.wpbooks-sudoku {
    max-width: min(1680px, calc(100vw - 32px));
    margin: 0 auto;
    padding: 2rem 0 4rem;
    color: #171717;
}

.wpbooks-sudoku__hero {
    display: grid;
    grid-template-columns: minmax(0, 1.3fr) minmax(280px, 420px);
    gap: 1.2rem;
    align-items: end;
    margin-bottom: 1.6rem;
}

.wpbooks-sudoku__eyebrow {
    margin: 0 0 0.55rem;
    font-size: 0.74rem;
    font-weight: 800;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: #777;
}

.wpbooks-sudoku__title {
    margin: 0;
    font-size: clamp(2.2rem, 5vw, 4.8rem);
    line-height: 0.95;
    letter-spacing: -0.06em;
}

.wpbooks-sudoku__lead {
    margin: 1rem 0 0;
    max-width: 58rem;
    color: #555;
    font-size: 1rem;
    line-height: 1.75;
}

.wpbooks-sudoku__status {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 0.75rem;
}

.wpbooks-sudoku__status div,
.wpbooks-sudoku__section {
    border: 1px solid rgba(17, 17, 17, 0.08);
    border-radius: 24px;
    background: #fff;
}

.wpbooks-sudoku__status div {
    padding: 1rem 1.1rem;
}

.wpbooks-sudoku__status span {
    display: block;
    color: #777;
    font-size: 0.76rem;
    font-weight: 700;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

.wpbooks-sudoku__status strong {
    display: block;
    margin-top: 0.45rem;
    font-size: 1.05rem;
}

.wpbooks-sudoku__shell {
    display: grid;
    grid-template-columns: 320px minmax(0, 1fr);
    gap: 1.2rem;
    align-items: start;
}

.wpbooks-sudoku__sidebar {
    display: grid;
    gap: 1rem;
    position: sticky;
    top: 2rem;
}

.wpbooks-sudoku__section {
    padding: 1.1rem;
}

.wpbooks-sudoku__section-title {
    display: block;
    margin: 0 0 0.75rem;
    color: #777;
    font-size: 0.78rem;
    font-weight: 800;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

.wpbooks-sudoku__mode-list,
.wpbooks-sudoku__actions {
    display: grid;
    gap: 0.55rem;
}

.wpbooks-sudoku__mode,
.wpbooks-sudoku__button,
.wpbooks-sudoku__select {
    width: 100%;
    min-height: 52px;
    border-radius: 18px;
    font: inherit;
}

.wpbooks-sudoku__mode,
.wpbooks-sudoku__button {
    border: 1px solid rgba(17, 17, 17, 0.08);
    background: #fff;
    color: #111;
    padding: 0.95rem 1rem;
    text-align: left;
    font-weight: 800;
    cursor: pointer;
    transition: transform 0.2s ease, background-color 0.2s ease, color 0.2s ease;
}

.wpbooks-sudoku__mode:hover,
.wpbooks-sudoku__button:hover {
    transform: translateY(-1px);
}

.wpbooks-sudoku__mode.is-active,
.wpbooks-sudoku__button {
    background: #111;
    color: #fff;
}

.wpbooks-sudoku__button.is-light {
    background: #f5cb48;
    color: #111;
}

.wpbooks-sudoku__select {
    border: 1px solid rgba(17, 17, 17, 0.1);
    background: #fff;
    padding: 0 1rem;
}

.wpbooks-sudoku__notes {
    margin: 0;
    padding-left: 1rem;
    color: #555;
    line-height: 1.7;
}

.wpbooks-sudoku__playground {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 320px;
    gap: 1.2rem;
}

.wpbooks-sudoku__board-wrap,
.wpbooks-sudoku__pad {
    border: 1px solid rgba(17, 17, 17, 0.08);
    border-radius: 32px;
    background: #fff;
}

.wpbooks-sudoku__board-wrap {
    padding: clamp(0.9rem, 2vw, 1.4rem);
    background: radial-gradient(circle at 50% 18%, rgba(255,255,255,.98) 0%, rgba(247,243,235,.98) 56%, rgba(236,229,214,.94) 100%);
}

.wpbooks-sudoku__board {
    --grid-size: 9;
    display: grid;
    grid-template-columns: repeat(var(--grid-size), minmax(0, 1fr));
    gap: 1px;
    width: min(100%, 860px);
    margin: 0 auto;
    padding: 3px;
    aspect-ratio: 1 / 1;
    background: #111;
}

.wpbooks-sudoku__cell {
    display: flex;
    align-items: center;
    justify-content: center;
    background: #fff;
    color: #111;
    font-weight: 800;
    font-size: clamp(1rem, 1.5vw, 1.6rem);
    cursor: pointer;
    user-select: none;
    transition: background-color 0.15s ease, color 0.15s ease, transform 0.15s ease;
}

.wpbooks-sudoku__cell.is-fixed {
    background: #f4efe0;
}

.wpbooks-sudoku__cell.is-selected {
    background: #f5cb48;
    transform: scale(1.02);
}

.wpbooks-sudoku__cell.is-related {
    background: #f8f5eb;
}

.wpbooks-sudoku__cell.is-error {
    color: #c62828;
    background: #ffe3e3;
}

.wpbooks-sudoku__pad {
    padding: 1rem;
    display: grid;
    gap: 1rem;
    align-content: start;
}

.wpbooks-sudoku__numbers {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 0.75rem;
}

.wpbooks-sudoku__number {
    min-height: 82px;
    border: 1px solid rgba(17, 17, 17, 0.08);
    border-radius: 24px;
    background: #fff;
    color: #111;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 0.2rem;
    cursor: pointer;
    transition: transform 0.2s ease, background-color 0.2s ease;
}

.wpbooks-sudoku__number:hover {
    transform: translateY(-2px);
    background: #fff7d0;
}

.wpbooks-sudoku__number strong {
    font-size: clamp(1.1rem, 1.8vw, 1.8rem);
}

.wpbooks-sudoku__number span {
    color: #777;
    font-size: 0.75rem;
    font-weight: 700;
}

.wpbooks-sudoku__number.is-erase {
    background: #111;
    color: #fff;
}

.wpbooks-sudoku__meta {
    border-top: 1px solid rgba(17, 17, 17, 0.08);
    padding-top: 1rem;
    color: #555;
    line-height: 1.65;
}

@media (max-width: 1180px) {
    .wpbooks-sudoku__hero,
    .wpbooks-sudoku__shell,
    .wpbooks-sudoku__playground {
        grid-template-columns: 1fr;
    }

    .wpbooks-sudoku__sidebar {
        position: static;
    }
}

@media (max-width: 720px) {
    .wpbooks-sudoku {
        max-width: calc(100vw - 20px);
        padding: 1.2rem 0 2.5rem;
    }

    .wpbooks-sudoku__status {
        grid-template-columns: 1fr;
    }

    .wpbooks-sudoku__board-wrap,
    .wpbooks-sudoku__pad {
        border-radius: 24px;
    }

    .wpbooks-sudoku__numbers {
        grid-template-columns: repeat(3, minmax(0, 1fr));
    }

    .wpbooks-sudoku__number {
        min-height: 68px;
        border-radius: 18px;
    }
}