* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: 'Segoe UI', sans-serif;
  background-color: #0e1a2b;
  color: #fff;
  padding: 20px;
}
h1 {
  text-align: center;
  color: #4cc9f0;
}
.container {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
  justify-content: center;
}
.panel {
  background-color: #1e2a3d;
  padding: 20px;
  border-radius: 12px;
  flex: 1;
  min-width: 300px;
  max-width: 500px;
  box-shadow: 0 0 10px rgba(0,0,0,0.3);
}
label {
  display: block;
  margin-top: 15px;
  margin-bottom: 5px;
}
input[type="file"],
select,
input[type="number"],
textarea {
  width: 100%;
  padding: 12px;
  font-size: 16px;
  border: none;
  border-radius: 8px;
  background-color: #2c3e50;
  color: white;
}
.slider {
  width: 100%;
}
.button-row {
  margin-top: 20px;
  display: flex;
  gap: 15px;
}
button {
  flex: 1;
  padding: 18px;
  border: none;
  border-radius: 8px;
  font-size: 18px;
  font-weight: bold;
  cursor: pointer;
  transition: background-color 0.3s ease, transform 0.2s ease;
}
.encrypt-btn {
  background-color: #2196f3;
  color: white;
}
.encrypt-btn:hover {
  background-color: #1976d2;
  transform: scale(1.05);
}
.decrypt-btn {
  background-color: #9c27b0;
  color: white;
}
.decrypt-btn:hover {
  background-color: #7b1fa2;
  transform: scale(1.05);
}
.download-btn {
  background-color: #4caf50;
  color: white;
  width: 100%;
  margin-top: 15px;
  font-size: 16px;
  padding: 14px;
}
.download-btn:hover {
  background-color: #388e3c;
  transform: scale(1.03);
}
.reload-btn {
  background-color: #ff9800;
  color: white;
  width: 100%;
  margin-top: 15px;
  font-size: 16px;
  padding: 14px;
  transition: background-color 0.3s ease, transform 0.2s ease;
}
.reload-btn:hover {
  background-color: #f57c00;
  transform: scale(1.05);
}
.text-area-section {
  display: flex;
  flex-direction: column;
  gap: 10px;
}
textarea {
  height: 150px;
  resize: vertical;
}
@media (min-width: 900px) {
  .text-area-section {
    flex-direction: row;
  }
  textarea {
    height: 300px;
  }
}