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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
  background-color: #f9fafb;
  min-height: 100vh;
}

/* Header */
.header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 1.5rem;
  background: white;
  border-bottom: 1px solid #e5e7eb;
}

.header-left {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.logo-link {
  display: flex;
  align-items: center;
}

.header-logo {
  height: 40px;
  width: 40px;
}

.header-title {
  font-size: 1.25rem;
  font-weight: 600;
  color: #111827;
}

.header-right {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.user-info {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.user-avatar {
  width: 32px;
  height: 32px;
  border-radius: 50%;
}

.user-name {
  font-size: 0.875rem;
  color: #4b5563;
}

.sign-out-btn {
  padding: 0.375rem 0.75rem;
  font-size: 0.875rem;
  background-color: #dc2626;
  color: white;
  border: none;
  border-radius: 0.5rem;
  cursor: pointer;
  transition: background-color 0.15s;
}

.sign-out-btn:hover {
  background-color: #b91c1c;
}

.main-content {
  max-width: 1200px;
  margin: 0 auto;
  padding: 2rem;
}

/* Auth Overlay */
.auth-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(255, 255, 255, 0.98);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
}

.auth-overlay.hidden {
  display: none;
}

.auth-card {
  text-align: center;
  padding: 3rem;
  max-width: 400px;
}

.auth-logo {
  width: 80px;
  height: 80px;
  margin-bottom: 1.5rem;
}

.auth-card h1 {
  font-size: 1.75rem;
  color: #111827;
  margin-bottom: 0.75rem;
}

.auth-card p {
  color: #6b7280;
  margin-bottom: 2rem;
  line-height: 1.5;
}

.sign-in-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.875rem 1.5rem;
  background: #2563eb;
  color: white;
  border: none;
  border-radius: 0.5rem;
  font-size: 1rem;
  font-weight: 500;
  cursor: pointer;
  transition: background-color 0.15s;
}

.sign-in-btn:hover {
  background: #1d4ed8;
}

.microsoft-icon {
  width: 20px;
  height: 20px;
}

/* Tools Grid */
.tools-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.5rem;
  margin-top: 2rem;
}

.tools-grid.hidden {
  display: none;
}

.tool-card {
  background: white;
  border: 1px solid #e5e7eb;
  border-radius: 0.75rem;
  padding: 1.5rem;
  text-decoration: none;
  color: inherit;
  transition: all 0.2s;
}

.tool-card:hover {
  border-color: #3b82f6;
  box-shadow: 0 4px 12px rgba(59, 130, 246, 0.15);
  transform: translateY(-2px);
}

.tool-icon {
  width: 48px;
  height: 48px;
  border-radius: 0.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 1rem;
}

.tool-icon svg {
  width: 24px;
  height: 24px;
}

.layout-icon {
  background: #dbeafe;
  color: #2563eb;
}

.lightout-icon {
  background: #fef3c7;
  color: #d97706;
}

.studies-icon {
  background: #d1fae5;
  color: #059669;
}

.tool-card h2 {
  font-size: 1.125rem;
  font-weight: 600;
  color: #111827;
  margin-bottom: 0.5rem;
}

.tool-card p {
  font-size: 0.875rem;
  color: #6b7280;
  line-height: 1.5;
}

/* Responsive */
@media (max-width: 640px) {
  .main-content {
    padding: 1rem;
  }

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

  .auth-card {
    padding: 2rem 1.5rem;
  }
}