:root {
    --bg: #0b1220;
    --panel: #121a2b;
    --panel-2: #182235;
    --border: #2a3957;
    --text: #e5ecf6;
    --muted: #98a7c2;
    --accent: #60a5fa;
    --accent-2: #93c5fd;
    --danger: #f87171;
    --success: #34d399;
    --table-head: #162033;
    --code-bg: #0a0f1a;
}

* {
    box-sizing: border-box;
}

body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    background: linear-gradient(180deg, #09111d 0%, #0b1220 100%);
    color: var(--text);
}

.container {
    max-width: 1180px;
    margin: 28px auto;
    background: rgba(18, 26, 43, 0.96);
    padding: 24px;
    border-radius: 14px;
    border: 1px solid var(--border);
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.35);
}

h1, h2, h3 {
    margin-top: 0;
    color: var(--text);
}

h1 {
    font-size: 30px;
    margin-bottom: 8px;
}

h2 {
    margin-top: 28px;
    margin-bottom: 10px;
    font-size: 20px;
    border-left: 4px solid var(--accent);
    padding-left: 10px;
}

p {
    color: var(--muted);
}

a {
    color: inherit;
}

.button-row {
    display: flex;
    gap: 12px;
    margin-top: 16px;
    margin-bottom: 8px;
    flex-wrap: wrap;
}

button {
    padding: 10px 16px;
    font-size: 14px;
    cursor: pointer;
    border: 1px solid var(--border);
    background: var(--panel-2);
    color: var(--text);
    border-radius: 8px;
    transition: background 0.15s ease, border-color 0.15s ease, transform 0.05s ease;
}

button:hover {
    background: #22314d;
    border-color: var(--accent);
}

button:active {
    transform: translateY(1px);
}

.message {
    margin-top: 12px;
    color: var(--danger);
    font-weight: bold;
    min-height: 24px;
}

.results-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 16px;
    background: var(--panel);
    border: 1px solid var(--border);
    border-radius: 10px;
    overflow: hidden;
}

.results-table th,
.results-table td {
    border: 1px solid var(--border);
    padding: 10px;
    text-align: right;
    color: var(--text);
}

.results-table th {
    background: var(--table-head);
    color: var(--accent-2);
    font-weight: 700;
}

.results-table th:first-child,
.results-table td:first-child {
    text-align: center;
}

#inputTable input {
    width: 100%;
    padding: 8px;
    box-sizing: border-box;
    font-size: 14px;
}

.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 16px;
    margin-top: 16px;
    margin-bottom: 16px;
}

.result-card {
    padding: 18px;
    border-radius: 12px;
    background: linear-gradient(180deg, #121a2b 0%, #162239 100%);
    border: 1px solid var(--border);
    min-height: 110px;
}

.result-card h3 {
    margin-bottom: 10px;
    font-size: 15px;
    color: var(--muted);
    text-transform: uppercase;
    letter-spacing: 0.04em;
}

.result-card div {
    margin-top: 8px;
}

.pv-value {
    font-size: 30px;
    font-weight: 700;
    color: var(--accent-2);
}

.form-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 16px;
    margin-top: 12px;
}

.form-grid label {
    display: block;
    margin-bottom: 6px;
    font-weight: bold;
    color: var(--muted);
    font-size: 13px;
    text-transform: uppercase;
    letter-spacing: 0.04em;
}

.form-grid input[type="number"],
.form-grid input[type="text"],
.form-grid select,
#inputTable input {
    width: 100%;
    padding: 10px;
    box-sizing: border-box;
    font-size: 14px;
    border-radius: 8px;
    border: 1px solid var(--border);
    background: #0f1728;
    color: var(--text);
    outline: none;
}

.form-grid input[type="number"]:focus,
.form-grid input[type="text"]:focus,
.form-grid select:focus,
#inputTable input:focus {
    border-color: var(--accent);
    box-shadow: 0 0 0 2px rgba(96, 165, 250, 0.18);
}

.form-grid input:disabled,
.form-grid select:disabled {
    opacity: 0.55;
    cursor: not-allowed;
}

.info-banner {
    margin-top: 14px;
    padding: 12px 14px;
    border-radius: 10px;
    background: rgba(96, 165, 250, 0.12);
    border: 1px solid rgba(96, 165, 250, 0.28);
    color: var(--accent-2);
}

.chart-card {
    margin-top: 16px;
    padding: 16px;
    border-radius: 12px;
    background: var(--panel);
    border: 1px solid var(--border);
}

.hidden {
    display: none;
}

pre {
    margin-top: 16px;
    background: var(--code-bg);
    color: #dbeafe;
    padding: 16px;
    border-radius: 10px;
    overflow-x: auto;
    border: 1px solid var(--border);
}

details {
    margin-top: 20px;
    background: var(--panel);
    border: 1px solid var(--border);
    border-radius: 10px;
    padding: 10px 14px;
}

details summary {
    cursor: pointer;
    color: var(--accent-2);
    font-weight: 700;
}

.tab-bar {
    display: flex;
    gap: 10px;
    margin: 20px 0;
    flex-wrap: wrap;
    padding-bottom: 8px;
    border-bottom: 1px solid var(--border);
}

.tab-btn {
    padding: 10px 16px;
    border-radius: 8px;
    border: 1px solid var(--border);
    background: var(--panel-2);
    color: var(--text);
    cursor: pointer;
}

.tab-btn.active {
    background: linear-gradient(180deg, #1d4ed8 0%, #1e40af 100%);
    border-color: #3b82f6;
    color: white;
    font-weight: bold;
}

.tab-panel {
    display: none;
    margin-top: 20px;
}

.tab-panel.active {
    display: block;
}

.status-bar {
    display: flex;
    flex-wrap: wrap;
    gap: 18px;
    align-items: center;
    padding: 8px 12px;
    margin: 8px 0 14px 0;
    border: 1px solid var(--border);
    border-radius: 8px;
    background: var(--panel-2);
    font-size: 13px;
}

.status-bar span {
    white-space: nowrap;
}

.container h1 {
    font-size: 22px;
    margin-bottom: 4px;
}

.container > p {
    font-size: 13px;
    margin-top: 0;
    margin-bottom: 10px;
    opacity: 0.85;
}

h2 {
    margin-top: 22px;
    margin-bottom: 10px;
    font-size: 18px;
    border-bottom: 1px solid var(--border);
    padding-bottom: 6px;
}

.chart-card,
.table-card,
.section-card {
    background: var(--panel);
    border: 1px solid var(--border);
    border-radius: 10px;
    padding: 14px;
    margin-top: 10px;
    margin-bottom: 16px;
    box-shadow: 0 1px 2px rgba(0, 0, 0, 0.08);
}

.chart-card canvas {
    width: 100% !important;
}

.results-table {
    margin-top: 0;
}

.button-row {
    margin-top: 10px;
    margin-bottom: 10px;
}

.form-grid {
    margin-bottom: 10px;
}

details {
    margin-top: 14px;
}

details summary {
    cursor: pointer;
    font-weight: 600;
    margin-bottom: 8px;
}

.hero-card {
    display: grid;
    grid-template-columns: minmax(0, 2.2fr) minmax(240px, 1fr);
    gap: 20px;
    padding: 24px;
    border-radius: 16px;
    background:
        radial-gradient(circle at top right, rgba(96, 165, 250, 0.22), transparent 35%),
        linear-gradient(180deg, rgba(18, 26, 43, 0.95) 0%, rgba(22, 34, 57, 0.98) 100%);
    border: 1px solid var(--border);
    margin-top: 8px;
}

.hero-copy h2 {
    margin-bottom: 12px;
}

.hero-copy p {
    max-width: 62ch;
}

.eyebrow {
    margin-bottom: 8px;
    color: var(--accent-2);
    font-size: 12px;
    font-weight: 700;
    letter-spacing: 0.12em;
    text-transform: uppercase;
}

.hero-actions {
    display: flex;
    flex-direction: column;
    gap: 10px;
    justify-content: center;
}

.hero-link,
.overview-link-card {
    text-decoration: none;
}

.hero-link {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 48px;
    padding: 12px 14px;
    border-radius: 10px;
    border: 1px solid var(--border);
    background: rgba(15, 23, 40, 0.9);
    color: var(--text);
    font-weight: 700;
    transition: background 0.15s ease, border-color 0.15s ease, transform 0.05s ease;
}

.hero-link:hover,
.overview-link-card:hover {
    background: #22314d;
    border-color: var(--accent);
}

.overview-card,
.overview-link-card {
    min-height: 150px;
}

.overview-card p,
.overview-link-card p {
    margin: 0;
}

.overview-link-card {
    display: block;
}

.overview-panel {
    margin-top: 16px;
    padding: 18px;
    border-radius: 12px;
    background: var(--panel);
    border: 1px solid var(--border);
}

.overview-list {
    margin: 0;
    padding-left: 20px;
    color: var(--text);
}

.overview-list li + li {
    margin-top: 10px;
}

.tree-graph-card {
    margin-top: 16px;
    padding: 16px;
    border-radius: 14px;
    background: linear-gradient(180deg, #10192a 0%, #131f33 100%);
    border: 1px solid var(--border);
    overflow-x: auto;
}

.tree-graph {
    width: 100%;
    min-width: 980px;
    height: auto;
    display: block;
}

.tree-edge {
    stroke: rgba(147, 197, 253, 0.42);
    stroke-width: 1.5;
}

.tree-node {
    fill: #17304f;
    stroke: #93c5fd;
    stroke-width: 1.5;
}

.tree-node-terminal {
    fill: #153a33;
    stroke: #34d399;
}

.tree-level-label {
    fill: var(--accent-2);
    font-size: 16px;
    font-weight: 700;
    text-anchor: middle;
}

.tree-node-label {
    fill: var(--text);
    font-size: 11px;
    font-weight: 700;
    text-anchor: middle;
}

.tree-node-sub {
    fill: var(--muted);
    font-size: 10px;
    text-anchor: middle;
}

.tree-node-payoff {
    fill: var(--success);
    font-size: 11px;
    font-weight: 700;
    text-anchor: middle;
}

@media (max-width: 860px) {
    .hero-card {
        grid-template-columns: 1fr;
    }
}