:root {
  --bg-gradient: linear-gradient(135deg, #1e3c72, #2a5298);
  --card-bg: #ffffff;
  --text-primary: #333333;
  --text-secondary: #666666;
  --text-muted: #555555;
  --shadow-color: rgba(0, 0, 0, 0.2);
  --btn-gradient: linear-gradient(90deg, #ff512f, #dd2476);
  --link-btn-bg: #2a5298;
  --link-btn-hover: #1e3c72;
  --transition: 0.3s;
}

[data-theme="dark"] {
  --bg-gradient: linear-gradient(135deg, #0f2027, #203a43, #2c5364);
  --card-bg: #1a1a1a;
  --text-primary: #f0f0f0;
  --text-secondary: #aaaaaa;
  --text-muted: #999999;
  --shadow-color: rgba(0, 0, 0, 0.6);
  --link-btn-bg: #4a6fa5;
  --link-btn-hover: #3d5a80;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
  background: var(--bg-gradient);
  background-attachment: fixed;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  transition: background var(--transition);
  padding: 40px 20px;
  gap: 30px;
}

.card {
  background: var(--card-bg);
  padding: 40px;
  border-radius: 20px;
  width: 100%;
  max-width: 400px;
  text-align: center;
  box-shadow: 0 20px 40px var(--shadow-color);
  animation: fadeIn 0.8s ease-in-out;
  transition: background var(--transition), box-shadow var(--transition);
  position: relative;
}

.form-card {
  text-align: left;
}

.form-card h2 {
  margin-top: 0;
  margin-bottom: 10px;
  color: var(--text-primary);
  text-align: center;
}

.contact-form {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.form-group label {
  font-size: 14px;
  font-weight: 600;
  color: var(--text-primary);
}

.form-group input,
.form-group textarea {
  padding: 12px;
  border-radius: 10px;
  border: 1px solid var(--text-secondary);
  background: var(--card-bg);
  color: var(--text-primary);
  font-family: inherit;
  transition: border-color 0.2s;
}

.form-group input:focus,
.form-group textarea:focus {
  outline: none;
  border-color: #ff512f;
}

h1 {
  margin-bottom: 10px;
  color: var(--text-primary);
  transition: color var(--transition);
}

.subtitle {
  color: var(--text-secondary);
  margin-bottom: 30px;
  font-size: 14px;
  transition: color var(--transition);
}

button {
  padding: 12px 25px;
  font-size: 16px;
  border: none;
  border-radius: 50px;
  background: var(--btn-gradient);
  color: white;
  cursor: pointer;
  transition: transform 0.2s, box-shadow 0.2s;
  font-weight: 600;
}

button:hover {
  transform: scale(1.05);
  box-shadow: 0 8px 20px var(--shadow-color);
}

button:active {
  transform: scale(0.98);
}

.result {
  margin-top: 25px;
  font-size: 14px;
  color: var(--text-primary);
  line-height: 1.6;
}

.link-btn {
  display: inline-block;
  margin-top: 15px;
  padding: 10px 20px;
  background: var(--link-btn-bg);
  color: white;
  border-radius: 30px;
  text-decoration: none;
  transition: background var(--transition), transform 0.2s;
  font-weight: 500;
}

.link-btn:hover {
  background: var(--link-btn-hover);
  transform: translateY(-2px);
}

.copy {
  margin-top: 12px;
  font-size: 12px;
  color: var(--text-muted);
  cursor: pointer;
  text-decoration: underline;
  opacity: 0.8;
  transition: opacity 0.2s;
}

.copy:hover {
  opacity: 1;
}

/* Theme Toggle Button */
.theme-toggle {
  position: absolute;
  top: 20px;
  right: 20px;
  background: none;
  border: none;
  padding: 8px;
  cursor: pointer;
  font-size: 20px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.3s;
  color: var(--text-primary);
}

.theme-toggle:hover {
  background: rgba(128, 128, 128, 0.1);
  transform: none;
  box-shadow: none;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}