.sliding-main { width: 100%; padding: 0 0 54px; }
.sliding-page-header { padding: 20px 22px; color: #fff; background: var(--color-brand); border-bottom: 4px solid var(--color-accent); }
.sliding-header-inner { width: min(1200px, 100%); margin: 0 auto; }
.sliding-header-inner h1 { margin: 0; color: #fff; font-size: clamp(1.7rem, 4vw, 2.5rem); }
.sliding-header-inner p { margin: 7px 0 0; color: #f3dfce; }
.back-link { display: inline-block; margin-bottom: 9px; color: #fff; font-size: .88rem; font-weight: 700; text-underline-offset: 3px; }
.board-section { width: min(760px, calc(100% - 40px)); margin: 22px auto 0; padding: 26px; text-align: center; background: var(--color-surface); border: 1px solid var(--color-border); border-radius: 14px; box-shadow: var(--shadow-card); }
.board-section > h2 { margin: 0 0 15px; }
.size-panel { width: min(540px, 100%); margin: 0 auto 16px; padding: 14px 16px; background: #fffaf2; border: 1px solid var(--color-border); border-radius: 10px; }
.size-panel h3 { margin: 0; font-size: 1rem; }
.size-buttons, .game-options { display: flex; flex-wrap: wrap; justify-content: center; gap: 7px; }
.size-buttons { margin: 10px 0 7px; }
.game-options { margin: 0 0 14px; }
.size-panel button, .game-options button, .celebration button { min-height: 44px; min-width: 100px; padding: 9px 12px; color: var(--color-ink); background: #fff; border: 1px solid var(--color-border); border-radius: 9px; font: inherit; font-weight: 700; cursor: pointer; touch-action: manipulation; }
.size-buttons button { flex: 1 1 100px; }
.size-panel button:hover, .game-options button:hover, .celebration button:hover { background: #f7ead9; }
.size-buttons button.active { color: #fff; background: var(--color-brand-strong); border-color: var(--color-brand-strong); }
button:disabled { cursor: default; opacity: .5; }
#status { min-height: 1.5em; margin: 0; color: var(--color-muted); font-size: .86rem; line-height: 1.5; }
#status.success-status { color: #246b3f; font-weight: 700; }
.game-stats { width: min(100%, 500px); margin: 0 auto; display: flex; justify-content: space-around; gap: 12px; color: var(--color-ink); font-variant-numeric: tabular-nums; }
.game-stats strong { color: var(--color-brand-strong); }
.sliding-board { --size: 3; position: relative; width: min(100%, 500px); aspect-ratio: 1; margin: 14px auto 0; overflow: hidden; border: 4px solid var(--color-brand-strong); border-radius: 8px; background: #d7c6b3; touch-action: manipulation; -webkit-user-select: none; user-select: none; }
.sliding-board:focus-visible { outline: 3px solid var(--color-accent); outline-offset: 3px; }
.empty-slot, .sliding-tile { position: absolute; width: calc(100% / var(--size)); height: calc(100% / var(--size)); box-sizing: border-box; }
.empty-slot { z-index: 0; padding: 4px; border: 4px solid #d7c6b3; border-radius: 10px; background: #aa9078; box-shadow: inset 0 2px 6px #6f574666; }
.sliding-board .sliding-tile { z-index: 1; min-width: 0; min-height: 0; display: grid; place-items: center; padding: 0; border: 4px solid #d7c6b3; border-radius: 10px; background: #fffaf2; color: var(--color-brand-strong); font-family: inherit; font-size: clamp(1.4rem, 7vw, 2.7rem); font-weight: 800; line-height: 1; font-variant-numeric: tabular-nums; cursor: default; transition: left 160ms ease, top 160ms ease; -webkit-tap-highlight-color: transparent; }
.sliding-board .sliding-tile.movable { cursor: pointer; background: #fff4df; }
.sliding-board .sliding-tile.movable:hover { background: #f7ead9; }
.sliding-board .sliding-tile:focus-visible { outline: 3px solid var(--color-accent); outline-offset: -6px; }
.tap-help { margin: 14px 0 0; color: var(--color-muted); font-size: .92rem; }
.rules-card { width: min(100%, 540px); margin: 20px auto 0; text-align: left; border: 1px solid var(--color-border); border-radius: 10px; background: #fff; }
.rules-card summary { padding: 13px 15px; font-weight: 800; cursor: pointer; }
.rules-content { padding: 0 16px 14px; line-height: 1.55; }
.rules-content p:first-child { margin-top: 0; }
.solved-example { width: 144px; display: grid; grid-template-columns: repeat(3, 1fr); gap: 3px; margin: 8px auto 12px; padding: 3px; border: 2px solid var(--color-brand-strong); background: #d7c6b3; text-align: center; font-weight: 800; }
.solved-example span { display: grid; place-items: center; height: 42px; background: #fffaf2; }
.solved-example .example-empty { background: #aa9078; }
.celebration[hidden] { display: none; }
.celebration { position: fixed; inset: 0; z-index: 1000; display: grid; place-items: center; padding: 20px; background: rgba(37, 22, 14, .62); }
.celebration-card { position: relative; z-index: 2; width: min(420px, 100%); padding: 30px; text-align: center; background: #fffaf2; border: 3px solid var(--color-accent); border-radius: 18px; box-shadow: 0 18px 60px rgba(0, 0, 0, .35); }
.celebration-kicker { margin: 0; color: var(--color-brand); font-weight: 800; text-transform: uppercase; letter-spacing: .08em; }
.celebration-card h2 { margin: 8px 0; }
.confetti-layer { position: absolute; inset: 0; overflow: hidden; pointer-events: none; }
.confetti-layer i { position: absolute; top: -20px; left: var(--left); width: 9px; height: 14px; background: var(--color); animation: confetti-fall 3s linear var(--delay) forwards; }
@keyframes confetti-fall { to { transform: translate3d(var(--drift), 110vh, 0) rotate(720deg); } }
@media (max-width: 600px) {
    .sliding-page-header { padding: 14px; }
    .sliding-main { padding-bottom: 36px; }
    .board-section { width: calc(100% - 20px); padding: 18px 8px; }
    .size-panel { padding: 12px 10px; }
    .size-buttons { flex-direction: column; }
    .size-buttons button { width: 100%; }
    .game-options { display: grid; grid-template-columns: repeat(2, 1fr); }
    .game-options button { min-width: 0; width: 100%; }
    .sliding-board .sliding-tile { border-width: 3px; }
}
@media (prefers-reduced-motion: reduce) { .sliding-board .sliding-tile, .confetti-layer i { transition: none; animation: none; } }