/* Sudoku Engine CSS - Mobile First, Accessible, Responsive */

.sdk-page-container {
    max-width: 640px;
    margin: 0 auto;
    padding: 0 16px 40px;
    box-sizing: border-box;
}

.sdk-breadcrumb {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.85rem;
    color: #64748b;
    margin-bottom: 16px;
}

.sdk-breadcrumb a {
    color: #475569;
    text-decoration: none;
    transition: color 0.15s;
}

.sdk-breadcrumb a:hover {
    color: #0284c7;
}

.sdk-breadcrumb .sep {
    color: #cbd5e1;
}

.sdk-breadcrumb .current {
    color: #0f172a;
    font-weight: 600;
}

/* Date Navigation Bar */
.sdk-date-nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: #f8fafc;
    border: 1px solid #e2e8f0;
    padding: 12px 18px;
    border-radius: 10px;
    margin-bottom: 20px;
}

.sdk-date-title-group h1 {
    font-size: 1.25rem;
    font-weight: 800;
    color: #0f172a;
    margin: 0;
    line-height: 1.2;
}

.sdk-date-subtitle {
    font-size: 0.85rem;
    color: #64748b;
    font-weight: 500;
}

.sdk-date-nav-links {
    display: flex;
    gap: 8px;
}

.sdk-nav-btn {
    background: #ffffff;
    border: 1px solid #cbd5e1;
    padding: 6px 12px;
    border-radius: 6px;
    font-size: 0.8rem;
    font-weight: 600;
    color: #334155;
    text-decoration: none;
    transition: all 0.15s ease;
    white-space: nowrap;
}

.sdk-nav-btn:hover {
    background: #f1f5f9;
    border-color: #94a3b8;
    color: #0f172a;
}

/* Stats Toolbar */
.sdk-toolbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: #ffffff;
    border: 1px solid #e2e8f0;
    border-radius: 10px;
    padding: 10px 16px;
    margin-bottom: 16px;
}

.sdk-stats-group {
    display: flex;
    align-items: center;
    gap: 16px;
}

.sdk-stat-item {
    display: flex;
    flex-direction: column;
}

.sdk-stat-label {
    font-size: 0.7rem;
    text-transform: uppercase;
    color: #64748b;
    font-weight: 700;
    letter-spacing: 0.5px;
}

.sdk-stat-value {
    font-size: 1.1rem;
    font-weight: 800;
    color: #0f172a;
    font-variant-numeric: tabular-nums;
}

.sdk-badge {
    padding: 4px 10px;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 700;
}

.sdk-badge-easy { background: #dcfce7; color: #15803d; }
.sdk-badge-medium { background: #fef3c7; color: #b45309; }
.sdk-badge-hard { background: #fee2e2; color: #b91c1c; }

.sdk-actions-group {
    display: flex;
    gap: 8px;
}

.sdk-tool-btn {
    background: #f8fafc;
    border: 1px solid #cbd5e1;
    padding: 6px 12px;
    border-radius: 6px;
    font-size: 0.8rem;
    font-weight: 600;
    color: #334155;
    cursor: pointer;
    transition: all 0.15s ease;
}

.sdk-tool-btn:hover {
    background: #e2e8f0;
    color: #0f172a;
}

.sdk-tool-btn.active {
    background: #0284c7;
    color: #ffffff;
    border-color: #0284c7;
}

/* 9x9 Board Wrapper */
.sdk-board-box {
    background: #ffffff;
    border: 1px solid #e2e8f0;
    border-radius: 12px;
    padding: 12px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.04);
    margin-bottom: 20px;
}

.sdk-board {
    display: grid;
    grid-template-columns: repeat(9, 1fr);
    aspect-ratio: 1 / 1;
    width: 100%;
    border: 3px solid #0f172a;
    background-color: #cbd5e1;
    gap: 1px;
    border-radius: 6px;
    overflow: hidden;
    user-select: none;
    -webkit-user-select: none;
}

/* Cell Button */
.sdk-cell {
    background: #ffffff;
    border: none;
    padding: 0;
    margin: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    cursor: pointer;
    font-family: inherit;
    transition: background-color 0.12s ease;
    outline: none;
}

.sdk-cell:focus-visible {
    outline: 2px solid #0284c7;
    z-index: 4;
}

/* 3x3 Major Box Dividers */
.sdk-cell[data-col="2"],
.sdk-cell[data-col="5"] {
    border-right: 2px solid #0f172a;
}

.sdk-cell[data-row="2"],
.sdk-cell[data-row="5"] {
    border-bottom: 2px solid #0f172a;
}

/* Cell Main Digit */
.sdk-cell-val {
    font-size: clamp(1.2rem, 4.5vw, 1.75rem);
    font-weight: 800;
    line-height: 1;
}

/* Cell Types */
.sdk-cell--given {
    background-color: #f8fafc;
    cursor: default;
}

.sdk-cell--given .sdk-cell-val {
    color: #0f172a;
    font-weight: 900;
}

.sdk-cell--user .sdk-cell-val {
    color: #0284c7;
}

/* Highlighting States */
.sdk-cell--selected {
    background-color: #fef08a !important;
    outline: 3px solid #eab308;
    z-index: 5;
}

.sdk-cell--peer {
    background-color: #f0f9ff;
}

.sdk-cell--same-digit {
    background-color: #bae6fd;
}

.sdk-cell--conflict {
    background-color: #fee2e2 !important;
    animation: sdk-shake 0.3s ease-in-out;
}

.sdk-cell--conflict .sdk-cell-val {
    color: #ef4444 !important;
}

.sdk-cell--incorrect {
    background-color: #fecaca !important;
}

.sdk-cell--incorrect .sdk-cell-val {
    color: #dc2626 !important;
}

/* 3x3 Pencil Notes Grid inside empty cell */
.sdk-notes-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    grid-template-rows: repeat(3, 1fr);
    width: 100%;
    height: 100%;
    position: absolute;
    top: 0;
    left: 0;
    padding: 2px;
    box-sizing: border-box;
    pointer-events: none;
}

.sdk-note-num {
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: clamp(0.55rem, 1.8vw, 0.75rem);
    font-weight: 700;
    color: #64748b;
    line-height: 1;
}

/* Mobile & Desktop Number Pad */
.sdk-numpad-container {
    background: #ffffff;
    border: 1px solid #e2e8f0;
    border-radius: 12px;
    padding: 12px;
    margin-bottom: 24px;
}

.sdk-numpad-digits {
    display: grid;
    grid-template-columns: repeat(9, 1fr);
    gap: 6px;
    margin-bottom: 10px;
}

.sdk-pad-btn {
    aspect-ratio: 1 / 1;
    display: flex;
    align-items: center;
    justify-content: center;
    background: #f8fafc;
    border: 1px solid #cbd5e1;
    border-radius: 8px;
    font-size: clamp(1.1rem, 3.5vw, 1.4rem);
    font-weight: 800;
    color: #0f172a;
    cursor: pointer;
    transition: all 0.12s ease;
    user-select: none;
    -webkit-tap-highlight-color: transparent;
}

.sdk-pad-btn:hover {
    background: #0284c7;
    color: #ffffff;
    border-color: #0284c7;
    transform: translateY(-1px);
}

.sdk-pad-btn:active {
    transform: translateY(1px);
}

.sdk-numpad-controls {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 8px;
}

.sdk-control-btn {
    padding: 10px 8px;
    border-radius: 8px;
    background: #f1f5f9;
    border: 1px solid #cbd5e1;
    font-size: 0.85rem;
    font-weight: 700;
    color: #334155;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    cursor: pointer;
    transition: all 0.12s ease;
}

.sdk-control-btn:hover {
    background: #e2e8f0;
    color: #0f172a;
}

.sdk-control-btn.active {
    background: #0284c7;
    color: #ffffff;
    border-color: #0284c7;
}

.sdk-control-btn--erase {
    background: #fee2e2;
    color: #b91c1c;
    border-color: #fecaca;
}

.sdk-control-btn--erase:hover {
    background: #fecaca;
    color: #991b1b;
}

/* Success Modal */
.sdk-modal-backdrop {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background: rgba(15, 23, 42, 0.6);
    backdrop-filter: blur(4px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 9999;
    opacity: 0;
    visibility: hidden;
    transition: all 0.25s ease;
}

.sdk-modal-backdrop.show {
    opacity: 1;
    visibility: visible;
}

.sdk-modal {
    background: #ffffff;
    border-radius: 16px;
    padding: 32px 24px;
    max-width: 440px;
    width: 90%;
    text-align: center;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.2);
    transform: scale(0.9);
    transition: transform 0.25s ease;
}

.sdk-modal-backdrop.show .sdk-modal {
    transform: scale(1);
}

.sdk-modal-icon {
    font-size: 3.5rem;
    margin-bottom: 12px;
}

.sdk-modal h2 {
    font-size: 1.5rem;
    font-weight: 800;
    color: #0f172a;
    margin-bottom: 8px;
}

.sdk-modal p {
    font-size: 0.95rem;
    color: #475569;
    margin-bottom: 24px;
    line-height: 1.5;
}

.sdk-modal-stats {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin-bottom: 24px;
    background: #f8fafc;
    padding: 12px;
    border-radius: 8px;
}

.sdk-modal-actions {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.sdk-modal-btn {
    padding: 12px;
    border-radius: 8px;
    font-weight: 700;
    font-size: 0.95rem;
    text-decoration: none;
    cursor: pointer;
    border: none;
    transition: all 0.15s ease;
}

.sdk-modal-btn-primary {
    background: #0284c7;
    color: #ffffff;
}

.sdk-modal-btn-primary:hover {
    background: #0369a1;
}

.sdk-modal-btn-light {
    background: #f1f5f9;
    color: #334155;
}

.sdk-modal-btn-light:hover {
    background: #e2e8f0;
}

/* Animations */
@keyframes sdk-shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-4px); }
    75% { transform: translateX(4px); }
}

/* Dark Mode */
@media (prefers-color-scheme: dark) {
    [data-theme="dark"] .sdk-page-container,
    .dark .sdk-page-container {
        color: #f8fafc;
    }
}

[data-theme="dark"] .sdk-date-nav,
.dark .sdk-date-nav,
[data-bs-theme="dark"] .sdk-date-nav {
    background: #1e293b;
    border-color: #334155;
}

[data-theme="dark"] .sdk-date-title-group h1,
.dark .sdk-date-title-group h1,
[data-bs-theme="dark"] .sdk-date-title-group h1 {
    color: #f8fafc;
}

[data-theme="dark"] .sdk-toolbar,
.dark .sdk-toolbar,
[data-bs-theme="dark"] .sdk-toolbar,
[data-theme="dark"] .sdk-board-box,
.dark .sdk-board-box,
[data-bs-theme="dark"] .sdk-board-box,
[data-theme="dark"] .sdk-numpad-container,
.dark .sdk-numpad-container,
[data-bs-theme="dark"] .sdk-numpad-container {
    background: #1e293b;
    border-color: #334155;
}

[data-theme="dark"] .sdk-board,
.dark .sdk-board,
[data-bs-theme="dark"] .sdk-board {
    border-color: #94a3b8;
    background-color: #475569;
}

[data-theme="dark"] .sdk-cell,
.dark .sdk-cell,
[data-bs-theme="dark"] .sdk-cell {
    background: #0f172a;
}

[data-theme="dark"] .sdk-cell--given,
.dark .sdk-cell--given,
[data-bs-theme="dark"] .sdk-cell--given {
    background: #1e293b;
}

[data-theme="dark"] .sdk-cell--given .sdk-cell-val,
.dark .sdk-cell--given .sdk-cell-val,
[data-bs-theme="dark"] .sdk-cell--given .sdk-cell-val {
    color: #f8fafc;
}

[data-theme="dark"] .sdk-cell--user .sdk-cell-val,
.dark .sdk-cell--user .sdk-cell-val,
[data-bs-theme="dark"] .sdk-cell--user .sdk-cell-val {
    color: #38bdf8;
}

[data-theme="dark"] .sdk-cell--selected,
.dark .sdk-cell--selected,
[data-bs-theme="dark"] .sdk-cell--selected {
    background-color: #713f12 !important;
    outline-color: #eab308;
}

[data-theme="dark"] .sdk-cell--peer,
.dark .sdk-cell--peer,
[data-bs-theme="dark"] .sdk-cell--peer {
    background-color: #1e293b;
}

[data-theme="dark"] .sdk-cell--same-digit,
.dark .sdk-cell--same-digit,
[data-bs-theme="dark"] .sdk-cell--same-digit {
    background-color: #0369a1;
}

[data-theme="dark"] .sdk-pad-btn,
.dark .sdk-pad-btn,
[data-bs-theme="dark"] .sdk-pad-btn,
[data-theme="dark"] .sdk-control-btn,
.dark .sdk-control-btn,
[data-bs-theme="dark"] .sdk-control-btn {
    background: #334155;
    border-color: #475569;
    color: #f8fafc;
}