:root {
  --primary-color: #3498db;
  --secondary-color: #2ecc71;
  --accent-color: #e74c3c;
  --bg-color: #f1f2f3;
  --card-bg: #ffffff;
  --text-color: #333333;
  --border-color: #ddd;
  --shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

* {
  margin: 0;
  padding: 0;
}

body {
  background-color: var(--bg-color);
}

.container {
  box-sizing: border-box;
  width: 100%;
  min-width: 1240px;
  max-width: 1560px;
  margin: 20px auto;
  color: var(--text-color);
}

.container *{
  box-sizing: border-box;
}

header {
  text-align: center;
  margin-bottom: 25px;
}

header h1 {
  margin-bottom: 5px;
  font-size: 2.2rem;
}

.subtitle {
  font-size: 1.1rem;
  opacity: 0.85;
}

.main-content {
  display: flex;
  gap: 20px;
}

.calculator-container {
  flex: 1;
  background-color: var(--card-bg);
  border-radius: 10px;
  padding: 20px;
  box-shadow: var(--shadow);
}

.formula-container {
  flex: 1;
  background-color: var(--card-bg);
  border-radius: 10px;
  padding: 20px;
  box-shadow: var(--shadow);
  display: flex;
  flex-direction: column;
}

.section-title {
  font-size: 1.2rem;
  margin-bottom: 15px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--border-color);
}

.shape-selector {
  margin-bottom: 25px;
}

.shape-dropdown {
  width: 100%;
  padding: 12px 15px;
  border: 1px solid var(--border-color);
  border-radius: 5px;
  font-size: 1rem;
  background-color: white;
  cursor: pointer;
}

.shape-dropdown:focus {
  outline: none;
  border-color: var(--primary-color);
  box-shadow: 0 0 0 2px rgba(52, 152, 219, 0.2);
}

.input-group {
  margin-bottom: 20px;
}

label {
  display: block;
  margin-bottom: 8px;
  font-weight: 500;
}

input {
  width: 100%;
  padding: 12px;
  border: 1px solid var(--border-color);
  border-radius: 5px;
  font-size: 1rem;
}

input:focus {
  outline: none;
  border-color: var(--primary-color);
  box-shadow: 0 0 0 2px rgba(52, 152, 219, 0.2);
}

.buttons {
  display: flex;
  gap: 15px;
  margin: 25px 0;
}

button {
  flex: 1;
  padding: 14px;
  border: none;
  border-radius: 5px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
}

.calculate-btn {
  background-color: var(--primary-color);
  color: white;
}

.copy-btn {
  background-color: var(--secondary-color);
  color: white;
}

.clear-btn {
  background-color: var(--accent-color);
  color: white;
}

button:hover {
  opacity: 0.9;
  transform: translateY(-2px);
}

.result-container {
  background-color: #e8f4fc;
  border-radius: 8px;
  padding: 20px;
  text-align: center;
  font-size: 1.3rem;
  margin-top: 20px;
}

.result-value {
  font-size: 1.6rem;
  font-weight: bold;
  color: var(--primary-color);
  margin-top: 10px;
}

.formula-display {
  min-height: 190px;
  background-color: #f8f9fa;
  border-radius: 8px;
  padding: 15px;
  margin-bottom: 20px;
  overflow: auto;
}

.shape-image {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: #f8f9fa;
  border-radius: 8px;
  padding: 20px;
  min-height: 150px;
}

.shape-svg {
  max-width: 100%;
  max-height: 300px;
}

.instructions {
  background-color: #fff8e1;
  border-left: 4px solid #ffc107;
  padding: 15px;
  margin-top: 25px;
  border-radius: 0 8px 8px 0;
  border-radius: 10px;
}

.instructions h3 {
  margin-bottom: 10px;
  color: #ff9800;
}

.instructions p{
  margin-top: 10px;
  opacity: 0.9;
}

footer {
  text-align: center;
  margin-top: 20px;
  color: #666;
  font-size: 0.9rem;
}

.katex-display {
  overflow-x: auto;
  padding: 10px 0;
}

.formula-detail {
  margin-top: 10px;
  padding: 10px;
  background-color: #eef7ff;
  border-radius: 5px;
}

.error-message {
  color: var(--accent-color);
  font-weight: bold;
  margin-top: 10px;
}