/* ========================================================================
   SUDOKU - Klassisches Design
   ======================================================================== */

:root {
    --sdk-cell-size: 56px;
    --sdk-font-size: 24px;
    --sdk-pencil-size: 11px;
    --sdk-bg: #1a2a3a;
    --sdk-bg-light: #243444;
    --sdk-grid-bg: #ffffff;
    --sdk-cell-border: #c0c8d0;
    --sdk-box-border: #2a3a4a;
    --sdk-given-color: #1a1a2e;
    --sdk-player-color: #2a6ab8;
    --sdk-error-color: #d03030;
    --sdk-error-bg: rgba(208, 48, 48, 0.08);
    --sdk-selected-bg: #c8ddf5;
    --sdk-selected-border: #4a8ad0;
    --sdk-highlight-bg: #e0ecf8;
    --sdk-number-highlight-bg: #d5e8ff;
    --sdk-pencil-color: #7a8a9a;
    --sdk-gold: #c8a84e;
    --sdk-gold-light: #e8c86e;
}

/* --- Container --- */
.sdk-game-container {
    background: radial-gradient(ellipse at center, var(--sdk-bg-light) 0%, var(--sdk-bg) 100%);
    box-sizing: border-box;
    user-select: none;
    -webkit-user-select: none;
    align-items: center;
    font-family: 'Segoe UI', 'Helvetica Neue', Arial, sans-serif;
}

/* --- Grid --- */
.sdk-grid-wrapper {
    background: var(--sdk-box-border);
    padding: 3px;
    border-radius: 6px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
}

.sdk-grid {
    display: grid;
    grid-template-columns: repeat(9, var(--sdk-cell-size));
    grid-template-rows: repeat(9, var(--sdk-cell-size));
    background: var(--sdk-cell-border);
    gap: 1px;
}

/* --- Cell --- */
.sdk-cell {
    width: var(--sdk-cell-size);
    height: var(--sdk-cell-size);
    background: var(--sdk-grid-bg);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    position: relative;
    transition: background 0.1s ease;
}

.sdk-cell:hover {
    background: #f0f4f8;
}

/* Box borders (thick lines between 3x3 boxes) */
.sdk-cell.sdk-br { border-right: 2px solid var(--sdk-box-border); margin-right: -1px; }
.sdk-cell.sdk-bb { border-bottom: 2px solid var(--sdk-box-border); margin-bottom: -1px; }

/* Alternating box shading for visual clarity */
.sdk-cell.sdk-box-shaded {
    background: #f8f9fb;
}

/* --- Cell States --- */
.sdk-cell.sdk-selected {
    background: var(--sdk-selected-bg) !important;
    box-shadow: inset 0 0 0 2px var(--sdk-selected-border);
    z-index: 2;
}

.sdk-cell.sdk-highlighted {
    background: var(--sdk-highlight-bg);
}

.sdk-cell.sdk-number-match {
    background: var(--sdk-number-highlight-bg);
}

.sdk-cell.sdk-error-cell {
    background: var(--sdk-error-bg);
}

/* --- Cell Values --- */
.sdk-value {
    font-size: var(--sdk-font-size);
    font-weight: 600;
    line-height: 1;
}

.sdk-cell.sdk-given .sdk-value {
    color: var(--sdk-given-color);
    font-weight: 700;
}

.sdk-cell.sdk-player .sdk-value {
    color: var(--sdk-player-color);
}

.sdk-cell.sdk-has-error .sdk-value {
    color: var(--sdk-error-color);
}

/* --- Pencil Marks --- */
.sdk-pencil {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    grid-template-rows: repeat(3, 1fr);
    width: 100%;
    height: 100%;
    padding: 2px;
}

.sdk-pencil-mark {
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: var(--sdk-pencil-size);
    color: var(--sdk-pencil-color);
    line-height: 1;
    font-weight: 500;
}

/* --- Number Pad --- */
.sdk-numpad {
    display: flex;
    gap: 6px;
    margin-top: 12px;
    flex-wrap: wrap;
    justify-content: center;
}

.sdk-num-btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    width: 48px;
    height: 56px;
    border: 1px solid rgba(255, 255, 255, 0.15);
    border-radius: 8px;
    background: rgba(255, 255, 255, 0.08);
    color: #e0e0e0;
    cursor: pointer;
    transition: all 0.15s ease;
    font-family: inherit;
    gap: 2px;
}

.sdk-num-btn:hover {
    background: rgba(255, 255, 255, 0.18);
    transform: translateY(-1px);
    border-color: rgba(255, 255, 255, 0.3);
}

.sdk-num-btn:active {
    transform: translateY(0);
}

.sdk-num-btn:disabled {
    opacity: 0.3;
    cursor: default;
    transform: none;
}

.sdk-num-btn.sdk-num-active {
    background: rgba(42, 106, 184, 0.35);
    border-color: var(--sdk-player-color);
    color: #fff;
    box-shadow: 0 0 8px rgba(42, 106, 184, 0.3);
}

.sdk-num-val {
    font-size: 22px;
    font-weight: 600;
    line-height: 1;
}

.sdk-num-remaining {
    font-size: 10px;
    opacity: 0.5;
    line-height: 1;
}

/* Action Buttons (Erase, Pencil, Undo) */
.sdk-action-btn {
    width: 48px;
    height: 56px;
    border: 1px solid rgba(255, 255, 255, 0.15);
    border-radius: 8px;
    background: rgba(255, 255, 255, 0.06);
    color: #b0b8c0;
    cursor: pointer;
    font-size: 20px;
    font-family: inherit;
    transition: all 0.15s ease;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 2px;
}

.sdk-action-btn:hover {
    background: rgba(255, 255, 255, 0.15);
    color: #e0e0e0;
    transform: translateY(-1px);
}

.sdk-action-btn.sdk-pencil-active {
    background: rgba(200, 168, 78, 0.25);
    border-color: var(--sdk-gold);
    color: var(--sdk-gold-light);
}

.sdk-action-btn:disabled {
    opacity: 0.3;
    cursor: default;
    transform: none;
}

.sdk-action-label {
    font-size: 9px;
    line-height: 1;
    opacity: 0.6;
}

/* --- Win Overlay --- */
.sdk-win-overlay {
    position: fixed;
    inset: 0;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    background: rgba(0, 0, 0, 0.7);
    z-index: 20000;
    animation: sdkFadeIn 0.5s ease;
    backdrop-filter: blur(6px);
}

.sdk-win-card {
    background: linear-gradient(135deg, var(--sdk-bg-light) 0%, var(--sdk-bg) 100%);
    border: 3px solid var(--sdk-gold);
    border-radius: 16px;
    padding: 40px 60px;
    text-align: center;
    color: #e0ddd4;
    box-shadow: 0 0 60px rgba(200, 168, 78, 0.3);
    animation: sdkScaleIn 0.5s ease 0.2s both;
}

.sdk-win-title {
    font-size: 32px;
    font-weight: 700;
    color: var(--sdk-gold-light);
    margin-bottom: 16px;
    letter-spacing: 2px;
}

.sdk-win-stats {
    font-size: 16px;
    margin-bottom: 24px;
    line-height: 1.8;
}

.sdk-win-stats strong {
    color: var(--sdk-gold-light);
}

@keyframes sdkFadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes sdkScaleIn {
    from { opacity: 0; transform: scale(0.8); }
    to { opacity: 1; transform: scale(1); }
}

/* --- Error shake --- */
.sdk-cell.sdk-shake {
    animation: sdkShake 0.3s ease;
}

@keyframes sdkShake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-3px); }
    75% { transform: translateX(3px); }
}

/* --- Responsive --- */
@media (max-width: 600px) {
    :root {
        --sdk-cell-size: 40px;
        --sdk-font-size: 18px;
        --sdk-pencil-size: 8px;
    }

    .sdk-num-btn { width: 36px; height: 44px; }
    .sdk-num-val { font-size: 18px; }
    .sdk-num-remaining { font-size: 8px; }
    .sdk-action-btn { width: 36px; height: 44px; font-size: 16px; }
    .sdk-action-label { font-size: 7px; }
    .sdk-numpad { gap: 4px; }
    .sdk-win-card { padding: 24px 32px; }
    .sdk-win-title { font-size: 24px; }
}

@media (max-width: 420px) {
    :root {
        --sdk-cell-size: 34px;
        --sdk-font-size: 16px;
        --sdk-pencil-size: 7px;
    }

    .sdk-num-btn { width: 30px; height: 38px; }
    .sdk-num-val { font-size: 16px; }
    .sdk-action-btn { width: 30px; height: 38px; font-size: 14px; }
    .sdk-numpad { gap: 3px; }
}