:root {
  --bg-color: #f0f4ff;
  --text-color: #222;
  --box-color: #ffffff;
  --primary: #6c63ff;
  --secondary: #48c9b0;
  --button-bg: #6c63ff;
  --button-hover: #4b43d8;
}

[data-theme="dark"] {
  --bg-color: #121212;
  --text-color: #f5f5f5;
  --box-color: #1e1e1e;
  --primary: #9575cd;
  --secondary: #4dd0e1;
  --button-bg: #9575cd;
  --button-hover: #7e57c2;
}

* {
  box-sizing: border-box;
}

body {
  font-family: 'Segoe UI', sans-serif;
  margin: 0;
  padding: 0;
  background: var(--bg-color);
  color: var(--text-color);
  transition: background 0.4s, color 0.4s;
}

header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 20px 40px;
  background: linear-gradient(90deg, var(--primary), var(--secondary));
  color: white;
  font-size: 1.5em;
}

.toggle-dark {
  background: white;
  color: var(--primary);
  padding: 6px 12px;
  border-radius: 20px;
  border: none;
  cursor: pointer;
  font-size: 0.9em;
  transition: all 0.3s;
}

.toggle-dark:hover {
  background: #eeeeee;
}

.container {
  max-width: 900px;
  margin: 40px auto;
  padding: 30px;
  background-color: var(--box-color);
  box-shadow: 0 12px 24px rgba(0, 0, 0, 0.1);
  border-radius: 15px;
  transition: background 0.4s;
}

.language-select {
  display: flex;
  gap: 15px;
  margin-bottom: 20px;
}

select {
  flex: 1;
  padding: 12px;
  border-radius: 10px;
  border: 1px solid #ccc;
  font-size: 1em;
}

textarea {
  width: 100%;
  height: 140px;
  padding: 15px;
  font-size: 1em;
  margin-bottom: 20px;
  border: 1px solid #ccc;
  border-radius: 12px;
  resize: vertical;
  background: #fff;
}

textarea[readonly] {
  background: #f9f9f9;
}

button {
  background: var(--button-bg);
  color: white;
  padding: 10px 18px;
  font-size: 1em;
  border: none;
  border-radius: 8px;
  margin-right: 10px;
  cursor: pointer;
  transition: background 0.3s ease;
}

button:hover {
  background: var(--button-hover);
}

h3 {
  margin-top: 0;
  color: var(--primary);
}

@media (max-width: 600px) {
  .language-select {
    flex-direction: column;
  }
}