:root { color-scheme: light; font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif; color: #172033; background: #f3f6fb; }
* { box-sizing: border-box; }
body { margin: 0; min-width: 320px; }
.container { width: min(100% - 2rem, 720px); margin-inline: auto; }
.site-header { padding: 3rem 0 1.5rem; }
.eyebrow { margin: 0 0 .5rem; color: #52627a; font-size: .85rem; font-weight: 700; letter-spacing: .08em; text-transform: uppercase; }
h1, h2 { margin: 0; line-height: 1.15; }
h1 { font-size: clamp(2rem, 6vw, 3.25rem); }
h2 { font-size: 1.4rem; }
.sum-card { padding: 2rem; border: 1px solid #dce3ef; border-radius: 1rem; background: #fff; box-shadow: 0 12px 30px rgb(31 51 84 / 10%); }
.intro { margin: .65rem 0 1.5rem; color: #52627a; }
.form-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 1rem; }
.form-field { display: grid; gap: .45rem; }
label { font-weight: 650; }
input { width: 100%; padding: .8rem .9rem; border: 1px solid #b9c4d5; border-radius: .55rem; color: inherit; background: #fff; font: inherit; }
input:focus { outline: 3px solid #bcd4ff; border-color: #2864d7; }
button { margin-top: 1.25rem; padding: .8rem 1.1rem; border: 0; border-radius: .55rem; color: #fff; background: #2864d7; font: inherit; font-weight: 700; cursor: pointer; }
button:hover { background: #1f52b5; }
.result { display: block; margin-top: 1.5rem; padding: 1rem; border-radius: .55rem; color: #153b24; background: #e8f5ec; font-size: 1.2rem; font-weight: 700; }
.error { margin: .75rem 0 0; color: #a22626; }
.site-footer { padding: 2.5rem 0; color: #52627a; font-size: .9rem; }
@media (max-width: 560px) { .sum-card { padding: 1.25rem; } .form-grid { grid-template-columns: 1fr; } }