:root {
  --bg: #f7f8fb;
  --ink: #17212b;
  --muted: #667085;
  --line: #d9e0e8;
  --panel: #ffffff;
  --panel-soft: #eef6f2;
  --resource: #146c94;
  --resource-dark: #0c4a66;
  --need: #b24556;
  --need-dark: #762a35;
  --path: #2f8a5f;
  --path-dark: #1d5e40;
  --blocker: #3a414b;
  --accent: #f3b34c;
  --focus: #1d70f2;
  --shadow: 0 18px 50px rgba(23, 33, 43, 0.14);
  color-scheme: light;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  background:
    linear-gradient(120deg, rgba(20, 108, 148, 0.08), transparent 34%),
    linear-gradient(300deg, rgba(178, 69, 86, 0.10), transparent 38%),
    var(--bg);
  color: var(--ink);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

button {
  font: inherit;
}

.app-shell {
  min-height: 100vh;
  width: min(1180px, 100%);
  margin: 0 auto;
  padding: 28px;
  position: relative;
}

.screen {
  display: none;
}

.screen.is-active {
  display: block;
}

.start-screen {
  min-height: calc(100vh - 56px);
  display: none;
  grid-template-columns: minmax(0, 1.05fr) minmax(320px, 0.75fr);
  gap: 28px;
  align-items: stretch;
}

.start-screen.is-active {
  display: grid;
}

.brand-panel,
.level-panel,
.toolbox,
.modal-card {
  background: rgba(255, 255, 255, 0.9);
  border: 1px solid rgba(217, 224, 232, 0.9);
  border-radius: 8px;
  box-shadow: var(--shadow);
}

.brand-panel {
  min-height: 580px;
  padding: clamp(28px, 5vw, 64px);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  overflow: hidden;
}

.eyebrow {
  margin: 0 0 10px;
  color: var(--resource-dark);
  font-size: 0.76rem;
  font-weight: 800;
  letter-spacing: 0;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  overflow-wrap: anywhere;
}

h1 {
  max-width: 780px;
  margin: 0;
  font-size: clamp(3.1rem, 8vw, 7.4rem);
  line-height: 0.88;
  letter-spacing: 0;
}

h2 {
  margin: 0;
  font-size: clamp(1.45rem, 3vw, 2.4rem);
  line-height: 1;
  letter-spacing: 0;
}

h3 {
  margin: 0;
  font-size: 1rem;
}

.intro-copy {
  max-width: 680px;
  margin: 28px 0 24px;
  color: #3c4855;
  font-size: clamp(1rem, 2vw, 1.25rem);
  line-height: 1.55;
}

.hero-board {
  display: grid;
  grid-template-columns: repeat(4, minmax(64px, 1fr));
  grid-auto-rows: minmax(64px, 1fr);
  gap: 12px;
  max-width: 540px;
  aspect-ratio: 4 / 2;
}

.hero-board > span {
  border-radius: 8px;
  min-width: 0;
  min-height: 0;
}

.node {
  display: grid;
  place-items: center;
  color: white;
  font-weight: 900;
  font-size: clamp(1.2rem, 4vw, 2.4rem);
  box-shadow: inset 0 -8px 0 rgba(0, 0, 0, 0.12);
}

.node.resource {
  background: var(--resource);
}

.node.need {
  background: var(--need);
}

.node.small {
  font-size: clamp(1rem, 3vw, 1.6rem);
}

.pipe {
  background-color: #e8f2ec;
  background-repeat: no-repeat;
}

.pipe-h {
  background-image: linear-gradient(0deg, transparent 0 16%, var(--path) 16% 84%, transparent 84%);
}

.pipe-v {
  background-image: linear-gradient(90deg, transparent 0 16%, var(--path) 16% 84%, transparent 84%);
}

.pipe-corner {
  background-image:
    linear-gradient(90deg, transparent 0 43%, var(--path) 43% 57%, transparent 57%),
    linear-gradient(0deg, transparent 0 43%, var(--path) 43% 100%);
}

.pipe-cross {
  background-image:
    linear-gradient(90deg, transparent 0 43%, var(--path) 43% 57%, transparent 57%),
    linear-gradient(0deg, transparent 0 43%, var(--path) 43% 57%, transparent 57%);
}

.block {
  background:
    repeating-linear-gradient(135deg, rgba(255, 255, 255, 0.14) 0 8px, transparent 8px 16px),
    var(--blocker);
}

.level-panel {
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.panel-header p,
.toolbox-header p {
  margin: 8px 0 0;
  color: var(--muted);
  line-height: 1.45;
}

.level-list {
  display: grid;
  gap: 12px;
}

.level-card {
  width: 100%;
  text-align: left;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 16px;
  color: var(--ink);
  cursor: pointer;
  transition: border-color 160ms ease, transform 160ms ease, box-shadow 160ms ease;
}

.level-card:hover,
.level-card.is-selected {
  border-color: var(--resource);
  box-shadow: 0 10px 24px rgba(20, 108, 148, 0.16);
  transform: translateY(-1px);
}

.level-card strong {
  font-size: 1rem;
}

.level-card-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
}

.difficulty-pill {
  display: inline-flex;
  align-items: center;
  min-height: 26px;
  padding: 0 10px;
  border-radius: 999px;
  background: #edf2f7;
  color: #3c4855;
  font-size: 0.76rem;
  font-weight: 900;
  text-transform: uppercase;
}

.difficulty-easy {
  background: #e8f6ef;
  color: #1d5e40;
}

.difficulty-medium {
  background: #fff3dc;
  color: #855000;
}

.difficulty-hard {
  background: #fde7ea;
  color: #762a35;
}

.difficulty-expert {
  background: #e9edf8;
  color: #263b76;
}

.level-summary,
.level-hint {
  display: block;
  margin-top: 6px;
  color: var(--muted);
  line-height: 1.4;
}

.level-hint {
  color: #315844;
  font-size: 0.9rem;
  font-weight: 700;
}

.primary-action,
.secondary-action,
.icon-button,
.tile-button {
  border: 0;
  border-radius: 8px;
  cursor: pointer;
  transition: transform 140ms ease, box-shadow 140ms ease, background 140ms ease, border-color 140ms ease;
}

.primary-action {
  min-height: 48px;
  padding: 0 18px;
  background: var(--ink);
  color: white;
  font-weight: 800;
  box-shadow: 0 12px 22px rgba(23, 33, 43, 0.18);
}

.secondary-action {
  min-height: 48px;
  padding: 0 18px;
  background: #edf2f7;
  color: var(--ink);
  font-weight: 800;
}

.primary-action:hover,
.secondary-action:hover,
.icon-button:hover,
.tile-button:hover {
  transform: translateY(-1px);
}

.primary-action:focus-visible,
.secondary-action:focus-visible,
.icon-button:focus-visible,
.tile-button:focus-visible,
.cell:focus-visible,
.level-card:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 3px;
}

.game-screen {
  min-height: calc(100vh - 56px);
}

.top-bar {
  display: grid;
  grid-template-columns: 48px minmax(0, 1fr) 48px;
  align-items: center;
  gap: 16px;
  margin-bottom: 18px;
}

.icon-button {
  width: 48px;
  height: 48px;
  display: grid;
  place-items: center;
  background: #fff;
  border: 1px solid var(--line);
  color: var(--ink);
  font-size: 1.5rem;
  font-weight: 800;
  box-shadow: 0 8px 18px rgba(23, 33, 43, 0.10);
}

.status-strip {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
  margin-bottom: 14px;
}

.status-strip div {
  min-height: 70px;
  padding: 12px 14px;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 8px;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.status-strip span {
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 750;
  text-transform: uppercase;
}

.status-strip strong {
  margin-top: 4px;
  font-size: clamp(1.35rem, 4vw, 2rem);
}

.theme-line {
  margin: 0 0 18px;
  color: #3c4855;
  line-height: 1.45;
}

.play-layout {
  display: grid;
  grid-template-columns: minmax(320px, 1fr) minmax(280px, 340px);
  gap: 22px;
  align-items: start;
}

.board-wrap {
  display: grid;
  place-items: center;
  background: rgba(255, 255, 255, 0.72);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: clamp(12px, 3vw, 22px);
  box-shadow: var(--shadow);
}

.board {
  --board-size: 6;
  width: min(100%, 650px);
  aspect-ratio: 1;
  display: grid;
  grid-template-columns: repeat(var(--board-size), 1fr);
  gap: clamp(4px, 1vw, 8px);
}

.cell {
  position: relative;
  aspect-ratio: 1;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  color: var(--ink);
  display: grid;
  place-items: center;
  cursor: pointer;
  overflow: hidden;
  min-width: 0;
}

.cell::before,
.cell::after {
  content: "";
  position: absolute;
  background: var(--path);
  opacity: 0;
  transition: opacity 120ms ease;
}

.cell::before {
  width: 22%;
  height: 100%;
  left: 39%;
  top: 0;
}

.cell::after {
  height: 22%;
  width: 100%;
  left: 0;
  top: 39%;
}

.cell.has-north::before {
  opacity: 1;
  clip-path: inset(0 0 50% 0);
}

.cell.has-south::before {
  opacity: 1;
  clip-path: inset(50% 0 0 0);
}

.cell.has-north.has-south::before {
  opacity: 1;
  clip-path: none;
}

.cell.has-west::after {
  opacity: 1;
  clip-path: inset(0 50% 0 0);
}

.cell.has-east::after {
  opacity: 1;
  clip-path: inset(0 0 0 50%);
}

.cell.has-west.has-east::after {
  opacity: 1;
  clip-path: none;
}

.cell.has-tile {
  background: #eef7f1;
}

.cell.source,
.cell.target {
  color: white;
  font-weight: 900;
  cursor: default;
}

.cell.source {
  background: var(--resource);
  border-color: var(--resource-dark);
}

.cell.target {
  background: var(--need);
  border-color: var(--need-dark);
}

.cell.blocker {
  background:
    repeating-linear-gradient(135deg, rgba(255, 255, 255, 0.14) 0 7px, transparent 7px 14px),
    var(--blocker);
  border-color: #222832;
  cursor: not-allowed;
}

.cell.is-connected {
  box-shadow: inset 0 0 0 4px rgba(243, 179, 76, 0.65);
}

.cell-label {
  position: relative;
  z-index: 2;
  width: 42%;
  aspect-ratio: 1;
  display: grid;
  place-items: center;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.18);
  font-size: clamp(0.9rem, 2.4vw, 1.35rem);
  line-height: 1;
}

.tile-dot {
  position: relative;
  z-index: 2;
  width: 26%;
  aspect-ratio: 1;
  border-radius: 50%;
  background: var(--path-dark);
  border: 3px solid #e6f4ec;
}

.toolbox {
  padding: 20px;
}

.inventory {
  display: grid;
  gap: 10px;
  margin: 18px 0;
}

.tile-button {
  min-height: 64px;
  width: 100%;
  padding: 10px 12px;
  background: #fff;
  border: 1px solid var(--line);
  display: grid;
  grid-template-columns: 52px minmax(0, 1fr) auto;
  gap: 12px;
  align-items: center;
  text-align: left;
  color: var(--ink);
}

.tile-button.is-selected {
  border-color: var(--path);
  box-shadow: 0 9px 18px rgba(47, 138, 95, 0.18);
  background: #f0faf4;
}

.tile-button.is-empty {
  opacity: 0.48;
  cursor: not-allowed;
}

.tile-preview {
  width: 48px;
  aspect-ratio: 1;
  border-radius: 8px;
  background-color: #eef7f1;
  background-repeat: no-repeat;
  border: 1px solid #cddfd3;
}

.preview-straight {
  background-image: linear-gradient(0deg, transparent 0 38%, var(--path) 38% 62%, transparent 62%);
}

.preview-corner {
  background-image:
    linear-gradient(90deg, transparent 0 38%, var(--path) 38% 62%, transparent 62%),
    linear-gradient(0deg, transparent 0 38%, var(--path) 38% 100%);
}

.preview-cross {
  background-image:
    linear-gradient(90deg, transparent 0 38%, var(--path) 38% 62%, transparent 62%),
    linear-gradient(0deg, transparent 0 38%, var(--path) 38% 62%, transparent 62%);
}

.preview-remove {
  display: grid;
  place-items: center;
  background: #fff2f4;
  border-color: #e9b8c0;
  color: var(--need-dark);
  font-size: 1.8rem;
  font-weight: 900;
  line-height: 1;
}

.remove-button.is-selected {
  border-color: var(--need);
  box-shadow: 0 9px 18px rgba(178, 69, 86, 0.16);
  background: #fff7f8;
}

.tile-name {
  font-weight: 800;
}

.tile-help {
  display: block;
  margin-top: 2px;
  color: var(--muted);
  font-size: 0.85rem;
}

.tile-count {
  min-width: 34px;
  height: 34px;
  border-radius: 50%;
  display: grid;
  place-items: center;
  background: #edf2f7;
  font-weight: 900;
}

.legend {
  display: grid;
  gap: 8px;
  color: #3c4855;
  font-size: 0.95rem;
}

.legend div {
  display: flex;
  align-items: center;
  gap: 8px;
}

.legend-chip {
  width: 18px;
  height: 18px;
  border-radius: 5px;
  display: inline-block;
}

.resource-chip {
  background: var(--resource);
}

.need-chip {
  background: var(--need);
}

.block-chip {
  background: var(--blocker);
}

.hint {
  margin: 18px 0 0;
  padding: 12px;
  background: var(--panel-soft);
  border: 1px solid #cee3d8;
  border-radius: 8px;
  color: #315844;
  line-height: 1.4;
}

.modal {
  position: fixed;
  inset: 0;
  display: none;
  place-items: center;
  padding: 20px;
  background: rgba(23, 33, 43, 0.48);
  z-index: 20;
}

.modal.is-open {
  display: grid;
}

.modal-card {
  width: min(460px, 100%);
  padding: 28px;
  text-align: center;
}

.stars {
  margin: 18px 0 8px;
  color: var(--accent);
  font-size: 2rem;
  line-height: 1;
}

.score-line {
  margin: 8px 0;
  color: #3c4855;
  line-height: 1.45;
}

.impact-line {
  margin: 16px 0 24px;
  color: var(--resource-dark);
  font-weight: 800;
  line-height: 1.45;
}

.modal-actions {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
}

@media (max-width: 860px) {
  .app-shell {
    padding: 18px;
  }

  .start-screen,
  .start-screen.is-active,
  .play-layout {
    grid-template-columns: 1fr;
  }

  .brand-panel {
    min-height: auto;
  }

  .hero-board {
    grid-template-columns: repeat(4, 1fr);
    max-width: none;
  }

  .toolbox {
    order: -1;
  }
}

@media (max-width: 560px) {
  .app-shell {
    padding: 12px;
  }

  .brand-panel,
  .level-panel,
  .toolbox,
  .modal-card {
    border-radius: 8px;
  }

  .brand-panel,
  .level-panel,
  .toolbox {
    padding: 16px;
  }

  .top-bar {
    grid-template-columns: 42px minmax(0, 1fr) 42px;
    gap: 10px;
  }

  .icon-button {
    width: 42px;
    height: 42px;
  }

  .status-strip {
    grid-template-columns: 1fr 1fr 1fr;
    gap: 6px;
  }

  .status-strip div {
    min-height: 60px;
    padding: 9px 8px;
  }

  .tile-button {
    grid-template-columns: 44px minmax(0, 1fr) 32px;
  }

  .tile-preview {
    width: 42px;
  }

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