* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif; background: linear-gradient(135deg, #667eea 0%, #764ba2 100%); min-height: 100vh; padding: 20px; color: #333; }
.container { max-width: 800px; margin: 0 auto; }
.header { text-align: center; color: white; margin-bottom: 30px; padding: 20px 0; }
.header h1 { font-size: 2.5em; margin-bottom: 10px; text-shadow: 2px 2px 4px rgba(0,0,0,0.3); }
.header p { font-size: 1.2em; opacity: 0.95; }
.screen { display: none; animation: slideIn 0.3s ease-in-out; }
.screen.active { display: block; }
@keyframes slideIn { from { opacity: 0; transform: translateY(20px); } to { opacity: 1; transform: translateY(0); } }
.card { background: white; border-radius: 12px; padding: 40px; box-shadow: 0 10px 40px rgba(0,0,0,0.1); animation: cardAppear 0.4s ease-in-out; }
@keyframes cardAppear { from { opacity: 0; transform: scale(0.95); } to { opacity: 1; transform: scale(1); } }
.card h2 { color: #667eea; margin-bottom: 20px; font-size: 1.8em; }
.card h3 { color: #667eea; margin-top: 30px; margin-bottom: 15px; font-size: 1.3em; }
.card p { color: #666; line-height: 1.6; margin-bottom: 20px; }
.features { list-style: none; margin: 30px 0; padding: 0; }
.features li { padding: 10px 0; font-size: 1.1em; color: #333; border-bottom: 1px solid #eee; }
.features li:last-child { border-bottom: none; }
.disclaimer { background: #fff3cd; border-left: 4px solid #ffc107; padding: 15px; border-radius: 4px; margin-top: 20px; font-size: 0.95em; color: #856404; }
.progress-bar { width: 100%; height: 8px; background: #eee; border-radius: 4px; overflow: hidden; margin-bottom: 20px; }
.progress-fill { height: 100%; background: linear-gradient(90deg, #667eea, #764ba2); width: 0%; transition: width 0.3s ease; }
.progress-text { text-align: center; color: #999; font-size: 0.9em; margin-bottom: 20px; }
.form-group { margin-bottom: 25px; animation: fadeInUp 0.3s ease-in-out; }
@keyframes fadeInUp { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: translateY(0); } }
label { display: block; margin-bottom: 8px; font-weight: 600; color: #333; font-size: 1.05em; }
.label-desc { display: block; font-size: 0.85em; color: #666; font-weight: 400; margin-top: 5px; }
input[type="text"], input[type="number"], select, textarea { width: 100%; padding: 12px; border: 2px solid #ddd; border-radius: 6px; font-size: 1em; transition: border-color 0.3s ease; font-family: inherit; }
input[type="text"]:focus, input[type="number"]:focus, select:focus, textarea:focus { outline: none; border-color: #667eea; box-shadow: 0 0 0 3px rgba(102,126,234,0.1); }
.radio-group, .checkbox-group { display: flex; gap: 20px; flex-wrap: wrap; margin-top: 10px; }
.radio-option, .checkbox-option { display: flex; align-items: center; gap: 8px; cursor: pointer; }
input[type="radio"], input[type="checkbox"] { cursor: pointer; width: 20px; height: 20px; accent-color: #667eea; }
.button-group { display: flex; gap: 15px; margin-top: 40px; justify-content: center; }
.btn { padding: 12px 30px; border: none; border-radius: 6px; font-size: 1em; font-weight: 600; cursor: pointer; transition: all 0.3s ease; text-decoration: none; display: inline-block; }
.btn-primary { background: linear-gradient(135deg, #667eea 0%, #764ba2 100%); color: white; min-width: 200px; }
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 5px 20px rgba(102,126,234,0.4); }
.btn-primary:active { transform: translateY(0); }
.btn-secondary { background: #f0f0f0; color: #333; min-width: 150px; }
.btn-secondary:hover { background: #e0e0e0; transform: translateY(-2px); }
.btn-secondary:active { transform: translateY(0); }
.results-summary { background: #f9f9f9; padding: 25px; border-radius: 8px; margin: 25px 0; }
.result-item { display: flex; justify-content: space-between; padding: 12px 0; border-bottom: 1px solid #eee; font-size: 1em; }
.result-item:last-child { border-bottom: none; }
.result-item label { margin: 0; font-weight: 500; color: #555; }
.result-item .value { font-weight: 600; color: #333; font-size: 1.05em; }
.result-item .value.large { font-size: 1.3em; color: #667eea; }
.result-item.highlight { background: #f0f4ff; padding: 15px; border-radius: 6px; margin: 10px 0; border-bottom: none; }
.result-item.highlight label { color: #333; }
.result-item.final .value-large { font-size: 1.8em; font-weight: 700; color: #28a745; }
.result-item.final.owed .value-large { color: #dc3545; }
.breakdown { margin: 30px 0; padding: 20px; background: #f9f9f9; border-radius: 8px; }
.breakdown canvas { max-height: 300px; }
.quarterly-estimate { margin: 30px 0; padding: 20px; background: #f0f4ff; border-left: 4px solid #667eea; border-radius: 8px; }
.quarterly-estimate h3 { margin-top: 0; }
.quarterly-amounts { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 15px; margin-top: 15px; }
.quarter { background: white; padding: 15px; border-radius: 6px; text-align: center; border: 1px solid #ddd; }
.quarter strong { display: block; margin-bottom: 8px; color: #333; font-size: 0.95em; }
.quarter span { display: block; font-size: 1.3em; font-weight: 700; color: #667eea; }
.footer { text-align: center; color: white; margin-top: 50px; padding: 30px 0; }
.footer p { margin: 10px 0; font-size: 0.95em; opacity: 0.9; }
.footer a { color: #fff; text-decoration: none; border-bottom: 1px solid rgba(255,255,255,0.5); transition: all 0.3s ease; }
.footer a:hover { opacity: 1; border-bottom-color: white; }
@media (max-width: 768px) {
  .header h1 { font-size: 1.8em; }
  .card { padding: 25px; }
  .button-group { flex-direction: column; }
  .btn { width: 100%; min-width: unset; }
  .quarterly-amounts { grid-template-columns: 1fr 1fr; }
  .radio-group, .checkbox-group { flex-direction: column; gap: 12px; }
}
@media (max-width: 480px) {
  body { padding: 10px; }
  .header { margin-bottom: 20px; }
  .header h1 { font-size: 1.5em; }
  .card { padding: 20px; }
  .card h2 { font-size: 1.4em; }
  .quarterly-amounts { grid-template-columns: 1fr; }
  .result-item { font-size: 0.95em; }
}