:root {
  color-scheme: light;
  font-family: "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background-color: #f7f9fc;
  color: #1a2a4a;
}

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.app-header,
.app-footer {
  text-align: center;
  padding: 1rem;
}

.tagline {
  margin: 0.5rem 0 0;
  font-size: 1.05rem;
  color: #334b7d;
}

#app-root {
  width: min(90vw, 960px);
  margin: 1rem auto 3rem;
  background: #ffffff;
  padding: 1.5rem;
  border-radius: 16px;
  box-shadow: 0 12px 32px rgba(26, 42, 74, 0.08);
}

.board {
  display: grid;
  grid-template-columns: repeat(8, minmax(36px, 1fr));
  gap: 2px;
  border: 4px solid #1a2a4a;
  border-radius: 12px;
  overflow: hidden;
  max-width: 420px;
}

.square {
  position: relative;
  padding-top: 100%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: clamp(1.4rem, 2.5vw, 2.1rem);
  transition: transform 0.15s ease;
}

.square-light {
  background: #f2f7ff;
}

.square-dark {
  background: #3a5ba0;
  color: #fefefe;
}

.square.highlighted {
  outline: 3px solid #ffcb2b;
  z-index: 1;
}

.square.legal-target {
  box-shadow: inset 0 0 0 4px rgba(255, 203, 43, 0.7);
}

.square:hover {
  transform: scale(1.03);
}

.game-layout {
  display: grid;
  gap: 1.5rem;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  align-items: start;
}

.panel {
  background: #eef3ff;
  border-radius: 12px;
  padding: 1rem;
  border: 1px solid rgba(26, 42, 74, 0.1);
}

.panel h2 {
  margin-top: 0;
  font-size: 1.2rem;
}

button {
  background: #ffcb2b;
  color: #1a2a4a;
  border: none;
  border-radius: 999px;
  padding: 0.6rem 1.2rem;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.1s ease, box-shadow 0.1s ease;
}

button:hover {
  transform: translateY(-1px);
  box-shadow: 0 8px 16px rgba(26, 42, 74, 0.12);
}

button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  box-shadow: none;
}

.status-text {
  margin: 0.5rem 0 0;
}

.moves-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 0.75rem;
}

.move-card {
  background: #ffffff;
  padding: 0.75rem;
  border-radius: 10px;
  border: 1px solid rgba(26, 42, 74, 0.1);
  display: grid;
  gap: 0.5rem;
}

.move-score {
  font-weight: 600;
  color: #25674d;
}

.tip-box {
  background: #fff5d8;
  border: 1px solid rgba(255, 203, 43, 0.35);
  padding: 0.75rem 1rem;
  border-radius: 10px;
  margin-top: 1rem;
}

.share-link-container {
  display: grid;
  gap: 0.5rem;
  margin-top: 1rem;
}

.share-link-container input {
  padding: 0.5rem;
  border-radius: 8px;
  border: 1px solid rgba(26, 42, 74, 0.25);
  font-size: 0.95rem;
}

@media (max-width: 640px) {
  #app-root {
    padding: 1rem;
  }

  .board {
    max-width: none;
  }
}