:root {
  --bg-primary: #f5f5f5;
  --bg-secondary: #ffffff;
  --bg-card: #ffffff;
  --text-primary: #1a1a1a;
  --text-secondary: #555555;
  --text-muted: #888888;
  --border-color: #e0e0e0;
  --accent: #ea580c;
  --accent-hover: #c2410c;
  --danger: #ef4444;
  --danger-hover: #dc2626;
  --spinner-color: #ea580c;
  --shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
}

[data-theme="dark"] {
  --bg-primary: #0f0f0f;
  --bg-secondary: #1a1a1a;
  --bg-card: #1e1e1e;
  --text-primary: #f0f0f0;
  --text-secondary: #a0a0a0;
  --text-muted: #666666;
  --border-color: #2e2e2e;
  --accent: #fb923c;
  --accent-hover: #fdba74;
  --spinner-color: #fb923c;
  --shadow: 0 2px 8px rgba(0, 0, 0, 0.4);
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  transition: background-color 0.3s ease, color 0.3s ease;
}

.app-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 2rem;
  background-color: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
  box-shadow: var(--shadow);
  position: sticky;
  top: 0;
  z-index: 100;
}

.app-title {
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: -0.5px;
}

.app-main {
  max-width: 720px;
  margin: 2rem auto;
  padding: 0 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  padding-bottom: 6rem;
}

.hidden {
  display: none !important;
}

.card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 1.5rem;
  box-shadow: var(--shadow);
}

.user-name {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 0.5rem;
}

.user-detail {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-bottom: 0.3rem;
}

.user-detail span {
  color: var(--text-muted);
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-right: 6px;
}

.posts-title {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 1rem;
}

.post-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 1rem 1.25rem;
  margin-bottom: 0.75rem;
  box-shadow: var(--shadow);
  transition: transform 0.15s ease;
}

.post-card:hover {
  transform: translateY(-2px);
}

.post-title {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.4rem;
  text-transform: capitalize;
}

.post-body {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.5;
}

.loading-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1rem;
  padding: 3rem;
  color: var(--text-muted);
}

.spinner {
  width: 40px;
  height: 40px;
  border: 3px solid var(--border-color);
  border-top-color: var(--spinner-color);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

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

.error-container {
  background-color: #fef2f2;
  border: 1px solid #fecaca;
  border-radius: 8px;
  padding: 1rem 1.25rem;
  color: var(--danger);
  font-size: 0.95rem;
}

[data-theme="dark"] .error-container {
  background-color: #2d1515;
  border-color: #7f1d1d;
}

.btn {
  cursor: pointer;
  border: none;
  border-radius: 8px;
  font-size: 0.9rem;
  font-weight: 500;
  transition: background-color 0.2s ease, transform 0.1s ease;
}

.btn:active {
  transform: scale(0.97);
}

.btn-primary {
  background-color: var(--accent);
  color: white;
  padding: 0.6rem 1.2rem;
}

.btn-primary:hover {
  background-color: var(--accent-hover);
}

.btn-danger {
  background-color: var(--danger);
  color: white;
  padding: 0.6rem 1.2rem;
}

.btn-danger:hover {
  background-color: var(--danger-hover);
}

.btn-icon {
  background: transparent;
  font-size: 1.3rem;
  padding: 0.3rem 0.5rem;
  border-radius: 50%;
}

.btn-icon:hover {
  background-color: var(--border-color);
}

.controls {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1rem;
  background-color: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  box-shadow: 0 -2px 8px rgba(0, 0, 0, 0.06);
}

.controls .btn {
  flex: 1 1 auto;
  min-width: 0;
  max-width: 200px;
  text-align: center;
}

@media (max-width: 480px) {
  .controls .btn {
    flex: 1 1 calc(50% - 0.5rem);
    max-width: none;
    font-size: 0.82rem;
    padding: 0.55rem 0.5rem;
  }
}