/* Halgoworks: ink-navy surfaces, one amber signal for "what the algorithm is looking at now". */

:root {
    color-scheme: dark;

    --ink-0: #0e1828;
    --ink-1: #14223a;
    --ink-2: #1b2c48;
    --ink-3: #243756;
    --line: #2a3d5e;
    --line-soft: rgba(170, 183, 203, 0.09);
    --grid: rgba(170, 183, 203, 0.055);

    --text-1: #eaf0f8;
    --text-2: #aab7cb;
    --text-3: #7d8ba3;

    --signal: #ffb23e;
    --signal-soft: rgba(255, 178, 62, 0.14);
    --signal-ink: #0e1828;

    --good: #0ca30c;
    --good-text: #3fcf5a;
    --bad: #d03b3b;
    --bad-text: #ff7a72;

    --s1: #3987e5;
    --s2: #d95926;
    --s3: #199e70;
    --s4: #c98500;
    --s5: #d55181;
    --s6: #008300;
    --s7: #9085e9;
    --s8: #e66767;

    --font-display: "Barlow Condensed", "Arial Narrow", "Roboto Condensed", system-ui, sans-serif;
    --font-ui: "Barlow", system-ui, -apple-system, "Segoe UI", sans-serif;
    --font-code: "IBM Plex Mono", ui-monospace, "Cascadia Code", Consolas, monospace;
    --font-math: "Cambria Math", "STIX Two Math", "Latin Modern Math", Cambria, Georgia, serif;

    --t-xs: 0.8125rem;
    --t-sm: 0.875rem;
    --t-md: 1rem;
    --t-lg: 1.125rem;
    --t-xl: 1.375rem;
    --t-2xl: 1.75rem;
    --t-3xl: 2.5rem;
    --t-4xl: clamp(2.75rem, 5.5vw, 4.5rem);

    --r-1: 4px;
    --r-2: 8px;
    --r-3: 14px;

    --page: 1440px;
    --gutter: clamp(16px, 3vw, 40px);
}

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

html {
    -webkit-text-size-adjust: 100%;
    scroll-padding-top: 84px;
}

body {
    margin: 0;
    background: var(--ink-0);
    color: var(--text-1);
    font-family: var(--font-ui);
    font-size: var(--t-md);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
    text-rendering: optimizeLegibility;
}

h1, h2, h3, h4 {
    margin: 0;
    font-weight: 600;
    line-height: 1.15;
}

p {
    margin: 0;
}

a {
    color: var(--text-1);
    text-decoration-color: var(--text-3);
    text-underline-offset: 3px;
}

a:hover {
    text-decoration-color: var(--signal);
}

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

:focus-visible {
    outline: 2px solid var(--signal);
    outline-offset: 2px;
    border-radius: 2px;
}

code {
    font-family: var(--font-code);
    font-size: 0.9em;
}

mark {
    background: none;
    color: var(--signal);
    font-weight: 600;
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    overflow: hidden;
    clip: rect(0 0 0 0);
    white-space: nowrap;
}

.num {
    font-variant-numeric: tabular-nums;
}

/* ------------------------------------------------------------------ Boot and error UI */

.boot {
    min-height: 100vh;
    display: grid;
    place-content: center;
    justify-items: center;
    gap: 14px;
}

.boot-mark {
    width: 56px;
    height: 56px;
}

.boot-text {
    color: var(--text-2);
    font-size: var(--t-sm);
}

.boot-bar {
    width: 160px;
    height: 3px;
    background: var(--ink-2);
    border-radius: 2px;
    overflow: hidden;
}

.boot-bar span {
    display: block;
    height: 100%;
    width: var(--blazor-load-percentage, 0%);
    background: var(--signal);
    transition: width 0.1s;
}

#blazor-error-ui {
    display: none;
    position: fixed;
    inset: auto 0 0 0;
    z-index: 1000;
    padding: 12px 48px 12px 20px;
    background: #3a1a1d;
    border-top: 1px solid var(--bad);
    color: var(--text-1);
}

#blazor-error-ui .dismiss {
    position: absolute;
    right: 12px;
    top: 8px;
    background: none;
    border: 0;
    font-size: 1.4rem;
    cursor: pointer;
}

.blazor-error-boundary {
    padding: 16px 20px;
    background: #3a1a1d;
    border: 1px solid var(--bad);
    border-radius: var(--r-2);
}

.blazor-error-boundary::after {
    content: "This part of the page failed to render.";
}

/* ------------------------------------------------------------------ Top bar */

.topbar {
    position: sticky;
    top: 0;
    z-index: 50;
    background: var(--ink-0);
    border-bottom: 1px solid var(--line);
}

.topbar-inner {
    max-width: var(--page);
    margin: 0 auto;
    padding: 0 var(--gutter);
    height: 60px;
    display: flex;
    align-items: center;
    gap: 28px;
}

.brand {
    display: flex;
    align-items: center;
    gap: 10px;
    text-decoration: none;
    font-family: var(--font-display);
    font-weight: 700;
    font-size: 1.45rem;
    letter-spacing: 0.01em;
}

.brand svg {
    width: 28px;
    height: 28px;
}

.nav {
    display: flex;
    gap: 2px;
    margin-left: auto;
    overflow-x: auto;
    scrollbar-width: none;
}

.nav a {
    padding: 7px 12px;
    border-radius: var(--r-2);
    color: var(--text-2);
    text-decoration: none;
    font-size: var(--t-sm);
    font-weight: 500;
    white-space: nowrap;
}

.nav a:hover {
    color: var(--text-1);
    background: var(--ink-2);
}

.nav a.active {
    color: var(--text-1);
    background: var(--ink-2);
    box-shadow: inset 0 -2px 0 var(--signal);
}

.footer {
    border-top: 1px solid var(--line);
    margin-top: 96px;
}

.footer-inner {
    max-width: var(--page);
    margin: 0 auto;
    padding: 28px var(--gutter) 40px;
    display: flex;
    flex-wrap: wrap;
    gap: 12px 32px;
    color: var(--text-3);
    font-size: var(--t-sm);
}

.page {
    max-width: var(--page);
    margin: 0 auto;
    padding: 0 var(--gutter);
}

/* ------------------------------------------------------------------ Lab header */

.lab-header {
    padding: 44px 0 28px;
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto;
    gap: 16px 40px;
    align-items: end;
}

.lab-title {
    font-family: var(--font-display);
    font-size: var(--t-4xl);
    font-weight: 700;
    line-height: 0.95;
    letter-spacing: -0.01em;
}

.lab-lede {
    margin-top: 14px;
    max-width: 62ch;
    color: var(--text-2);
    font-size: var(--t-lg);
}

.lab-facts {
    display: grid;
    grid-template-columns: auto auto;
    gap: 6px 18px;
    margin: 0;
    font-size: var(--t-sm);
}

.lab-facts dt {
    color: var(--text-3);
}

.lab-facts dd {
    margin: 0;
    color: var(--text-1);
}

.complexity {
    display: inline-flex;
    align-items: center;
    gap: 6px;
}

.complexity::before {
    content: "";
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--bad-text);
}

.complexity.easy::before {
    background: var(--good-text);
}

/* ------------------------------------------------------------------ Lab */

.lab {
    border: 1px solid var(--line);
    border-radius: var(--r-3);
    background: var(--ink-1);
}

.toolbar {
    display: flex;
    flex-wrap: wrap;
    align-items: end;
    gap: 14px 22px;
    padding: 16px 18px;
    border-bottom: 1px solid var(--line);
}

.field {
    display: grid;
    gap: 6px;
    font-size: var(--t-xs);
    color: var(--text-3);
}

.field > span {
    font-weight: 500;
}

.field output {
    color: var(--text-1);
    font-variant-numeric: tabular-nums;
    margin-left: 4px;
}

.toolbar .spacer {
    flex: 1;
}

select,
.input {
    height: 34px;
    padding: 0 30px 0 10px;
    background: var(--ink-2) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='6'%3E%3Cpath d='M1 1l4 4 4-4' fill='none' stroke='%23aab7cb' stroke-width='1.5'/%3E%3C/svg%3E") no-repeat right 10px center;
    border: 1px solid var(--line);
    border-radius: var(--r-2);
    font-size: var(--t-sm);
    appearance: none;
    cursor: pointer;
}

select:hover {
    border-color: var(--text-3);
}

option {
    background: var(--ink-1);
}

input[type="range"] {
    --pct: 50%;
    width: 140px;
    height: 34px;
    margin: 0;
    background: transparent;
    appearance: none;
    cursor: pointer;
}

input[type="range"]::-webkit-slider-runnable-track {
    height: 4px;
    border-radius: 2px;
    background: linear-gradient(to right, var(--text-2) var(--pct), var(--line) var(--pct));
}

input[type="range"]::-moz-range-track {
    height: 4px;
    border-radius: 2px;
    background: linear-gradient(to right, var(--text-2) var(--pct), var(--line) var(--pct));
}

input[type="range"]::-webkit-slider-thumb {
    appearance: none;
    width: 16px;
    height: 16px;
    margin-top: -6px;
    border-radius: 50%;
    background: var(--text-1);
    border: 3px solid var(--ink-1);
    box-shadow: 0 0 0 1px var(--text-3);
}

input[type="range"]::-moz-range-thumb {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: var(--text-1);
    border: 3px solid var(--ink-1);
    box-shadow: 0 0 0 1px var(--text-3);
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    height: 34px;
    padding: 0 14px;
    border: 1px solid var(--line);
    border-radius: var(--r-2);
    background: var(--ink-2);
    color: var(--text-1);
    font-size: var(--t-sm);
    font-weight: 500;
    cursor: pointer;
    white-space: nowrap;
}

.btn:hover {
    border-color: var(--text-3);
    background: var(--ink-3);
}

.btn svg {
    width: 16px;
    height: 16px;
}

.check {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    height: 34px;
    font-size: var(--t-sm);
    color: var(--text-2);
    cursor: pointer;
}

.check input {
    width: 16px;
    height: 16px;
    accent-color: var(--signal);
    margin: 0;
}

/* Segmented control */
.seg {
    display: inline-flex;
    padding: 3px;
    gap: 2px;
    background: var(--ink-0);
    border: 1px solid var(--line);
    border-radius: 10px;
}

.seg-btn {
    height: 28px;
    padding: 0 12px;
    border: 0;
    border-radius: 7px;
    background: transparent;
    color: var(--text-2);
    font-size: var(--t-sm);
    font-weight: 500;
    cursor: pointer;
    white-space: nowrap;
}

.seg-btn:hover {
    color: var(--text-1);
}

.seg-btn.on {
    background: var(--ink-3);
    color: var(--text-1);
    box-shadow: inset 0 0 0 1px var(--line);
}

.seg-btn:disabled {
    opacity: 0.4;
    cursor: not-allowed;
}

/* Fixed height on desktop: steps change how much text and data there is, and the
   lab shouldn't grow and shrink (pushing the page around) while it plays. */
.lab-body {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 384px;
    /* The row must not grow with its content, or the panels spill over the playback bar instead of scrolling. */
    grid-template-rows: minmax(0, 1fr);
    height: clamp(600px, calc(100vh - 150px), 880px);
}

.stage {
    position: relative;
    min-width: 0;
    min-height: 0;
    display: flex;
    flex-direction: column;
    border-right: 1px solid var(--line);
    background-color: var(--ink-1);
    background-image:
        linear-gradient(var(--grid) 1px, transparent 1px),
        linear-gradient(90deg, var(--grid) 1px, transparent 1px);
    background-size: 24px 24px;
    background-position: -1px -1px;
}

.stage-head {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 10px 18px;
    padding: 12px 16px;
    min-height: 52px;
}

.stage-head .spacer {
    flex: 1;
}

.stage-body {
    flex: 1;
    min-height: 0;
    overflow-y: auto;
    scrollbar-width: thin;
    scrollbar-gutter: stable;
    padding: 4px 16px 16px;
    display: flex;
    flex-direction: column;
    gap: 14px;
}

.stage-body > svg,
.viz {
    width: 100%;
    height: auto;
    display: block;
}

.scroll-x {
    overflow-x: auto;
    scrollbar-width: thin;
}

.legend {
    display: flex;
    flex-wrap: wrap;
    gap: 6px 16px;
    margin: 0;
    padding: 0;
    list-style: none;
    font-size: var(--t-xs);
    color: var(--text-2);
}

.legend li {
    display: inline-flex;
    align-items: center;
    gap: 7px;
}

.swatch {
    width: 10px;
    height: 10px;
    border-radius: 3px;
    flex: none;
}

.swatch.line {
    height: 3px;
    width: 16px;
    border-radius: 2px;
}

.swatch.ring {
    background: transparent;
    border: 2px solid var(--signal);
}

/* ------------------------------------------------------------------ Narration side panel */

.side {
    display: flex;
    flex-direction: column;
    min-width: 0;
    min-height: 0;
    overflow-y: auto;
    scrollbar-width: thin;
    scrollbar-gutter: stable;
}

.side-section {
    padding: 18px 20px;
    border-bottom: 1px solid var(--line);
}

.side-section:last-child {
    border-bottom: 0;
}

.step-meta {
    display: flex;
    justify-content: space-between;
    gap: 12px;
    font-size: var(--t-xs);
    color: var(--text-3);
}

.step-phase {
    color: var(--signal);
    font-weight: 600;
}

.step-title {
    margin-top: 10px;
    font-family: var(--font-display);
    font-size: 1.6rem;
    font-weight: 600;
    line-height: 1.1;
}

.step-text {
    margin-top: 10px;
    color: var(--text-2);
    font-size: 0.9875rem;
    line-height: 1.6;
}

.step-text strong {
    color: var(--text-1);
    font-weight: 600;
}

.narration {
    flex: none;
    min-height: 236px;
}

.side-label {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    gap: 10px;
    margin-bottom: 10px;
    font-size: var(--t-xs);
    color: var(--text-3);
}

.side-label strong {
    color: var(--text-1);
    font-weight: 600;
    font-size: var(--t-sm);
    white-space: nowrap;
}

.side-label span {
    text-align: right;
}

.pseudo {
    margin: 0 -8px;
    padding: 0;
    list-style: none;
    counter-reset: line;
    font-family: var(--font-code);
    font-size: 0.75rem;
    line-height: 1.55;
}

.pseudo li {
    counter-increment: line;
    display: grid;
    grid-template-columns: 22px minmax(0, 1fr);
    gap: 6px;
    padding: 1px 8px;
    border-radius: var(--r-1);
    color: var(--text-3);
}

.pseudo li::before {
    content: counter(line);
    text-align: right;
    color: var(--line);
    font-size: 0.7rem;
    padding-top: 1px;
}

.pseudo li code {
    display: block;
    white-space: pre-wrap;
    font-size: inherit;
    /* Hanging indent, so a wrapped line doesn't look like a new statement. */
    padding-left: 2ch;
    text-indent: -2ch;
}

.pseudo li.on {
    background: var(--signal-soft);
    color: var(--text-1);
    box-shadow: inset 2px 0 0 var(--signal);
}

.pseudo li.on::before {
    color: var(--signal);
}

.watch-list {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 1px;
    margin: 0;
    background: var(--line);
    border: 1px solid var(--line);
    border-radius: var(--r-2);
    overflow: hidden;
}

.watch-list div {
    padding: 7px 10px;
    background: var(--ink-1);
    min-width: 0;
}

.watch-list dt {
    font-size: 0.72rem;
    color: var(--text-3);
    font-family: var(--font-code);
}

.watch-list dd {
    margin: 2px 0 0;
    font-size: var(--t-sm);
    font-weight: 600;
    font-variant-numeric: tabular-nums;
    overflow-wrap: anywhere;
}

.algo-summary {
    margin-top: 10px;
    font-size: var(--t-xs);
    color: var(--text-3);
    line-height: 1.5;
}

/* ------------------------------------------------------------------ Playback */

.playback {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 10px 14px;
    padding: 12px 16px;
    border-top: 1px solid var(--line);
    background: var(--ink-0);
    border-radius: 0 0 var(--r-3) var(--r-3);
}

.pb-buttons {
    display: flex;
    gap: 4px;
}

.pb-btn {
    width: 36px;
    height: 36px;
    display: grid;
    place-items: center;
    border: 1px solid var(--line);
    border-radius: var(--r-2);
    background: var(--ink-1);
    cursor: pointer;
}

.pb-btn:hover:not(:disabled) {
    background: var(--ink-3);
    border-color: var(--text-3);
}

.pb-btn:disabled {
    opacity: 0.35;
    cursor: default;
}

.pb-btn svg {
    width: 16px;
    height: 16px;
}

.pb-btn.play {
    width: 48px;
    background: var(--signal);
    border-color: var(--signal);
    color: var(--signal-ink);
}

.pb-btn.play:hover:not(:disabled) {
    background: #ffc266;
    border-color: #ffc266;
}

.timeline {
    position: relative;
    flex: 1;
    min-width: 200px;
}

.timeline input[type="range"] {
    width: 100%;
    display: block;
}

.timeline-marks {
    position: absolute;
    inset: 0 8px;
    pointer-events: none;
}

.timeline-marks span {
    position: absolute;
    top: 9px;
    width: 1px;
    height: 16px;
    background: var(--text-3);
}

.pb-count {
    min-width: 76px;
    text-align: right;
    font-size: var(--t-sm);
    color: var(--text-2);
    font-variant-numeric: tabular-nums;
}

.pb-hint {
    font-size: var(--t-xs);
    color: var(--text-3);
}

.pb-hint kbd {
    font-family: var(--font-code);
    font-size: 0.7rem;
    padding: 1px 5px;
    border: 1px solid var(--line);
    border-radius: 4px;
    background: var(--ink-1);
    color: var(--text-2);
}

/* ------------------------------------------------------------------ Results under the lab */

.results {
    margin-top: 28px;
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    gap: 28px;
}

.results.single {
    grid-template-columns: minmax(0, 1fr);
}

.panel {
    padding: 20px 22px 22px;
    border: 1px solid var(--line);
    border-radius: var(--r-3);
    background: var(--ink-1);
    min-width: 0;
}

.panel-title {
    font-size: var(--t-lg);
    font-weight: 600;
}

.panel-sub {
    margin-top: 4px;
    font-size: var(--t-sm);
    color: var(--text-3);
    max-width: 70ch;
}

.panel-body {
    margin-top: 16px;
}

.figures {
    display: flex;
    flex-wrap: wrap;
    gap: 18px 40px;
    margin: 0;
}

.figures div {
    display: grid;
    gap: 2px;
}

.figures dt {
    font-size: var(--t-xs);
    color: var(--text-3);
}

.figures dd {
    margin: 0;
    font-size: var(--t-2xl);
    font-weight: 600;
    line-height: 1.1;
}

.figures dd small {
    font-size: var(--t-sm);
    color: var(--text-3);
    font-weight: 500;
    margin-left: 4px;
}

.data-table {
    width: 100%;
    border-collapse: collapse;
    font-size: var(--t-sm);
}

.data-table th {
    text-align: left;
    font-weight: 500;
    color: var(--text-3);
    font-size: var(--t-xs);
    padding: 6px 10px;
    border-bottom: 1px solid var(--line);
}

.data-table td {
    padding: 7px 10px;
    border-bottom: 1px solid var(--line-soft);
    font-variant-numeric: tabular-nums;
}

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

.data-table tr.on td {
    background: var(--signal-soft);
}

.data-table tr.on td:first-child {
    box-shadow: inset 2px 0 0 var(--signal);
}

.status-ok {
    color: var(--good-text);
}

.status-bad {
    color: var(--bad-text);
}

.muted {
    color: var(--text-3);
}

/* ------------------------------------------------------------------ Charts */

.chart {
    position: relative;
}

.chart svg {
    width: 100%;
    height: auto;
    display: block;
    overflow: visible;
}

.chart text {
    font-family: var(--font-ui);
}

.chart .tick {
    fill: var(--text-3);
    font-size: 12px;
    font-variant-numeric: tabular-nums;
}

.chart .label {
    fill: var(--text-2);
    font-size: 13px;
}

.chart .value {
    fill: var(--text-1);
    font-size: 13px;
    font-weight: 600;
    font-variant-numeric: tabular-nums;
}

.chart .gridline {
    stroke: var(--line-soft);
    stroke-width: 1;
}

.chart .axis {
    stroke: var(--line);
    stroke-width: 1;
}

.chart .ref {
    stroke: var(--text-2);
    stroke-width: 1.5;
    stroke-dasharray: 4 4;
}

.chart .ref-label {
    fill: var(--text-2);
    font-size: 12px;
}

.chart .hit {
    fill: transparent;
    cursor: crosshair;
}

.chart-tip {
    position: absolute;
    pointer-events: none;
    z-index: 5;
    min-width: 120px;
    padding: 8px 10px;
    background: var(--ink-0);
    border: 1px solid var(--line);
    border-radius: var(--r-2);
    font-size: var(--t-xs);
    color: var(--text-2);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.35);
    transform: translate(-50%, calc(-100% - 10px));
    white-space: nowrap;
}

.chart-tip strong {
    display: block;
    color: var(--text-1);
    font-size: var(--t-sm);
    margin-bottom: 2px;
}

.chart-tip .row {
    display: flex;
    align-items: center;
    gap: 6px;
}

/* ------------------------------------------------------------------ 3D scenes */

.scene3d {
    position: relative;
    flex: 1;
    min-height: 420px;
    border-radius: var(--r-2);
    overflow: hidden;
    background: var(--ink-1);
}

.scene3d canvas {
    position: absolute;
    inset: 0;
    width: 100%;
    height: 100%;
    display: block;
    touch-action: none;
}

.scene-hint {
    position: absolute;
    left: 12px;
    bottom: 10px;
    font-size: var(--t-xs);
    color: var(--text-3);
    pointer-events: none;
}

.scene-note {
    position: absolute;
    inset: 0;
    display: grid;
    place-content: center;
    padding: 24px;
    text-align: center;
    color: var(--text-2);
}

/* ------------------------------------------------------------------ Visualization primitives (SVG) */

.viz text {
    font-family: var(--font-ui);
}

.viz .t-1 {
    fill: var(--text-1);
}

.viz .t-2 {
    fill: var(--text-2);
}

.viz .t-3 {
    fill: var(--text-3);
}

.viz .t-signal {
    fill: var(--signal);
}

.viz .tabular {
    font-variant-numeric: tabular-nums;
}

.viz .glow {
    filter: drop-shadow(0 0 6px rgba(255, 178, 62, 0.65));
}

.flowing {
    animation: flow 0.9s linear infinite;
}

@keyframes flow {
    to {
        stroke-dashoffset: -24;
    }
}

.pulse {
    animation: pulse 1.6s ease-in-out infinite;
}

@keyframes pulse {
    50% {
        opacity: 0.45;
    }
}

/* Knapsack */
.items {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.item {
    position: relative;
    display: grid;
    grid-template-columns: auto minmax(0, 1fr);
    align-items: center;
    gap: 2px 10px;
    min-width: 132px;
    padding: 8px 12px 8px 10px;
    border: 1px solid var(--line);
    border-radius: var(--r-2);
    background: var(--ink-1);
    transition: opacity 0.25s, border-color 0.25s, background 0.25s;
}

.item-icon {
    grid-row: span 2;
    font-size: 1.6rem;
    line-height: 1;
}

.item-name {
    font-size: var(--t-sm);
    font-weight: 600;
}

.item-meta {
    font-size: var(--t-xs);
    color: var(--text-3);
    font-variant-numeric: tabular-nums;
}

.item.focus {
    border-color: var(--signal);
    box-shadow: 0 0 0 1px var(--signal), 0 0 18px rgba(255, 178, 62, 0.25);
}

.item.taken {
    border-color: var(--s1);
    background: rgba(57, 135, 229, 0.14);
}

.item.skipped {
    opacity: 0.45;
}

.item-badge {
    position: absolute;
    top: -8px;
    right: -6px;
    padding: 1px 6px;
    border-radius: 999px;
    font-size: 0.7rem;
    font-weight: 600;
}

.item.taken .item-badge {
    background: var(--s1);
    color: #fff;
}

.item.skipped .item-badge {
    background: var(--ink-3);
    color: var(--text-2);
}

.decision {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    font-size: var(--t-sm);
}

.decision > div {
    display: flex;
    align-items: baseline;
    gap: 8px;
    padding: 8px 12px;
    border: 1px solid var(--line);
    border-radius: var(--r-2);
    background: var(--ink-1);
    color: var(--text-2);
}

.decision strong {
    font-size: var(--t-xl);
    color: var(--text-1);
    font-variant-numeric: tabular-nums;
}

.decision > div.win {
    border-color: var(--signal);
    box-shadow: inset 0 0 0 1px var(--signal);
}

.decision > div.win::after {
    content: "wins";
    color: var(--signal);
    font-size: var(--t-xs);
    font-weight: 600;
}

/* Gauge (knapsack fill, truck load) */
.gauge {
    display: grid;
    gap: 6px;
}

.gauge-head {
    display: flex;
    justify-content: space-between;
    font-size: var(--t-xs);
    color: var(--text-3);
}

.gauge-head strong {
    color: var(--text-1);
    font-size: var(--t-sm);
}

.gauge-track {
    display: flex;
    gap: 2px;
    height: 26px;
    padding: 2px;
    border: 1px solid var(--line);
    border-radius: 6px;
    background: var(--ink-0);
}

.gauge-seg {
    display: grid;
    place-items: center;
    min-width: 0;
    border-radius: 3px;
    background: var(--s1);
    color: #fff;
    font-size: 0.85rem;
    overflow: hidden;
    transition: flex-basis 0.3s;
}

/* ------------------------------------------------------------------ Article */

.article {
    margin-top: 72px;
    display: grid;
    grid-template-columns: 220px minmax(0, 1fr);
    gap: 56px;
}

.toc {
    position: sticky;
    top: 92px;
    align-self: start;
    display: grid;
    gap: 2px;
    font-size: var(--t-sm);
}

.toc-title {
    margin-bottom: 8px;
    color: var(--text-3);
    font-size: var(--t-xs);
}

.toc a {
    padding: 5px 10px;
    border-left: 1px solid var(--line);
    color: var(--text-2);
    text-decoration: none;
}

.toc a:hover {
    color: var(--text-1);
    border-left-color: var(--signal);
}

.prose {
    max-width: 72ch;
    font-size: var(--t-lg);
    line-height: 1.7;
    color: var(--text-2);
}

.prose > section + section {
    margin-top: 64px;
}

.prose h2 {
    font-family: var(--font-display);
    font-size: var(--t-3xl);
    font-weight: 600;
    color: var(--text-1);
    line-height: 1.05;
    margin-bottom: 18px;
}

.prose h3 {
    font-size: var(--t-xl);
    color: var(--text-1);
    margin: 32px 0 10px;
}

.prose p + p,
.prose p + ul,
.prose ul + p,
.prose p + ol,
.prose ol + p {
    margin-top: 14px;
}

.prose strong {
    color: var(--text-1);
    font-weight: 600;
}

.prose em {
    color: var(--text-1);
}

.prose ul,
.prose ol {
    margin: 0;
    padding-left: 1.3em;
}

.prose li + li {
    margin-top: 6px;
}

.prose li::marker {
    color: var(--text-3);
}

.prose code {
    color: var(--text-1);
    background: var(--ink-2);
    padding: 1px 5px;
    border-radius: 4px;
    font-size: 0.85em;
}

.formula {
    margin: 22px 0;
    padding: 18px 22px;
    border-left: 2px solid var(--signal);
    background: var(--ink-1);
    border-radius: 0 var(--r-2) var(--r-2) 0;
    font-family: var(--font-math);
    font-size: 1.15rem;
    line-height: 1.9;
    color: var(--text-1);
    overflow-x: auto;
}

.formula .row {
    display: grid;
    grid-template-columns: 7.5em minmax(0, 1fr);
    gap: 16px;
}

.formula .row > span:first-child {
    color: var(--text-3);
    font-family: var(--font-ui);
    font-size: var(--t-md);
}

.formula i {
    font-style: italic;
}

.note {
    margin: 22px 0;
    padding: 14px 18px;
    border: 1px solid var(--line);
    border-radius: var(--r-2);
    background: var(--ink-1);
    font-size: var(--t-md);
}

.note strong:first-child {
    display: block;
    margin-bottom: 4px;
}

.compare-table {
    width: 100%;
    margin: 22px 0;
    border-collapse: collapse;
    font-size: var(--t-md);
    line-height: 1.5;
}

.compare-table th {
    text-align: left;
    color: var(--text-3);
    font-weight: 500;
    font-size: var(--t-sm);
    padding: 8px 12px 8px 0;
    border-bottom: 1px solid var(--line);
}

.compare-table td {
    padding: 10px 12px 10px 0;
    border-bottom: 1px solid var(--line-soft);
    vertical-align: top;
}

.compare-table td:first-child {
    color: var(--text-1);
    font-weight: 600;
    white-space: nowrap;
}

.figure {
    margin: 24px 0;
}

.figure figcaption {
    margin-top: 10px;
    font-size: var(--t-sm);
    color: var(--text-3);
}

/* ------------------------------------------------------------------ Home */

/* Grows with its content: the verbs scale with the window, so a fixed cap would clip the text. */
.hero {
    position: relative;
    min-height: calc(100vh - 60px);
    overflow: hidden;
    border-bottom: 1px solid var(--line);
}

.hero-scene {
    position: absolute;
    inset: 0;
}

.hero-scene .scene3d {
    position: absolute;
    inset: 0;
    min-height: 0;
    border-radius: 0;
    background: var(--ink-0);
}

.hero-scene .scene-hint {
    display: none;
}

/* Keeps the headline readable where the landscape runs behind it. */
.hero-scene::after {
    content: "";
    position: absolute;
    inset: 0;
    background: linear-gradient(90deg, rgba(14, 24, 40, 0.92) 0%, rgba(14, 24, 40, 0.72) 32%, rgba(14, 24, 40, 0) 60%);
    pointer-events: none;
}

.hero-inner {
    position: relative;
    max-width: var(--page);
    height: 100%;
    margin: 0 auto;
    padding: 72px var(--gutter) 56px;
    display: grid;
    align-content: space-between;
    gap: 40px;
    pointer-events: none;
    min-height: inherit;
}

.hero-inner a,
.hero-inner button {
    pointer-events: auto;
}

.hero-intro {
    max-width: 34rem;
    font-size: var(--t-xl);
    line-height: 1.45;
    color: var(--text-2);
}

.hero-intro strong {
    color: var(--text-1);
    font-weight: 600;
}

.verbs {
    margin: 0;
    padding: 0;
    list-style: none;
    display: grid;
    gap: 0;
}

.verbs a {
    display: inline-grid;
    grid-template-columns: auto auto;
    align-items: baseline;
    gap: 22px;
    text-decoration: none;
}

.verb {
    font-family: var(--font-display);
    font-weight: 700;
    /* Limited by height too, so all five verbs and the caption fit on short, wide screens. */
    font-size: clamp(3.2rem, min(9.5vw, 9.6vh), 8.4rem);
    line-height: 0.86;
    letter-spacing: -0.015em;
    color: var(--text-1);
    transition: color 0.2s;
}

.verb-note {
    font-size: var(--t-md);
    color: var(--text-3);
    transition: color 0.2s;
}

.verbs a:hover .verb,
.verbs a:focus-visible .verb {
    color: var(--signal);
}

.verbs a:hover .verb-note,
.verbs a:focus-visible .verb-note {
    color: var(--text-1);
}

.hero-caption {
    max-width: 30rem;
    font-size: var(--t-sm);
    color: var(--text-3);
}

.hero-caption .dot {
    display: inline-block;
    width: 9px;
    height: 9px;
    border-radius: 50%;
    background: var(--signal);
    margin-right: 6px;
    vertical-align: 0;
}

.section {
    padding-top: 96px;
}

.section-head {
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    gap: 16px 56px;
    align-items: end;
    margin-bottom: 36px;
}

.section-title {
    font-family: var(--font-display);
    font-size: clamp(2.25rem, 4.5vw, 3.5rem);
    font-weight: 700;
    line-height: 1;
}

.section-lede {
    color: var(--text-2);
    font-size: var(--t-lg);
    max-width: 56ch;
}

.problem-list {
    margin: 0;
    padding: 0;
    list-style: none;
    border-top: 1px solid var(--line);
}

.problem-row {
    display: grid;
    grid-template-columns: 112px minmax(0, 1.1fr) minmax(0, 1fr) auto;
    gap: 28px;
    align-items: center;
    padding: 26px 0;
    border-bottom: 1px solid var(--line);
}

.problem-glyph {
    width: 112px;
    height: 80px;
    border-radius: var(--r-2);
    background: var(--ink-1);
    border: 1px solid var(--line);
}

.problem-name {
    font-family: var(--font-display);
    font-size: 2rem;
    font-weight: 600;
    line-height: 1;
}

.problem-name a {
    text-decoration: none;
}

.problem-name a:hover {
    color: var(--signal);
}

.problem-desc {
    margin-top: 8px;
    color: var(--text-2);
    max-width: 52ch;
}

.problem-meta {
    display: grid;
    grid-template-columns: auto minmax(0, 1fr);
    gap: 4px 14px;
    margin: 0;
    font-size: var(--t-sm);
}

.problem-meta dt {
    color: var(--text-3);
}

.problem-meta dd {
    margin: 0;
    color: var(--text-2);
}

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

.steps-list li {
    padding: 22px 24px 0 0;
}

.steps-list .n {
    font-family: var(--font-display);
    font-size: 2.6rem;
    font-weight: 700;
    color: var(--text-3);
    line-height: 1;
}

.steps-list h3 {
    margin-top: 12px;
    font-size: var(--t-lg);
}

.steps-list p {
    margin-top: 6px;
    color: var(--text-2);
    font-size: var(--t-md);
}

/* ------------------------------------------------------------------ Responsive */

@media (max-width: 1180px) {
    .lab-body {
        grid-template-columns: minmax(0, 1fr);
    }

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

    .lab-body {
        height: auto;
        grid-template-rows: none;
    }

    .stage-body,
    .side {
        overflow: visible;
    }

    .stage-body {
        min-height: 520px;
    }

    .narration {
        min-height: 210px;
    }

    .side {
        display: grid;
        grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    }

    .side-section.narration {
        grid-column: 1 / -1;
    }

    .side-section {
        border-bottom: 1px solid var(--line);
    }

    .results {
        grid-template-columns: minmax(0, 1fr);
    }
}

@media (max-width: 900px) {
    .lab-header {
        grid-template-columns: minmax(0, 1fr);
    }

    .article {
        grid-template-columns: minmax(0, 1fr);
        gap: 24px;
    }

    .toc {
        position: static;
        grid-auto-flow: row;
    }

    .section-head {
        grid-template-columns: minmax(0, 1fr);
    }

    .problem-row {
        grid-template-columns: 88px minmax(0, 1fr);
    }

    .problem-glyph {
        width: 88px;
        height: 64px;
    }

    .problem-meta,
    .problem-row > .btn {
        grid-column: 2;
    }

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

    .side {
        grid-template-columns: minmax(0, 1fr);
    }
}

@media (max-width: 640px) {
    .topbar-inner {
        gap: 12px;
    }

    .brand span {
        display: none;
    }

    .toolbar {
        padding: 14px;
    }

    .pb-hint {
        display: none;
    }

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

    .verbs a {
        grid-template-columns: minmax(0, 1fr);
        gap: 0;
    }

    .verb-note {
        margin-bottom: 12px;
    }

    .formula .row {
        grid-template-columns: minmax(0, 1fr);
        gap: 0;
    }
}

@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.001ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.001ms !important;
    }
}

/* ------------------------------------------------------------------ Knapsack: greedy ranking */

h1:focus {
    outline: none;
}

.density-list {
    margin: 0;
    padding: 0;
    list-style: none;
    display: grid;
    gap: 6px;
}

.density-list li {
    display: grid;
    grid-template-columns: minmax(120px, 170px) minmax(80px, 1fr) 110px 120px 72px;
    align-items: center;
    gap: 14px;
    padding: 8px 12px;
    border: 1px solid var(--line);
    border-radius: var(--r-2);
    background: var(--ink-1);
    font-size: var(--t-sm);
    transition: opacity 0.25s, border-color 0.25s;
}

.density-list .d-name {
    font-weight: 600;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.density-list .d-track {
    height: 12px;
}

.density-list .d-bar {
    display: block;
    height: 100%;
    border-radius: 0 4px 4px 0;
    background: var(--ink-3);
    transition: background 0.25s;
}

.density-list .d-value {
    color: var(--text-1);
}

.density-list .d-meta,
.density-list .d-state {
    color: var(--text-3);
    font-size: var(--t-xs);
}

.density-list li.taken .d-bar {
    background: var(--s1);
}

.density-list li.taken .d-state {
    color: var(--text-1);
}

.density-list li.focus {
    border-color: var(--signal);
    box-shadow: 0 0 0 1px var(--signal);
}

.density-list li.focus .d-state {
    color: var(--signal);
    font-weight: 600;
}

.density-list li.skipped {
    opacity: 0.5;
}

@media (max-width: 760px) {
    .density-list li {
        grid-template-columns: minmax(0, 1fr) auto;
    }

    .density-list .d-track {
        grid-column: 1 / -1;
        order: 5;
    }
}

/* ------------------------------------------------------------------ Bin packing: waiting items */

.queue {
    display: flex;
    flex-wrap: wrap;
    align-content: flex-start;
    align-items: center;
    gap: 6px;
    /* Room for two rows, so the bins below don't move as the queue empties. */
    min-height: 58px;
}

.queue-label {
    margin-right: 6px;
    font-size: var(--t-xs);
    color: var(--text-3);
}

.queue-item {
    display: inline-grid;
    place-items: center;
    height: 26px;
    border-radius: 4px;
    font-size: 0.78rem;
    font-weight: 600;
    font-variant-numeric: tabular-nums;
}

.queue-item.focus {
    outline: 2px solid var(--signal);
    outline-offset: 2px;
    box-shadow: 0 0 14px rgba(255, 178, 62, 0.45);
}

.queue-more {
    font-size: var(--t-xs);
    color: var(--text-3);
}

/* ------------------------------------------------------------------ Max flow: search frontier */

.flow-foot {
    display: flex;
    flex-wrap: wrap;
    align-items: end;
    justify-content: space-between;
    gap: 14px 28px;
}

.frontier {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 6px;
    font-size: var(--t-sm);
}

.chip {
    display: inline-flex;
    align-items: center;
    height: 26px;
    padding: 0 10px;
    border: 1px solid var(--line);
    border-radius: 999px;
    background: var(--ink-1);
    font-size: var(--t-xs);
    font-weight: 600;
    color: var(--text-1);
}

/* ------------------------------------------------------------------ Job shop: routing list */

.jobs {
    margin: 0;
    padding: 0;
    list-style: none;
    display: grid;
    gap: 6px;
}

.jobs li {
    display: grid;
    grid-template-columns: 10px 30px minmax(0, 1fr) auto;
    align-items: center;
    gap: 10px;
    font-size: var(--t-sm);
}

.jobs .job-route {
    display: flex;
    flex-wrap: wrap;
    gap: 4px;
}

.jobs .op {
    padding: 2px 8px;
    border: 1px solid var(--line);
    border-radius: 999px;
    font-size: var(--t-xs);
    color: var(--text-3);
    white-space: nowrap;
}

.jobs .op b {
    font-weight: 600;
    font-variant-numeric: tabular-nums;
}

.jobs .op.done {
    color: var(--text-1);
    border-color: var(--text-3);
    background: var(--ink-2);
}

.jobs .op.focus {
    border-color: var(--signal);
    color: var(--signal);
}

.jobs .job-end {
    font-size: var(--t-xs);
    color: var(--text-2);
    font-variant-numeric: tabular-nums;
    white-space: nowrap;
}

/* ------------------------------------------------------------------ Vehicle routing */

.vrp-grid {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 250px;
    gap: 18px;
    align-items: start;
}

.routes {
    display: grid;
    gap: 10px;
    max-height: 600px;
    overflow-y: auto;
    scrollbar-width: thin;
    padding-right: 4px;
}

.route {
    padding: 10px 12px;
    border: 1px solid var(--line);
    border-radius: var(--r-2);
    background: var(--ink-1);
    font-size: var(--t-sm);
}

.route.active {
    border-color: var(--signal);
}

.route-head {
    display: flex;
    align-items: center;
    gap: 8px;
}

.route-head .muted {
    margin-left: auto;
    font-size: var(--t-xs);
}

.route-stops {
    display: flex;
    flex-wrap: wrap;
    gap: 3px;
    margin: 8px 0;
}

.stop {
    padding: 1px 6px;
    border-radius: 4px;
    background: var(--ink-2);
    font-size: 0.72rem;
    font-weight: 600;
    font-variant-numeric: tabular-nums;
}

.stop.depot {
    background: transparent;
    color: var(--text-3);
    font-weight: 500;
}

.stop.focus {
    background: var(--signal);
    color: var(--signal-ink);
}

.stop.late {
    background: var(--bad);
    color: #fff;
}

.route-load {
    height: 6px;
    border-radius: 3px;
    background: var(--ink-0);
    overflow: hidden;
}

.route-load span {
    display: block;
    height: 100%;
    border-radius: 3px;
}

.route-meta {
    margin-top: 4px;
    font-size: var(--t-xs);
}

.savings {
    max-width: 520px;
}

@media (max-width: 760px) {
    .vrp-grid {
        grid-template-columns: minmax(0, 1fr);
    }

    .routes {
        max-height: none;
    }
}

.decision.placeholder {
    visibility: hidden;
}

/* ------------------------------------------------------------------ Sharing */

.share {
    display: flex;
    align-items: end;
    gap: 10px;
}

.share-fallback {
    display: grid;
    gap: 4px;
    font-size: var(--t-xs);
    color: var(--text-3);
}

.share-fallback .input {
    width: 260px;
    padding-right: 10px;
    background-image: none;
    cursor: text;
}

.notice {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    margin-bottom: 16px;
    padding: 10px 12px 10px 16px;
    border: 1px solid var(--bad);
    border-radius: var(--r-2);
    background: #2a1a22;
    color: var(--text-1);
    font-size: var(--t-sm);
}

.tree-stats {
    font-size: var(--t-sm);
    color: var(--text-2);
}

.tree-stats strong {
    color: var(--text-1);
}

/* The stage scrolls as a whole; its children keep their natural height instead of being squeezed. */
.stage-body > * {
    flex-shrink: 0;
}

/* ------------------------------------------------------------------ Integer program view */

.ip-model {
    margin: 0;
    font-size: 1rem;
    line-height: 1.8;
}

.ip-model .term {
    border-radius: 4px;
    padding: 0 2px;
}

.ip-model .term.frac {
    color: var(--signal);
    font-weight: 700;
}

.ip-model .term.one {
    color: var(--text-1);
    font-weight: 700;
}

.ip-model .term.fixed {
    text-decoration: underline;
    text-decoration-color: var(--text-3);
    text-underline-offset: 4px;
}

.ip-model .term:not(.frac):not(.one):not(.fixed) {
    color: var(--text-3);
}

.ip-status {
    display: flex;
    flex-wrap: wrap;
    gap: 6px 26px;
    font-size: var(--t-sm);
    color: var(--text-2);
}

.ip-status strong {
    color: var(--text-1);
    font-variant-numeric: tabular-nums;
}

.ip-vars {
    margin: 0;
    padding: 0;
    list-style: none;
    display: grid;
    gap: 4px;
}

.ip-vars li {
    display: grid;
    grid-template-columns: minmax(150px, 220px) minmax(80px, 1fr) 52px 100px;
    align-items: center;
    gap: 12px;
    font-size: var(--t-sm);
}

.ip-name {
    font-family: var(--font-math);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.ip-name .muted {
    font-family: var(--font-ui);
    margin-left: 6px;
}

.ip-bar {
    height: 10px;
    border-radius: 3px;
    background: var(--ink-0);
    border: 1px solid var(--line);
    overflow: hidden;
}

.ip-bar span {
    display: block;
    height: 100%;
    background: var(--s1);
}

.ip-vars li.frac .ip-bar span {
    background: var(--signal);
}

.ip-vars li.frac .ip-val,
.ip-vars li.frac .ip-tag {
    color: var(--signal);
    font-weight: 600;
}

.ip-val {
    text-align: right;
}

.ip-tag {
    font-size: var(--t-xs);
    color: var(--text-3);
}

.ip-grid {
    border-collapse: separate;
    border-spacing: 3px;
    font-size: var(--t-sm);
    font-variant-numeric: tabular-nums;
}

.ip-grid th {
    padding: 4px 10px;
    font-weight: 500;
    color: var(--text-2);
    text-align: left;
    white-space: nowrap;
}

.ip-grid td {
    width: 64px;
    height: 32px;
    text-align: center;
    border-radius: 4px;
    border: 1px solid var(--line);
    background: color-mix(in srgb, var(--s1) calc(var(--fill, 0) * 85%), var(--ink-0));
    color: var(--text-1);
    font-weight: 600;
}

.ip-grid td.frac {
    background: color-mix(in srgb, var(--signal) calc(var(--fill, 0) * 70% + 15%), var(--ink-0));
    color: var(--signal-ink);
}

.ip-grid td.fixed {
    border-color: var(--text-2);
    border-style: dashed;
}

.ip-grid td.ip-off {
    background: repeating-linear-gradient(135deg, transparent 0 5px, var(--line-soft) 5px 7px);
    border-color: transparent;
}

.ip-grid tr.ip-y th {
    color: var(--text-1);
}

/* ------------------------------------------------------------------ Matching */

.match-chips {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 6px;
    font-size: var(--t-sm);
}

/* ------------------------------------------------------------------ Play and edit modes */

.btn.primary {
    background: var(--signal);
    border-color: var(--signal);
    color: var(--signal-ink);
    font-weight: 600;
}

.btn.primary:hover:not(:disabled) {
    background: #ffc266;
    border-color: #ffc266;
}

.btn:disabled {
    opacity: 0.45;
    cursor: not-allowed;
}

.btn.small {
    height: 28px;
    padding: 0 10px;
    font-size: var(--t-xs);
}

.play-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 14px;
}

.play-message {
    margin-top: 12px;
    padding: 8px 12px;
    border-radius: var(--r-2);
    font-size: var(--t-sm);
    border: 1px solid var(--line);
}

.play-message.bad {
    border-color: var(--bad);
    color: var(--bad-text);
    background: rgba(208, 59, 59, 0.08);
}

.play-message.ok {
    color: var(--text-2);
}

.play-verdict {
    margin-bottom: 14px;
    color: var(--text-2);
    font-size: var(--t-sm);
    line-height: 1.6;
}

.play-verdict strong {
    color: var(--text-1);
}

.play-figures {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 12px 18px;
    margin: 0;
}

.play-figures dt {
    font-size: var(--t-xs);
    color: var(--text-3);
}

.play-figures dd {
    margin: 2px 0 0;
    font-size: var(--t-xl);
    font-weight: 600;
    font-variant-numeric: tabular-nums;
}

.drop-zone {
    border: 1.5px dashed var(--line);
    border-radius: var(--r-2);
    transition: border-color 0.15s, background 0.15s;
}

.drop-zone.over {
    border-color: var(--signal);
    background: var(--signal-soft);
}

.draggable {
    cursor: grab;
    user-select: none;
    touch-action: none;
}

.draggable:active {
    cursor: grabbing;
}

.selected-outline {
    outline: 2px solid var(--signal);
    outline-offset: 2px;
}

.edit-panel .side-section h3 {
    font-size: var(--t-md);
    margin-bottom: 10px;
}

.edit-row {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 4px 0;
    font-size: var(--t-sm);
}

.edit-row > span:first-child {
    flex: 1;
    min-width: 0;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.stepper {
    display: inline-flex;
    align-items: center;
    border: 1px solid var(--line);
    border-radius: var(--r-2);
    overflow: hidden;
}

.stepper button {
    width: 28px;
    height: 28px;
    border: 0;
    background: var(--ink-2);
    color: var(--text-1);
    cursor: pointer;
    font-size: 1rem;
}

.stepper button:hover:not(:disabled) {
    background: var(--ink-3);
}

.stepper button:disabled {
    opacity: 0.35;
    cursor: not-allowed;
}

.stepper output {
    min-width: 42px;
    text-align: center;
    font-size: var(--t-sm);
    font-weight: 600;
    font-variant-numeric: tabular-nums;
}

.edit-hint {
    font-size: var(--t-xs);
    color: var(--text-3);
    line-height: 1.5;
}

/* Bin packing play */
.shelf {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 6px;
    min-height: 58px;
    padding: 10px;
}

.play-bins {
    display: flex;
    flex-wrap: wrap;
    gap: 14px;
    align-items: flex-end;
}

.play-bin-wrap {
    display: grid;
    justify-items: center;
    gap: 6px;
}

.play-bin {
    width: 64px;
    height: 250px;
    display: flex;
    flex-direction: column-reverse;
    gap: 2px;
    padding: 3px;
    border-style: solid;
    background: var(--ink-0);
    cursor: pointer;
}

.play-bin.new {
    border-style: dashed;
    background: transparent;
    justify-content: center;
}

.play-bin.full {
    opacity: 0.5;
}

.play-new {
    align-self: center;
    font-size: var(--t-xs);
    color: var(--signal);
    font-weight: 600;
    text-align: center;
}

.play-block {
    display: grid;
    place-items: center;
    border-radius: 3px;
    font-size: 0.78rem;
    font-weight: 600;
    min-height: 0;
    overflow: hidden;
}

.play-block.focus {
    outline: 2px solid var(--signal);
    outline-offset: 1px;
}

.play-bin-label {
    font-size: var(--t-xs);
    color: var(--text-3);
    white-space: nowrap;
}

.knapsack-bag {
    padding: 12px;
}

/* ------------------------------------------------------------------ Race mode */

.race-picker {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 8px;
    padding: 12px 16px;
    border-bottom: 1px solid var(--line);
}

.race-picker-label {
    margin-right: 6px;
    font-size: var(--t-xs);
    font-weight: 600;
    color: var(--text-2);
}

.chip-toggle {
    display: inline-flex;
    align-items: center;
    gap: 7px;
    height: 30px;
    padding: 0 12px;
    border: 1px solid var(--line);
    border-radius: 999px;
    background: var(--ink-1);
    color: var(--text-2);
    font: inherit;
    font-size: var(--t-xs);
    font-weight: 600;
    cursor: pointer;
    transition: border-color 0.15s, background 0.15s, color 0.15s;
}

.chip-toggle:hover:not(:disabled) {
    border-color: var(--text-3);
    color: var(--text-1);
}

.chip-toggle.on {
    border-color: var(--text-3);
    background: var(--ink-3);
    color: var(--text-1);
}

.chip-toggle:disabled {
    cursor: not-allowed;
    opacity: 0.55;
}

.race-dot {
    width: 9px;
    height: 9px;
    border-radius: 50%;
    flex: none;
}

/* Same fixed height as the lab body, so racing doesn't push the page around either. */
.race-body {
    display: grid;
    grid-template-columns: repeat(var(--lanes, 2), minmax(0, 1fr));
    grid-template-rows: minmax(0, 1fr);
    height: clamp(560px, calc(100vh - 210px), 820px);
}

.race-lane {
    display: flex;
    flex-direction: column;
    min-width: 0;
    min-height: 0;
    border-right: 1px solid var(--line);
    background-color: var(--ink-1);
    background-image:
        linear-gradient(var(--grid) 1px, transparent 1px),
        linear-gradient(90deg, var(--grid) 1px, transparent 1px);
    background-size: 24px 24px;
}

.race-lane:last-child {
    border-right: 0;
}

.race-head {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 12px;
    padding: 14px 16px 6px;
}

.race-name {
    display: flex;
    align-items: center;
    gap: 8px;
    font-family: var(--font-display);
    font-size: var(--t-xl);
    font-weight: 600;
    line-height: 1.15;
}

.race-score {
    display: grid;
    justify-items: end;
    font-size: var(--t-xs);
    color: var(--text-3);
}

.race-score strong {
    font-size: var(--t-xl);
    color: var(--text-1);
    font-variant-numeric: tabular-nums;
}

.race-status {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 6px 10px;
    min-height: 44px;
    padding: 0 16px 8px;
    font-size: var(--t-xs);
}

.race-track {
    flex: 1 0 100%;
    height: 4px;
    border-radius: 2px;
    background: var(--ink-3);
    overflow: hidden;
}

.race-track span {
    display: block;
    height: 100%;
    background: var(--s1);
    transition: width 0.2s;
}

.race-badge {
    display: inline-flex;
    align-items: center;
    height: 22px;
    padding: 0 9px;
    border-radius: 999px;
    background: var(--ink-3);
    color: var(--text-1);
    font-weight: 600;
}

.race-badge.best {
    background: var(--signal);
    color: var(--signal-ink);
}

.race-viz {
    flex: 1;
    min-height: 0;
    overflow: auto;
    scrollbar-width: thin;
    padding: 4px 12px;
}

.race-viz > * {
    flex-shrink: 0;
}

.race-text {
    height: 8.6em;
    flex: none;
    overflow-y: auto;
    scrollbar-width: thin;
    padding: 10px 16px 12px;
    border-top: 1px solid var(--line);
    background: var(--ink-0);
    font-size: var(--t-xs);
    line-height: 1.5;
    color: var(--text-2);
}

.race-text .race-title {
    display: block;
    margin-bottom: 2px;
    color: var(--text-1);
    font-size: var(--t-sm);
}

.race-text p {
    margin: 0;
}

.race-summary {
    min-height: 2.8em;
    margin: 0;
    padding: 10px 16px;
    border-top: 1px solid var(--line);
    font-size: var(--t-sm);
    color: var(--text-2);
}

@media (max-width: 900px) {
    .race-body {
        grid-template-columns: minmax(0, 1fr);
        grid-template-rows: none;
        height: auto;
    }

    .race-lane {
        height: 620px;
        border-right: 0;
        border-bottom: 1px solid var(--line);
    }
}

/* ------------------------------------------------------------------ Scale mode */

.scale-controls {
    display: grid;
    gap: 14px;
    margin-top: 12px;
}

.scale-progress {
    display: grid;
    grid-template-columns: auto 1fr;
    align-items: center;
    gap: 10px 12px;
    padding: 14px 16px;
    border: 1px solid var(--line);
    border-radius: var(--r-2);
    background: var(--ink-2);
    font-size: var(--t-sm);
    color: var(--text-2);
}

.scale-progress .race-track {
    grid-column: 1 / -1;
}

.spinner {
    width: 16px;
    height: 16px;
    border: 2px solid var(--ink-3);
    border-top-color: var(--signal);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

.scale-caption {
    margin: 4px 0 0;
    font-size: var(--t-sm);
    color: var(--text-2);
}

.scale-caption strong {
    color: var(--text-1);
}

.scale-chart {
    max-width: 760px;
}

.scale-chart h3 {
    margin: 8px 0 2px;
    font-size: var(--t-md);
}

.scale-chart p {
    margin: 0 0 8px;
    font-size: var(--t-xs);
}

.field.inline {
    grid-auto-flow: column;
    align-items: center;
    gap: 8px;
}

.muted.small {
    margin: 10px 0 0;
    font-size: var(--t-xs);
    line-height: 1.5;
}

.scale-figures {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(130px, 1fr));
    gap: 10px 18px;
    margin: 0;
}

.scale-figures dt {
    font-size: var(--t-xs);
    color: var(--text-3);
}

.scale-figures dd {
    margin: 2px 0 0;
    font-size: var(--t-lg);
    font-weight: 600;
    font-variant-numeric: tabular-nums;
}

/* ------------------------------------------------------------------ Real street map (Leaflet) */

.realmap {
    width: 100%;
    height: clamp(380px, 58vh, 600px);
    border: 1px solid var(--line);
    border-radius: var(--r-2);
    background: var(--ink-0);
    cursor: crosshair;
}

.realmap .leaflet-tile-pane {
    /* A dark map from the standard light tiles: invert, then turn the hues back around. */
    filter: invert(1) hue-rotate(180deg) brightness(0.82) contrast(0.92) saturate(0.6);
}

.realmap .leaflet-control-attribution {
    background: rgba(14, 24, 40, 0.82);
    color: var(--text-3);
    font-size: 11px;
}

.realmap .leaflet-control-attribution a {
    color: var(--text-2);
}

.realmap .leaflet-bar a {
    background: var(--ink-2);
    border-color: var(--line);
    color: var(--text-1);
}

.realmap .leaflet-bar a:hover {
    background: var(--ink-3);
}

.realmap .leaflet-tooltip {
    background: var(--ink-2);
    border: 1px solid var(--line);
    color: var(--text-1);
    font: 600 12px var(--font-ui);
    box-shadow: none;
}

.realmap .leaflet-tooltip-top::before {
    border-top-color: var(--line);
}

.realmap-depot span {
    display: block;
    width: 24px;
    height: 24px;
    border: 2px solid var(--ink-0);
    border-radius: 5px;
    background: #d8e1ee;
    box-shadow: 0 0 0 2px rgba(216, 225, 238, 0.35);
}

.road-status {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    font-size: var(--t-xs);
    color: var(--text-2);
}

.road-status.problem {
    color: var(--bad-text);
}

.road-status .spinner {
    width: 12px;
    height: 12px;
}

.scale-charts {
    display: grid;
    grid-template-columns: minmax(0, 1fr);
    gap: 18px;
    max-width: 760px;
}

.scale-charts h3 {
    margin: 8px 0 6px;
    font-size: var(--t-md);
}

.scale-charts h3 small {
    margin-left: 6px;
    font-size: var(--t-xs);
    font-weight: 400;
}

.scale-table tbody tr {
    cursor: pointer;
}

.scale-table tbody tr:hover td {
    background: var(--ink-2);
}

.scale-table tr.pending td {
    color: var(--text-3);
    cursor: default;
}