:root {
  /* Premium Dark Theme Colors */
  --bg-color: #0f172a; /* Slate 900 */
  --surface-color: #1e293b; /* Slate 800 */
  --surface-light: #334155; /* Slate 700 */
  
  --primary-color: #8b5cf6; /* Violet 500 */
  --primary-hover: #7c3aed; /* Violet 600 */
  --secondary-color: #10b981; /* Emerald 500 */
  --secondary-hover: #059669; /* Emerald 600 */
  --danger-color: #ef4444; /* Red 500 */
  
  --text-main: #f8fafc; /* Slate 50 */
  --text-muted: #cbd5e1; /* Slate 300 */
  
  --border-radius: 12px;
  --transition-speed: 0.3s;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background-color: var(--bg-color);
  color: var(--text-main);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

/* Typography */
h1, h2, h3, h4 {
  font-weight: 700;
  margin-bottom: 1rem;
  color: var(--text-main);
}

a {
  color: var(--primary-color);
  text-decoration: none;
  transition: color var(--transition-speed);
}

a:hover {
  color: var(--primary-hover);
}

/* Layout */
.container {
  max-width: 600px; /* Mobile first logic, we cap width on desktop */
  margin: 0 auto;
  padding: 1.5rem;
}

.header {
  text-align: center;
  padding: 2rem 0;
  margin-bottom: 2rem;
  border-bottom: 1px solid var(--surface-light);
}

.header h1 {
  font-size: 2rem;
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  margin: 0;
}

/* Cards (Glassmorphism inspired) */
.card {
  background-color: var(--surface-color);
  border-radius: var(--border-radius);
  padding: 2rem;
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
  margin-bottom: 1.5rem;
  border: 1px solid rgba(255, 255, 255, 0.05);
}

/* Forms */
.form-group {
  margin-bottom: 1.5rem;
}

.form-group label {
  display: block;
  margin-bottom: 0.5rem;
  font-weight: 500;
  color: var(--text-muted);
}

.form-control {
  width: 100%;
  padding: 0.75rem 1rem;
  background-color: var(--bg-color);
  border: 1px solid var(--surface-light);
  border-radius: 8px;
  color: var(--text-main);
  font-size: 1rem;
  transition: border-color var(--transition-speed), box-shadow var(--transition-speed);
}

.form-control:focus {
  outline: none;
  border-color: var(--primary-color);
  box-shadow: 0 0 0 3px rgba(139, 92, 246, 0.2);
}

/* Buttons */
.btn {
  display: inline-block;
  width: 100%;
  padding: 0.875rem 1.5rem;
  font-size: 1rem;
  font-weight: 600;
  text-align: center;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  transition: all var(--transition-speed);
  margin-bottom: 0.5rem;
}

.btn-primary {
  background-color: var(--primary-color);
  color: white;
}

.btn-primary:hover {
  background-color: var(--primary-hover);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(139, 92, 246, 0.4);
}

.btn-secondary {
  background-color: var(--secondary-color);
  color: white;
}

.btn-secondary:hover {
  background-color: var(--secondary-hover);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(16, 185, 129, 0.4);
}

.btn-danger {
  background-color: var(--danger-color);
  color: white;
}

.btn-danger:hover {
  background-color: #dc2626;
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(239, 68, 68, 0.4);
}

.btn-outline {
  background-color: transparent;
  border: 1px solid var(--primary-color);
  color: var(--primary-color);
}

.btn-outline:hover {
  background-color: rgba(139, 92, 246, 0.1);
}

/* Alerts */
.alert {
  padding: 1rem;
  border-radius: 8px;
  margin-bottom: 1.5rem;
  font-weight: 500;
}

.alert-success {
  background-color: rgba(16, 185, 129, 0.1);
  color: var(--secondary-color);
  border: 1px solid var(--secondary-color);
}

.alert-danger {
  background-color: rgba(239, 68, 68, 0.1);
  color: var(--danger-color);
  border: 1px solid var(--danger-color);
}

.alert-info {
  background-color: rgba(56, 187, 248, 0.1);
  color: #38bdf8;
  border: 1px solid #38bdf8;
}

/* Navigation */
.nav {
  display: flex;
  justify-content: center;
  gap: 1rem;
  margin-bottom: 2rem;
}

.nav a {
  padding: 0.5rem 1rem;
  border-radius: 20px;
  background-color: var(--surface-color);
  font-size: 0.9rem;
  font-weight: 600;
}

.nav a:hover {
  background-color: var(--surface-light);
  color: var(--text-main);
}

/* Utilities */
.text-center { text-align: center; }
.mt-2 { margin-top: 1rem; }
.mb-2 { margin-bottom: 1rem; }
.hidden { display: none !important; }