html, body, main, header, footer {
  padding: 0px;
  margin: 0px;
}

#app {
  max-width: 720px;
  margin: 0 auto;
  padding: 20px 16px;
}

#app-title {
  text-align: center;
  font-size: 28px;
  color: #1a1a2e;
  margin-bottom: 24px;
}

.card {
  background: #ffffff;
  border-radius: 12px;
  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.08);
  padding: 24px;
  margin-bottom: 20px;
}

#calculator-form {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.input-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.input-group label {
  font-size: 15px;
  font-weight: 500;
  color: #333;
}

.input-wrapper {
  display: flex;
  align-items: center;
  border: 1px solid #d0d5dd;
  border-radius: 8px;
  overflow: hidden;
  transition: border-color 0.2s ease;
}

.input-wrapper:focus-within {
  border-color: #3b82f6;
  box-shadow: 0 0 0 2px rgba(59, 130, 246, 0.15);
}

.input-wrapper input {
  flex: 1;
  border: none;
  outline: none;
  padding: 10px 14px;
  font-size: 16px;
  color: #333;
  background: #f9fafb;
  min-width: 0;
}

.input-wrapper .unit {
  padding: 10px 14px;
  background: #f3f4f6;
  color: #6b7280;
  font-size: 14px;
  white-space: nowrap;
  border-left: 1px solid #e5e7eb;
}

.btn-group {
  display: flex;
  justify-content: center;
}

.btn-secondary {
  padding: 10px 32px;
  font-size: 15px;
  background: #e5e7eb;
  color: #374151;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  transition: background 0.2s ease, transform 0.1s ease;
}

.btn-secondary:hover {
  background: #d1d5db;
}

.btn-secondary:active {
  transform: scale(0.97);
}

.result-card {
  background: linear-gradient(135deg, #1e3a5f 0%, #2d5a8e 100%);
  color: #ffffff;
}

#result-title {
  font-size: 20px;
  margin-top: 0;
  margin-bottom: 20px;
  text-align: center;
  color: #e0e7ff;
}

.result-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 14px 0;
  border-bottom: 1px solid rgba(255, 255, 255, 0.12);
}

.result-item:last-child {
  border-bottom: none;
}

.result-label {
  font-size: 15px;
  color: #c7d2fe;
}

.result-value {
  font-size: 22px;
  font-weight: 700;
  color: #4ade80;
}

#features, #scenarios, #FAQ {
  max-width: 720px;
  margin: 0 auto;
  padding: 0 16px 20px 16px;
}

#features h2, #scenarios h2, #FAQ h2 {
  font-size: 20px;
  color: #1a1a2e;
  margin-bottom: 12px;
  border-left: 4px solid #3b82f6;
  padding-left: 12px;
}

#features p {
  font-size: 15px;
  color: #4b5563;
  line-height: 1.7;
}

#scenarios ul {
  padding-left: 20px;
}

#scenarios li {
  font-size: 15px;
  color: #4b5563;
  line-height: 1.8;
}

#FAQ dl {
  margin: 0;
}

#FAQ dt {
  font-size: 15px;
  font-weight: 600;
  color: #1f2937;
  margin-bottom: 6px;
  margin-top: 16px;
}

#FAQ dd {
  font-size: 14px;
  color: #6b7280;
  line-height: 1.7;
  margin-left: 0;
  padding-bottom: 12px;
  border-bottom: 1px solid #f3f4f6;
}

@media (max-width: 480px) {
  #app-title {
    font-size: 22px;
  }

  .card {
    padding: 16px;
  }

  .result-value {
    font-size: 18px;
  }

  .input-wrapper input {
    font-size: 14px;
    padding: 8px 10px;
  }
}