/* Design tokens. The series and ramp values are the validated reference
 * palette from the dataviz method; series slots are assigned to solvers
 * in fixed registry order and never cycled. */

:root {
  color-scheme: light;
  --surface: #fcfcfb;
  --surface-2: #f4f3f0;
  --text: #0b0b0b;
  --text-2: #52514e;
  --text-3: #767570;
  --border: #dcdbd6;
  --grid: #eceae6;
  --link: #1c5cab;
  --series-1: #2a78d6;
  --series-2: #eb6834;
  --series-3: #1baf7a;
  --series-4: #eda100;
  --series-5: #e87ba4;
  --accent: #2a78d6;
}

@media (prefers-color-scheme: dark) {
  :root {
    color-scheme: dark;
    --surface: #1a1a19;
    --surface-2: #232322;
    --text: #ffffff;
    --text-2: #c3c2b7;
    --text-3: #8f8e86;
    --border: #3a3a37;
    --grid: #2c2c2a;
    --link: #86b6ef;
    --series-1: #3987e5;
    --series-2: #d95926;
    --series-3: #199e70;
    --series-4: #c98500;
    --series-5: #d55181;
    --accent: #3987e5;
  }
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--surface);
  color: var(--text);
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  font-size: 15px;
  line-height: 1.55;
}

main {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 20px 80px;
}

a {
  color: var(--link);
}

h1 {
  font-size: 1.7rem;
  font-weight: 650;
  margin: 1.6rem 0 0.2rem;
}

h2 {
  font-size: 1.25rem;
  font-weight: 650;
  margin: 2.6rem 0 0.6rem;
  padding-top: 1.2rem;
  border-top: 1px solid var(--border);
}

h3 {
  font-size: 1.02rem;
  font-weight: 650;
  margin: 1.4rem 0 0.4rem;
}

p {
  margin: 0.5rem 0;
  max-width: 72ch;
}

.subtitle {
  color: var(--text-2);
  margin-top: 0;
}

code,
pre {
  font-family: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  font-size: 0.88em;
}

pre {
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 10px 14px;
  overflow-x: auto;
}

.muted {
  color: var(--text-2);
}

.small {
  font-size: 0.85rem;
}

.row {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
  align-items: flex-start;
}

.panel {
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 14px 16px;
  background: var(--surface);
}

button {
  font: inherit;
  font-size: 0.9rem;
  padding: 5px 14px;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--surface-2);
  color: var(--text);
  cursor: pointer;
}

button:hover:not(:disabled) {
  border-color: var(--text-3);
}

button:disabled {
  opacity: 0.5;
  cursor: default;
}

button.primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #ffffff;
}

select,
input[type="text"] {
  font: inherit;
  font-size: 0.9rem;
  padding: 4px 8px;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--surface);
  color: var(--text);
}

label {
  font-size: 0.9rem;
}

table.data {
  border-collapse: collapse;
  font-size: 0.85rem;
  font-variant-numeric: tabular-nums;
}

table.data th,
table.data td {
  border: 1px solid var(--border);
  padding: 3px 10px;
  text-align: right;
}

table.data th {
  background: var(--surface-2);
  font-weight: 600;
}

table.data td.left,
table.data th.left {
  text-align: left;
}

.legend-swatch {
  display: inline-block;
  width: 14px;
  height: 3px;
  border-radius: 2px;
  vertical-align: middle;
  margin-right: 6px;
}

.chart-tooltip {
  position: absolute;
  pointer-events: none;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 6px 10px;
  font-size: 0.8rem;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.12);
  z-index: 10;
  white-space: nowrap;
}

.field-caption {
  font-size: 0.85rem;
  color: var(--text-2);
  margin-top: 4px;
}

footer {
  margin-top: 4rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border);
  color: var(--text-3);
  font-size: 0.85rem;
}

.topnav {
  padding-top: 1.1rem;
  font-size: 0.9rem;
}

.topnav a {
  color: var(--text-2);
  text-decoration: none;
  font-weight: 600;
}

.topnav a:hover {
  color: var(--text);
}

.problem-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
  max-width: 720px;
}

.problem-card {
  display: block;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 14px 18px;
  text-decoration: none;
  color: var(--text);
  background: var(--surface);
}

.problem-card:hover {
  border-color: var(--text-3);
}

.problem-card-title {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.02rem;
  font-weight: 650;
}

.problem-card-summary {
  color: var(--text-2);
  margin-top: 4px;
  font-size: 0.92rem;
}

.problem-card-meta {
  color: var(--text-3);
  margin-top: 6px;
  font-size: 0.82rem;
}

.badge {
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--text-2);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 1px 6px;
  background: var(--surface-2);
}