/* Science Balancer & Chemical Solver Styling */

:root {
    --primary-color: #059669;
    --primary-hover: #047857;
    --bg-color: #f8fafc;
    --card-bg: #ffffff;
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --border-color: #e2e8f0;
    --accent-teal: #0d9488;
    --success-bg: #ecfdf5;
    --success-border: #a7f3d0;
    --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: #d1fae5;
    color: #065f46;
    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;
}

/* Presets */
.presets-wrapper {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 8px;
    margin-bottom: 20px;
}

.presets-label {
    font-size: 13px;
    font-weight: 600;
    color: var(--text-secondary);
}

.preset-btn {
    background: #ffffff;
    border: 1px solid var(--border-color);
    color: #334155;
    padding: 6px 12px;
    font-size: 13px;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s ease;
}

.preset-btn:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
    background: #ecfdf5;
}

/* Input Card */
.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: 16px;
}

.input-group label {
    display: block;
    font-weight: 600;
    font-size: 14px;
    margin-bottom: 8px;
}

.input-row {
    display: flex;
    gap: 12px;
}

#chem-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;
}

#chem-input:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(5, 150, 105, 0.1);
}

.primary-btn {
    background: var(--primary-color);
    color: white;
    font-weight: 600;
    font-size: 15px;
    padding: 12px 20px;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.2s;
    white-space: nowrap;
}

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

/* Chemistry Keypad */
.keypad-wrapper {
    margin-top: 16px;
    padding-top: 14px;
    border-top: 1px dashed var(--border-color);
}

.keypad-label {
    display: block;
    font-size: 12px;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 8px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.chem-keypad {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
}

.key-btn {
    background: #f1f5f9;
    border: 1px solid #cbd5e1;
    color: #0f172a;
    font-weight: 600;
    font-size: 13.5px;
    padding: 7px 12px;
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.15s ease;
}

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

.key-action {
    background: #fee2e2;
    border-color: #fca5a5;
    color: #991b1b;
}

/* Preview Card */
.preview-card {
    background: #f1f5f9;
    border-radius: 8px;
    padding: 12px 16px;
    margin-bottom: 24px;
    display: flex;
    align-items: center;
    gap: 12px;
}

.preview-label {
    font-size: 12px;
    font-weight: 600;
    color: var(--text-secondary);
    white-space: nowrap;
}

.katex-preview {
    font-size: 18px;
    overflow-x: auto;
}

/* Solution Output Card */
.solution-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;
}

.solution-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 16px;
    margin-bottom: 20px;
}

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

.balanced-result-box {
    background: var(--success-bg);
    border: 1px solid var(--success-border);
    border-radius: 8px;
    padding: 18px;
    margin-bottom: 24px;
}

.result-label {
    font-size: 12px;
    font-weight: 700;
    color: #047857;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 8px;
    display: block;
}

.katex-sol {
    font-size: 22px;
    overflow-x: auto;
}

.secondary-btn {
    background: #ffffff;
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    padding: 6px 12px;
    font-size: 12px;
    font-weight: 500;
    border-radius: 6px;
    cursor: pointer;
}

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

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

.atom-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 13px;
    background: #ffffff;
    border: 1px solid var(--border-color);
    border-radius: 8px;
}

.atom-table th {
    background: #f1f5f9;
    padding: 10px 12px;
    border-bottom: 2px solid #cbd5e1;
    text-align: center;
}

.atom-table td {
    padding: 8px 12px;
    border-bottom: 1px solid #e2e8f0;
    text-align: center;
}

.match-badge {
    display: inline-block;
    background: #dcfce7;
    color: #15803d;
    font-weight: 700;
    padding: 2px 8px;
    border-radius: 12px;
    font-size: 11px;
}

/* SEO Content & 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) {
    .input-row { flex-direction: column; }
    .solution-header { flex-direction: column; align-items: flex-start; gap: 12px; }
}