*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
body { font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif; background: #18181b; color: #f4f4f5; line-height: 1.6; }
.container { max-width: 960px; margin: 0 auto; padding: 40px 20px; }
header { text-align: center; margin-bottom: 40px; }
h1 { font-size: 2.2rem; color: #f97316; }
.subtitle { color: #a1a1aa; font-size: 1.05rem; margin-top: 6px; }

.tool-nav { display: flex; gap: 10px; justify-content: center; flex-wrap: wrap; margin-bottom: 40px; }
.tool-nav a { color: #a1a1aa; text-decoration: none; padding: 6px 16px; border-radius: 20px; border: 1px solid #3f3f46; font-size: .9rem; transition: all .2s; }
.tool-nav a:hover { background: #27272a; color: #f97316; border-color: #f97316; }

.calc-section { background: #27272a; border-radius: 12px; padding: 28px; margin-bottom: 28px; border: 1px solid #3f3f46; }
.calc-section h2 { font-size: 1.3rem; color: #f97316; margin-bottom: 20px; padding-bottom: 12px; border-bottom: 1px solid #3f3f46; }

.calc-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 24px; }
@media (max-width: 640px) { .calc-grid { grid-template-columns: 1fr; } }

.calc-inputs label { display: block; margin-bottom: 12px; font-size: .9rem; color: #a1a1aa; }
.calc-inputs input, .calc-inputs select { width: 100%; padding: 10px 12px; margin-top: 4px; border-radius: 8px; border: 1px solid #52525b; background: #18181b; color: #f4f4f5; font-size: .95rem; }
.calc-inputs input:focus, .calc-inputs select:focus { outline: none; border-color: #f97316; }

.btn-calc { margin-top: 8px; padding: 10px 28px; font-size: .95rem; background: #f97316; color: #fff; border: none; border-radius: 8px; cursor: pointer; font-weight: 600; transition: background .2s; }
.btn-calc:hover { background: #ea580c; }

.calc-results { display: flex; flex-direction: column; justify-content: center; background: #18181b; border-radius: 10px; padding: 24px; gap: 14px; }
.result-row { display: flex; justify-content: space-between; align-items: center; padding-bottom: 10px; border-bottom: 1px solid #27272a; color: #a1a1aa; font-size: .9rem; }
.result-row strong { font-size: 1.4rem; color: #fafafa; }

footer { text-align: center; color: #71717a; font-size: .85rem; margin-top: 40px; padding-top: 20px; border-top: 1px solid #27272a; }
a { color: #f97316; text-decoration: none; }
a:hover { text-decoration: underline; }

section p { color: #a1a1aa; line-height: 1.7; margin-bottom: 12px; }
section h2 { font-size: 1.3rem; color: #f4f4f5; margin: 24px 0 8px; }