/**
 * Universal Calculator CSS - Production Grade
 * Unified UI/UX across all domains (Math, Finance, Science, etc.)
 * Phase U4/U5/U8: Visual consistency, responsive, clean architecture
 */

/* ============================================
   GLOBAL CONTAINER LAYOUT – all outputs inside container
   ============================================ */
.calculator-container {
    max-width: 100%;
    min-width: 0;
    overflow-x: hidden;
}

/* When calculator is inside Bootstrap .container, keep content from escaping */
.container:has(.calculator-container) {
    overflow-x: hidden;
    max-width: 100%;
}

.calculator-wrapper {
    max-width: 100%;
    min-width: 0;
}

.calculator-wrapper > * {
    max-width: 100%;
    min-width: 0;
}

/* ============================================
   DESIGN TOKENS (Phase U4 - Visual Consistency)
   ============================================ */
:root {
    --calc-card-radius: 16px;
    --calc-card-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
    --calc-card-bg: #fafbfc;
    --calc-card-padding: 1.25rem;
    --calc-primary: #2962ff;
    --calc-primary-hover: #1a237e;
    --calc-accent-positive: #10b981;
    --calc-accent-neutral: #6b7280;
    --calc-heading-color: #1f2937;
    --calc-text-muted: #6b7280;
    --calc-border: 1px solid rgba(0, 0, 0, 0.06);
}

/* ============================================
   PHASE U1 - CALCULATOR WRAPPER LAYOUT
   ============================================ */
.calculator-wrapper {
    display: block;
    margin-top: 0;
}

.calculator-header {
    margin-bottom: 1.5rem;
}

.calculator-header .calculator-title {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--calc-heading-color);
    margin: 0 0 0.5rem 0;
    line-height: 1.3;
}

.calculator-header .calculator-verified-badge {
    font-size: 0.875rem;
    color: var(--calc-text-muted);
    margin: 0 0 0.75rem 0;
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
}

.calculator-header .calculator-verified-badge i {
    color: var(--calc-accent-positive);
}

.calculator-main {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1.5rem;
    margin-bottom: 2rem;
    max-width: 100%;
    min-width: 0;
}

.calculator-inputs-card,
.calculator-results-card {
    background: var(--calc-card-bg);
    border-radius: var(--calc-card-radius);
    box-shadow: var(--calc-card-shadow);
    padding: var(--calc-card-padding);
    border: var(--calc-border);
    min-width: 0;
}

.calculator-inputs-card { order: 1; }
.calculator-results-card { order: 2; }

.calculator-results-card {
    max-width: 100%;
    overflow-wrap: break-word;
}

.calculator-secondary-content {
    margin-bottom: 2rem;
    max-width: 100%;
    min-width: 0;
}

.calculator-seo-content {
    margin-top: 2rem;
    padding-top: 1.5rem;
    border-top: var(--calc-border);
    max-width: 100%;
    min-width: 0;
}

.calculator-related {
    margin-top: 2rem;
    padding-top: 1.5rem;
    border-top: var(--calc-border);
    max-width: 100%;
    min-width: 0;
}

/* Keep all cards and blocks inside container */
.calculator-container .card,
.calculator-container .collapsible-block,
.calculator-wrapper .card,
.calculator-wrapper .collapsible-block {
    max-width: 100%;
    min-width: 0;
}

/* Single-column layout on all screen sizes; no media override needed */
@media (max-width: 768px) {
    .calculator-main {
        gap: 1.25rem;
    }
}

/* ============================================
   PHASE U2 - RESULT METRIC CARD (unified)
   ============================================ */
.result-metric-card {
    background: var(--calc-card-bg);
    border: var(--calc-border);
    border-radius: var(--calc-card-radius);
    padding: var(--calc-card-padding);
    box-shadow: var(--calc-card-shadow);
    position: relative;
    transition: transform 0.2s, box-shadow 0.2s;
}

.result-metric-card:hover {
    box-shadow: 0 6px 16px rgba(0, 0, 0, 0.1);
}

.result-metric-card .result-metric-label {
    font-size: 0.8125rem;
    color: var(--calc-text-muted);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.04em;
    margin-bottom: 0.5rem;
}

.result-metric-card .result-metric-value {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--calc-heading-color);
    line-height: 1.2;
}

.result-metric-card.result-metric-positive .result-metric-value {
    color: var(--calc-accent-positive);
}

.result-metric-card .result-metric-icon {
    font-size: 1.5rem;
    margin-bottom: 0.5rem;
    opacity: 0.85;
}

.result-metric-cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 1rem;
    max-width: 100%;
    min-width: 0;
}

.result-metric-copy-btn {
    position: absolute;
    top: 0.75rem;
    right: 0.75rem;
    padding: 0.25rem 0.5rem;
    font-size: 0.75rem;
    border: none;
    background: rgba(0, 0, 0, 0.06);
    border-radius: 6px;
    cursor: pointer;
    color: var(--calc-text-muted);
}

.result-metric-copy-btn:hover {
    background: rgba(0, 0, 0, 0.1);
    color: var(--calc-heading-color);
}

/* Heading hierarchy: H1 = title, H2 = section, H3 = FAQ only */
.calculator-wrapper h1 { font-size: 1.75rem; font-weight: 700; }
.calculator-wrapper h2 { font-size: 1.35rem; font-weight: 600; margin-top: 1.5rem; margin-bottom: 0.75rem; }
.calculator-wrapper h3 { font-size: 1.1rem; font-weight: 600; margin-top: 1rem; margin-bottom: 0.5rem; }

/* ============================================
   HEADER & NAVIGATION
   ============================================ */

.universal-header {
    position: sticky;
    top: 0;
    z-index: 1000;
    background: linear-gradient(135deg, #1A237E 0%, #0E1117 100%) !important;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.universal-header .navbar-brand {
    text-decoration: none;
}

.universal-header .nav-link {
    color: #1f2937;
    font-weight: 500;
    transition: color 0.2s;
    padding: 0.5rem 1rem;
}

.universal-header .nav-link:hover {
    color: #667eea;
}

/* ============================================
   MAIN CONTENT
   ============================================ */

.universal-main {
    min-height: calc(100vh - 200px);
    padding-top: 20px;
    padding-bottom: 40px;
}

/* ============================================
   CALCULATOR CONTAINER (mandatory layout)
   ============================================ */

.calculator-container {
    max-width: 1040px;
    margin-left: auto;
    margin-right: auto;
    padding-left: 1rem;
    padding-right: 1rem;
}

.calculator-title {
    font-size: 1.75rem;
    font-weight: 600;
    color: #1f2937;
    margin: 0 0 1rem 0;
    line-height: 1.3;
}

.calculator-verified-badge {
    font-size: 0.875rem;
    color: var(--text-muted, #6b7280);
    margin: 0 0 0.5rem 0;
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
}

.calculator-verified-badge i {
    color: #10b981;
}

/* ============================================
   CARD HEADER (no gradient inside calculator body)
   ============================================ */

.universal-card-header {
    background: #374151;
    color: white;
    padding: 1.5rem;
    border-radius: 0.375rem 0.375rem 0 0 !important;
}

.universal-card-header h1 {
    color: white;
    margin: 0;
}

.universal-card-header p {
    color: rgba(255, 255, 255, 0.9);
}

/* ============================================
   FORM STYLES
   ============================================ */

#calc-form .form-label {
    font-weight: 500;
    color: #1f2937;
    margin-bottom: 0.5rem;
    font-size: 0.95rem;
}

#calc-form .form-control {
    border: 1px solid #e5e7eb;
    border-radius: 0.375rem;
    padding: 0.625rem 0.75rem;
    transition: border-color 0.2s, box-shadow 0.2s;
    font-size: 1rem;
}

#calc-form .form-control:focus {
    border-color: #667eea;
    box-shadow: 0 0 0 0.2rem rgba(102, 126, 234, 0.25);
    outline: none;
}

#calc-form .form-control.is-valid {
    border-color: #10b981;
}

#calc-form .form-control.is-invalid {
    border-color: #ef4444;
}

#calc-form .btn-primary {
    background: #4f46e5;
    border: none;
    padding: 0.75rem 2rem;
    font-weight: 600;
    transition: transform 0.2s, box-shadow 0.2s, background-color 0.2s;
    font-size: 1rem;
    width: 100%;
}

#calc-form .btn-primary:hover:not(:disabled) {
    background: #4338ca;
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(79, 70, 229, 0.35);
}

#calc-form .btn-primary:active:not(:disabled) {
    transform: translateY(0);
}

#calc-form .btn-primary:focus-visible {
    outline: 2px solid #4f46e5;
    outline-offset: 2px;
    box-shadow: 0 0 0 0.2rem rgba(79, 70, 229, 0.35);
}

#calc-form .btn-primary:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

/* Sticky Calculate Button on Mobile */
@media (max-width: 768px) {
    #calc-form .btn-primary {
        position: sticky;
        bottom: 0;
        z-index: 100;
        border-radius: 0;
        margin: 0 -1rem;
        padding: 1rem;
        box-shadow: 0 -2px 8px rgba(0,0,0,0.1);
    }
}

/* ============================================
   TASK 1: FINANCE RESULT CARDS
   ============================================ */

.result-cards {
    margin-top: 2rem;
}

.result-card {
    background: #f8fafc;
    border: 1px solid #e5e7eb;
    border-radius: 0.5rem;
    padding: 1.5rem;
    height: 100%;
    transition: transform 0.2s, box-shadow 0.2s;
    position: relative;
    overflow: hidden;
}

.result-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

.result-card-icon {
    font-size: 2rem;
    margin-bottom: 0.75rem;
    opacity: 0.8;
}

.result-card-label {
    font-size: 0.875rem;
    color: #6b7280;
    margin-bottom: 0.5rem;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.result-card-value {
    font-size: 1.75rem;
    font-weight: 700;
    color: #1f2937;
    line-height: 1.2;
}

/* Card Type Colors */
.result-card.card-investment {
    border-left: 4px solid #6b7280;
}

.result-card.card-investment .result-card-icon {
    color: #6b7280;
}

.result-card.card-returns {
    border-left: 4px solid #10b981;
}

.result-card.card-returns .result-card-icon {
    color: #10b981;
}

.result-card.card-returns .result-card-value {
    color: #10b981;
}

.result-card.card-interest {
    border-left: 4px solid #f59e0b;
}

.result-card.card-interest .result-card-icon {
    color: #f59e0b;
}

.result-card.card-interest .result-card-value {
    color: #f59e0b;
}

.result-card.card-final {
    border-left: 4px solid #667eea;
}

.result-card.card-final .result-card-icon {
    color: #667eea;
}

.result-card.card-final .result-card-value {
    color: #667eea;
}

.result-card.card-emi {
    border-left: 4px solid #3b82f6;
}

.result-card.card-emi .result-card-icon {
    color: #3b82f6;
}

.result-card.card-emi .result-card-value {
    color: #3b82f6;
}

.result-card.card-default {
    border-left: 4px solid #9ca3af;
}

/* ============================================
   TASK 2: FINANCE TABLES
   ============================================ */

.finance-table-card {
    margin-top: 1.5rem;
}

.finance-table-card .card-header {
    cursor: pointer;
    user-select: none;
}

.toggle-table-btn {
    transition: transform 0.3s;
}

.toggle-table-btn.collapsed {
    transform: rotate(-90deg);
}

.finance-schedule-table {
    font-size: 0.9rem;
}

.finance-schedule-table thead.sticky-header {
    position: sticky;
    top: 0;
    z-index: 10;
}

.finance-schedule-table th {
    white-space: nowrap;
    font-weight: 600;
    padding: 0.75rem;
}

.finance-schedule-table td {
    padding: 0.75rem;
    white-space: nowrap;
}

.finance-schedule-table tbody tr:hover {
    background-color: #f9fafb;
}

/* Keep schedule tables inside container: horizontal scroll on all screen sizes */
.table-responsive {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    max-width: 100%;
}

/* Mobile Table Scroll */
@media (max-width: 768px) {
    .finance-schedule-table {
        min-width: 600px;
    }
}

/* ============================================
   TASK 3: FINANCE GRAPHS
   ============================================ */

.chart-container {
    position: relative;
    height: 300px;
    margin-bottom: 2rem;
    max-width: 100%;
}

.chart-container canvas {
    max-height: 300px;
}

@media (max-width: 768px) {
    .chart-container {
        height: 250px;
    }
}

/* ============================================
   RESULTS SECTION
   ============================================ */

#results-section,
.results-section {
    margin-top: 2rem;
    padding-top: 1rem;
    max-width: 100%;
    min-width: 0;
    overflow-x: hidden;
}

.card.shadow-sm {
    border: none;
    border-radius: 0.5rem;
    margin-top: 1.5rem;
}

.card-header.bg-success {
    background: #059669 !important;
    color: white;
    border: none;
}

.card-header.bg-info {
    background: #2563eb !important;
    color: white;
    border: none;
}

.card-header.bg-secondary {
    background: #4b5563 !important;
    color: white;
    border: none;
}

.card-header.bg-warning {
    background: #d97706 !important;
    color: #1f2937;
    border: none;
    cursor: pointer;
    user-select: none;
}

/* Phase U4: Single primary button - use brand blue */
#calc-form .btn-primary {
    background: var(--calc-primary, #2962ff);
    border: none;
}
#calc-form .btn-primary:hover:not(:disabled) {
    background: var(--calc-primary-hover, #1a237e);
}

/* ============================================
   TASK 4: WORKED EXAMPLES
   ============================================ */

.examples-section {
    margin-top: 2rem;
}

.example-load-button {
    transition: transform 0.2s, box-shadow 0.2s;
    margin-top: 0.5rem;
}

.example-load-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(102, 126, 234, 0.3);
}

.example-load-button:active {
    transform: translateY(0);
}

/* Input Value Loaded Animation */
.input-value-loaded {
    background-color: #dbeafe !important;
    border-color: #3b82f6 !important;
    transition: background-color 0.6s ease, border-color 0.6s ease;
}

/* ============================================
   STEPS DISPLAY
   ============================================ */

.card-body ol {
    padding-left: 1.5rem;
}

.card-body ol li {
    margin-bottom: 0.75rem;
    line-height: 1.6;
}

.card-body code {
    background-color: #f3f4f6;
    padding: 0.25rem 0.5rem;
    border-radius: 0.25rem;
    font-size: 0.9em;
    color: #1f2937;
}

/* ============================================
   ALERTS & MESSAGES
   ============================================ */

.alert-danger {
    border-left: 4px solid #ef4444;
    background-color: #fef2f2;
    color: #991b1b;
}

.alert-info {
    border-left: 4px solid #3b82f6;
    background-color: #eff6ff;
    color: #1e40af;
}

.alert-light {
    border-left: 4px solid #9ca3af;
    background-color: #f9fafb;
    color: #374151;
}

/* ============================================
   FOOTER
   ============================================ */

.universal-footer {
    background-color: #f9fafb;
    border-top: 1px solid #e5e7eb;
    margin-top: 4rem;
    padding: 2rem 0;
}

.universal-footer a {
    transition: color 0.2s;
}

.universal-footer a:hover {
    color: #667eea !important;
}

/* ============================================
   BREADCRUMB
   ============================================ */

.breadcrumb {
    background-color: transparent;
    padding: 0;
    margin-bottom: 1rem;
}

.breadcrumb-item a {
    color: #667eea;
    text-decoration: none;
}

.breadcrumb-item a:hover {
    text-decoration: underline;
}

.breadcrumb-item.active {
    color: #6b7280;
}

.breadcrumb-item.breadcrumb-sep {
    pointer-events: none;
    color: #9ca3af;
    padding-left: 0.25rem;
    padding-right: 0.25rem;
}

/* Phase U6: Consistent breadcrumb spacing */
.calculator-container nav[aria-label="breadcrumb"] {
    margin-bottom: 1.25rem;
}

/* ============================================
   ACCESSIBILITY (focus states)
   ============================================ */

.calculator-container .btn:focus-visible,
.calculator-container [data-bs-toggle="collapse"]:focus-visible {
    outline: 2px solid #4f46e5;
    outline-offset: 2px;
}

.calculator-container .form-control:focus-visible {
    outline: 2px solid #4f46e5;
    outline-offset: 0;
}

/* ============================================
   MOBILE RESPONSIVE
   ============================================ */

@media (max-width: 768px) {
    .calculator-container {
        padding-left: 0.75rem;
        padding-right: 0.75rem;
    }
    
    .calculator-title {
        font-size: 1.35rem;
    }
    
    .universal-card-header {
        padding: 1rem;
    }
    
    .universal-card-header h1 {
        font-size: 1.25rem;
    }
    
    .universal-card-header .fs-2 {
        font-size: 1.5rem !important;
    }
    
    .card-body {
        padding: 1rem !important;
    }
    
    .result-card {
        padding: 1rem;
    }
    
    .result-card-value {
        font-size: 1.5rem;
    }
    
    .result-card-icon {
        font-size: 1.5rem;
    }
}

/* ============================================
   LOADING STATES
   ============================================ */

.calculator-loading {
    display: none;
    text-align: center;
    padding: 2rem;
}

.calculator-loading.active {
    display: block;
}

.calculator-loading .spinner-border {
    width: 3rem;
    height: 3rem;
    border-width: 0.3rem;
    color: #667eea;
}

/* ============================================
   PRINT STYLES
   ============================================ */

@media print {
    .universal-header,
    .universal-footer,
    .btn,
    .breadcrumb {
        display: none !important;
    }
    
    .card {
        box-shadow: none !important;
        border: 1px solid #e5e7eb !important;
    }
}

/* ===== Result Panel Upgrade ===== */

.result-panel {
    margin-top: 2rem;
    padding: 1.5rem;
    border-radius: var(--radius-card, 0.5rem);
    background: var(--surface-card, #f8fafc);
    box-shadow: var(--shadow-soft, 0 2px 8px rgba(0, 0, 0, 0.08));
}

.result-primary-card {
    text-align: center;
    padding: 1.25rem;
    border-radius: var(--radius-card, 0.5rem);
    background: linear-gradient(135deg, var(--accent-primary, #667eea), var(--accent-secondary, #10b981));
    color: #fff;
    box-shadow: var(--shadow-medium, 0 4px 16px rgba(0, 0, 0, 0.12));
}

.result-label {
    font-size: 0.9rem;
    opacity: 0.9;
    letter-spacing: 0.05em;
    text-transform: uppercase;
}

.result-value {
    font-size: 2.5rem;
    font-weight: 700;
    margin-top: 0.25rem;
}

.result-secondary {
    margin-top: 1rem;
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    justify-content: center;
}

.result-pill {
    background: #f0f4ff;
    color: #333;
    border-radius: 999px;
    padding: 0.35rem 0.75rem;
    font-size: 0.85rem;
    box-shadow: var(--shadow-soft, 0 2px 8px rgba(0, 0, 0, 0.08));
}

/* ===== Collapsible Blocks ===== */

.collapsible-block {
    margin-top: 1rem;
    border-radius: var(--radius-card, 12px);
    background: var(--surface-section, #f8f9fb);
    box-shadow: var(--shadow-soft, 0 2px 8px rgba(0,0,0,0.05));
    overflow: hidden;
}

.collapsible-toggle {
    width: 100%;
    background: none;
    border: none;
    padding: 0.9rem 1rem;
    font-weight: 600;
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
}

.collapsible-content {
    display: none;
    padding: 1rem;
    border-top: 1px solid var(--border-color, #ddd);
}

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

.collapsible-block.active .bi-chevron-down {
    transform: rotate(180deg);
}

/* ===== Calculator Device Frame: single-column on all screens (inputs above, results below) ===== */
.calc-frame {
    display: grid;
    grid-template-columns: 1fr;
    gap: 1.5rem;
    margin-top: 1.5rem;
}

.calc-input-panel,
.calc-output-panel {
    background: var(--calc-card-bg, #fff);
    border-radius: var(--calc-card-radius, 16px);
    box-shadow: var(--calc-card-shadow, 0 4px 12px rgba(0,0,0,0.08));
    padding: var(--calc-card-padding, 1.25rem);
    border: var(--calc-border);
}

.calc-input-panel { order: 1; }
.calc-output-panel { order: 2; }

.panel-title {
    font-weight: 600;
    margin-bottom: 0.75rem;
    color: var(--text-muted, #666);
    text-transform: uppercase;
    font-size: 0.8rem;
    letter-spacing: 0.08em;
}

/* ===== Subtle Result Animation ===== */

.result-primary-card {
    animation: popIn 0.35s ease-out;
}

@keyframes popIn {
    from { transform: scale(0.95); opacity: 0.7; }
    to { transform: scale(1); opacity: 1; }
}

/* ===== Visual Polish + Accessibility ===== */

/* Domain accent: set --accent-primary from body[data-domain] (PHP outputs domain) */
body[data-domain="finance"]      { --accent-primary: #2563eb; --accent-glow: rgba(37, 99, 235, 0.2); }
body[data-domain="physics"]      { --accent-primary: #7c3aed; --accent-glow: rgba(124, 58, 237, 0.2); }
body[data-domain="chemistry"]     { --accent-primary: #059669; --accent-glow: rgba(5, 150, 105, 0.2); }
body[data-domain="math"]         { --accent-primary: #0ea5e9; --accent-glow: rgba(14, 165, 233, 0.2); }
body[data-domain="engineering"]  { --accent-primary: #f97316; --accent-glow: rgba(249, 115, 22, 0.2); }
body[data-domain="health"]       { --accent-primary: #22c55e; --accent-glow: rgba(34, 197, 94, 0.2); }
body:not([data-domain])         { --accent-primary: #0ea5e9; --accent-glow: rgba(14, 165, 233, 0.2); }

/* Contrast & spacing: WCAG AA, increased line-height */
#calc-form .form-label {
    line-height: 1.5;
    color: #111827;
}
.result-value,
.result-primary-card .result-value {
    color: #fff;
    line-height: 1.3;
}
.result-pill {
    line-height: 1.5;
    color: #1f2937;
    background: #e0e7ff;
}
.panel-title {
    color: #4b5563;
    line-height: 1.4;
}

/* :focus-visible for all inputs and buttons */
#calc-form .form-control:focus-visible,
#calc-form .form-select:focus-visible,
#calc-form button:focus-visible,
#calc-form .btn:focus-visible,
.collapsible-toggle:focus-visible {
    outline: 2px solid var(--accent-primary, #0ea5e9);
    outline-offset: 2px;
}
#calc-form .form-control:focus,
#calc-form .form-control:focus-visible {
    border-color: var(--accent-primary, #0ea5e9);
    box-shadow: 0 0 0 3px var(--accent-glow, rgba(14, 165, 233, 0.2));
}
#calc-form .form-control:focus {
    outline: none;
}
#calc-form .btn-primary {
    background: var(--accent-primary, #0ea5e9);
}
#calc-form .btn-primary:hover:not(:disabled) {
    background: var(--accent-primary, #0ea5e9);
    filter: brightness(1.08);
    transform: scale(1.02);
}
#calc-form .btn-primary:focus-visible {
    outline: 2px solid var(--accent-primary, #0ea5e9);
    outline-offset: 2px;
}

/* Result pills highlight on hover */
.result-pill:hover {
    background: var(--accent-primary, #0ea5e9);
    color: #fff;
    transition: background 0.2s, color 0.2s;
}
.result-pill {
    transition: background 0.2s, color 0.2s;
}

/* Input border glows in accent when focused */
#calc-form .form-select:focus {
    border-color: var(--accent-primary, #0ea5e9);
    box-shadow: 0 0 0 3px var(--accent-glow, rgba(14, 165, 233, 0.2));
}

/* Loading feedback: .is-calculating class on form submit */
#calc-form.is-calculating {
    pointer-events: none;
    opacity: 0.85;
}
#calc-form.is-calculating .btn-primary {
    cursor: wait;
}
#calc-form.is-calculating .btn-primary .spinner-border {
    display: inline-block;
}

/* ===== Dark mode: Worked Examples and secondary content ===== */
[data-theme="dark"] .calculator-secondary-content,
[data-theme="dark"] .calculator-secondary-content * {
    color: #e5e7eb !important;
}
[data-theme="dark"] .calculator-secondary-content .card {
    background: #1f2937 !important;
    border-color: #374151 !important;
}
[data-theme="dark"] .calculator-secondary-content .card-body,
[data-theme="dark"] .collapsible-content .card .card-body {
    background: #1f2937 !important;
    color: #e5e7eb !important;
}
[data-theme="dark"] .calculator-secondary-content .card-body .text-muted,
[data-theme="dark"] .calculator-secondary-content .card-body .small,
[data-theme="dark"] .calculator-secondary-content .card-body p.text-muted,
[data-theme="dark"] .collapsible-content .card .card-body .text-muted,
[data-theme="dark"] .collapsible-content .card .card-body .small,
[data-theme="dark"] .collapsible-content .card .card-body p {
    color: #d1d5db !important;
}
[data-theme="dark"] .calculator-secondary-content .card-body h6,
[data-theme="dark"] .calculator-secondary-content .card-body strong,
[data-theme="dark"] .collapsible-content .card .card-body h6,
[data-theme="dark"] .collapsible-content .card .card-body strong,
[data-theme="dark"] .collapsible-content .card .card-body li {
    color: #f3f4f6 !important;
}
[data-theme="dark"] .collapsible-block {
    background: #111827 !important;
}
[data-theme="dark"] .collapsible-toggle {
    color: #f9fafb !important;
}
[data-theme="dark"] .collapsible-content {
    background: #1f2937 !important;
    border-color: #374151 !important;
}