/* ===========================================================
   Автоматический решатель и составитель судоку
   Стилевой файл — современный «калькуляторный» интерфейс
   =========================================================== */

* { box-sizing: border-box; margin: 0; padding: 0; }
[hidden] { display: none !important; }

:root {
    /* Светлая тема */
    --bg: #f5f5f0;
    --bg-grad-1: #f5f5f0;
    --bg-grad-2: #f5f5f0;

    --surface: #ffffff;
    --surface-2: #f7f6f1;
    --surface-3: #eeece4;

    --border: #d9d6cc;
    --border-strong: #b8b3a3;
    --divider: #d9d6cc;

    --text: #1f1f1f;
    --text-muted: #5a5a5a;
    --text-soft: #8a8a8a;

    --primary: #2c4a7e;
    --primary-600: #1f3a66;
    --primary-soft: rgba(44, 74, 126, 0.10);

    --accent: #2c7a52;
    --accent-600: #1f5e3e;
    --accent-soft: rgba(44, 122, 82, 0.12);

    --danger: #b53b3b;
    --danger-soft: rgba(181, 59, 59, 0.10);

    --warning: #c47900;

    --given: #1f1f1f;
    --user: #1f3a66;
    --conflict: #b53b3b;
    --hint: #2c7a52;

    --highlight-cell: rgba(44, 74, 126, 0.10);
    --highlight-related: rgba(44, 74, 126, 0.05);
    --highlight-same: rgba(44, 74, 126, 0.16);
    --highlight-conflict: rgba(181, 59, 59, 0.16);

    --shadow-sm: 0 1px 1px rgba(0, 0, 0, 0.04);
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.06), 0 1px 2px rgba(0, 0, 0, 0.04);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.10), 0 2px 6px rgba(0, 0, 0, 0.05);

    --radius-sm: 6px;
    --radius: 10px;
    --radius-lg: 14px;

    --font-sans: 'Inter', system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
    --font-mono: 'JetBrains Mono', ui-monospace, Menlo, Consolas, monospace;
}

[data-theme="dark"] {
    --bg: #1a1d22;
    --bg-grad-1: #1a1d22;
    --bg-grad-2: #1a1d22;

    --surface: #23272e;
    --surface-2: #2a2e36;
    --surface-3: #343941;

    --border: #383d46;
    --border-strong: #525861;
    --divider: #383d46;

    --text: #e6e6e6;
    --text-muted: #a0a4ab;
    --text-soft: #767a82;

    --primary: #6b8fc4;
    --primary-600: #4a72b0;
    --primary-soft: rgba(107, 143, 196, 0.16);

    --accent: #6ab084;
    --accent-600: #4d9468;
    --accent-soft: rgba(106, 176, 132, 0.16);

    --danger: #d97777;
    --danger-soft: rgba(217, 119, 119, 0.16);

    --given: #e6e6e6;
    --user: #a3bfe0;
    --conflict: #e0a3a3;
    --hint: #a3d4b6;

    --highlight-cell: rgba(107, 143, 196, 0.18);
    --highlight-related: rgba(107, 143, 196, 0.08);
    --highlight-same: rgba(107, 143, 196, 0.26);
    --highlight-conflict: rgba(217, 119, 119, 0.22);

    --shadow-sm: 0 1px 1px rgba(0, 0, 0, 0.25);
    --shadow: 0 2px 8px rgba(0, 0, 0, 0.35), 0 1px 2px rgba(0, 0, 0, 0.2);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.5), 0 2px 6px rgba(0, 0, 0, 0.3);
}

html, body {
    height: 100%;
}

body {
    font-family: var(--font-sans);
    color: var(--text);
    background: var(--bg);
    min-height: 100vh;
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
    text-rendering: optimizeLegibility;
    transition: background-color .25s ease, color .25s ease;
}

.app {
    max-width: 1200px;
    margin: 0 auto;
    padding: 24px 20px 48px;
}

/* ====================== ШАПКА ====================== */
.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 16px;
    margin-bottom: 24px;
}

.header__left {
    display: flex;
    align-items: center;
    gap: 14px;
}

.logo {
    width: 48px;
    height: 48px;
    border-radius: 8px;
    background: var(--surface);
    border: 1.5px solid var(--text);
    color: var(--text);
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    grid-template-rows: repeat(3, 1fr);
    font-family: var(--font-mono);
    font-weight: 700;
    flex-shrink: 0;
    overflow: hidden;
}
.logo span {
    display: flex;
    align-items: center;
    justify-content: center;
    border-right: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
    font-size: 10px;
    color: var(--text-muted);
}
.logo span:nth-child(3n) { border-right: none; }
.logo span:nth-child(n+7) { border-bottom: none; }
.logo span:nth-child(1),
.logo span:nth-child(5),
.logo span:nth-child(9) {
    color: var(--text);
    font-weight: 700;
}

.header__title {
    font-size: clamp(22px, 3.2vw, 28px);
    font-weight: 700;
    letter-spacing: -0.01em;
}

.header__subtitle {
    font-size: 13px;
    color: var(--text-muted);
    margin-top: 2px;
}

.icon-btn {
    width: 40px;
    height: 40px;
    border-radius: 8px;
    border: 1px solid var(--border);
    background: var(--surface);
    color: var(--text);
    cursor: pointer;
    display: grid;
    place-items: center;
    transition: border-color .2s ease, background-color .2s ease;
}
.icon-btn:hover {
    border-color: var(--border-strong);
    background: var(--surface-2);
}

.icon-sun { display: none; }
.icon-moon { display: block; }
[data-theme="dark"] .icon-sun { display: block; }
[data-theme="dark"] .icon-moon { display: none; }

/* ====================== ОСНОВНАЯ СЕТКА ====================== */
.main {
    display: grid;
    grid-template-columns: minmax(0, 1.2fr) minmax(300px, 360px);
    gap: 22px;
    align-items: start;
}

/* ====================== КАРТОЧКА ДОСКИ ====================== */
.board-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 20px;
    box-shadow: var(--shadow);
}

.board-card__top {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 12px;
    margin-bottom: 16px;
}

.status {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 8px 12px;
    background: var(--surface-2);
    border: 1px solid var(--border);
    border-radius: 999px;
    font-size: 13px;
    color: var(--text-muted);
    max-width: 100%;
}

.status__dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: var(--text-soft);
    box-shadow: 0 0 0 3px rgba(0, 0, 0, 0.04);
    flex-shrink: 0;
}
.status.is-success .status__dot { background: var(--accent); box-shadow: 0 0 0 3px var(--accent-soft); }
.status.is-error .status__dot { background: var(--danger); box-shadow: 0 0 0 3px var(--danger-soft); }
.status.is-info .status__dot { background: var(--primary); box-shadow: 0 0 0 3px var(--primary-soft); }

.status__text {
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.timer {
    font-family: var(--font-mono);
    font-weight: 600;
    font-size: 17px;
    background: var(--surface-2);
    padding: 7px 12px;
    border-radius: 6px;
    border: 1px solid var(--border);
    color: var(--text);
    letter-spacing: 0.02em;
}

/* ====================== ТУЛБАР ДЕЙСТВИЙ ====================== */
.toolbar {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 16px;
    padding: 10px;
    background: var(--surface-2);
    border: 1px solid var(--border);
    border-radius: 10px;
}

.toolbar__primary {
    padding: 10px 20px;
    font-size: 14px;
    flex-shrink: 0;
}

.toolbar__group {
    display: flex;
    flex-wrap: wrap;
    gap: 4px;
    margin-left: auto;
}

.tool-btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 7px 10px;
    border: 1px solid transparent;
    background: transparent;
    color: var(--text-muted);
    border-radius: 6px;
    font-family: inherit;
    font-size: 13px;
    font-weight: 500;
    cursor: pointer;
    transition: background-color .15s ease, color .15s ease, border-color .15s ease;
}
.tool-btn svg { opacity: 0.85; }
.tool-btn:hover {
    background: var(--surface);
    color: var(--text);
    border-color: var(--border);
}
.tool-btn:active { background: var(--surface-3); }
.tool-btn:disabled {
    opacity: 0.4;
    cursor: not-allowed;
    background: transparent;
}

.tool-btn--danger:hover {
    color: var(--danger);
    background: var(--danger-soft);
    border-color: var(--danger);
}

@media (max-width: 560px) {
    .toolbar {
        flex-direction: column;
        align-items: stretch;
        gap: 8px;
    }
    .toolbar__group {
        margin-left: 0;
        justify-content: space-between;
    }
    .tool-btn { flex: 1; justify-content: center; }
    .tool-btn span { display: none; }
    .tool-btn { padding: 9px; }
}

/* ====================== ДОСКА ====================== */
.board-wrapper {
    display: flex;
    justify-content: center;
}

.board {
    width: 100%;
    max-width: 560px;
    aspect-ratio: 1 / 1;
    display: grid;
    grid-template-columns: repeat(9, 1fr);
    grid-template-rows: repeat(9, 1fr);
    background: var(--border-strong);
    border: 2px solid var(--text);
    border-radius: var(--radius);
    overflow: hidden;
    user-select: none;
    box-shadow: var(--shadow-sm);
}

[data-theme="dark"] .board {
    border-color: var(--border-strong);
}

.cell {
    position: relative;
    background: var(--surface);
    border: 1px solid var(--border);
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: var(--font-mono);
    font-size: clamp(18px, 3.5vw, 28px);
    font-weight: 600;
    color: var(--user);
    cursor: pointer;
    transition: background-color .12s ease, color .12s ease, transform .12s ease;
    outline: none;
}

.cell:hover { background: var(--highlight-related); }

.cell.is-given { color: var(--given); font-weight: 700; background: var(--surface-2); }

.cell.is-related { background: var(--highlight-related); }
.cell.is-same-num { background: var(--highlight-same); }
.cell.is-selected {
    background: var(--highlight-cell);
    box-shadow: inset 0 0 0 2px var(--primary);
    z-index: 2;
}
.cell.is-conflict { color: var(--conflict); background: var(--highlight-conflict); }
.cell.is-hint {
    animation: cellPop .35s ease;
    color: var(--hint);
    background: var(--accent-soft);
}
.cell.is-solving {
    animation: solvingPulse .6s ease;
    color: var(--primary);
}

@keyframes cellPop {
    0% { transform: scale(1); }
    40% { transform: scale(1.18); }
    100% { transform: scale(1); }
}
@keyframes solvingPulse {
    0% { transform: scale(1); background: var(--accent-soft); }
    100% { transform: scale(1); background: var(--surface); }
}

/* Границы блоков 3×3 */
.cell[data-col="2"], .cell[data-col="5"] { border-right: 2px solid var(--text); }
.cell[data-row="2"], .cell[data-row="5"] { border-bottom: 2px solid var(--text); }
[data-theme="dark"] .cell[data-col="2"],
[data-theme="dark"] .cell[data-col="5"] { border-right-color: var(--border-strong); }
[data-theme="dark"] .cell[data-row="2"],
[data-theme="dark"] .cell[data-row="5"] { border-bottom-color: var(--border-strong); }

/* Заметки (карандашные пометки) */
.cell .notes {
    position: absolute;
    inset: 0;
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    grid-template-rows: repeat(3, 1fr);
    padding: 2px;
    font-size: clamp(8px, 1.2vw, 11px);
    font-weight: 500;
    color: var(--text-muted);
    pointer-events: none;
}
.cell .notes span {
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
}
.cell .notes span.on { opacity: 1; }

/* ====================== СТАТИСТИКА ====================== */
.stats {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 10px;
    margin-top: 18px;
}

.stat {
    background: var(--surface-2);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 12px 14px;
    text-align: center;
}

.stat__label {
    font-size: 11px;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--text-soft);
    margin-bottom: 4px;
    font-weight: 600;
}

.stat__value {
    font-family: var(--font-mono);
    font-weight: 700;
    font-size: 18px;
    color: var(--text);
}

/* ====================== ПАНЕЛЬ УПРАВЛЕНИЯ ====================== */
.panel {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 20px;
    box-shadow: var(--shadow);
    display: flex;
    flex-direction: column;
    gap: 18px;
    position: sticky;
    top: 16px;
}

.panel__section {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.panel__section + .panel__section {
    padding-top: 18px;
    border-top: 1px solid var(--divider);
}

.panel__title {
    font-size: 12px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-soft);
    margin-bottom: 2px;
}

/* Панель цифр */
.numpad {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 8px;
}

.num {
    aspect-ratio: 1 / 1;
    border-radius: 6px;
    border: 1px solid var(--border);
    background: var(--surface-2);
    color: var(--text);
    font-family: var(--font-mono);
    font-weight: 600;
    font-size: 18px;
    cursor: pointer;
    transition: border-color .15s ease, background-color .15s ease;
    display: grid;
    place-items: center;
}
.num:hover {
    background: var(--primary-soft);
    color: var(--primary);
    border-color: var(--primary);
}
.num.num--erase { color: var(--danger); }
.num.num--erase:hover {
    background: var(--danger-soft);
    color: var(--danger);
    border-color: var(--danger);
}
.num.is-done {
    opacity: 0.35;
    text-decoration: line-through;
    text-decoration-thickness: 2px;
}

.mode-toggle {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4px;
    padding: 3px;
    background: var(--surface-2);
    border: 1px solid var(--border);
    border-radius: 8px;
}

.mode-btn {
    padding: 7px 10px;
    border: none;
    background: transparent;
    border-radius: 5px;
    color: var(--text-muted);
    font-weight: 500;
    font-size: 13px;
    cursor: pointer;
    transition: background-color .15s ease, color .15s ease;
}
.mode-btn.is-active {
    background: var(--surface);
    color: var(--text);
    box-shadow: var(--shadow-sm);
}

/* Уровни сложности */
.difficulty {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 8px;
}

.diff {
    position: relative;
    cursor: pointer;
}

.diff input {
    position: absolute;
    opacity: 0;
    pointer-events: none;
}

.diff span {
    display: block;
    padding: 9px 12px;
    text-align: center;
    border: 1px solid var(--border);
    background: var(--surface-2);
    border-radius: 6px;
    color: var(--text-muted);
    font-weight: 500;
    font-size: 13px;
    transition: border-color .15s ease, background-color .15s ease, color .15s ease;
}

.diff:hover span {
    color: var(--text);
    border-color: var(--border-strong);
}

.diff input:checked + span {
    background: var(--primary-soft);
    color: var(--primary);
    border-color: var(--primary);
}

[data-theme="dark"] .diff input:checked + span { color: var(--primary); }

/* Кнопки */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 10px 14px;
    border: 1px solid var(--border);
    background: var(--surface-2);
    color: var(--text);
    border-radius: 8px;
    font-family: inherit;
    font-weight: 500;
    font-size: 14px;
    cursor: pointer;
    transition: border-color .15s ease, background-color .15s ease;
}
.btn:hover {
    border-color: var(--border-strong);
    background: var(--surface-3);
}
.btn:active { background: var(--surface-2); }
.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.btn--block { width: 100%; }

.btn--primary {
    background: var(--primary);
    color: #fff;
    border-color: var(--primary);
}
.btn--primary:hover {
    background: var(--primary-600);
    border-color: var(--primary-600);
}

.btn--accent {
    background: var(--accent);
    color: #fff;
    border-color: var(--accent);
}
.btn--accent:hover {
    background: var(--accent-600);
    border-color: var(--accent-600);
}

/* Подсказка */
.panel__section--hint .hint-text {
    padding: 12px 14px;
    background: var(--accent-soft);
    border-left: 3px solid var(--accent);
    border-radius: 4px;
    color: var(--text);
    font-size: 13.5px;
    line-height: 1.5;
}

/* ====================== ИНФО-БЛОК ====================== */
.info {
    margin-top: 22px;
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 14px;
    align-items: start;
}

.info__card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 14px 18px;
    box-shadow: var(--shadow-sm);
    transition: border-color .2s ease, box-shadow .2s ease;
    align-self: start;
}

.info__card[open] {
    box-shadow: var(--shadow);
    border-color: var(--border-strong);
}

.info__card summary {
    cursor: pointer;
    font-weight: 600;
    font-size: 14px;
    list-style: none;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 8px;
    color: var(--text);
    outline: none;
    padding: 2px 0;
}

.info__card summary::after {
    content: '';
    width: 8px;
    height: 8px;
    border-right: 2px solid var(--text-muted);
    border-bottom: 2px solid var(--text-muted);
    transform: rotate(45deg) translate(-2px, -2px);
    transition: transform .2s ease;
}
.info__card[open] summary::after {
    transform: rotate(-135deg) translate(-2px, -2px);
}

.info__card summary::-webkit-details-marker { display: none; }

.info__card[open] > *:not(summary) {
    animation: fadeIn .25s ease;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(-4px); }
    to { opacity: 1; transform: translateY(0); }
}

.info__card p, .info__card ul {
    margin-top: 10px;
    color: var(--text-muted);
    font-size: 13.5px;
    line-height: 1.6;
}
.info__card ul { padding-left: 20px; }
.info__card li + li { margin-top: 4px; }
.info__card p + p { margin-top: 8px; }

kbd {
    font-family: var(--font-mono);
    font-size: 11px;
    padding: 2px 6px;
    background: var(--surface-2);
    border: 1px solid var(--border);
    border-bottom-width: 2px;
    border-radius: 4px;
    color: var(--text);
}

/* ====================== ПОДВАЛ ====================== */
.footer {
    margin-top: 28px;
    text-align: center;
    color: var(--text-soft);
    font-size: 12px;
}

/* ====================== TOAST ====================== */
.toast {
    position: fixed;
    bottom: 24px;
    left: 50%;
    transform: translateX(-50%) translateY(120%);
    background: var(--surface);
    color: var(--text);
    padding: 12px 18px;
    border-radius: 12px;
    border: 1px solid var(--border);
    box-shadow: var(--shadow-lg);
    font-weight: 500;
    font-size: 14px;
    z-index: 999;
    transition: transform .3s cubic-bezier(.34,1.56,.64,1);
    max-width: 90vw;
}
.toast.is-visible {
    transform: translateX(-50%) translateY(0);
}
.toast.is-success { border-color: var(--accent); }
.toast.is-error { border-color: var(--danger); }

/* ====================== АДАПТИВ ====================== */
@media (max-width: 920px) {
    .main {
        grid-template-columns: 1fr;
    }
    .panel { position: static; }
    .info { grid-template-columns: 1fr; }
}

@media (max-width: 560px) {
    .app { padding: 16px 12px 32px; }
    .header { margin-bottom: 18px; }
    .header__subtitle { display: none; }
    .board-card, .panel { padding: 14px; }
    .stats { grid-template-columns: repeat(2, 1fr); }
    .numpad { grid-template-columns: repeat(5, 1fr); }
    .cell { font-size: 5vw; }
}

/* ====================== PRINT ====================== */
@media print {
    body { background: #fff; }
    .panel, .info, .footer, .header__right, .toolbar { display: none !important; }
    .main { grid-template-columns: 1fr; }
    .board-card { box-shadow: none; border: none; }
}