:root {
  font-family: Inter, system-ui, Avenir, Helvetica, Arial, sans-serif;
  line-height: 1.6;
  font-weight: 400;
  color: #213547;
  background-color: #ffffff;
}

body {
  margin: 0;
  min-width: 320px;
}

#app {
  max-width: 800px;
  margin: 0 auto;
  padding: 1rem;
}

header {
  text-align: center;
  padding: 1rem 0;
  margin-bottom: 2rem;
  border-bottom: 1px solid #eaeaea;
}

h1 {
  font-size: 2.5em;
  line-height: 1.1;
  color: #2c5282;
  margin-bottom: 1.5rem;
}

h2 {
  color: #2d3748;
  margin-top: 2rem;
}

h3 {
  color: #4a5568;
}

section {
  margin-bottom: 2.5rem;
  padding: 1rem;
  background: #f7fafc;
  border-radius: 8px;
}

.calculation-guide ol {
  padding-left: 1.5rem;
}

.example {
  background: #ebf4ff;
  padding: 1rem;
  border-radius: 4px;
  margin: 1rem 0;
}

.question {
  margin-bottom: 1.5rem;
  padding: 1rem;
  background: white;
  border-radius: 4px;
  box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}

.cta {
  text-align: center;
  background: #2c5282;
  color: white;
  padding: 2rem;
}

.cta h2 {
  color: white;
}

.cta-button {
  display: inline-block;
  background: #48bb78;
  color: white;
  padding: 0.8rem 1.5rem;
  border-radius: 4px;
  text-decoration: none;
  font-weight: 600;
  transition: background-color 0.3s;
}

.cta-button:hover {
  background: #38a169;
  color: white;
}

@media (max-width: 640px) {
  #app {
    padding: 1rem;
  }
  
  h1 {
    font-size: 2em;
  }
  
  .cta {
    padding: 1.5rem;
  }
}