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

#app {
  max-width: 720px;
  margin: 0 auto;
  padding: 24px 16px;
}

#app-title {
  text-align: center;
  font-size: 28px;
  font-weight: 700;
  color: #1a73e8;
  margin-bottom: 32px;
}

#calculator {
  background: #ffffff;
  border-radius: 16px;
  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.08);
  padding: 24px;
}

#input-section {
  display: flex;
  gap: 16px;
  margin-bottom: 24px;
  flex-wrap: wrap;
}

.input-group {
  flex: 1;
  min-width: 200px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.input-group label {
  font-size: 15px;
  font-weight: 600;
  color: #333;
}

.input-group input {
  width: 100%;
  padding: 12px 16px;
  font-size: 18px;
  border: 2px solid #e0e0e0;
  border-radius: 10px;
  outline: none;
  transition: border-color 0.2s ease;
  box-sizing: border-box;
}

.input-group input:focus {
  border-color: #1a73e8;
}

.input-group input::-webkit-outer-spin-button,
.input-group input::-webkit-inner-spin-button {
  opacity: 1;
}

#result-section {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.result-card {
  flex: 1;
  min-width: 220px;
  background: #f5f7fa;
  border-radius: 12px;
  padding: 20px;
  text-align: center;
}

.result-card h3 {
  font-size: 16px;
  font-weight: 600;
  color: #555;
  margin: 0 0 6px 0;
}

.formula-text {
  font-size: 12px;
  color: #999;
  margin-bottom: 12px;
  font-style: italic;
}

.result-value {
  font-size: 36px;
  font-weight: 700;
  color: #1a73e8;
  margin-bottom: 4px;
  font-variant-numeric: tabular-nums;
}

.result-unit {
  font-size: 14px;
  color: #888;
  font-weight: 500;
}

#__fork {
  text-align: center;
  margin-top: 24px;
}

#__fork button {
  padding: 10px 24px;
  font-size: 14px;
  border: 1px solid #ddd;
  border-radius: 8px;
  background: #fff;
  color: #666;
  cursor: pointer;
  transition: all 0.2s ease;
}

#__fork button:hover {
  border-color: #1a73e8;
  color: #1a73e8;
}

#features,
#scenarios,
#FAQ {
  max-width: 720px;
  margin: 0 auto;
  padding: 24px 16px;
}

#features h2,
#scenarios h2,
#FAQ h2 {
  font-size: 20px;
  font-weight: 700;
  color: #333;
  margin-bottom: 12px;
}

#features p {
  font-size: 15px;
  line-height: 1.8;
  color: #555;
}

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

#scenarios li {
  font-size: 15px;
  line-height: 1.8;
  color: #555;
  margin-bottom: 6px;
}

#FAQ dl {
  margin: 0;
}

#FAQ dt {
  font-size: 15px;
  font-weight: 600;
  color: #333;
  margin-top: 16px;
  margin-bottom: 6px;
}

#FAQ dd {
  font-size: 14px;
  line-height: 1.7;
  color: #666;
  margin-left: 0;
  margin-bottom: 8px;
}

@media (max-width: 600px) {
  #app-title {
    font-size: 22px;
  }

  #input-section {
    flex-direction: column;
  }

  #result-section {
    flex-direction: column;
  }

  .result-value {
    font-size: 28px;
  }
}