:root {
  --bg-1: #e5e5e5;
  --bg-2: #c9c9c9;
  --bg-3: #909090;
  --surface: #ffffff;
  --ink: #000000;
  --muted: #4a4a4a;
  --brand: #dc0000;
  --brand-strong: #9d0000;
  --accent: #000000;
  --ok: #706f6f;
  --danger: #dc0000;
  --slot: #f3f3f3;
  --slot-border: #909090;
  --card: #ffffff;
  --shadow: 0 14px 30px rgba(0, 0, 0, 0.2);
  --radius: 6px;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  min-height: 100%;
}

body {
  font-family: "IBM Plex Sans", "Segoe UI", sans-serif;
  color: var(--ink);
  background: #e5e5e5;
  min-height: 100vh;
}

body.lightbox-open {
  overflow: hidden;
}

.page-bg {
  position: fixed;
  inset: 0;
  background: transparent;
  pointer-events: none;
}

.app {
  position: relative;
  width: min(1100px, 100% - 2rem);
  margin: 1.2rem auto 2rem;
  padding: clamp(1rem, 2vw, 1.5rem);
  border-radius: 8px;
  background: var(--surface);
  box-shadow: var(--shadow);
}

.hero h1,
.hero h2,
.panel h2,
.solution h2 {
  font-family: "Changa", "Arial Narrow", sans-serif;
  letter-spacing: 0.02em;
}

.kicker {
  margin: 0;
  display: inline-block;
  padding: 0.3rem 0.7rem;
  border-radius: 4px;
  background: #dc0000;
  color: #ffffff;
  font-weight: 700;
}

.hero h1 {
  margin: 0.7rem 0 0.5rem;
  font-size: clamp(1.4rem, 3.3vw, 2.2rem);
}

.hint {
  margin: 0;
  color: var(--muted);
  max-width: 80ch;
}

.game {
  margin-top: 1.2rem;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.panel {
  border: 2px solid #b2b2b2;
  border-radius: var(--radius);
  background: #ffffff;
  padding: 0.9rem;
}

.panel h2 {
  margin: 0;
  font-size: 1.3rem;
}

.panel-help {
  margin: 0.35rem 0 0.7rem;
  color: var(--muted);
  font-size: 0.94rem;
}

.card-pool,
.target-slots {
  display: grid;
  gap: 0.65rem;
}

.card {
  display: flex;
  align-items: flex-start;
  gap: 0.55rem;
  width: 100%;
  border: 2px solid #c9c9c9;
  background: var(--card);
  color: var(--ink);
  border-radius: 6px;
  text-align: left;
  padding: 0.75rem;
  font-size: 1rem;
  line-height: 1.3;
  cursor: grab;
  transition: transform 0.15s ease, border-color 0.15s ease, background 0.15s ease;
}

.card:hover {
  border-color: var(--brand);
  transform: translateY(-1px);
}

.card:focus-visible,
.slot:focus-visible,
.btn:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 2px;
}

.card[aria-pressed="true"] {
  border-color: var(--brand-strong);
  background: #ffe8e8;
}

.card-number {
  flex: 0 0 auto;
  width: 1.8rem;
  height: 1.8rem;
  border-radius: 4px;
  background: #dc0000;
  color: #ffffff;
  display: inline-grid;
  place-items: center;
  font-weight: 700;
  font-size: 0.95rem;
}

.slot {
  border: 2px dashed var(--slot-border);
  border-radius: 6px;
  min-height: 72px;
  background: var(--slot);
  display: grid;
  align-items: center;
  padding: 0.5rem;
}

.slot-label {
  color: #3a3a3a;
  font-weight: 700;
  font-size: 0.93rem;
  margin-bottom: 0.45rem;
}

.slot.empty {
  justify-content: start;
}

.slot.drag-over {
  border-color: var(--brand-strong);
  background: #ffd7d7;
}

.slot-placeholder {
  color: #4a4a4a;
  font-size: 0.95rem;
}

.actions {
  margin-top: 1rem;
  display: flex;
  gap: 0.6rem;
  flex-wrap: wrap;
}

.btn {
  border: 0;
  border-radius: 6px;
  padding: 0.7rem 1rem;
  font: inherit;
  font-weight: 700;
  cursor: pointer;
}

.btn-primary {
  background: #dc0000;
  color: #fff;
}

.btn-primary:disabled {
  opacity: 0.55;
  cursor: not-allowed;
}

.btn-secondary {
  background: #e5e5e5;
  color: #000000;
}

.solution {
  margin-top: 1rem;
  border-radius: var(--radius);
  border: 2px solid #b2b2b2;
  background: #ffffff;
  padding: 0.9rem;
  animation: reveal 260ms ease;
}

@keyframes reveal {
  from {
    opacity: 0;
    transform: translateY(8px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.solution-head p {
  margin-top: 0;
  color: var(--muted);
}

.solution-blocks {
  display: grid;
  gap: 0.7rem;
}

.solution-item {
  border: 1px solid #c9c9c9;
  border-radius: 6px;
  padding: 0.5rem;
  background: #fff;
}

.solution-zoom-trigger {
  display: block;
  width: 100%;
  border: 0;
  margin: 0;
  padding: 0;
  background: transparent;
  text-align: left;
  cursor: zoom-in;
}

.solution-zoom-trigger:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 2px;
}

.solution-item img {
  display: block;
  max-width: 100%;
  height: auto;
  border-radius: 4px;
}

.zoomable-solution-image {
  cursor: zoom-in;
  pointer-events: auto;
}

.image-lightbox {
  position: fixed;
  inset: 0;
  z-index: 2000;
  display: grid;
  place-items: center;
  background: rgba(0, 0, 0, 0.84);
  padding: 1rem;
}

.image-lightbox[hidden] {
  display: none;
}

.image-lightbox-img {
  max-width: min(96vw, 1400px);
  max-height: 92vh;
  width: auto;
  height: auto;
  border-radius: 8px;
  box-shadow: 0 14px 38px rgba(0, 0, 0, 0.45);
  cursor: zoom-out;
}

.solution-fallback {
  border: 2px dashed #909090;
  border-radius: 6px;
  padding: 0.8rem;
  background: #f3f3f3;
  color: #000000;
  font-weight: 600;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}

.toast {
  position: fixed;
  left: 50%;
  bottom: 1.4rem;
  transform: translateX(-50%) translateY(18px);
  opacity: 0;
  pointer-events: none;
  background: #dc0000;
  color: #ffffff;
  border: 1px solid #9d0000;
  border-radius: 4px;
  padding: 0.65rem 0.9rem;
  font-weight: 700;
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.25);
  z-index: 1000;
  transition: opacity 150ms ease, transform 150ms ease;
}

.toast.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

@media (max-width: 1280px), (max-height: 900px) {
  .app {
    width: min(1080px, 100% - 1rem);
    margin: 0.6rem auto 1rem;
    padding: 0.75rem;
    min-height: calc(100vh - 1.2rem);
    display: flex;
    flex-direction: column;
  }

  .hero h1 {
    margin: 0.45rem 0 0.35rem;
    font-size: clamp(1.25rem, 2.6vw, 1.9rem);
  }

  .hint {
    font-size: 0.95rem;
  }

  .game {
    margin-top: 0.85rem;
    gap: 0.7rem;
    flex: 1 1 auto;
    min-height: 0;
  }

  .panel {
    padding: 0.65rem;
    display: flex;
    flex-direction: column;
    min-height: 0;
  }

  .panel h2 {
    font-size: 1.15rem;
  }

  .panel-help {
    margin: 0.2rem 0 0.45rem;
    font-size: 0.88rem;
  }

  .card-pool,
  .target-slots {
    gap: 0.45rem;
    flex: 1 1 auto;
    min-height: 0;
    overflow: auto;
    padding-right: 0.2rem;
  }

  .card {
    padding: 0.52rem;
    font-size: 0.92rem;
    line-height: 1.2;
  }

  .card-number {
    width: 1.55rem;
    height: 1.55rem;
    font-size: 0.86rem;
  }

  .slot {
    min-height: 58px;
    padding: 0.35rem;
  }

  .slot-label {
    margin-bottom: 0.22rem;
    font-size: 0.86rem;
  }

  .slot-placeholder {
    font-size: 0.88rem;
  }

  .actions {
    margin-top: 0.75rem;
    gap: 0.45rem;
    flex: 0 0 auto;
  }

  .btn {
    padding: 0.58rem 0.85rem;
    font-size: 0.95rem;
  }
}

@media (max-height: 760px) {
  .kicker {
    padding: 0.2rem 0.55rem;
    font-size: 0.9rem;
  }

  .hero h1 {
    font-size: clamp(1.1rem, 2.2vw, 1.55rem);
    margin: 0.35rem 0 0.25rem;
  }

  .hint {
    font-size: 0.9rem;
  }

  .panel h2 {
    font-size: 1.05rem;
  }
}

@media (max-width: 860px) {
  .game {
    grid-template-columns: 1fr;
    min-height: initial;
    overflow: visible;
  }

  .app {
    width: min(900px, 100% - 1rem);
    margin-top: 0.8rem;
    padding: 0.8rem;
    min-height: initial;
    display: block;
  }

  .panel,
  .card-pool,
  .target-slots {
    min-height: initial;
    overflow: visible;
  }

  .card {
    min-height: 58px;
    cursor: pointer;
  }
}