/* K-Map & Boolean Algebra Solver Styling */

:root {
    --primary-color: #0284c7;
    --primary-hover: #0369a1;
    --bg-color: #f8fafc;
    --card-bg: #ffffff;
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --border-color: #e2e8f0;
    --accent-indigo: #4f46e5;
    --val-0-bg: #f1f5f9;
    --val-0-color: #64748b;
    --val-1-bg: #dcfce7;
    --val-1-color: #15803d;
    --val-x-bg: #fef3c7;
    --val-x-color: #b45309;
    --radius: 12px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    margin: 0;
    padding: 24px 16px;
    line-height: 1.6;
}

.solver-container {
    max-width: 880px;
    margin: 0 auto;
}

/* Header */
.solver-header {
    text-align: center;
    margin-bottom: 24px;
}

.badge {
    display: inline-block;
    background: #e0f2fe;
    color: #0369a1;
    font-weight: 600;
    font-size: 12px;
    padding: 4px 12px;
    border-radius: 20px;
    margin-bottom: 12px;
}

.solver-header h1 {
    font-size: 28px;
    font-weight: 800;
    margin: 0 0 8px 0;
    letter-spacing: -0.5px;
}

.solver-header p {
    color: var(--text-secondary);
    font-size: 15px;
    margin: 0;
}

/* Variable Selector Card */
.variable-selector-card {
    background: #ffffff;
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 16px 20px;
    margin-bottom: 16px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 12px;
}

.var-label {
    font-weight: 600;
    font-size: 14px;
}

.var-buttons {
    display: flex;
    gap: 8px;
}

.var-btn {
    background: #f1f5f9;
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    padding: 8px 14px;
    font-size: 13px;
    font-weight: 600;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s;
}

.var-btn:hover {
    background: #e2e8f0;
}

.var-btn.active {
    background: var(--primary-color);
    color: #ffffff;
    border-color: var(--primary-color);
}

/* Input Card & Tabs */
.input-card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 20px;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
    margin-bottom: 24px;
}

.tab-header {
    display: flex;
    gap: 8px;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 12px;
    margin-bottom: 16px;
}

.tab-btn {
    background: transparent;
    border: none;
    padding: 8px 16px;
    font-size: 14px;
    font-weight: 600;
    color: var(--text-secondary);
    cursor: pointer;
    border-radius: 6px;
    transition: all 0.2s;
}

.tab-btn.active {
    background: #f0f9ff;
    color: var(--primary-color);
}

.tab-content {
    display: none;
}

.tab-content.active {
    display: block;
}

.tab-instruction {
    font-size: 13px;
    color: var(--text-secondary);
    margin-bottom: 16px;
}

/* Interactive K-Map Grid Styling */
.kmap-grid-wrapper {
    display: flex;
    justify-content: center;
    overflow-x: auto;
    padding: 12px 0;
}

.kmap-table {
    border-collapse: collapse;
    margin: 0 auto;
    font-family: 'Consolas', 'Courier New', monospace;
}

.kmap-table th, .kmap-table td {
    border: 1px solid #cbd5e1;
    text-align: center;
    padding: 10px;
}

.kmap-header-cell {
    background: #f1f5f9;
    font-weight: 700;
    font-size: 13px;
    color: #334155;
    min-width: 50px;
}

.kmap-cell {
    width: 60px;
    height: 54px;
    font-size: 18px;
    font-weight: 800;
    cursor: pointer;
    user-select: none;
    transition: all 0.15s ease;
    position: relative;
}

.kmap-cell.val-0 {
    background-color: var(--val-0-bg);
    color: var(--val-0-color);
}

.kmap-cell.val-1 {
    background-color: var(--val-1-bg);
    color: var(--val-1-color);
    box-shadow: inset 0 0 0 2px #22c55e;
}

.kmap-cell.val-x {
    background-color: var(--val-x-bg);
    color: var(--val-x-color);
    box-shadow: inset 0 0 0 2px #f59e0b;
}

.kmap-cell:hover {
    opacity: 0.85;
    transform: scale(1.03);
}

.cell-index {
    position: absolute;
    bottom: 2px;
    right: 4px;
    font-size: 9px;
    font-weight: 500;
    color: #94a3b8;
}

/* Expression Tab */
.expr-row {
    display: flex;
    gap: 10px;
    margin-top: 8px;
    margin-bottom: 12px;
}

#boolean-expr-input {
    flex: 1;
    padding: 12px 16px;
    font-size: 16px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    outline: none;
    font-family: 'Consolas', 'Courier New', monospace;
}

.symbol-helper {
    display: flex;
    align-items: center;
    gap: 6px;
    flex-wrap: wrap;
}

.symbol-helper span {
    font-size: 12px;
    color: var(--text-secondary);
    font-weight: 600;
}

.sym-btn {
    background: #f1f5f9;
    border: 1px solid #cbd5e1;
    padding: 4px 10px;
    border-radius: 4px;
    font-weight: 700;
    cursor: pointer;
}

/* Controls */
.controls-bar {
    display: flex;
    gap: 12px;
    margin-top: 20px;
    padding-top: 16px;
    border-top: 1px solid var(--border-color);
}

.primary-btn {
    background: var(--primary-color);
    color: white;
    font-weight: 600;
    font-size: 14px;
    padding: 10px 18px;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: background 0.2s;
}

.primary-btn:hover {
    background: var(--primary-hover);
}

.primary-btn.large {
    flex: 1;
    font-size: 15px;
    padding: 12px 20px;
}

.secondary-btn {
    background: #ffffff;
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    padding: 8px 14px;
    font-size: 13px;
    font-weight: 600;
    border-radius: 8px;
    cursor: pointer;
}

.secondary-btn:hover {
    background: #f8fafc;
}

/* Results Card */
.results-card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 24px;
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.05);
    margin-bottom: 32px;
}

.hidden {
    display: none;
}

.results-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 14px;
    margin-bottom: 20px;
}

.results-header h2 {
    font-size: 20px;
    margin: 0;
}

.solution-boxes {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 16px;
    margin-bottom: 24px;
}

.sol-box {
    border-radius: 8px;
    padding: 16px;
    border: 1px solid;
}

.sop-box {
    background: #f0fdf4;
    border-color: #bbf7d0;
}

.pos-box {
    background: #f0f9ff;
    border-color: #bae6fd;
}

.box-label {
    display: block;
    font-size: 12px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 8px;
}

.sop-box .box-label { color: #15803d; }
.pos-box .box-label { color: #0369a1; }

.katex-sol {
    font-size: 20px;
    overflow-x: auto;
}

.explanation-box {
    background: #f8fafc;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    padding: 16px;
    font-size: 14px;
    margin-bottom: 24px;
}

/* Truth Table */
.table-responsive {
    overflow-x: auto;
}

.truth-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 13px;
    background: #ffffff;
    border: 1px solid var(--border-color);
}

.truth-table th {
    background: #f1f5f9;
    padding: 8px 12px;
    border-bottom: 2px solid #cbd5e1;
    text-align: center;
}

.truth-table td {
    padding: 6px 12px;
    border-bottom: 1px solid #e2e8f0;
    text-align: center;
}

/* SEO Article & FAQ */
.seo-guide-content, .seo-faq-section {
    margin-top: 40px;
    padding-top: 24px;
    border-top: 1px solid var(--border-color);
}

.faq-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 16px;
}

.faq-item {
    background: #ffffff;
    border: 1px solid var(--border-color);
    padding: 16px;
    border-radius: 8px;
}

.faq-item h3 { font-size: 14px; margin: 0 0 8px 0; }
.faq-item p { font-size: 13px; color: var(--text-secondary); margin: 0; }

@media (max-width: 600px) {
    .variable-selector-card { flex-direction: column; align-items: flex-start; }
    .controls-bar { flex-direction: column; }
    .expr-row { flex-direction: column; }
}