* {
  margin: 0;
  padding: 0;
}

body {
  background-color: #f1f2f3;
}

.container {
  box-sizing: border-box;
  max-width: 1540px;
  min-width: 1240px;
  width: 100%;
  margin: 25px auto;
  color: #333;
}

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

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

header h1 {
  font-size: 2.2rem;
  margin-bottom: 5px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 15px;
}

header p{
  font-size: 1rem;
  opacity: 0.9;
  max-width: 90%;
  margin: 0 auto;
  line-height: 1.6;
}

.calculator {
  display: flex;
  width: 100%;
  padding: 20px;
  background: #fff;
  border-radius: 12px;
  gap: 30px;
  margin-bottom: 25px;
}

.input-section, .output-section {
  flex: 1;
}

.section-title {
  font-size: 18px;
  margin-bottom: 15px;
  color: #34495e;
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 700;
}

textarea {
  width: 100%;
  height: 300px;
  padding: 15px;
  border: 1px solid #ddd;
  border-radius: 5px;
  resize: none;
  font-size: 16px;
  line-height: 1.5;
}

textarea:focus {
  outline: none;
  border-color: #3498db;
  box-shadow: 0 0 5px rgba(52, 152, 219, 0.5);
}

.buttons {
  display: flex;
  gap: 15px;
  margin-top: 20px;
}

button {
  padding: 12px 25px;
  border: none;
  border-radius: 5px;
  font-size: 16px;
  cursor: pointer;
  transition: all 0.3s;
  display: flex;
  align-items: center;
  gap: 8px;
}

.calculate-btn {
  background-color: #3498db;
  color: white;
}

.calculate-btn:hover {
  background-color: #2980b9;
}

.copy-btn {
  background-color: #2ecc71;
  color: white;
}

.copy-btn:hover {
  background-color: #27ae60;
}

.clear-btn {
  background-color: #e74c3c;
  color: white;
}

.clear-btn:hover {
  background-color: #c0392b;
}

.about-section {
  margin-bottom: 25px;
  padding:20px;
  border-radius: 12px;
  background: #fff;
}

.about-section h2 {
  margin-bottom: 20px;
  color: #2c3e50;
  font-size: 20px;
}

.about-section h3 {
  margin-bottom: 15px;
  font-size: 18px;
}

.about-section p {
  margin-bottom: 15px;
  line-height: 1.6;
  font-size: 15px;
}

.about-section ul {
  margin-bottom: 20px;
  padding-left: 20px;
  font-size: 15px;
}

.about-section li {
  margin-bottom: 10px;
  line-height: 1.5;
}

.notice {
  position: fixed;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%);
  background-color: rgba(0, 0, 0, 0.8);
  color: white;
  padding: 12px 25px;
  border-radius: 5px;
  font-size: 16px;
  opacity: 0;
  transition: opacity 0.3s;
  z-index: 1000;
}

.notice.show {
  opacity: 1;
}