:root {
  color-scheme: light;
  --bg: #f3f0ec;
  --panel: #ffffff;
  --board: #c7e0de;
  --board-border: #497170;
  --text: #162120;
  --muted: #526967;
  --accent: #2d6c68;
  --accent-soft: #d6ecea;
  --black-piece: #2f3134;
  --white-piece: #f8f8f8;
  --shadow: 0 12px 30px rgba(22, 33, 32, 0.12);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: Arial, Helvetica, sans-serif;
  background: linear-gradient(180deg, #f7f4f1 0%, var(--bg) 100%);
  color: var(--text);
}

.page {
  width: min(1000px, calc(100% - 32px));
  margin: 0 auto;
  padding: 32px 0 48px;
}

.hero h1,
.rules h2,
.steps-panel h2 {
  margin: 0 0 12px;
}

.subtitle {
  margin: 0 0 24px;
  color: var(--muted);
  font-size: 1.1rem;
}

.game-panel,
.steps-panel {
  background: var(--panel);
  border-radius: 20px;
  box-shadow: var(--shadow);
  padding: 24px;
}

.steps-panel {
  margin-top: 20px;
}

.toolbar {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.toolbar button {
  border: 0;
  border-radius: 999px;
  padding: 12px 18px;
  font-size: 1rem;
  font-weight: 700;
  color: #fff;
  background: var(--accent);
  cursor: pointer;
  transition: transform 0.15s ease, opacity 0.15s ease;
}

.toolbar button:hover {
  transform: translateY(-1px);
}

.toolbar button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none;
}

.status-message {
  margin: 16px 0 20px;
  padding: 14px 16px;
  border-radius: 14px;
  background: var(--accent-soft);
  color: var(--accent);
  font-weight: 700;
}

.status-message.solved {
  background: #dff4d7;
  color: #2f6b23;
}

.board-wrapper {
  overflow-x: auto;
  padding-bottom: 8px;
}

.board {
  display: grid;
  grid-template-columns: repeat(7, minmax(88px, 1fr));
  border: 3px solid var(--board-border);
  background: var(--board);
  min-width: 616px;
}

.slot {
  position: relative;
  min-height: 120px;
  border-right: 2px solid var(--board-border);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 12px;
}

.slot:last-child {
  border-right: 0;
}

.slot-index {
  position: absolute;
  top: 8px;
  left: 8px;
  color: var(--board-border);
  font-size: 1rem;
  font-weight: 700;
}

.slot.valid-target {
  background: rgba(255, 255, 255, 0.32);
}

.slot.empty::after {
  content: "vazio";
  color: rgba(22, 33, 32, 0.38);
  font-size: 0.9rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.piece {
  width: 84px;
  height: 84px;
  border-radius: 50%;
  border: 2px solid rgba(22, 33, 32, 0.25);
  cursor: grab;
  box-shadow: inset 0 3px 6px rgba(255, 255, 255, 0.08);
}

.piece:active {
  cursor: grabbing;
}

.piece.black {
  background: var(--black-piece);
}

.piece.white {
  background: var(--white-piece);
}

.piece.dragging {
  opacity: 0.55;
}

.rules {
  margin-top: 24px;
}

.rules ul {
  margin: 0;
  padding-left: 24px;
  line-height: 1.5;
}

.steps-list {
  margin: 0;
  padding-left: 24px;
  line-height: 1.6;
}

.steps-list li + li {
  margin-top: 8px;
}

@media (max-width: 720px) {
  .page {
    width: min(100%, calc(100% - 20px));
    padding-top: 20px;
  }

  .game-panel,
  .steps-panel {
    padding: 18px;
  }
}