/* ===== Reset & Base ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
    --bg: #f6f4f0;
    --card: #ffffff;
    --text: #1a1a1a;
    --text-2: #555;
    --text-3: #888;
    --accent: #1a6b4f;
    --accent-light: #e4f3ec;
    --accent-dark: #145a41;
    --border: #ddd9d3;
    --warn: #8b6914;
    --warn-bg: #fdf8ec;
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.04);
    --shadow-md: 0 2px 12px rgba(0,0,0,0.06), 0 0 1px rgba(0,0,0,0.08);
    --radius: 14px;
    --radius-sm: 8px;
    --font: system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', sans-serif;
    --font-serif: Georgia, 'Times New Roman', Times, serif;
}

html { font-size: 16px; }

body {
    font-family: var(--font);
    background: var(--bg);
    color: var(--text);
    line-height: 1.55;
    -webkit-font-smoothing: antialiased;
    min-height: 100vh;
}

/* ===== Layout ===== */
.page {
    max-width: 540px;
    margin: 0 auto;
    padding: 2.5rem 1.25rem 3rem;
}

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

h1 {
    font-family: var(--font-serif);
    font-size: 2rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    color: var(--text);
    margin-bottom: 0.35rem;
}

.tagline {
    font-size: 0.95rem;
    color: var(--text-2);
}

/* ===== Card ===== */
.card {
    background: var(--card);
    border-radius: var(--radius);
    box-shadow: var(--shadow-md);
    padding: 1.75rem 1.5rem 1.5rem;
    position: relative;
}

/* ===== Fields ===== */
.field { margin-bottom: 0.75rem; }
.field:last-child { margin-bottom: 0; }

.field label {
    display: block;
    font-size: 0.82rem;
    font-weight: 500;
    color: var(--text-2);
    margin-bottom: 0.3rem;
    text-transform: uppercase;
    letter-spacing: 0.04em;
}

.label-hint {
    text-transform: none;
    font-weight: 400;
    color: var(--text-3);
    letter-spacing: 0;
    font-size: 0.78rem;
}

.input-wrap {
    display: flex;
    align-items: center;
    border: 1.5px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 0 0.75rem;
    height: 2.75rem;
    background: #fff;
    transition: border-color 0.15s;
}

.input-wrap:focus-within {
    border-color: var(--accent);
    box-shadow: 0 0 0 3px rgba(26,107,79,0.1);
}

.input-wrap::before {
    content: '$';
    font-size: 1.05rem;
    font-weight: 600;
    color: var(--text-3);
    margin-right: 0.25rem;
    flex-shrink: 0;
}

.input-wrap.yearly::after {
    content: '/year';
    font-size: 0.8rem;
    color: var(--text-3);
    margin-left: 0.35rem;
    flex-shrink: 0;
}

.input-wrap input {
    border: none;
    outline: none;
    font-size: 1.1rem;
    font-weight: 500;
    width: 100%;
    background: transparent;
    color: var(--text);
    font-variant-numeric: tabular-nums;
}

/* ===== Person blocks ===== */
.person-block {
    margin-bottom: 0;
}

/* ===== Wealth toggle button ===== */
.wealth-toggle {
    display: inline-block;
    margin-top: 0.35rem;
    padding: 0.2rem 0;
    background: none;
    border: none;
    font-size: 0.78rem;
    font-weight: 500;
    color: var(--text-3);
    cursor: pointer;
    transition: color 0.15s;
}

.wealth-toggle:hover,
.wealth-toggle.active {
    color: var(--accent);
}

/* ===== Wealth panel ===== */
.wealth-panel {
    margin-top: 0.35rem;
    padding-left: 0.75rem;
    border-left: 2px solid var(--border);
}

.wealth-panel .field {
    margin-bottom: 0.4rem;
}

.wealth-panel .field label {
    font-size: 0.78rem;
}

.wealth-panel .input-wrap {
    height: 2.4rem;
}

.wealth-panel .input-wrap input {
    font-size: 1rem;
}

/* ===== Effective income line ===== */
.effective-line {
    font-size: 0.78rem;
    color: var(--accent);
    margin-top: 0.25rem;
    padding: 0.3rem 0.5rem;
    background: var(--accent-light);
    border-radius: 4px;
    display: flex;
    align-items: center;
    gap: 0.3rem;
}

.eff-arrow {
    font-size: 0.9rem;
    line-height: 1;
}

.effective-line strong {
    font-weight: 700;
    font-variant-numeric: tabular-nums;
}

/* ===== Divider row (feels-like + swap) ===== */
.divider-row {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 0;
}

.feels-like {
    flex: 1;
    text-align: center;
    position: relative;
}

.feels-like::before {
    content: '';
    position: absolute;
    left: 0; right: 0;
    top: 50%;
    height: 1px;
    background: var(--border);
}

.feels-like span {
    position: relative;
    z-index: 1;
    background: var(--card);
    padding: 0 1rem;
    font-family: var(--font-serif);
    font-style: italic;
    font-size: 0.95rem;
    color: var(--text-3);
}

/* ===== Result ===== */
.result-row {
    margin-bottom: 0.75rem;
}

.result-display {
    display: flex;
    align-items: baseline;
    gap: 0.6rem;
    justify-content: center;
    padding: 0.75rem 0;
    background: var(--accent-light);
    border-radius: var(--radius-sm);
}

.result-amount {
    font-size: 2.2rem;
    font-weight: 700;
    color: var(--accent-dark);
    font-variant-numeric: tabular-nums;
    letter-spacing: -0.02em;
    transition: opacity 0.15s;
}

.result-amount.animate {
    animation: pop 0.2s ease-out;
}

@keyframes pop {
    0%   { opacity: 0.4; transform: scale(0.97); }
    100% { opacity: 1;   transform: scale(1); }
}

.result-mult {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--accent);
    white-space: nowrap;
}

/* ===== Swap button ===== */
.swap-btn {
    flex-shrink: 0;
    width: 32px;
    height: 32px;
    border-radius: 50%;
    border: 1.5px solid var(--border);
    background: var(--card);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-3);
    transition: all 0.2s;
}

.swap-btn:hover {
    background: var(--accent-light);
    color: var(--accent);
    border-color: var(--accent);
}

.swap-btn.spinning svg {
    animation: spin 0.3s ease;
}

@keyframes spin {
    from { transform: rotate(0deg); }
    to   { transform: rotate(180deg); }
}

/* ===== Eta slider ===== */
.eta-section {
    margin-top: 1.5rem;
    padding-top: 1.25rem;
    border-top: 1px solid var(--border);
}

.eta-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 0.5rem;
}

.eta-header label {
    font-size: 0.82rem;
    font-weight: 500;
    color: var(--text-2);
}

.eta-header label em {
    font-family: var(--font-serif);
    font-size: 0.95rem;
}

.eta-badge {
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--accent);
    background: var(--accent-light);
    padding: 0.15rem 0.5rem;
    border-radius: 4px;
    font-variant-numeric: tabular-nums;
}

.slider-wrap {
    position: relative;
    padding: 0.5rem 0;
}

/* Band covers η 1.2–2.0 on a 0.5–2.5 scale:
   left = (1.2-0.5)/(2.5-0.5) = 35%
   width = (2.0-1.2)/(2.5-0.5) = 40% */
.empirical-band {
    position: absolute;
    left: 35%;
    width: 40%;
    height: 10px;
    background: rgba(26,107,79,0.18);
    border-radius: 5px;
    top: 50%;
    transform: translateY(-50%);
    pointer-events: none;
    border: 1px solid rgba(26,107,79,0.25);
}

input[type="range"] {
    -webkit-appearance: none;
    appearance: none;
    width: 100%;
    height: 8px;
    border-radius: 4px;
    background: #e8e5e0;
    outline: none;
    position: relative;
    z-index: 1;
    cursor: pointer;
}

input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 22px;
    height: 22px;
    border-radius: 50%;
    background: var(--accent);
    border: 3px solid #fff;
    box-shadow: 0 1px 4px rgba(0,0,0,0.2);
    cursor: pointer;
    transition: transform 0.1s;
}

input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.12);
}

input[type="range"]::-moz-range-thumb {
    width: 22px;
    height: 22px;
    border-radius: 50%;
    background: var(--accent);
    border: 3px solid #fff;
    box-shadow: 0 1px 4px rgba(0,0,0,0.2);
    cursor: pointer;
}

input[type="range"]::-moz-range-track {
    height: 8px;
    border-radius: 4px;
    background: #e8e5e0;
}

.eta-footnotes {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.72rem;
    color: var(--text-3);
    margin-top: 0.15rem;
}

.eta-range-label {
    color: var(--accent);
    font-weight: 600;
    letter-spacing: 0.04em;
    text-transform: uppercase;
    font-size: 0.68rem;
}

/* ===== Annuity settings ===== */
.annuity-section {
    margin-top: 1.25rem;
    padding-top: 1rem;
    border-top: 1px solid var(--border);
}

.annuity-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 0.6rem;
    flex-wrap: wrap;
    gap: 0.25rem;
}

.annuity-title {
    font-size: 0.82rem;
    font-weight: 600;
    color: var(--text-2);
}

.assumption-flag {
    font-size: 0.7rem;
    font-weight: 500;
    color: var(--warn);
    background: var(--warn-bg);
    padding: 0.15rem 0.5rem;
    border-radius: 4px;
    text-transform: uppercase;
    letter-spacing: 0.03em;
}

.annuity-body {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.annuity-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 0.75rem;
}

.annuity-row label {
    font-size: 0.8rem;
    color: var(--text-2);
    flex-shrink: 0;
}

.annuity-input {
    display: flex;
    align-items: center;
    gap: 0.35rem;
}

.annuity-input input[type="number"] {
    width: 4.5rem;
    height: 2rem;
    border: 1.5px solid var(--border);
    border-radius: 4px;
    padding: 0 0.4rem;
    font-size: 0.88rem;
    font-weight: 500;
    color: var(--text);
    text-align: right;
    background: #fff;
    font-variant-numeric: tabular-nums;
}

.annuity-input input[type="number"]:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 2px rgba(26,107,79,0.1);
}

/* Hide number input spinners for cleaner look */
.annuity-input input[type="number"]::-webkit-inner-spin-button,
.annuity-input input[type="number"]::-webkit-outer-spin-button {
    -webkit-appearance: none;
    margin: 0;
}
.annuity-input input[type="number"] { -moz-appearance: textfield; }

.annuity-input span {
    font-size: 0.8rem;
    color: var(--text-3);
}

.annuity-note {
    font-size: 0.75rem;
    color: var(--text-3);
    line-height: 1.45;
    margin-top: 0.15rem;
}

/* ===== Presets ===== */
.presets-section {
    margin-top: 1.5rem;
}

.presets-label {
    font-size: 0.78rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-3);
    margin-bottom: 0.5rem;
}

.presets {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.preset {
    font-size: 0.8rem;
    padding: 0.45rem 0.75rem;
    border: 1px solid var(--border);
    border-radius: 2rem;
    background: var(--card);
    color: var(--text-2);
    cursor: pointer;
    transition: all 0.15s;
    white-space: nowrap;
}

.preset:hover {
    border-color: var(--accent);
    color: var(--accent);
    background: var(--accent-light);
}

/* ===== Info panels ===== */
.info-panels {
    margin-top: 2rem;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.info-panel {
    background: var(--card);
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
    overflow: hidden;
}

.info-panel summary {
    padding: 0.85rem 1.25rem;
    font-weight: 600;
    font-size: 0.88rem;
    cursor: pointer;
    color: var(--text-2);
    transition: color 0.15s;
    list-style: none;
}

.info-panel summary::-webkit-details-marker { display: none; }

.info-panel summary::before {
    content: '+ ';
    font-weight: 400;
    color: var(--text-3);
}

.info-panel[open] summary::before {
    content: '\2212  ';
}

.info-panel summary:hover { color: var(--accent); }

.info-content {
    padding: 0 1.25rem 1.5rem;
    font-size: 0.86rem;
    line-height: 1.6;
    color: var(--text-2);
}

.info-content h3 {
    font-size: 0.92rem;
    font-weight: 700;
    color: var(--text);
    margin: 1.25rem 0 0.35rem;
}

.info-content h3:first-child { margin-top: 0; }

.info-content h4 {
    font-size: 0.86rem;
    font-weight: 600;
    color: var(--text);
    margin: 1rem 0 0.25rem;
}

.info-content p { margin-bottom: 0.6rem; }

.info-content .formula {
    font-family: 'Cambria Math', var(--font-serif);
    font-size: 0.95rem;
    text-align: center;
    padding: 0.5rem 0;
    color: var(--text);
    letter-spacing: 0.02em;
    overflow-x: auto;
}

.info-content table {
    width: 100%;
    border-collapse: collapse;
    margin: 0.5rem 0 0.75rem;
    font-size: 0.8rem;
}

.info-content th {
    text-align: left;
    font-weight: 600;
    padding: 0.4rem 0.5rem;
    border-bottom: 2px solid var(--border);
    color: var(--text);
}

.info-content td {
    padding: 0.35rem 0.5rem;
    border-bottom: 1px solid #eee;
    vertical-align: top;
}

.info-content .note {
    font-size: 0.8rem;
    color: var(--text-3);
    font-style: italic;
}

.info-content ul {
    padding-left: 1.25rem;
    margin-bottom: 0.5rem;
}

.info-content li { margin-bottom: 0.3rem; }

.info-content .references {
    font-size: 0.78rem;
    color: var(--text-3);
}

.info-content .references em {
    font-style: italic;
}

/* Definition list for params */
.info-content dl.param-list {
    margin: 0.5rem 0 0.75rem;
}

.info-content dl.param-list dt {
    font-weight: 600;
    color: var(--text);
    margin-top: 0.6rem;
    font-size: 0.84rem;
}

.info-content dl.param-list dd {
    margin-left: 0;
    padding-left: 1rem;
    margin-top: 0.15rem;
    font-size: 0.84rem;
    color: var(--text-2);
}

/* ===== Footer ===== */
footer {
    text-align: center;
    margin-top: 2rem;
    padding-top: 1rem;
    font-size: 0.75rem;
    color: var(--text-3);
}

/* ===== Responsive ===== */
@media (max-width: 560px) {
    .page {
        padding: 1.5rem 0.75rem 2rem;
    }

    h1 { font-size: 1.6rem; }

    .card {
        border-radius: var(--radius-sm);
        padding: 1.25rem 1rem 1.25rem;
    }

    .result-amount { font-size: 1.75rem; }

    .presets {
        flex-direction: column;
    }

    .preset {
        text-align: center;
        white-space: normal;
    }

    .annuity-row {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.25rem;
    }

    .info-content .formula {
        font-size: 0.85rem;
    }

    .info-content table {
        font-size: 0.75rem;
    }
}

@media (max-width: 380px) {
    h1 { font-size: 1.35rem; }
    .result-amount { font-size: 1.5rem; }
    .card { padding: 1rem 0.75rem; }
}