:root {
  --bg-primary: #f8fafc;
  --bg-card: #ffffff;
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #94a3b8;
  --primary: #4f46e5;
  --primary-hover: #4338ca;
  --primary-light: #e0e7ff;
  --secondary: #64748b;
  --secondary-hover: #475569;
  --secondary-light: #f1f5f9;
  --accent: #06b6d4;
  --border-color: #e2e8f0;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.05), 0 2px 4px -1px rgba(0, 0, 0, 0.03);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.08), 0 4px 6px -2px rgba(0, 0, 0, 0.04);
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --font-family: 'Inter', system-ui, -apple-system, sans-serif;
}

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

body {
  font-family: var(--font-family);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 24px;
}

.app-container {
  width: 100%;
  max-width: 900px;
  display: flex;
  flex-direction: column;
  gap: 24px;
}

/* Header */
.app-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: var(--bg-card);
  padding: 16px 24px;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border-color);
}

.logo {
  display: flex;
  align-items: center;
  gap: 8px;
}

.logo-icon {
  font-size: 1.5rem;
}

.logo-text {
  font-size: 1.25rem;
  font-weight: 700;
  background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.status-badge {
  font-size: 0.85rem;
  font-weight: 600;
  color: #059669;
  background-color: #d1fae5;
  padding: 4px 12px;
  border-radius: 9999px;
  display: inline-flex;
  align-items: center;
}

.pulse {
  position: relative;
}

.pulse::before {
  content: '';
  display: inline-block;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background-color: #10b981;
  margin-right: 6px;
}

/* Hero Card */
.hero-card {
  background: linear-gradient(135deg, #ffffff 0%, #f1f5f9 100%);
  border-radius: var(--radius-lg);
  padding: 32px;
  box-shadow: var(--shadow-md);
  border: 1px solid var(--border-color);
  text-align: center;
}

.hero-card h1 {
  font-size: 1.75rem;
  font-weight: 700;
  margin-bottom: 12px;
  color: var(--text-primary);
}

.hero-description {
  color: var(--text-secondary);
  font-size: 1rem;
}

/* Grid Layout */
.interactive-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}

.card {
  background: var(--bg-card);
  border-radius: var(--radius-md);
  padding: 24px;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border-color);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
  display: flex;
  flex-direction: column;
}

.card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.card-icon {
  font-size: 2rem;
  margin-bottom: 12px;
}

.card h3 {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.card p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-bottom: 16px;
}

/* Counter Display */
.counter-display {
  background-color: var(--bg-primary);
  border-radius: var(--radius-sm);
  padding: 16px;
  text-align: center;
  margin-bottom: 20px;
}

#counter-value {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--primary);
}

/* Buttons */
.button-group {
  display: flex;
  gap: 12px;
  margin-top: auto;
}

.btn {
  flex: 1;
  padding: 10px 16px;
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  transition: background-color 0.2s ease, transform 0.1s ease;
}

.btn:active {
  transform: scale(0.98);
}

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

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

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

.btn-secondary:hover {
  background-color: #e2e8f0;
}

.btn-outline {
  background-color: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  width: 100%;
  margin-top: auto;
}

.btn-outline:hover {
  background-color: var(--bg-primary);
  border-color: var(--text-muted);
}

/* Info Box */
.info-box {
  background-color: var(--bg-primary);
  border-radius: var(--radius-sm);
  padding: 16px;
  margin-bottom: 20px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.info-item {
  display: flex;
  justify-content: space-between;
  font-size: 0.9rem;
}

.info-label {
  color: var(--text-secondary);
}

.info-value {
  font-weight: 600;
}

.highlight {
  color: var(--primary);
}

/* Message Banner */
.message-banner {
  background-color: var(--primary-light);
  border: 1px solid var(--primary);
  color: var(--primary);
  padding: 16px;
  border-radius: var(--radius-md);
  text-align: center;
  font-weight: 500;
  transition: opacity 0.3s ease;
}

.hidden {
  display: none;
}

/* Footer */
.app-footer {
  text-align: center;
  color: var(--text-muted);
  font-size: 0.85rem;
  margin-top: 12px;
}