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

:root {
    --bg: #101728;
    --bg-soft: #19233a;
    --card: rgba(255, 255, 255, 0.05);
    --text: #f4f7ff;
    --muted: #9cb0d3;
    --accent: #f5a623;
    --accent-2: #58d3ff;
    --good: #43d587;
    --bad: #ff7d7d;
    --border: rgba(255, 255, 255, 0.12);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    background: radial-gradient(circle at 10% 10%, #213154 0%, var(--bg) 45%), linear-gradient(160deg, #111a2c 0%, #0b111f 100%);
    color: var(--text);
    min-height: 100vh;
    padding: 22px;
}

.container {
    max-width: 1080px;
    margin: 0 auto;
}

.header {
    margin-bottom: 16px;
}

.back-link {
    color: var(--accent-2);
    text-decoration: none;
    font-size: 0.9rem;
    display: inline-block;
    margin-bottom: 8px;
}

.back-link:hover {
    text-decoration: underline;
}

h1 {
    font-size: 2rem;
    background: linear-gradient(90deg, #ffd15f, #f7931e);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 4px;
}

.subtitle {
    color: var(--muted);
}

.equation-card,
.input-card,
.chart-card,
.table-card {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: 14px;
    padding: 18px;
    margin-bottom: 18px;
    backdrop-filter: blur(4px);
}

.equation-label {
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--muted);
    margin-bottom: 8px;
}

.equation {
    color: var(--accent);
    font-size: 1.15rem;
    font-weight: 600;
    margin-bottom: 8px;
}

.equation-note {
    color: var(--muted);
    font-size: 0.95rem;
}

.input-card h2,
.chart-card h3,
.table-card h3 {
    margin-bottom: 8px;
}

.help-text,
.chart-subtitle {
    color: var(--muted);
    font-size: 0.9rem;
    margin-bottom: 12px;
}

.grid {
    display: grid;
    grid-template-columns: 70px 1fr 1fr;
    gap: 10px;
    align-items: center;
}

.header-row {
    color: var(--muted);
    font-size: 0.85rem;
    margin-bottom: 8px;
}

.what-if-card {
    border-color: rgba(67, 213, 135, 0.45);
}

.what-if-grid {
    margin-top: 8px;
}

.what-if-grid > div {
    color: var(--muted);
    font-size: 0.9rem;
}

.data-row {
    margin-bottom: 10px;
}

.data-row input,
.what-if-grid input {
    width: 100%;
    padding: 10px 12px;
    border-radius: 10px;
    border: 1px solid var(--border);
    background: var(--bg-soft);
    color: var(--text);
    font-size: 0.96rem;
}

.data-row input:focus,
.what-if-grid input:focus {
    outline: 2px solid rgba(88, 211, 255, 0.35);
    border-color: transparent;
}

.index-pill {
    width: 36px;
    text-align: center;
    background: rgba(245, 166, 35, 0.2);
    border: 1px solid rgba(245, 166, 35, 0.45);
    border-radius: 999px;
    padding: 5px 0;
    font-size: 0.85rem;
}

.actions {
    margin-top: 14px;
    display: flex;
    gap: 10px;
}

.btn {
    padding: 10px 16px;
    border-radius: 10px;
    border: 1px solid var(--border);
    background: #22304b;
    color: var(--text);
    cursor: pointer;
    font-weight: 600;
}

.btn.primary {
    background: linear-gradient(90deg, #f99b19, #e65c00);
    border: none;
}

.btn:hover {
    transform: translateY(-1px);
}

.message {
    min-height: 20px;
    margin-top: 10px;
    color: var(--muted);
}

.message.error {
    color: var(--bad);
}

.message.success {
    color: var(--good);
}

.hidden {
    display: none;
}

.metrics {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 12px;
    margin-bottom: 18px;
}

.metric-card {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 14px;
}

.metric-label {
    color: var(--muted);
    font-size: 0.85rem;
    margin-bottom: 6px;
}

.metric-value {
    font-size: 1.4rem;
    font-weight: 700;
}

.chart-wrap {
    height: 320px;
}

.table-wrap {
    overflow-x: auto;
}

table {
    width: 100%;
    border-collapse: collapse;
}

th,
td {
    padding: 10px 8px;
    border-bottom: 1px solid var(--border);
    text-align: left;
    white-space: nowrap;
}

th {
    color: var(--muted);
    font-size: 0.85rem;
    font-weight: 600;
}

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

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

@media (max-width: 780px) {
    body {
        padding: 14px;
    }

    .metrics {
        grid-template-columns: 1fr;
    }

    .grid {
        grid-template-columns: 54px 1fr 1fr;
        gap: 8px;
    }

    .chart-wrap {
        height: 280px;
    }
}