* {
  margin: 0;
  padding: 0;

  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
  background-color: #f1f2f3;

}

.container {
  box-sizing: border-box;
  max-width: 1540px;
  min-width: 1240px;
  width: 100%;
  margin: 20px auto;
  color: #333;
}

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

header {
  text-align: center;
  position: relative;
}

h1 {
  font-size: 2.4rem;
  margin-bottom: 5px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 15px;
}

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

.tool-container {
  display: flex;
  padding: 20px;
  gap: 20px;
}

.tool-section {
  flex: 1;
  background: #fff;
  border-radius: 10px;
  padding: 20px;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.05);
}

.tool-section-title {
  font-size: 1.5rem;
  margin-bottom: 20px;
  padding-bottom: 15px;
  border-bottom: 2px solid #f0f0f0;
  display: flex;
  align-items: center;
  gap: 10px;
}

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

label {
  display: block;
  margin-bottom: 8px;
  font-weight: 500;
  color: #555;
}

textarea {
  width: 100%;
  height: 260px;
  padding: 15px;
  border: 1px solid #ddd;
  border-radius: 8px;
  font-size: 1rem;
  resize: vertical;
  transition: border-color 0.3s;
}

textarea:focus {
  outline: none;
  border-color: #2575fc;
  box-shadow: 0 0 0 2px rgba(37, 117, 252, 0.2);
}

.settings {
  display: flex;
  gap: 20px;
  margin-bottom: 25px;
}

.setting-group {
  flex: 1;
}

input[type="number"] {
  width: 100%;
  padding: 12px 15px;
  border: 1px solid #ddd;
  border-radius: 8px;
  font-size: 1rem;
}

select {
  width: 100%;
  padding: 12px 15px;
  border: 1px solid #ddd;
  border-radius: 8px;
  font-size: 1rem;
  background-color: white;
}

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

button {
  flex: 1;
  padding: 14px 20px;
  font-size: 1.1rem;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  font-weight: 600;
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
}

.encrypt-btn {
  background: linear-gradient(to right, #00b09b, #96c93d);
  color: white;
}

.encrypt-btn:hover {
  background: linear-gradient(to right, #009c7d, #85b82a);
  transform: translateY(-2px);
  box-shadow: 0 5px 15px rgba(0, 176, 155, 0.3);
}

.decrypt-btn {
  background: linear-gradient(to right, #ff416c, #ff4b2b);
  color: white;
}

.decrypt-btn:hover {
  background: linear-gradient(to right, #e03a5f, #e04427);
  transform: translateY(-2px);
  box-shadow: 0 5px 15px rgba(255, 65, 108, 0.3);
}

.result {
  margin-top: 15px;
}

.instructions {
  background: #f9fafb;
  padding: 20px;
  border-top: 1px solid #eee;
}

.instructions h2 {
  font-size: 1.2rem;
  margin-bottom: 20px;
  color: #2c3e50;
  display: flex;
  align-items: center;
  gap: 10px;
}

.instructions-content {
  max-width: 1000px;
  margin: 0 auto;
}

.instructions p {
  margin-bottom: 15px;
  line-height: 1.7;
  color: #444;
}

.note {
  background: #e3f2fd;
  border-left: 4px solid #2196f3;
  padding: 15px 20px;
  margin: 20px 0;
  border-radius: 0 8px 8px 0;
}

.example {
  margin: 20px 0;
  padding: 20px;
  background: #fff;
  border-radius: 8px;
  box-shadow: 0 3px 10px rgba(0, 0, 0, 0.05);
}

.example-title {
  font-weight: 600;
  margin-bottom: 10px;
  color: #2c3e50;
}

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

.example-box {
  flex: 1;
  padding: 15px;
  background: #f8f9fa;
  border-radius: 6px;
}

.char-range {
  margin-top: 20px;
  font-size: 0.9rem;
  color: #666;
}

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