.4rem;
  text-align: left;
  font-weight: 750;
}

th,
td {
  border-bottom: 1px solid var(--border);
  padding: 0.65rem;
  text-align: left;
}

tbody tr[data-status="infeasible"],
tbody tr[data-status="no_finite_joint_solution"] {
  background: #fff5f4;
}

textarea {
  resize: vertical;
  line-height: 1.5;
}

.figure-caption {
  color: var(--muted);
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
}

footer {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1rem;
  padding-block: 1rem 2rem;
}

footer section {
  padding: 1rem;
}

footer h2 {
  font-size: 1rem;
}

@media (max-width: 52rem) {
  .site-header,
  .app-shell,
  footer {
    grid-template-columns: minmax(0, 1fr);
  }

  .controls {
    position: static;
  }

  .two-column,
  .guardrail-row,
  .metric-grid {
    grid-template-columns: 1fr;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition: none !important;
  }
}