:root {
    font-family: system-ui, sans-serif;
    color: #172033;
    background: #f3f6fb;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
}

header {
    background: #172033;
    color: white;
    padding: 1.25rem max(1rem, calc((100% - 1100px) / 2));
}

header h1 {
    margin: 0 0 1rem;
}

nav {
    display: flex;
    gap: 1rem;
}

nav a {
    color: white;
    text-decoration: none;
    padding: .5rem .75rem;
    border-radius: .5rem;
}

nav a[aria-current="page"] {
    background: #34445f;
}

main {
    max-width: 1100px;
    margin: 2rem auto;
    padding: 0 1rem;
}

.cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 1rem;
}

.card, .chart, .controls {
    background: white;
    border-radius: 1rem;
    padding: 1.25rem;
    box-shadow: 0 3px 14px #1720330d;
}

.card h2 {
    color: #64748b;
    font-size: 1rem;
}

.value {
    font-size: clamp(1.8rem, 5vw, 2.6rem);
    font-weight: 700;
    margin-bottom: .5rem;
}

.controls {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    align-items: center;
    margin-bottom: 1rem;
}

button, select {
    font: inherit;
    padding: .65rem .8rem;
}

.chart {
    min-height: 350px;
}

@media (max-width: 600px) {
    main {
        margin-top: 1rem;
    }

    .controls {
        align-items: flex-start;
        flex-direction: column;
    }
}