:root {
  --font-family-base: Arial, sans-serif;
  --text-color-base: #1f2937;
  --muted-color: #444;
  --surface-color: #ffffff;
  --surface-border-color: #d1d5db;
  --radius-medium: 8px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

body {
  margin: 2rem;
  font-family: var(--font-family-base);
  color: var(--text-color-base);
  background: #f8fafc;
}

.card {
  background: var(--surface-color);
  border: 1px solid var(--surface-border-color);
  border-radius: var(--radius-medium);
  padding: 1.5rem;
}

label {
  display: block;
  margin-top: 0.75rem;
}

input,
select,
textarea {
  width: 100%;
  margin-top: 0.25rem;
  padding: 0.5rem;
}

button {
  margin-top: 1rem;
  padding: 0.5rem 1rem;
}

#message,
#status {
  margin-top: 1rem;
  color: var(--muted-color);
  white-space: pre-wrap;
}

#message.error {
  color: #b00020;
}

/* Web Components */
app-header,
app-footer,
flash-message {
  display: block;
}

app-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 1.5rem;
  background: var(--surface-color);
  border-bottom: 1px solid var(--surface-border-color);
  margin: -2rem -2rem 1.5rem;
}

app-header .app-header__title {
  font-weight: bold;
  font-size: 1.1rem;
  text-decoration: none;
  color: var(--text-color-base);
}

app-header nav {
  display: flex;
  gap: 1rem;
}

app-footer {
  margin-top: 2rem;
  padding: 1rem;
  text-align: center;
  color: var(--muted-color);
  font-size: 0.85rem;
  border-top: 1px solid var(--surface-border-color);
}

/* Loading Overlay */
loading-overlay {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 9999;
}

loading-overlay.is-visible {
  display: block;
}

.loading-overlay__backdrop {
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.45);
  display: flex;
  align-items: center;
  justify-content: center;
}

.loading-overlay__box {
  background: var(--surface-color);
  border: 1px solid var(--surface-border-color);
  border-radius: var(--radius-medium);
  padding: 2rem 2.5rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1rem;
  min-width: 200px;
}

.loading-overlay__spinner {
  width: 2.5rem;
  height: 2.5rem;
  border: 3px solid var(--surface-border-color);
  border-top-color: var(--text-color-base);
  border-radius: 50%;
  animation: loading-spin 0.8s linear infinite;
}

.loading-overlay__text {
  margin: 0;
  font-family: var(--font-family-base);
  color: var(--muted-color);
  font-size: 0.9rem;
  text-align: center;
}

@keyframes loading-spin {
  to { transform: rotate(360deg); }
}