:root {
  --hue: 240;
  --primary-color: hsl(var(--hue), 80%, 60%);
  --primary-color-hover: hsl(var(--hue), 80%, 50%);
  --secondary-color: hsl(280, 80%, 60%);
  --bg-gradient: linear-gradient(135deg, hsl(230, 80%, 95%), hsl(280, 80%, 95%));
  --card-bg: rgba(255, 255, 255, 0.7);
  --card-border: rgba(255, 255, 255, 0.5);
  --text-main: hsl(220, 30%, 20%);
  --text-muted: hsl(220, 20%, 40%);
  --shadow-sm: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 10px 20px -5px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 20px 30px -10px rgba(0, 0, 0, 0.1);
  --success: hsl(150, 80%, 40%);
  --danger: hsl(350, 80%, 50%);
  --input-bg: rgba(255, 255, 255, 0.9);
}

[data-theme="dark"] {
  --bg-gradient: linear-gradient(135deg, hsl(230, 40%, 10%), hsl(280, 40%, 15%));
  --card-bg: rgba(30, 40, 60, 0.7);
  --card-border: rgba(255, 255, 255, 0.1);
  --text-main: hsl(220, 30%, 95%);
  --text-muted: hsl(220, 20%, 70%);
  --input-bg: rgba(20, 30, 50, 0.9);
}

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

body {
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  background: var(--bg-gradient);
  background-attachment: fixed;
  color: var(--text-main);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  transition: background 0.4s ease, color 0.4s ease;
  overflow-x: hidden;
}

.glass-panel {
  background: var(--card-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--card-border);
  border-radius: 20px;
  box-shadow: var(--shadow-md);
}

header {
  padding: 1rem 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  position: sticky;
  top: 0;
  z-index: 1000;
}

.logo {
  font-size: 1.5rem;
  font-weight: 800;
  background: linear-gradient(45deg, var(--primary-color), var(--secondary-color));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  text-decoration: none;
}

.nav-links {
  display: flex;
  gap: 1.5rem;
  align-items: center;
}

.nav-links a {
  text-decoration: none;
  color: var(--text-main);
  font-weight: 500;
  transition: color 0.3s;
}

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

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.8rem 1.5rem;
  border-radius: 12px;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: all 0.3s ease;
  text-decoration: none;
}

.btn-primary {
  background: linear-gradient(45deg, var(--primary-color), var(--secondary-color));
  color: white;
  box-shadow: 0 4px 15px rgba(var(--hue), 80%, 60%, 0.4);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(var(--hue), 80%, 60%, 0.6);
}

.btn-outline {
  background: transparent;
  border: 2px solid var(--primary-color);
  color: var(--primary-color);
}

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

main {
  flex: 1;
  padding: 2rem;
  max-width: 1200px;
  margin: 0 auto;
  width: 100%;
}

/* 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: 0.8rem 1rem;
  border-radius: 10px;
  border: 1px solid var(--card-border);
  background: var(--input-bg);
  color: var(--text-main);
  font-family: inherit;
  transition: all 0.3s ease;
}

.form-control:focus {
  outline: none;
  border-color: var(--primary-color);
  box-shadow: 0 0 0 3px rgba(var(--hue), 80%, 60%, 0.2);
}

/* Card Grid */
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 2rem;
}

.card {
  padding: 2rem;
  text-align: center;
  transition: transform 0.3s ease;
}

.card:hover {
  transform: translateY(-5px);
}

.card h3 {
  margin-bottom: 1rem;
  font-size: 1.25rem;
}

/* Game Styles */
.game-container {
  max-width: 600px;
  margin: 0 auto;
  text-align: center;
}

.question-card {
  font-size: 1.5rem;
  font-weight: 700;
  padding: 3rem 2rem;
  margin-bottom: 2rem;
  background: linear-gradient(135deg, rgba(255,255,255,0.1), rgba(255,255,255,0));
}

.options-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.option-btn {
  padding: 1.5rem;
  font-size: 1.1rem;
  border-radius: 15px;
  background: var(--card-bg);
  border: 2px solid var(--primary-color);
  color: var(--text-main);
  cursor: pointer;
  transition: all 0.2s ease;
  font-weight: 500;
}

.option-btn:hover {
  background: var(--primary-color);
  color: white;
  transform: scale(1.02);
}

.option-btn.correct {
  background: var(--success);
  border-color: var(--success);
  color: white;
}

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

/* Table */
table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 1rem;
}

th, td {
  padding: 1rem;
  text-align: left;
  border-bottom: 1px solid var(--card-border);
}

th {
  font-weight: 600;
  color: var(--text-muted);
}

.badge {
  padding: 0.2rem 0.6rem;
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: bold;
}

.badge-online { background: rgba(0,200,0,0.2); color: var(--success); }
.badge-offline { background: rgba(200,0,0,0.2); color: var(--danger); }

/* Theme Toggle */
.theme-toggle {
  background: none;
  border: none;
  color: var(--text-main);
  font-size: 1.5rem;
  cursor: pointer;
}

@media (max-width: 768px) {
  .options-grid {
    grid-template-columns: 1fr;
  }
}