body { font-family: 'Segoe UI', sans-serif; background: #f0f2f5; display: flex; justify-content: center; align-items: center; min-height: 100vh; padding: 20px; margin: 0; }
.calculator-card { background: white; padding: 25px; border-radius: 12px; box-shadow: 0 10px 30px rgba(0,0,0,0.1); width: 100%; max-width: 520px; }
h2 { text-align: center; color: #1a365d; margin-bottom: 20px; font-size: 1.5rem; }
.tabs { display: flex; margin-bottom: 20px; border-bottom: 2px solid #e2e8f0; }
.tab-btn { flex: 1; padding: 12px; border: none; background: none; cursor: pointer; font-weight: bold; color: #718096; font-size: 1rem; transition: all 0.2s; }
.tab-btn:hover { background: #f7fafc; }
.tab-btn.active { color: #2c5282; border-bottom: 3px solid #2c5282; }
.field { margin-bottom: 16px; }
.field-row { display: flex; gap: 12px; align-items: flex-start; margin-bottom: 16px; flex-wrap: wrap; }
.field-row .field { flex: 1; margin-bottom: 0; }
.field-row div[style*="padding-top"] { padding-top: 28px; }
label { display: block; font-size: 0.8rem; font-weight: 600; color: #4a5568; margin-bottom: 4px; }
input { width: 100%; padding: 10px; border: 1px solid #cbd5e0; border-radius: 6px; box-sizing: border-box; font-size: 1rem; transition: border-color 0.2s; }
input:focus { outline: none; border-color: #2c5282; box-shadow: 0 0 0 3px rgba(44,82,130,0.1); }
small { display: block; margin-top: 4px; color: #718096; font-size: 0.7rem; }
button[type="submit"] { width: 100%; padding: 12px; background: #2c5282; color: white; border: none; border-radius: 6px; font-weight: bold; cursor: pointer; font-size: 1rem; transition: background 0.2s; margin-top: 8px; }
button[type="submit"]:hover { background: #1a365d; }
.results-area { margin-top: 20px; padding: 18px; background: #ebf8ff; border-radius: 8px; border: 1px solid #bee3f8; }
.result-item { display: flex; justify-content: space-between; margin-bottom: 10px; flex-wrap: wrap; gap: 8px; }
.result-item .label { font-weight: 500; }
.value { font-weight: bold; }
.note { font-size: 0.75rem; color: #4a5568; font-style: italic; margin-top: 10px; border-top: 1px solid #bee3f8; padding-top: 10px; }
#errorMessage { font-size: 0.85rem; font-weight: 500; }

@media (max-width: 480px) {
    .calculator-card { padding: 20px; }
    h2 { font-size: 1.3rem; }
    .field-row { flex-direction: column; }
    .field-row div[style*="padding-top"] { display: none; }
    .result-item { flex-direction: column; align-items: flex-start; }
}