*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
  :root { --bg: #F7F5F0; --surface: #FFFFFF; --text: #1A1A18; --muted: #6B6B67; --accent: #2D6A4F; --accent-light: #EAF3DE; --border: #E2DED6; }
  body { font-family: 'DM Sans', sans-serif; background: var(--bg); color: var(--text); min-height: 100vh; display: flex; flex-direction: column; }
  header { background: var(--surface); border-bottom: 1px solid var(--border); padding: 0 2rem; height: 56px; display: flex; align-items: center; justify-content: space-between; }
  .logo { font-family: 'Instrument Serif', serif; font-size: 20px; color: var(--accent); text-decoration: none; }
  .logo span { font-style: italic; }
  .nav-links { display: flex; gap: 1.25rem; align-items: center; }
  .nav-links a { font-size: 13px; text-decoration: none; color: var(--muted); font-weight: 500; }
  .nav-links a:hover { color: var(--accent); }
  @media (max-width: 520px) { .nav-links a:not(.nav-home) { display: none; } }
  .ad-banner { background: #f0f0f0; border: 1px dashed #ccc; text-align: center; padding: 12px; font-size: 12px; color: #999; width: 100%; }
  .ad-label { font-size: 10px; color: var(--muted); text-transform: uppercase; letter-spacing: 1px; margin-bottom: 4px; }
  main { flex: 1; max-width: 680px; margin: 0 auto; width: 100%; padding: 3rem 1.5rem; }
  .hero { text-align: center; margin-bottom: 2.5rem; }
  .hero h1 { font-family: 'Instrument Serif', serif; font-size: clamp(2rem, 5vw, 3rem); font-weight: 400; line-height: 1.15; margin-bottom: 0.75rem; }
  .hero h1 em { font-style: italic; color: var(--accent); }
  .hero p { font-size: 15px; color: var(--muted); font-weight: 300; }
  .calculator { background: var(--surface); border: 1px solid var(--border); border-radius: 20px; padding: 2rem; margin-bottom: 1.5rem; }
  .date-row { display: grid; grid-template-columns: 1fr 1fr; gap: 1.5rem; margin-bottom: 1.5rem; }
  @media (max-width: 480px) { .date-row { grid-template-columns: 1fr; } }
  .field label { display: block; font-size: 11px; font-weight: 500; text-transform: uppercase; letter-spacing: 0.08em; color: var(--muted); margin-bottom: 0.5rem; }
  .field input[type="date"] { width: 100%; padding: 0.75rem 1rem; border: 1px solid var(--border); border-radius: 10px; font-family: 'DM Sans', sans-serif; font-size: 15px; color: var(--text); background: var(--bg); outline: none; transition: border-color 0.2s; }
  .field input[type="date"]:focus { border-color: var(--accent); }
  .options { display: flex; gap: 0.75rem; flex-wrap: wrap; margin-bottom: 1.5rem; }
  .option-chip { display: flex; align-items: center; gap: 6px; font-size: 13px; color: var(--muted); cursor: pointer; user-select: none; }
  .option-chip input[type="checkbox"] { width: 16px; height: 16px; accent-color: var(--accent); cursor: pointer; }
  .calc-btn { width: 100%; padding: 0.9rem; background: var(--accent); color: white; border: none; border-radius: 12px; font-family: 'DM Sans', sans-serif; font-size: 16px; font-weight: 500; cursor: pointer; transition: opacity 0.2s; }
  .calc-btn:hover { opacity: 0.9; }
  .result-box { display: none; background: #2D6A4F; border-radius: 16px; padding: 2rem; text-align: center; margin-bottom: 1.5rem; }
  .result-box.show { display: block; animation: fadeIn 0.3s ease; }
  @keyframes fadeIn { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: translateY(0); } }
  .result-number { font-family: 'Instrument Serif', serif; font-size: clamp(3rem, 10vw, 5rem); font-weight: 400; color: white; line-height: 1; margin-bottom: 0.25rem; }
  .result-label { font-size: 14px; color: rgba(255,255,255,0.75); margin-bottom: 1.5rem; }
  .result-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 0.75rem; }
  .result-card { background: rgba(255,255,255,0.12); border-radius: 10px; padding: 0.75rem 0.5rem; }
  .result-card .num { font-family: 'Instrument Serif', serif; font-size: 1.5rem; color: white; line-height: 1; }
  .result-card .lbl { font-size: 11px; color: rgba(255,255,255,0.65); margin-top: 2px; }
  .quick-links { background: var(--surface); border: 1px solid var(--border); border-radius: 16px; padding: 1.25rem 1.5rem; margin-bottom: 1.5rem; }
  .quick-links h2 { font-size: 12px; font-weight: 500; text-transform: uppercase; letter-spacing: 0.08em; color: var(--muted); margin-bottom: 0.75rem; }
  .quick-btns { display: flex; flex-wrap: wrap; gap: 0.5rem; }
  .quick-btn { padding: 0.4rem 0.85rem; border: 1px solid var(--border); border-radius: 100px; font-size: 13px; color: var(--text); background: var(--bg); cursor: pointer; transition: all 0.15s; font-family: 'DM Sans', sans-serif; }
  .quick-btn:hover { background: var(--accent-light); border-color: var(--accent); color: var(--accent); }
  .faq { margin-bottom: 2rem; }
  .faq h2 { font-family: 'Instrument Serif', serif; font-size: 1.5rem; font-weight: 400; margin-bottom: 1rem; }
  .faq-item { border-bottom: 1px solid var(--border); padding: 1rem 0; }
  .faq-item h3 { font-size: 14px; font-weight: 500; margin-bottom: 0.4rem; }
  .faq-item p { font-size: 13px; color: var(--muted); line-height: 1.6; }
  .ad-block { background: #f0f0f0; border: 1px dashed #ccc; border-radius: 8px; padding: 1rem; text-align: center; font-size: 12px; color: #999; margin-bottom: 1.5rem; min-height: 250px; display: flex; flex-direction: column; align-items: center; justify-content: center; }
  footer { background: var(--surface); border-top: 1px solid var(--border); padding: 1.5rem 2rem; text-align: center; font-size: 12px; color: var(--muted); }
  footer a { color: var(--accent); text-decoration: underline; }
  .error-msg { display: none; color: #c0392b; font-size: 13px; margin-top: 0.5rem; text-align: center; }
  .error-msg.show { display: block; }