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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: #0f0f0f;
  color: #e0e0e0;
  line-height: 1.6;
}

.container {
  height: 100vh;
  display: flex;
  flex-direction: column;
}

header {
  background: linear-gradient(135deg, #1a1a1a 0%, #2d2d2d 100%);
  padding: 1.5rem;
  border-bottom: 1px solid #333;
  box-shadow: 0 2px 10px rgba(0,0,0,0.3);
}

header h1 {
  font-size: 1.8rem;
  margin-bottom: 0.5rem;
}

.breadcrumb {
  font-size: 0.9rem;
  color: #888;
}

.breadcrumb button {
  background: none;
  border: none;
  color: #4a9eff;
  cursor: pointer;
  text-decoration: none;
  padding: 0 0.25rem;
  font-size: inherit;
}

.breadcrumb button:hover {
  text-decoration: underline;
}

.main {
  display: flex;
  flex: 1;
  overflow: hidden;
}

.sidebar {
  width: 250px;
  background: #1a1a1a;
  border-right: 1px solid #333;
  overflow-y: auto;
  padding: 1rem;
}

.file-list {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.file-item {
  padding: 0.75rem;
  border-radius: 6px;
  cursor: pointer;
  transition: all 0.2s;
  font-size: 0.95rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  border: none;
  background: transparent;
  color: #e0e0e0;
  text-align: left;
  width: 100%;
}

.file-item:hover {
  background: #2d2d2d;
}

.file-item.active {
  background: #4a9eff;
  color: #fff;
  font-weight: 600;
}

.file-icon {
  width: 18px;
  display: flex;
  justify-content: center;
  flex-shrink: 0;
}

.file-name {
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.content {
  flex: 1;
  overflow-y: auto;
  padding: 2rem;
  background: #0f0f0f;
}

.file-content {
  max-width: 900px;
  margin: 0 auto;
}

.file-content img {
  max-width: 100%;
  height: auto;
  border-radius: 8px;
  margin: 1rem 0;
  box-shadow: 0 4px 12px rgba(0,0,0,0.5);
}

.file-content h1,
.file-content h2,
.file-content h3 {
  margin-top: 1.5rem;
  margin-bottom: 0.5rem;
  color: #4a9eff;
}

.file-content h1 {
  font-size: 2rem;
}

.file-content h2 {
  font-size: 1.5rem;
  border-bottom: 1px solid #333;
  padding-bottom: 0.5rem;
}

.file-content h3 {
  font-size: 1.2rem;
}

.file-content p {
  margin-bottom: 1rem;
  color: #d0d0d0;
}

.file-content code {
  background: #1a1a1a;
  padding: 0.2em 0.4em;
  border-radius: 3px;
  font-family: 'Monaco', 'Menlo', monospace;
  font-size: 0.9em;
}

.file-content pre {
  background: #1a1a1a;
  padding: 1rem;
  border-radius: 6px;
  overflow-x: auto;
  margin: 1rem 0;
  border-left: 3px solid #4a9eff;
}

.file-content pre code {
  background: none;
  padding: 0;
  color: #76d4ff;
}

.file-content ul,
.file-content ol {
  margin-left: 2rem;
  margin-bottom: 1rem;
}

.file-content li {
  margin-bottom: 0.5rem;
}

.file-content a {
  color: #4a9eff;
  text-decoration: none;
}

.file-content a:hover {
  text-decoration: underline;
}

.file-content blockquote {
  border-left: 4px solid #4a9eff;
  padding-left: 1rem;
  margin-left: 0;
  color: #a0a0a0;
  font-style: italic;
}

.placeholder {
  text-align: center;
  color: #666;
  padding: 3rem;
}

/* Scrollbars */
::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}

::-webkit-scrollbar-track {
  background: #1a1a1a;
}

::-webkit-scrollbar-thumb {
  background: #444;
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: #555;
}