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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    padding: 2rem 1rem;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
}

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

.header h1 {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--text-heading);
}

.header p {
    color: var(--text-muted);
    margin-top: 0.25rem;
}

.card {
    background: var(--bg-white);
    border-radius: 12px;
    padding: 1.5rem;
    box-shadow: 0 1px 3px rgba(0,0,0,0.08), 0 1px 2px rgba(0,0,0,0.06);
    margin-bottom: 1.5rem;
}

.card h2 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-heading);
}

.hidden {
    display: none !important;
}

.divider {
    border: none;
    border-top: 1px solid var(--border-light);
    margin: 1.25rem 0;
}

.mode-toggle {
    display: flex;
    gap: 0;
    margin-bottom: 1.25rem;
    border-radius: 8px;
    overflow: hidden;
    border: 1px solid var(--border);
    background: var(--bg);
}

.mode-option {
    flex: 1;
    text-align: center;
    padding: 0.55rem 1rem;
    cursor: pointer;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-muted);
    transition: background 0.15s, color 0.15s;
    user-select: none;
}

.mode-option input {
    position: absolute;
    opacity: 0;
    width: 0;
    height: 0;
    pointer-events: none;
}

.mode-option.active {
    background: var(--primary);
    color: var(--bg-white);
}

.mode-option:not(.active):hover {
    background: var(--border-light);
}

.investment-row {
    display: flex;
    gap: 0.75rem;
    align-items: end;
    margin-bottom: 0.75rem;
    flex-wrap: wrap;
    border: 2px solid transparent;
    border-radius: 8px;
    padding: 0.25rem 0.4rem 0.25rem 0;
    transition: border-color 0.15s, background 0.15s;
}

.investment-row:hover {
    background: #f0f4ff;
    border-color: #c7d2fe;
    cursor: grab;
}

.investment-row.dragging {
    opacity: 0.35;
    background: #eef2ff;
    border-color: #818cf8;
}

.investment-row.drag-over-top {
    border-top-color: var(--border-drag);
    border-top-width: 3px;
}

.investment-row.drag-over-bottom {
    border-bottom-color: var(--border-drag);
    border-bottom-width: 3px;
}

.drag-handle {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0 0.1rem 0 0.25rem;
    cursor: grab;
    color: var(--text-placeholder);
    align-self: stretch;
    min-width: 18px;
    border-radius: 4px 0 0 4px;
}

.grip-lines {
    display: block;
    width: 14px;
    height: 2px;
    background: currentColor;
    border-radius: 1px;
    box-shadow: 0 5px 0 0 currentColor, 0 10px 0 0 currentColor;
}

.investment-row .form-group {
    flex: 1;
    min-width: 100px;
    margin-bottom: 0;
}

.investment-row .form-group.amount-group {
    flex: 1.5;
    min-width: 130px;
}

.investment-row .form-group.month-group {
    flex: 1.2;
    min-width: 110px;
}

.investment-row .form-group.year-group {
    flex: 0.8;
    min-width: 90px;
}

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

.form-group label {
    display: block;
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--text-label);
    margin-bottom: 0.35rem;
    text-transform: uppercase;
    letter-spacing: 0.03em;
}

input[type="number"],
input[type="text"],
select {
    width: 100%;
    padding: 0.55rem 0.75rem;
    border: 1px solid var(--border);
    border-radius: 6px;
    font-size: 0.95rem;
    font-family: inherit;
    color: var(--text);
    background: var(--bg-white);
    transition: border-color 0.15s ease;
}

input[type="number"]:focus,
input[type="text"]:focus,
select:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(37,99,235,0.1);
}

input[type="number"]::placeholder {
    color: var(--text-placeholder);
}

.date-picker {
    display: flex;
    gap: 0.5rem;
}

.date-picker select {
    flex: 1;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.6rem 1.25rem;
    border: none;
    border-radius: 6px;
    font-size: 0.9rem;
    font-weight: 500;
    font-family: inherit;
    cursor: pointer;
    transition: background 0.15s ease, transform 0.1s ease;
}

.btn:active {
    transform: scale(0.97);
}

.btn-primary {
    background: var(--primary);
    color: var(--bg-white);
    width: 100%;
    padding: 0.75rem;
    font-size: 1rem;
    font-weight: 600;
    margin-top: 0.5rem;
}

.btn-primary:hover {
    background: #1d4ed8;
}

.btn-secondary {
    background: var(--bg);
    color: var(--text-label);
    font-size: 0.85rem;
    border: 1px dashed var(--text-placeholder);
    width: 100%;
}

.btn-secondary:hover {
    background: var(--border-light);
    border-color: var(--text-muted);
}

.btn-danger {
    background: transparent;
    color: var(--text-placeholder);
    padding: 0.55rem 0.6rem;
    font-size: 0.85rem;
    min-width: 32px;
    flex: 0 0 auto;
}

.btn-danger:hover {
    color: var(--negative);
    background: #fef2f2;
}

.error-message {
    color: var(--negative);
    font-size: 0.9rem;
    margin-top: 0.75rem;
    min-height: 1.2em;
}

.form-row {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.form-row .form-group {
    flex: 1;
    min-width: 200px;
}

#custom-ticker {
    margin-top: 0.5rem;
}

.summary-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.summary-item {
    background: var(--bg-summary);
    border: 1px solid var(--border-light);
    border-radius: 8px;
    padding: 1rem;
    text-align: center;
}

.summary-label {
    display: block;
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.04em;
    margin-bottom: 0.35rem;
}

.summary-value {
    font-size: 1.35rem;
    font-weight: 700;
    color: var(--text-heading);
}

.positive {
    color: var(--positive);
}

.negative {
    color: var(--negative);
}

.results-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.85rem;
}

.results-table thead {
    background: var(--bg-summary);
}

.results-table th {
    text-align: right;
    padding: 0.6rem 0.75rem;
    font-weight: 600;
    color: var(--text-label);
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.04em;
    border-bottom: 2px solid var(--border-light);
}

.results-table th:first-child {
    text-align: left;
}

.results-table td {
    text-align: right;
    padding: 0.6rem 0.75rem;
    border-bottom: 1px solid var(--bg);
    font-variant-numeric: tabular-nums;
}

.results-table td:first-child {
    text-align: left;
}

.results-table tbody tr:hover {
    background: var(--bg-summary);
}

.partial-year {
    font-style: italic;
    opacity: 0.75;
}

.table-footnote {
    margin-top: 0.75rem;
    font-size: 0.8rem;
    color: var(--text-placeholder);
    font-style: italic;
}

.chart-wrapper {
    width: 100%;
    position: relative;
}

#chart-canvas {
    width: 100%;
    display: block;
}

@media (max-width: 900px) {
    .summary-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

@media (max-width: 640px) {
    body {
        padding: 1rem 0.75rem;
    }

    .card {
        padding: 1rem;
    }

    .investment-row {
        gap: 0.5rem;
    }

    .investment-row .form-group {
        min-width: 80px;
    }

    .investment-row .form-group.amount-group {
        min-width: 100px;
    }

    .summary-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 0.5rem;
    }

    .summary-value {
        font-size: 1.1rem;
    }

    .form-row {
        flex-direction: column;
        gap: 0;
    }
}

.footer {
    text-align: center;
    font-size: 0.8rem;
    color: var(--text-placeholder);
    padding: 1rem 0 0.5rem;
}

:root {
    --bg: #f1f5f9;
    --bg-white: #fff;
    --bg-summary: #f8fafc;
    --text: #1e293b;
    --text-heading: #0f172a;
    --text-muted: #64748b;
    --text-placeholder: #94a3b8;
    --text-label: #475569;
    --border: #cbd5e1;
    --border-light: #e2e8f0;
    --border-drag: #6366f1;
    --primary: #2563eb;
    --positive: #059669;
    --negative: #dc2626;
}