:root {
  --bg: #000000;             /* default dark background */
  --text: #ffffff;
  --border: #555;
  --button-bg: #333;
  --button-hover: #444;
}

body.light {
  --bg: #f0f0f0;
  --text: #000000;
  --border: #ccc;
  --button-bg: #007BFF;
  --button-hover: #0056b3;
}

body {
  background-color: var(--bg);
  color: var(--text);
  font-family: sans-serif;
  margin: 0;
  padding: 2rem;
  text-align: center;
  transition: background 0.3s, color 0.3s;
}

/* Header with title and toggle button */
header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  max-width: 800px;
  margin: -1rem auto 2rem auto;
  padding: 0 1rem;
}

header h1 {
  font-size: 1.75rem;
  margin: 0;
}

header a {
  text-decoration: none;
  color: var(--text);
}

header a:hover {
  color: var(--button-bg);
}

.dark-toggle {
  padding: 0.4rem 0.75rem;
  border: none;
  background: var(--button-bg);
  color: white;
  cursor: pointer;
  border-radius: 5px;
}

.dark-toggle:hover {
  background: var(--button-hover);
}

/* Upload Zone */
#drop-zone {
  margin: 2rem auto;
  padding: 3rem;
  max-width: 600px;
  border: 3px dashed var(--border);
  border-radius: 10px;
  font-size: 1.2rem;
  background-color: var(--bg);
  color: var(--text);
  cursor: pointer;
  transition: border-color 0.3s, background 0.3s;
}

#drop-zone.dragover {
  border-color: var(--button-bg);
  background-color: rgba(255, 255, 255, 0.05);
}

input[type="file"] {
  display: none;
}

/* Uploaded Preview */
#preview {
  margin-top: 2rem;
}

#preview img {
  max-width: 100%;
  max-height: 90vh;
  border: 1px solid var(--border);
  border-radius: 8px;
  margin-top: 1rem;
}

/* Button styles */
.copy-btn {
  display: inline-block;
  margin-top: 1rem;
  padding: 0.5rem 1rem;
  font-size: 1rem;
  background: var(--button-bg);
  color: white;
  border: none;
  cursor: pointer;
  border-radius: 5px;
}

.copy-btn:hover {
  background: var(--button-hover);
}