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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: #f5f5f5;
  color: #1a1a1a;
  min-height: 100vh;
  display: flex;
  justify-content: center;
  padding-top: 60px;
}

.container {
  width: 100%;
  max-width: 520px;
  background: #fff;
  border-radius: 12px;
  padding: 32px;
  box-shadow: 0 2px 12px rgba(0,0,0,0.08);
}

.header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 24px;
  padding-bottom: 16px;
  border-bottom: 1px solid #eee;
}

#user-greeting {
  font-weight: 600;
  font-size: 15px;
}

.btn-primary {
  display: block;
  width: 100%;
  padding: 14px;
  font-size: 16px;
  font-weight: 600;
  color: #fff;
  background: #2563eb;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  transition: background 0.15s;
}

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

.btn-primary:active {
  background: #1e40af;
}

.btn-secondary {
  padding: 8px 16px;
  font-size: 14px;
  color: #4b5563;
  background: #f3f4f6;
  border: 1px solid #d1d5db;
  border-radius: 6px;
  cursor: pointer;
}

.btn-secondary:hover {
  background: #e5e7eb;
}

.status {
  text-align: center;
  margin-top: 8px;
  font-size: 14px;
  color: #6b7280;
  min-height: 20px;
}

.status.success {
  color: #059669;
}

.status.error {
  color: #dc2626;
}

h2 {
  font-size: 16px;
  font-weight: 600;
  margin: 24px 0 12px;
  color: #374151;
}

#activity-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.activity-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px 14px;
  background: #f9fafb;
  border-radius: 8px;
  border: 1px solid #e5e7eb;
  font-size: 14px;
}

.activity-row .user-id {
  font-weight: 500;
  color: #374151;
}

.activity-row .timestamp {
  color: #9ca3af;
  font-size: 13px;
}

.empty {
  text-align: center;
  color: #9ca3af;
  font-size: 14px;
  padding: 20px 0;
}

.hidden {
  display: none;
}

#login-section {
  text-align: center;
  padding: 40px 0;
  font-size: 15px;
  color: #6b7280;
}

#login-section h2 {
  margin-top: 0;
  margin-bottom: 16px;
}

#login-form {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

#login-form input {
  padding: 12px;
  font-size: 15px;
  border: 1px solid #d1d5db;
  border-radius: 8px;
  outline: none;
  transition: border-color 0.15s;
}

#login-form input:focus {
  border-color: #2563eb;
  box-shadow: 0 0 0 3px rgba(37,99,235,0.15);
}

#login-error {
  margin-top: 12px;
}