/* Document Viewer Styles */

body {
  background-color: var(--viewer-bg);
  color: var(--viewer-text);
  transition: background-color 0.2s, color 0.2s;
}

:root {
  --viewer-bg: #f8f9fa;
  --viewer-content-bg: #fff;
  --viewer-text: #212529;
  --viewer-text-muted: #6c757d;
  --viewer-border: #dee2e6;
  --viewer-sidebar-width: 240px;
}

[data-theme="dark"] {
  --viewer-bg: #1a1d21;
  --viewer-content-bg: #212529;
  --viewer-text: #e9ecef;
  --viewer-text-muted: #adb5bd;
  --viewer-border: #495057;
}

/* Scroll Progress */
.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  width: 0%;
  height: 3px;
  background: #0d6efd;
  z-index: 1030;
  transition: width 0.1s ease;
}

/* Viewer Nav */
.viewer-nav {
  background: var(--viewer-content-bg) !important;
  border-bottom: 1px solid var(--viewer-border);
  padding: 0.5rem 1rem;
}

.viewer-nav .navbar-brand {
  color: var(--viewer-text);
  font-weight: 600;
}

.viewer-nav .navbar-brand:hover {
  color: #0d6efd;
}

/* Layout */
.viewer-layout {
  display: flex;
  gap: 2rem;
  max-width: 1400px;
  margin: 0 auto;
  padding: 1.5rem;
}

.viewer-main {
  flex: 1;
  min-width: 0;
}

.viewer-article {
  background: var(--viewer-content-bg);
  border: 1px solid var(--viewer-border);
  border-radius: 8px;
  padding: 2rem;
  margin-bottom: 2rem;
}

/* Breadcrumb */
.viewer-breadcrumb {
  margin-bottom: 1rem;
}

.viewer-breadcrumb .breadcrumb-item a {
  color: #0d6efd;
}

.viewer-breadcrumb .breadcrumb-item.active {
  color: var(--viewer-text-muted);
}

/* Doc Header */
.viewer-header {
  margin-bottom: 2rem;
}

.viewer-badge {
  display: inline-block;
  padding: 0.25rem 0.5rem;
  font-size: 0.75rem;
  font-weight: 600;
  background: #0d6efd;
  color: white;
  border-radius: 4px;
  margin-right: 0.5rem;
}

.viewer-readtime {
  font-size: 0.85rem;
  color: var(--viewer-text-muted);
}

.viewer-title {
  font-size: 1.75rem;
  font-weight: 700;
  margin-top: 0.5rem;
}

/* Markdown Content */
.viewer-content {
  line-height: 1.7;
}

.markdown-body h1,
.markdown-body h2,
.markdown-body h3,
.markdown-body h4 {
  margin-top: 1.5rem;
  margin-bottom: 0.75rem;
  font-weight: 600;
}

.markdown-body h1 { font-size: 1.5rem; }
.markdown-body h2 { font-size: 1.35rem; border-bottom: 1px solid var(--viewer-border); padding-bottom: 0.25rem; }
.markdown-body h3 { font-size: 1.15rem; }
.markdown-body h4 { font-size: 1rem; }

.markdown-body h1[id],
.markdown-body h2[id],
.markdown-body h3[id],
.markdown-body h4[id] {
  scroll-margin-top: 100px;
}

.markdown-body p {
  margin-bottom: 1rem;
}

.markdown-body ul,
.markdown-body ol {
  margin-bottom: 1rem;
  padding-left: 1.5rem;
}

.markdown-body li {
  margin-bottom: 0.35rem;
}

.markdown-body table {
  width: 100%;
  margin-bottom: 1rem;
  border-collapse: collapse;
}

.markdown-body th,
.markdown-body td {
  padding: 0.5rem 0.75rem;
  border: 1px solid var(--viewer-border);
}

.markdown-body th {
  background: var(--viewer-bg);
  font-weight: 600;
}

.markdown-body blockquote {
  margin: 1rem 0;
  padding: 0.5rem 1rem;
  border-left: 4px solid #0d6efd;
  background: var(--viewer-bg);
  color: var(--viewer-text-muted);
}

.markdown-body code {
  padding: 0.2em 0.4em;
  font-size: 0.9em;
  background: var(--viewer-bg);
  border-radius: 4px;
}

.markdown-body pre {
  margin: 1rem 0;
  padding: 1rem;
  overflow-x: auto;
  border-radius: 6px;
  background: #1e1e1e;
}

[data-theme="dark"] .markdown-body pre {
  background: #0d1117;
}

.markdown-body pre code {
  padding: 0;
  background: transparent;
}

.markdown-body hr {
  margin: 2rem 0;
  border: 0;
  border-top: 1px solid var(--viewer-border);
}

.markdown-body a {
  color: #0d6efd;
}

.markdown-body a:hover {
  text-decoration: underline;
}

/* TOC Sidebar */
.viewer-toc {
  flex: 0 0 var(--viewer-sidebar-width);
  position: sticky;
  top: 80px;
  height: fit-content;
  max-height: calc(100vh - 120px);
  overflow-y: auto;
}

.toc-title {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--viewer-text-muted);
  margin-bottom: 0.75rem;
}

.toc-nav {
  position: sticky;
  top: 0;
}

.toc-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.toc-list li {
  margin-bottom: 0.35rem;
}

.toc-list a {
  font-size: 0.875rem;
  color: var(--viewer-text-muted);
  text-decoration: none;
  display: block;
  padding: 0.2rem 0;
  border-left: 2px solid transparent;
  padding-left: 0.5rem;
}

.toc-list a:hover {
  color: #0d6efd;
}

.toc-list a.active {
  color: #0d6efd;
  border-left-color: #0d6efd;
}

.toc-list .toc-h2 { padding-left: 0.5rem; }
.toc-list .toc-h3 { padding-left: 1rem; font-size: 0.8rem; }
.toc-list .toc-h4 { padding-left: 1.5rem; font-size: 0.75rem; }

/* Lesson navigation (bottom) */
.viewer-lesson-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1.5rem 0 0;
  margin-top: 2rem;
  border-top: 1px solid var(--viewer-border);
}

.btn-lesson {
  display: inline-flex;
  align-items: center;
  padding: 0.5rem 1rem;
  font-size: 0.9rem;
  font-weight: 600;
  color: #0d6efd;
  text-decoration: none;
  border-radius: 6px;
  transition: background 0.2s, color 0.2s;
}

.btn-lesson:hover {
  background: rgba(13, 110, 253, 0.1);
}

.btn-lesson-prev {
  margin-right: auto;
}

.btn-lesson-next {
  margin-left: auto;
}

/* Loading / Error */
.loading-state,
.error-state {
  text-align: center;
  padding: 3rem 2rem;
}

/* Responsive */
@media (max-width: 992px) {
  .viewer-toc {
    display: none;
  }

  .viewer-layout {
    flex-direction: column;
  }
}

@media (max-width: 768px) {
  .viewer-article {
    padding: 1rem;
  }

  .viewer-title {
    font-size: 1.4rem;
  }
}