:root {
  --bg: #f7f7f5;
  --card-bg: #ffffff;
  --text: #1a1a1a;
  --text-muted: #6b6b6b;
  --border: #e3e2de;
  --accent: #2563eb;
  --accent-contrast: #ffffff;
  --success-bg: #eef6ee;
  --success-border: #b8ddb8;
  --warn-bg: #fff8e6;
  --warn-border: #f0d99a;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #16171a;
    --card-bg: #1f2023;
    --text: #f0f0ee;
    --text-muted: #a3a3a0;
    --border: #333437;
    --accent: #5b8def;
    --accent-contrast: #0b0d10;
    --success-bg: #16261a;
    --success-border: #2f4a34;
    --warn-bg: #2a2412;
    --warn-border: #59491d;
  }
}

:root[data-theme="dark"] {
  --bg: #16171a;
  --card-bg: #1f2023;
  --text: #f0f0ee;
  --text-muted: #a3a3a0;
  --border: #333437;
  --accent: #5b8def;
  --accent-contrast: #0b0d10;
  --success-bg: #16261a;
  --success-border: #2f4a34;
  --warn-bg: #2a2412;
  --warn-border: #59491d;
}

* { box-sizing: border-box; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  margin: 0;
}

.wrap {
  max-width: 640px;
  margin: 0 auto;
  padding: 0 20px;
}

.site-header {
  border-bottom: 1px solid var(--border);
  padding: 18px 0;
}

.site-header .wrap {
  display: flex;
  align-items: baseline;
  gap: 12px;
  flex-wrap: wrap;
}

.logo {
  font-weight: 800;
  font-size: 1.3rem;
}
.logo .accent { color: var(--accent); }

.tagline {
  color: var(--text-muted);
  font-size: 0.9rem;
}

main.wrap {
  padding-top: 32px;
  padding-bottom: 48px;
}

.card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 28px;
}

h1 {
  font-size: 1.5rem;
  margin: 0 0 8px;
}

.lede {
  color: var(--text-muted);
  margin: 0 0 24px;
}

.field {
  margin-bottom: 16px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

label {
  font-size: 0.88rem;
  font-weight: 600;
}

select, input {
  padding: 10px 12px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--bg);
  color: var(--text);
  font-size: 1rem;
}

select:focus, input:focus {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}

.btn-primary {
  width: 100%;
  padding: 12px 16px;
  border: none;
  border-radius: 8px;
  background: var(--accent);
  color: var(--accent-contrast);
  font-size: 1rem;
  font-weight: 700;
  cursor: pointer;
  margin-top: 8px;
}
.btn-primary:hover { opacity: 0.92; }

.result {
  margin-top: 24px;
  padding: 18px;
  border-radius: 10px;
  background: var(--success-bg);
  border: 1px solid var(--success-border);
}

.result.zero {
  background: var(--success-bg);
  border-color: var(--success-border);
}

.result h2 {
  margin: 0 0 10px;
  font-size: 1.1rem;
}

.result .total {
  font-size: 1.8rem;
  font-weight: 800;
  margin: 4px 0 14px;
}

.result .breakdown {
  font-size: 0.92rem;
  color: var(--text-muted);
  line-height: 1.6;
}

.result .note {
  margin-top: 14px;
  padding-top: 12px;
  border-top: 1px dashed var(--success-border);
  font-size: 0.85rem;
  color: var(--text-muted);
}

.disclaimer {
  margin-top: 22px;
  font-size: 0.8rem;
  color: var(--text-muted);
  line-height: 1.5;
}

.site-footer {
  border-top: 1px solid var(--border);
  padding: 16px 0 40px;
  color: var(--text-muted);
  font-size: 0.8rem;
}