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

#app {
  max-width: 480px;
  margin: 20px auto;
  padding: 0 16px;
}

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

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

.input-group {
  margin-bottom: 16px;
}

.input-group label {
  display: block;
  font-size: 14px;
  color: #555;
  margin-bottom: 6px;
  font-weight: 500;
}

.input-group input {
  width: 100%;
  height: 48px;
  padding: 0 12px;
  font-size: 18px;
  border: 1px solid #ddd;
  border-radius: 8px;
  text-align: right;
  box-sizing: border-box;
  transition: border-color 0.2s ease;
  outline: none;
}

.input-group input:focus {
  border-color: #4a90d9;
  box-shadow: 0 0 0 3px rgba(74, 144, 217, 0.15);
}

#results {
  display: flex;
  gap: 12px;
  margin: 20px 0;
}

.result-card {
  flex: 1;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  border-radius: 10px;
  padding: 16px;
  text-align: center;
  color: #ffffff;
}

.result-label {
  display: block;
  font-size: 13px;
  opacity: 0.85;
  margin-bottom: 6px;
}

.result-value {
  display: block;
  font-size: 28px;
  font-weight: 700;
  margin-bottom: 2px;
}

.result-unit {
  display: block;
  font-size: 12px;
  opacity: 0.8;
}

#error-message {
  text-align: center;
  color: #e74c3c;
  font-size: 13px;
  min-height: 20px;
  margin-bottom: 12px;
  display: none;
}

#error-message.visible {
  display: block;
}

#reset-btn {
  width: 100%;
  height: 44px;
  font-size: 16px;
  color: #ffffff;
  background: #4a90d9;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  transition: background 0.2s ease;
}

#reset-btn:hover {
  background: #357abd;
}

#reset-btn:active {
  background: #2a6cb0;
}

#features, #scenarios, #FAQ {
  max-width: 480px;
  margin: 32px auto;
  padding: 0 16px;
}

#features h2, #scenarios h2, #FAQ h2 {
  font-size: 20px;
  color: #1a1a2e;
  margin-bottom: 12px;
}

#features p {
  font-size: 15px;
  line-height: 1.8;
  color: #444;
}

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

#scenarios li {
  font-size: 14px;
  line-height: 1.8;
  color: #444;
  margin-bottom: 8px;
}

#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;
  color: #555;
  line-height: 1.7;
  margin-left: 0;
}

#__fork {
  max-width: 480px;
  margin: 24px auto;
  padding: 0 16px;
}

#__fork button {
  width: 100%;
  height: 44px;
  font-size: 15px;
  color: #4a90d9;
  background: transparent;
  border: 1px solid #4a90d9;
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.2s ease;
}

#__fork button:hover {
  background: #4a90d9;
  color: #ffffff;
}

@media (max-width: 768px) {
  #app {
    margin: 12px auto;
    padding: 0 12px;
  }

  #app-title {
    font-size: 20px;
    margin-bottom: 16px;
  }

  #calculator {
    padding: 16px;
  }

  .input-group input {
    height: 44px;
    font-size: 16px;
  }

  .result-value {
    font-size: 24px;
  }

  #features, #scenarios, #FAQ {
    margin: 24px auto;
    padding: 0 12px;
  }
}