/* =========================================================
   Nekoh.it — Sudoku / style.css
   Stili specifici del gioco, organizzato in tre schermate
   (menu, partita, statistiche) alternate via attributo hidden.
   Mobile-first: layout a colonna singola con tastierino sotto
   la griglia; da 860px in su la colonna comandi affianca la
   board. Tutti i colori derivano dai token --nk-* del design
   system condiviso (theme.css), con fallback per l'uso
   stand-alone della pagina.
   ========================================================= */

.sudoku-page {
    display: grid;
    gap: 18px;
}

/* ---------- Schermate ---------- */

.screen {
    display: grid;
    gap: 18px;
}

/* `display: grid` sopra vincerebbe su [hidden]: va ribadito. */
.screen[hidden] {
    display: none;
}

/* Testo solo per screen reader (etichette dei pulsanti-icona). */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* ---------- Schermata menu ---------- */

.menu-intro h2 {
    margin: 0 0 4px;
    font-size: 1.25rem;
    color: var(--nk-text, #edf4fb);
}

.menu-intro p {
    margin: 0;
    font-size: 0.92rem;
    color: var(--nk-muted, #94a6bb);
}

.difficulty-list {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
    gap: 12px;
}

.difficulty-card {
    display: grid;
    justify-items: start;
    gap: 5px;
    padding: 16px 14px;
    border-radius: var(--nk-radius-sm, 10px);
    border: 1px solid var(--nk-border, rgba(148, 163, 184, 0.18));
    background: var(--nk-surface-soft, rgba(22, 31, 46, 0.82));
    color: var(--nk-text, #edf4fb);
    font: inherit;
    text-align: left;
    cursor: pointer;
    -webkit-tap-highlight-color: transparent;
    transition: border-color 0.15s ease, background-color 0.15s ease;
}

.difficulty-card:hover {
    border-color: var(--nk-accent, #38d9a9);
    background: color-mix(in srgb, var(--nk-accent, #38d9a9) 8%, transparent);
}

.difficulty-name {
    font-size: 1.05rem;
    font-weight: 800;
}

.difficulty-desc {
    font-size: 0.78rem;
    font-weight: 700;
    color: var(--nk-muted, #94a6bb);
}

.difficulty-best {
    font-size: 0.78rem;
    font-weight: 700;
    color: var(--nk-accent, #38d9a9);
    font-variant-numeric: tabular-nums;
}

.menu-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.menu-actions .btn {
    flex: 1 1 180px;
}

.sudoku-layout {
    display: grid;
    gap: 18px;
    justify-items: center;
}

.sudoku-board-column {
    display: grid;
    gap: 14px;
    width: min(100%, 520px);
}

/* ---------- Barra statistiche ---------- */

.sudoku-stats {
    display: flex;
    align-items: stretch;
    gap: 10px;
}

.stat {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 2px;
    padding: 8px 12px;
    border-radius: var(--nk-radius-sm, 10px);
    border: 1px solid var(--nk-border, rgba(148, 163, 184, 0.18));
    background: var(--nk-surface-soft, rgba(22, 31, 46, 0.82));
}

.stat-label {
    font-size: 0.72rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--nk-muted, #94a6bb);
}

.stat-value {
    font-size: 1.05rem;
    font-weight: 800;
    font-variant-numeric: tabular-nums;
    color: var(--nk-text, #edf4fb);
}

.stat.danger .stat-value {
    color: var(--nk-danger-strong, #f87171);
}

/* Pulsanti-icona ai lati della barra (menu e pausa). */
.sudoku-stats .icon-btn {
    flex: 0 0 auto;
    width: 48px;
    padding: 0;
    display: grid;
    place-items: center;
    border-radius: var(--nk-radius-sm, 10px);
    border: 1px solid var(--nk-border, rgba(148, 163, 184, 0.18));
    background: var(--nk-surface-soft, rgba(22, 31, 46, 0.82));
    color: var(--nk-text-secondary, #c2d0e0);
    font: inherit;
    font-size: 1.1rem;
    cursor: pointer;
    -webkit-tap-highlight-color: transparent;
    transition: border-color 0.15s ease, color 0.15s ease;
}

.sudoku-stats .icon-btn:hover {
    border-color: var(--nk-border-strong, rgba(56, 189, 248, 0.32));
    color: var(--nk-text, #edf4fb);
    background: var(--nk-surface-soft, rgba(22, 31, 46, 0.82));
    transform: none;
}

/* Su schermi stretti la barra (2 pulsanti + 3 stat) va compattata
   per non forzare la colonna della board oltre il viewport. */
@media (max-width: 480px) {
    .sudoku-stats {
        gap: 6px;
    }

    .stat {
        padding: 8px;
    }

    .stat-label {
        font-size: 0.62rem;
        letter-spacing: 0.04em;
    }

    .stat-value {
        font-size: 0.95rem;
    }

    .sudoku-stats .icon-btn {
        width: 40px;
    }
}

/* ---------- Griglia ---------- */

.board-wrap {
    position: relative;
}

.board {
    display: grid;
    grid-template-columns: repeat(9, 1fr);
    grid-template-rows: repeat(9, 1fr);
    aspect-ratio: 1;
    width: 100%;
    border: 2px solid var(--nk-text-secondary, #c2d0e0);
    border-radius: var(--nk-radius-sm, 10px);
    overflow: hidden;
    background: var(--nk-surface-solid, #101a26);
    user-select: none;
    -webkit-user-select: none;
    touch-action: manipulation;
}

.board.locked {
    pointer-events: none;
    opacity: 0.7;
}

/* In pausa i numeri vengono nascosti: niente sbirciatine
   mentre il timer è fermo. */
.board.paused .cell-value,
.board.paused .note {
    visibility: hidden;
}

/* Le regole globali di style.css danno a ogni <button> gradiente,
   raggio 12px e lift su hover: sulle celle vanno neutralizzate.
   L'hover ridefinisce anche il background, quindi gli stati delle
   celle più sotto usano il prefisso .board per vincere in specificità. */
.board .cell,
.board .cell:hover {
    border-radius: 0;
    transform: none;
    background: transparent;
}

.cell {
    position: relative;
    display: grid;
    place-items: center;
    margin: 0;
    padding: 0;
    border: none;
    border-right: 1px solid var(--nk-border, rgba(148, 163, 184, 0.18));
    border-bottom: 1px solid var(--nk-border, rgba(148, 163, 184, 0.18));
    background: transparent;
    font: inherit;
    font-size: clamp(1rem, 4.6vw, 1.55rem);
    font-weight: 600;
    color: var(--nk-accent-2, #38bdf8);
    cursor: pointer;
    -webkit-tap-highlight-color: transparent;
    transition: background-color 0.12s ease;
}

/* Separatori spessi tra i blocchi 3x3 (colonne 3 e 6, righe 3 e 6). */
.cell:nth-child(9n) {
    border-right: none;
}

.cell:nth-child(9n + 3),
.cell:nth-child(9n + 6) {
    border-right: 2px solid var(--nk-text-secondary, #c2d0e0);
}

.cell:nth-child(n + 19):nth-child(-n + 27),
.cell:nth-child(n + 46):nth-child(-n + 54) {
    border-bottom: 2px solid var(--nk-text-secondary, #c2d0e0);
}

.cell:nth-child(n + 73) {
    border-bottom: none;
}

/* Stati delle celle: il prefisso .board + :hover incluso garantisce
   che vincano sempre sulla regola globale `button:hover` del sito.
   L'ordine definisce la priorità visiva. */
.cell.fixed {
    color: var(--nk-text, #edf4fb);
    font-weight: 800;
    cursor: default;
}

.board .cell.peer,
.board .cell.peer:hover {
    background: color-mix(in srgb, var(--nk-accent-2, #38bdf8) 8%, transparent);
}

.board .cell.same-value,
.board .cell.same-value:hover {
    background: color-mix(in srgb, var(--nk-accent-2, #38bdf8) 22%, transparent);
}

.board .cell.error,
.board .cell.error:hover {
    color: var(--nk-danger-strong, #f87171);
    background: color-mix(in srgb, var(--nk-danger, #ef4444) 14%, transparent);
}

.board .cell.selected,
.board .cell.selected:hover {
    background: color-mix(in srgb, var(--nk-accent, #38d9a9) 30%, transparent);
    box-shadow: inset 0 0 0 2px var(--nk-accent, #38d9a9);
}

.cell:focus-visible {
    outline: none;
    box-shadow: inset 0 0 0 2px var(--nk-accent, #38d9a9);
}

.cell-value {
    grid-area: 1 / 1;
    line-height: 1;
}

/* Appunti: mini-griglia 3x3 sovrapposta al valore (vuoto). */
.cell-notes {
    grid-area: 1 / 1;
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    grid-template-rows: repeat(3, 1fr);
    width: 100%;
    height: 100%;
    pointer-events: none;
}

.note {
    display: grid;
    place-items: center;
    font-size: clamp(0.42rem, 1.8vw, 0.62rem);
    font-weight: 700;
    line-height: 1;
    color: var(--nk-muted, #94a6bb);
}

/* ---------- Colonna comandi ---------- */

.sudoku-controls {
    display: grid;
    gap: 14px;
    width: min(100%, 520px);
    align-content: start;
}

.actions {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 10px;
}

.action-btn {
    display: grid;
    justify-items: center;
    gap: 4px;
    padding: 10px 6px;
    border-radius: var(--nk-radius-sm, 10px);
    border: 1px solid var(--nk-border, rgba(148, 163, 184, 0.18));
    background: var(--nk-surface-soft, rgba(22, 31, 46, 0.82));
    color: var(--nk-text-secondary, #c2d0e0);
    font: inherit;
    cursor: pointer;
    -webkit-tap-highlight-color: transparent;
    transition: border-color 0.15s ease, color 0.15s ease, background-color 0.15s ease;
}

.action-btn:hover:not(:disabled) {
    border-color: var(--nk-border-strong, rgba(56, 189, 248, 0.32));
    color: var(--nk-text, #edf4fb);
}

.action-btn:disabled {
    opacity: 0.45;
    cursor: default;
}

.action-btn.active {
    border-color: var(--nk-accent, #38d9a9);
    color: var(--nk-accent, #38d9a9);
    background: color-mix(in srgb, var(--nk-accent, #38d9a9) 12%, transparent);
}

.action-icon {
    font-size: 1.15rem;
    line-height: 1;
}

.action-label {
    font-size: 0.78rem;
    font-weight: 700;
}

/* ---------- Tastierino numerico ---------- */

.numpad {
    display: grid;
    grid-template-columns: repeat(9, 1fr);
    gap: 6px;
}

.numpad button {
    display: grid;
    justify-items: center;
    gap: 1px;
    padding: 8px 0 6px;
    min-height: 52px;
    border-radius: var(--nk-radius-sm, 10px);
    border: 1px solid var(--nk-border, rgba(148, 163, 184, 0.18));
    background: var(--nk-surface-soft, rgba(22, 31, 46, 0.82));
    color: var(--nk-accent-2, #38bdf8);
    font: inherit;
    cursor: pointer;
    -webkit-tap-highlight-color: transparent;
    transition: border-color 0.15s ease, background-color 0.15s ease, opacity 0.15s ease;
}

.numpad button:hover:not(:disabled) {
    border-color: var(--nk-border-strong, rgba(56, 189, 248, 0.32));
    background: color-mix(in srgb, var(--nk-accent-2, #38bdf8) 10%, transparent);
}

.numpad button:disabled {
    opacity: 0.3;
    cursor: default;
}

.numpad .digit {
    font-size: 1.3rem;
    font-weight: 800;
    line-height: 1;
}

.numpad .digit-count {
    font-size: 0.66rem;
    font-weight: 700;
    color: var(--nk-muted, #94a6bb);
    min-height: 0.8em;
    line-height: 1;
}

/* ---------- Pulsanti partita ---------- */

.game-buttons {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 10px;
}

.sudoku-page .btn {
    padding: 12px 16px;
    border-radius: var(--nk-radius-sm, 10px);
    border: 1px solid var(--nk-border, rgba(148, 163, 184, 0.18));
    background: var(--nk-surface-soft, rgba(22, 31, 46, 0.82));
    color: var(--nk-text, #edf4fb);
    font: inherit;
    font-weight: 800;
    cursor: pointer;
    -webkit-tap-highlight-color: transparent;
    transition: border-color 0.15s ease, filter 0.15s ease;
}

.sudoku-page .btn:hover {
    border-color: var(--nk-border-strong, rgba(56, 189, 248, 0.32));
}

.sudoku-page .btn.primary {
    border-color: transparent;
    background: var(--nk-accent, #38d9a9);
    color: var(--nk-on-accent, #041016);
}

.sudoku-page .btn.primary:hover {
    filter: brightness(1.08);
}

/* Variante distruttiva (azzeramento statistiche). */
.sudoku-page .btn.danger {
    border-color: color-mix(in srgb, var(--nk-danger, #ef4444) 45%, transparent);
    color: var(--nk-danger-strong, #f87171);
}

.sudoku-page .btn.danger:hover {
    border-color: var(--nk-danger-strong, #f87171);
}

.sudoku-page .btn.danger.armed {
    background: var(--nk-danger, #ef4444);
    border-color: transparent;
    color: #fff;
}

.kbd-hint {
    margin: 0;
    font-size: 0.82rem;
    color: var(--nk-muted, #94a6bb);
    line-height: 1.5;
}

.kbd-hint kbd {
    padding: 1px 5px;
    border-radius: 5px;
    border: 1px solid var(--nk-border, rgba(148, 163, 184, 0.18));
    background: var(--nk-surface-solid-alt, #0b141f);
    font-family: inherit;
    font-size: 0.78rem;
    font-weight: 700;
}

/* La scorciatoia da tastiera non ha senso su touch. */
@media (hover: none) and (pointer: coarse) {
    .kbd-hint {
        display: none;
    }
}

/* ---------- Overlay (caricamento / pausa / vittoria / game over) ---------- */

.overlay {
    position: absolute;
    inset: 0;
    display: grid;
    place-items: center;
    padding: 16px;
    border-radius: var(--nk-radius-sm, 10px);
    background: var(--nk-overlay, rgba(4, 8, 14, 0.6));
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.2s ease, visibility 0.2s ease;
    z-index: 5;
}

.overlay.visible {
    opacity: 1;
    visibility: visible;
}

.overlay-card {
    display: grid;
    gap: 10px;
    justify-items: center;
    text-align: center;
    max-width: 320px;
    padding: 22px 20px;
    border-radius: var(--nk-radius, 16px);
    border: 1px solid var(--nk-border, rgba(148, 163, 184, 0.18));
    background: var(--nk-surface-solid, #101a26);
    box-shadow: var(--nk-shadow, 0 24px 60px rgba(0, 0, 0, 0.32));
}

.overlay-card h2 {
    margin: 0;
    font-size: 1.3rem;
    color: var(--nk-text, #edf4fb);
}

.overlay[data-kind="win"] .overlay-card h2 {
    color: var(--nk-success, #22c55e);
}

.overlay[data-kind="gameover"] .overlay-card h2 {
    color: var(--nk-danger-strong, #f87171);
}

/* In pausa lo sfondo è quasi opaco: la griglia non deve leggersi
   (i valori sono comunque nascosti da .board.paused). */
.overlay[data-kind="pause"] {
    background: color-mix(in srgb, var(--nk-surface-solid, #101a26) 88%, transparent);
}

/* ---------- Stelle di fine partita ---------- */

.overlay-stars {
    display: flex;
    gap: 8px;
    font-size: 2.3rem;
    line-height: 1;
}

/* `display: flex` sopra vincerebbe su [hidden]: va ribadito. */
.overlay-stars[hidden] {
    display: none;
}

.overlay-stars .star {
    color: color-mix(in srgb, var(--nk-muted, #94a6bb) 35%, transparent);
}

.overlay-stars .star.earned {
    color: #fbbf24;
    text-shadow: 0 0 14px rgba(251, 191, 36, 0.45);
}

/* Ingresso "a cascata" delle stelle guadagnate. */
.overlay.visible .star.earned {
    animation: star-pop 0.45s ease backwards;
}

.overlay.visible .star.earned[data-star="2"] {
    animation-delay: 0.18s;
}

.overlay.visible .star.earned[data-star="3"] {
    animation-delay: 0.36s;
}

@keyframes star-pop {
    from {
        transform: scale(0.2);
        opacity: 0;
    }
    60% {
        transform: scale(1.25);
    }
    to {
        transform: scale(1);
        opacity: 1;
    }
}

.overlay-card p {
    margin: 0;
    font-size: 0.92rem;
    color: var(--nk-text-secondary, #c2d0e0);
    line-height: 1.5;
}

.overlay-actions {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 10px;
    margin-top: 6px;
}

/* I pulsanti visibili dipendono dal tipo di overlay (data-kind):
   loading → nessuno; pause → Riprendi/Menu; win → Nuova/Menu;
   gameover → Nuova/Riavvia/Menu. */
.overlay-actions button {
    display: none;
}

.overlay[data-kind="pause"] #overlayResume,
.overlay[data-kind="pause"] #overlayMenu,
.overlay[data-kind="win"] #overlayNewGame,
.overlay[data-kind="win"] #overlayMenu,
.overlay[data-kind="gameover"] #overlayNewGame,
.overlay[data-kind="gameover"] #overlayRestart,
.overlay[data-kind="gameover"] #overlayMenu {
    display: block;
}

/* ---------- Schermata statistiche ---------- */

.stats-header {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    gap: 12px;
    flex-wrap: wrap;
}

.stats-header h2 {
    margin: 0;
    font-size: 1.25rem;
    color: var(--nk-text, #edf4fb);
}

.stats-total {
    margin: 0;
    font-size: 0.95rem;
    font-weight: 800;
    color: #fbbf24;
    font-variant-numeric: tabular-nums;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 12px;
}

.stats-card {
    display: grid;
    gap: 10px;
    align-content: start;
    padding: 16px 14px;
    border-radius: var(--nk-radius-sm, 10px);
    border: 1px solid var(--nk-border, rgba(148, 163, 184, 0.18));
    background: var(--nk-surface-soft, rgba(22, 31, 46, 0.82));
}

.stats-card h3 {
    margin: 0;
    font-size: 1rem;
    color: var(--nk-accent, #38d9a9);
}

.stats-card dl {
    display: grid;
    grid-template-columns: 1fr auto;
    gap: 6px 12px;
    margin: 0;
}

.stats-card dt {
    font-size: 0.82rem;
    color: var(--nk-muted, #94a6bb);
}

.stats-card dd {
    margin: 0;
    font-size: 0.82rem;
    font-weight: 700;
    color: var(--nk-text, #edf4fb);
    font-variant-numeric: tabular-nums;
    text-align: right;
}

.stats-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.stats-actions .btn {
    flex: 1 1 180px;
}

/* ---------- Modale: ripresa partita ---------- */

.resume-modal {
    position: fixed;
    inset: 0;
    display: grid;
    place-items: center;
    padding: 16px;
    background: var(--nk-overlay, rgba(4, 8, 14, 0.6));
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
    z-index: 50;
}

.resume-modal[hidden] {
    display: none;
}

.resume-modal-card {
    display: grid;
    gap: 14px;
    justify-items: center;
    text-align: center;
    max-width: 320px;
    padding: 24px 20px;
    border-radius: var(--nk-radius, 16px);
    border: 1px solid var(--nk-border, rgba(148, 163, 184, 0.18));
    background: var(--nk-surface-solid, #101a26);
    box-shadow: var(--nk-shadow, 0 24px 60px rgba(0, 0, 0, 0.32));
}

.resume-modal-card h2 {
    margin: 0;
    font-size: 1.2rem;
    color: var(--nk-text, #edf4fb);
}

.resume-modal-card p {
    margin: 0;
    font-size: 0.92rem;
    color: var(--nk-text-secondary, #c2d0e0);
    line-height: 1.5;
}

.resume-modal-actions {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 10px;
}

/* ---------- Layout desktop ---------- */

@media (min-width: 860px) {
    .sudoku-layout {
        grid-template-columns: minmax(0, 520px) minmax(240px, 320px);
        justify-content: center;
        align-items: start;
    }

    .sudoku-controls {
        width: 100%;
    }

    /* Sul desktop il tastierino diventa un blocco 3x3, più comodo
       da usare col mouse accanto alla griglia. */
    .numpad {
        grid-template-columns: repeat(3, 1fr);
    }

    .numpad button {
        min-height: 60px;
    }

    .cell {
        font-size: 1.55rem;
    }

    .note {
        font-size: 0.62rem;
    }
}