/* Reset and Base Styles */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  /* Color System */
  --primary-900: #0f172a;
  --primary-800: #1e293b;
  --primary-700: #334155;
  --primary-600: #475569;
  --primary-500: #64748b;
  --primary-400: #94a3b8;
  --primary-300: #cbd5e1;
  --primary-200: #e2e8f0;
  --primary-100: #f1f5f9;
  --primary-50: #f8fafc;

  --accent-600: #2563eb;
  --accent-500: #3b82f6;
  --accent-400: #60a5fa;
  --accent-300: #93c5fd;
  --accent-200: #dbeafe;
  --accent-100: #eff6ff;

  --success-600: #059669;
  --success-500: #10b981;
  --success-400: #34d399;
  --success-300: #6ee7b7;
  --success-200: #a7f3d0;
  --success-100: #d1fae5;

  --warning-600: #d97706;
  --warning-500: #f59e0b;
  --warning-400: #fbbf24;
  --warning-300: #fcd34d;
  --warning-200: #fde68a;
  --warning-100: #fef3c7;

  --error-600: #dc2626;
  --error-500: #ef4444;
  --error-400: #f87171;
  --error-300: #fca5a5;
  --error-200: #fecaca;
  --error-100: #fee2e2;

  /* Spacing System */
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 20px;
  --space-6: 24px;
  --space-8: 32px;
  --space-10: 40px;
  --space-12: 48px;
  --space-16: 64px;
  --space-20: 80px;
  --space-24: 96px;

  /* Typography */
  --font-family: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    sans-serif;
  --font-size-xs: 12px;
  --font-size-sm: 14px;
  --font-size-base: 16px;
  --font-size-lg: 18px;
  --font-size-xl: 20px;
  --font-size-2xl: 24px;
  --font-size-3xl: 30px;
  --font-size-4xl: 36px;

  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1),
    0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1),
    0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1),
    0 10px 10px -5px rgba(0, 0, 0, 0.04);

  /* Border Radius */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-2xl: 24px;

  /* Transitions */
  --transition-fast: 150ms ease-in-out;
  --transition-normal: 250ms ease-in-out;
  --transition-slow: 350ms ease-in-out;
}

body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  line-height: 1.5;
  color: var(--primary-100);
  background: linear-gradient(
    135deg,
    var(--primary-900) 0%,
    var(--primary-800) 100%
  );
  min-height: 100vh;
  overflow-x: hidden;
}

/* App Container */
.app-container {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Header */
.header {
  background: rgba(15, 23, 42, 0.8);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid rgba(148, 163, 184, 0.1);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-content {
  max-width: 1200px;
  margin: 0 auto;
  padding: var(--space-4) var(--space-6);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.logo-icon {
  width: 40px;
  height: 40px;
  color: var(--accent-400);
}

.logo-text {
  font-size: var(--font-size-2xl);
  font-weight: 700;
  color: var(--primary-50);
  letter-spacing: -0.025em;
}

.nav {
  display: flex;
  gap: var(--space-2);
}

.nav-btn {
  padding: var(--space-2) var(--space-4);
  background: transparent;
  border: 1px solid transparent;
  border-radius: var(--radius-lg);
  color: var(--primary-300);
  font-size: var(--font-size-sm);
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.nav-btn:hover {
  color: var(--primary-100);
  background: rgba(148, 163, 184, 0.1);
}

.nav-btn.active {
  color: var(--accent-400);
  background: rgba(59, 130, 246, 0.1);
  border-color: rgba(59, 130, 246, 0.2);
}

/* Main Content */
.main-content {
  flex: 1;
  max-width: 1200px;
  margin: 0 auto;
  padding: var(--space-8) var(--space-6);
  width: 100%;
}

/* Tab System */
.tab-content {
  display: none;
  animation: fadeIn 0.3s ease-in-out;
}

.tab-content.active {
  display: block;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Responsive Design */
@media (max-width: 768px) {
  .header-content {
    padding: var(--space-4);
    flex-direction: column;
    gap: var(--space-4);
  }

  .nav {
    width: 100%;
    justify-content: center;
  }

  .nav-btn {
    flex: 1;
    text-align: center;
  }

  .main-content {
    padding: var(--space-6) var(--space-4);
  }

  .logo-text {
    font-size: var(--font-size-xl);
  }
}

@media (max-width: 480px) {
  .header-content {
    padding: var(--space-3);
  }

  .main-content {
    padding: var(--space-4) var(--space-3);
  }

  .nav {
    gap: var(--space-1);
  }

  .nav-btn {
    padding: var(--space-2) var(--space-3);
    font-size: var(--font-size-xs);
  }
}
footer {
  border-top: 1px solid #444;
  margin-top: 3rem;
  padding-top: 1rem;
  font-size: 0.85rem;
  color: #888;
}
footer a {
  color: #888;
  text-decoration: underline;
}
footer a:hover {
  color: #ccc;
}