/* ===========================================
   Mortgage Calculator - Dark Theme
   Mobile-first, clean design
   =========================================== */

:root {
    --bg-primary: #0a0f0d;
    --bg-secondary: #111916;
    --bg-card: #1a2420;
    --bg-card-hover: #243029;
    --text-primary: #e8f5e9;
    --text-secondary: #a5d6a7;
    --text-muted: #6b8e6f;
    --accent: #4caf50;
    --accent-hover: #66bb6a;
    --border: #2d3d35;
    --success: #4caf50;
    --highlight: #2e7d32;
    --warning: #ff9800;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
}

.app {
    max-width: 600px;
    margin: 0 auto;
    padding: 1.5rem 1rem;
}

/* Header */
.header {
    text-align: center;
    margin-bottom: 2rem;
}

.title {
    font-size: 1.75rem;
    font-weight: 800;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.subtitle {
    font-size: 1rem;
    color: var(--text-secondary);
}

/* Calculator */
.calculator {
    background: var(--bg-secondary);
    border-radius: 16px;
    padding: 1.5rem;
    margin-bottom: 1.5rem;
}

/* Inputs */
.inputs-section {
    margin-bottom: 2rem;
}

.input-group {
    margin-bottom: 1rem;
}

.input-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
}

label {
    display: block;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
}

input, select {
    width: 100%;
    padding: 0.875rem 1rem;
    font-size: 1rem;
    font-family: inherit;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 10px;
    color: var(--text-primary);
    transition: border-color 0.2s, box-shadow 0.2s;
}

input:focus, select:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 3px rgba(76, 175, 80, 0.2);
}

.input-wrapper {
    position: relative;
}

.input-wrapper.currency input {
    padding-left: 2rem;
}

.input-wrapper.percent input {
    padding-right: 2.5rem;
}

.prefix {
    position: absolute;
    left: 1rem;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-muted);
    font-weight: 500;
}

.suffix {
    position: absolute;
    right: 1rem;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-muted);
    font-weight: 500;
}

/* Extras Toggle */
.extras-toggle {
    margin-top: 1rem;
    background: var(--bg-card);
    border-radius: 10px;
    overflow: hidden;
}

.extras-toggle summary {
    padding: 1rem;
    font-weight: 600;
    cursor: pointer;
    list-style: none;
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: var(--text-secondary);
}

.extras-toggle summary::-webkit-details-marker {
    display: none;
}

.extras-toggle summary::after {
    content: '+';
    font-size: 1.25rem;
    color: var(--text-muted);
}

.extras-toggle[open] summary::after {
    content: '−';
}

.extras-content {
    padding: 0 1rem 1rem;
}

/* Tooltips */
.tooltip {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 16px;
    height: 16px;
    background: var(--border);
    border-radius: 50%;
    font-size: 0.625rem;
    font-weight: 700;
    color: var(--text-muted);
    cursor: help;
    margin-left: 0.375rem;
    position: relative;
    vertical-align: middle;
}

.tooltip:hover {
    background: var(--accent);
    color: var(--bg-primary);
}

.tooltip:hover::after {
    content: attr(data-tip);
    position: absolute;
    bottom: calc(100% + 8px);
    left: 50%;
    transform: translateX(-50%);
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 0.75rem;
    font-size: 0.75rem;
    font-weight: 400;
    color: var(--text-secondary);
    width: 220px;
    line-height: 1.5;
    z-index: 100;
    box-shadow: 0 4px 12px rgba(0,0,0,0.3);
}

.tooltip:hover::before {
    content: '';
    position: absolute;
    bottom: calc(100% + 2px);
    left: 50%;
    transform: translateX(-50%);
    border: 6px solid transparent;
    border-top-color: var(--border);
    z-index: 101;
}

/* Rate Note */
.rate-note {
    display: block;
    font-size: 0.75rem;
    color: var(--text-muted);
    margin-top: 0.375rem;
    font-style: italic;
}

.pmi-group .pmi-display {
    padding: 0.875rem 1rem;
    background: var(--bg-card-hover);
    border-radius: 10px;
    color: var(--warning);
    font-weight: 600;
}

/* Results */
.results-section {
    margin-top: 1.5rem;
}

.result-card {
    background: var(--bg-card);
    border-radius: 12px;
    padding: 1rem;
    text-align: center;
}

.result-card.primary {
    background: linear-gradient(135deg, var(--highlight), var(--bg-card));
    padding: 1.5rem;
    margin-bottom: 1rem;
}

.result-label {
    display: block;
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 0.25rem;
}

.result-value {
    display: block;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
}

.result-card.primary .result-value {
    font-size: 2.5rem;
    color: var(--accent);
}

.result-sublabel {
    display: block;
    font-size: 0.75rem;
    color: var(--text-muted);
    margin-top: 0.25rem;
}

.results-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 0.75rem;
    margin-bottom: 1.5rem;
}

/* Charts */
.chart-container {
    margin: 1.5rem 0;
    padding: 1rem;
    background: var(--bg-card);
    border-radius: 12px;
}

.chart-container h3 {
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: 1rem;
    text-align: center;
    color: var(--text-secondary);
}

/* Comparison Section */
.comparison-section {
    margin-top: 1.5rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--border);
}

.comparison-section h3 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.comparison-table {
    font-size: 0.875rem;
}

.comp-row {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    padding: 0.75rem 0.5rem;
    border-bottom: 1px solid var(--border);
    text-align: center;
}

.comp-row.header {
    font-weight: 600;
    color: var(--text-secondary);
    font-size: 0.75rem;
    text-transform: uppercase;
}

.comp-row.highlight {
    background: var(--bg-card);
    border-radius: 8px;
    border: 1px solid var(--accent);
    color: var(--accent);
    font-weight: 600;
}

.comp-row:last-of-type {
    border-bottom: none;
}

/* Extra Payment Section */
.extra-payment-section {
    margin-top: 1.5rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--border);
}

.extra-payment-section h3 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.extra-results {
    background: var(--bg-card);
    border-radius: 10px;
    padding: 1rem;
    margin-top: 1rem;
}

.extra-results p {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.extra-results .savings {
    color: var(--accent);
    font-weight: 600;
}

/* Share Section */
.share-section {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 2rem;
}

.share-section p {
    font-size: 0.875rem;
    color: var(--text-muted);
}

.share-btn {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.625rem 1rem;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 8px;
    color: var(--text-primary);
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
}

.share-btn:hover {
    background: var(--bg-card-hover);
    border-color: var(--accent);
}

.share-btn.copied {
    background: var(--highlight);
    border-color: var(--accent);
}

/* Quick Reference Table */
.quick-reference {
    background: var(--bg-secondary);
    border-radius: 16px;
    padding: 1.5rem;
    margin-bottom: 1.5rem;
}

.quick-reference h2 {
    font-size: 1.125rem;
    font-weight: 700;
    margin-bottom: 1rem;
    text-align: center;
}

.reference-table {
    font-size: 0.875rem;
}

.ref-row {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    padding: 0.75rem 0.5rem;
    border-bottom: 1px solid var(--border);
    text-align: center;
}

.ref-row.header {
    font-weight: 600;
    color: var(--text-secondary);
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.ref-row.highlight {
    background: var(--bg-card);
    border-radius: 8px;
    border: 1px solid var(--accent);
    color: var(--accent);
    font-weight: 600;
}

.ref-row:last-of-type {
    border-bottom: none;
}

.ref-note {
    font-size: 0.75rem;
    color: var(--text-muted);
    text-align: center;
    margin-top: 1rem;
}

/* FAQ Section */
.faq-section {
    background: var(--bg-secondary);
    border-radius: 16px;
    padding: 1.5rem;
    margin-bottom: 1.5rem;
}

.faq-section h2 {
    font-size: 1.125rem;
    font-weight: 700;
    margin-bottom: 1rem;
    text-align: center;
}

.faq-item {
    background: var(--bg-card);
    border-radius: 10px;
    margin-bottom: 0.75rem;
    overflow: hidden;
}

.faq-item summary {
    padding: 1rem;
    font-weight: 600;
    cursor: pointer;
    list-style: none;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.faq-item summary::-webkit-details-marker {
    display: none;
}

.faq-item summary::after {
    content: '+';
    font-size: 1.25rem;
    color: var(--text-muted);
    transition: transform 0.2s;
}

.faq-item[open] summary::after {
    content: '−';
}

.faq-answer {
    padding: 0 1rem 1rem;
    font-size: 0.9375rem;
    color: var(--text-secondary);
    line-height: 1.7;
}

.faq-answer p {
    margin-bottom: 0.75rem;
}

.faq-answer ul {
    margin: 0.75rem 0;
    padding-left: 1.5rem;
}

.faq-answer li {
    margin-bottom: 0.5rem;
}

/* Footer */
.footer {
    text-align: center;
    padding: 1.5rem 0;
    font-size: 0.875rem;
    color: var(--text-muted);
}

.disclaimer {
    font-size: 0.75rem;
    margin-top: 0.5rem;
    opacity: 0.7;
}

/* Responsive */
@media (min-width: 480px) {
    .app {
        padding: 2rem 1.5rem;
    }

    .title {
        font-size: 2rem;
    }

    .result-card.primary .result-value {
        font-size: 3rem;
    }

    .results-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}

@media (min-width: 640px) {
    .app {
        max-width: 700px;
    }

    .calculator {
        padding: 2rem;
    }
}