:root {
  --bg: #f4f6f8;
  --surface: #ffffff;
  --ink: #16202b;
  --muted: #5a6574;
  --line: #dbe1e8;
  --line-strong: #c3ccd6;
  --accent: #1f4e79;
  --accent-ink: #ffffff;
  --accent-soft: #e5edf5;
  --warm: #c25416;
  --warm-soft: #fbeee4;
  --good: #2b7a4b;
  --good-soft: #e3f2e9;
  --bad: #b3261e;
  --bad-soft: #fbe7e5;
  --violet: #6a4c93;
  --soft: #f7f9fb;
  --radius: 8px;
  --font: "Segoe UI", system-ui, -apple-system, "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  color-scheme: light;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font);
  font-size: 15px;
  line-height: 1.5;
}

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

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

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* Каркас */
.app-header {
  background: var(--surface);
  border-bottom: 1px solid var(--line);
}

.app-header__inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 24px;
  max-width: 1280px;
  margin: 0 auto;
  padding: 12px max(16px, env(safe-area-inset-left, 0px));
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  font-weight: 700;
  font-size: 18px;
  text-decoration: none;
}

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

.nav {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
}

.nav a {
  padding: 6px 10px;
  border-radius: 6px;
  color: var(--muted);
  text-decoration: none;
  font-size: 14px;
}

.nav a:hover {
  background: var(--accent-soft);
  color: var(--accent);
}

.nav a.active,
.nav a[aria-current="page"] {
  background: var(--accent);
  color: var(--accent-ink);
}

.page {
  max-width: 1280px;
  margin: 0 auto;
  padding: 24px max(16px, env(safe-area-inset-left, 0px)) 48px;
}

/* Каталог */
.catalog__lead {
  max-width: 68ch;
  margin: 0 0 24px;
  color: var(--muted);
  font-size: 16px;
}

.catalog__title {
  margin: 8px 0 8px;
  font-size: 28px;
  text-wrap: balance;
}

.catalog__grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 16px;
}

.module-card {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 18px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  color: inherit;
  text-decoration: none;
  transition: border-color 0.15s;
}

.module-card:hover {
  border-color: var(--accent);
}

.module-card h2 {
  margin: 0;
  font-size: 18px;
}

.module-card__concept {
  color: var(--muted);
  font-size: 14px;
}

.module-card__it {
  margin-top: auto;
  padding-top: 8px;
  border-top: 1px solid var(--line);
  color: var(--accent);
  font-size: 13px;
  font-weight: 600;
}

/* Страница модуля */
.module__eyebrow {
  margin: 0;
  color: var(--muted);
  font-size: 13px;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.module__title {
  margin: 4px 0 4px;
  font-size: 26px;
  text-wrap: balance;
}

.module__subtitle {
  margin: 0 0 20px;
  color: var(--muted);
  max-width: 75ch;
}

.workspace {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 340px;
  gap: 16px;
  align-items: start;
}

.scene {
  min-width: 0;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 12px;
}

.panel {
  display: flex;
  flex-direction: column;
  gap: 16px;
  min-width: 0;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px;
}

.panel h3 {
  margin: 0 0 8px;
  font-size: 13px;
  color: var(--muted);
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.texts {
  display: grid;
  grid-template-columns: minmax(0, 3fr) minmax(0, 2fr);
  gap: 16px;
  margin-top: 16px;
}

.text-block {
  min-width: 0;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 4px 20px 12px;
}

.text-block--it {
  background: var(--accent-soft);
  border-color: transparent;
}

.text-block h2 {
  font-size: 18px;
}

.text-block p,
.text-block li {
  max-width: 70ch;
}

.text-block .katex-display,
.panel .katex-display {
  overflow-x: auto;
  overflow-y: hidden;
  padding: 4px 0;
}

.text-block table {
  border-collapse: collapse;
  margin: 8px 0 12px;
  font-size: 14px;
}

.text-block th,
.text-block td {
  padding: 6px 12px;
  border-bottom: 1px solid var(--line);
  text-align: left;
}

.text-block th {
  color: var(--muted);
  font-weight: 600;
}

.upload {
  position: relative;
  align-self: flex-start;
}

.row > .upload .button {
  width: 100%;
}

.upload input {
  position: absolute;
  width: 1px;
  height: 1px;
  opacity: 0;
}

.upload input:focus-visible + span {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

@media (max-width: 960px) {
  .workspace,
  .texts {
    grid-template-columns: minmax(0, 1fr);
  }
}

/* Элементы управления */
.field {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.field label,
.field__label {
  font-size: 13px;
  color: var(--muted);
}

.input,
.select {
  width: 100%;
  min-width: 0;
  padding: 7px 9px;
  background: var(--surface);
  border: 1px solid var(--line-strong);
  border-radius: 6px;
  font-variant-numeric: tabular-nums;
}

.input:focus,
.select:focus {
  border-color: var(--accent);
  outline: none;
  box-shadow: 0 0 0 3px var(--accent-soft);
}

.input--invalid {
  border-color: var(--bad);
}

.row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.row > * {
  flex: 1 1 0;
  min-width: 0;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 7px 12px;
  background: var(--surface);
  border: 1px solid var(--line-strong);
  border-radius: 6px;
  cursor: pointer;
  font-size: 14px;
  white-space: nowrap;
}

.button:hover:not(:disabled) {
  border-color: var(--accent);
  color: var(--accent);
}

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

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

.button--primary:hover:not(:disabled) {
  color: var(--accent-ink);
  filter: brightness(1.12);
}

.button--active {
  background: var(--accent-soft);
  border-color: var(--accent);
  color: var(--accent);
}

.chips {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.chips .button {
  padding: 4px 10px;
  font-size: 13px;
}

.slider {
  width: 100%;
  accent-color: var(--accent);
}

.matrix-input {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 6px;
  padding: 6px 10px;
  border-left: 2px solid var(--ink);
  border-right: 2px solid var(--ink);
  border-radius: 10px;
}

.matrix-input--3 {
  grid-template-columns: repeat(3, 1fr);
}

.matrix-input .input {
  text-align: center;
}

/* Результаты */
.facts {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 6px 12px;
  margin: 0;
  font-size: 14px;
}

.facts dt {
  color: var(--muted);
}

.facts dd {
  margin: 0;
  font-variant-numeric: tabular-nums;
  min-width: 0;
  overflow-wrap: anywhere;
}

.callout {
  padding: 10px 12px;
  border-radius: 6px;
  background: var(--accent-soft);
  font-size: 14px;
}

.callout strong {
  display: block;
  margin-bottom: 2px;
}

.status {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 10px;
  border-radius: 999px;
  font-size: 13px;
  font-weight: 600;
}

.status--good {
  background: var(--good-soft);
  color: var(--good);
}

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

.status--neutral {
  background: var(--accent-soft);
  color: var(--accent);
}

.status--warm {
  background: var(--warm-soft);
  color: var(--warm);
}

.error {
  padding: 8px 10px;
  border-radius: 6px;
  background: var(--bad-soft);
  color: var(--bad);
  font-size: 14px;
}

.hint {
  margin: 0;
  color: var(--muted);
  font-size: 13px;
}

.formula-preview {
  min-height: 28px;
  padding: 6px 8px;
  border-radius: 6px;
  background: var(--bg);
  overflow-x: auto;
}

.table-wrap {
  overflow-x: auto;
}

.table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
  font-variant-numeric: tabular-nums;
}

.table th,
.table td {
  padding: 4px 6px;
  border-bottom: 1px solid var(--line);
  text-align: right;
  white-space: nowrap;
}

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

.table th {
  color: var(--muted);
  font-weight: 600;
}

.table .is-current {
  background: var(--warm-soft);
}

.table .is-visited {
  color: var(--accent);
  font-weight: 600;
}

[hidden] {
  display: none !important;
}

/* Сцены */
.canvas-pair {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 12px;
}

.canvas-pair figure {
  margin: 0;
  min-width: 0;
}

.canvas-pair canvas {
  display: block;
  width: 100%;
  max-width: 512px;
  height: auto;
  aspect-ratio: 1;
  image-rendering: pixelated;
  background: repeating-conic-gradient(#eef1f4 0% 25%, #ffffff 0% 50%) 50% / 16px 16px;
  border: 1px solid var(--line);
  border-radius: 4px;
}

.canvas-pair figcaption {
  margin-top: 6px;
  color: var(--muted);
  font-size: 13px;
}

.thumbs {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 6px;
}

.thumb {
  padding: 0;
  border: 2px solid transparent;
  border-radius: 6px;
  background: none;
  cursor: pointer;
}

.thumb img {
  display: block;
  width: 100%;
  border-radius: 4px;
}

.thumb--active {
  border-color: var(--accent);
}

.toolbar {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-bottom: 10px;
}

.step-log {
  margin: 0;
  padding: 0;
  list-style: none;
  font-size: 14px;
}

.step-log li {
  padding: 2px 0;
}

.improved {
  color: var(--good);
  font-weight: 600;
}

.scene-canvas {
  display: block;
  width: 100%;
  border-radius: 6px;
  border: 1px solid var(--line);
  background: var(--soft);
  touch-action: manipulation;
}

.scene-canvas--drag {
  cursor: grab;
  touch-action: none;
}

.scene-canvas--drag:active {
  cursor: grabbing;
}

.scene-canvas--click {
  cursor: crosshair;
}

.scene-stack {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.scene-caption {
  margin: 0;
  color: var(--muted);
  font-size: 13px;
}

.legend {
  display: flex;
  flex-wrap: wrap;
  gap: 4px 16px;
  margin: 0;
  padding: 0;
  list-style: none;
  color: var(--muted);
  font-size: 13px;
}

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

.legend__mark {
  display: inline-block;
  width: 16px;
  height: 0;
  border-top: 3px solid currentColor;
  border-radius: 2px;
}

.legend__mark--dash {
  border-top-style: dashed;
  border-top-width: 2px;
}

.legend__mark--dot {
  width: 10px;
  height: 10px;
  border: 0;
  border-radius: 50%;
  background: currentColor;
}

.legend__mark--box {
  width: 12px;
  height: 12px;
  border: 0;
  border-radius: 3px;
  background: currentColor;
}

.metrics {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 10px;
  margin: 12px 0 0;
}

.metric {
  min-width: 0;
  padding: 10px 12px;
  border: 1px solid var(--line);
  border-radius: 6px;
}

.metric dt {
  color: var(--muted);
  font-size: 13px;
}

.metric dd {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px 8px;
  margin: 2px 0 0;
}

.metric__value {
  font-size: 20px;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
  overflow-wrap: anywhere;
}

.slider-label {
  display: flex;
  justify-content: space-between;
  gap: 8px;
}

.slider-label output {
  color: var(--ink);
  font-weight: 600;
  font-variant-numeric: tabular-nums;
}

.formula-card {
  padding: 8px 12px;
  border-radius: 6px;
  background: var(--bg);
  overflow-x: auto;
}

.formula-card .katex-display {
  margin: 6px 0;
}

.mono-note {
  margin: 0;
  padding: 8px 10px;
  border-radius: 6px;
  background: var(--bg);
  font-family: var(--mono);
  font-size: 13px;
  line-height: 1.6;
  white-space: pre-wrap;
  overflow-wrap: anywhere;
}

.texts__side {
  display: flex;
  flex-direction: column;
  gap: 16px;
  min-width: 0;
}

.code-card__head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.code-card__body {
  margin: 0 0 8px;
  padding: 12px;
  border-radius: 6px;
  background: #0f1923;
  color: #e6edf3;
  font-family: var(--mono);
  font-size: 13px;
  line-height: 1.55;
  overflow-x: auto;
}

.module-pager {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 8px 16px;
  margin-top: 24px;
  padding-top: 16px;
  border-top: 1px solid var(--line);
  font-size: 14px;
}

.catalog__filters {
  margin-bottom: 16px;
}

.module-card__section {
  color: var(--muted);
  font-size: 12px;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.module-card__engine {
  float: right;
  color: var(--muted);
  font-weight: 400;
}

.matrix-input--4 {
  grid-template-columns: repeat(4, 1fr);
}

.matrix-input .cell--translation {
  border-color: var(--warm);
  background: var(--warm-soft);
}

.matrix-input .cell--projective {
  color: var(--muted);
  background: var(--bg);
}

.bits {
  display: grid;
  grid-template-columns: repeat(8, minmax(0, 1fr));
  gap: 6px;
}

.bits--16 {
  grid-template-columns: repeat(8, minmax(0, 1fr));
}

.bit {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  padding: 10px 0 6px;
  border: 1px solid var(--line-strong);
  border-radius: 6px;
  background: var(--surface);
  font-family: var(--mono);
  font-size: 22px;
  font-weight: 600;
  cursor: pointer;
}

.bit small {
  color: var(--muted);
  font-size: 11px;
  font-weight: 400;
}

.bit[aria-pressed="true"] {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--accent-ink);
}

.bit[aria-pressed="true"] small {
  color: var(--accent-soft);
}

.bit--sign {
  border-color: var(--warm);
  border-width: 2px;
}

.bit--sign[aria-pressed="true"] {
  background: var(--warm);
  border-color: var(--warm);
}

.buckets {
  display: flex;
  flex-direction: column;
  gap: 4px;
  max-height: 520px;
  overflow-y: auto;
}

.bucket {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 4px;
  min-height: 30px;
  padding: 3px 6px;
  border-radius: 6px;
  background: var(--soft);
}

.bucket__index {
  width: 28px;
  color: var(--muted);
  font-family: var(--mono);
  font-size: 12px;
  text-align: right;
}

.key {
  padding: 2px 8px;
  border-radius: 4px;
  background: var(--accent);
  color: var(--accent-ink);
  font-family: var(--mono);
  font-size: 13px;
}

.key--collision {
  background: var(--warm);
}

.table--truth {
  width: auto;
  min-width: 260px;
}

.table--truth td,
.table--truth th {
  padding: 4px 16px;
  text-align: center;
}

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

.table--truth tbody tr:hover {
  background: var(--accent-soft);
}

.table--truth .is-one {
  color: var(--good);
  font-weight: 700;
}

.toggles {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 6px;
}

.toggles .button[aria-pressed="true"] {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--accent-ink);
}

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

.image-pair figure {
  margin: 0;
  min-width: 0;
}

.image-pair img {
  display: block;
  width: 100%;
  aspect-ratio: 1;
  image-rendering: pixelated;
  border: 1px solid var(--line);
  border-radius: 4px;
  background: var(--soft);
}

.image-pair figcaption {
  margin-top: 6px;
  color: var(--muted);
  font-size: 13px;
  text-align: center;
}

@media (max-width: 960px) {
  .nav {
    flex-wrap: nowrap;
    overflow-x: auto;
    max-width: 100%;
    scrollbar-width: thin;
  }

  .nav a {
    white-space: nowrap;
  }
}

@media (max-width: 520px) {
  .bits {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

@media (prefers-reduced-motion: reduce) {
  * {
    transition: none !important;
    animation: none !important;
  }
}