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

body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background: #f5f7fa;
}

.app {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

/* HEADER */
.app-header {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
  padding: 2rem;
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.header-content {
  max-width: 1400px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.header-title h1 {
  font-size: 2rem;
  margin-bottom: 0.5rem;
}

.header-title p {
  opacity: 0.9;
  font-size: 0.95rem;
}

.header-date {
  font-size: 0.9rem;
  opacity: 0.8;
}

/* NAVIGATION */
.app-nav {
  display: flex;
  gap: 0;
  background: white;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
  overflow-x: auto;
  position: sticky;
  top: 0;
  z-index: 100;
}

.nav-btn {
  flex: 1;
  min-width: 120px;
  padding: 1rem;
  border: none;
  background: white;
  color: #333;
  font-size: 0.95rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.3s ease;
  border-bottom: 3px solid transparent;
}

.nav-btn:hover {
  background: #f5f7fa;
}

.nav-btn.active {
  background: white;
  color: #667eea;
  border-bottom-color: #667eea;
}

/* CONTENT */
.app-content {
  flex: 1;
  max-width: 1400px;
  width: 100%;
  margin: 0 auto;
  padding: 2rem 1rem;
}

/* CHARTS PAGE */
.charts-page {
  color: white;
}

.charts-header {
  margin-bottom: 2rem;
}

.charts-header h1 {
  font-size: 2rem;
  margin-bottom: 0.5rem;
}

.charts-header p {
  opacity: 0.9;
}

.charts-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(500px, 1fr));
  gap: 2rem;
}

/* FOOTER */
.app-footer {
  background: rgba(0, 0, 0, 0.2);
  color: white;
  text-align: center;
  padding: 1.5rem;
  margin-top: auto;
  font-size: 0.9rem;
}

/* RESPONSIVE */
@media (max-width: 768px) {
  .header-content {
    flex-direction: column;
    gap: 1rem;
  }

  .nav-btn {
    min-width: 100px;
    padding: 0.75rem;
    font-size: 0.85rem;
  }

  .charts-grid {
    grid-template-columns: 1fr;
  }
}
