feat(reader): full markdown rendering, styled code blocks and precise popup positioning

app/static/css/style.css

@@ -2664,17 +2664,150 @@ body {
 
 .reader-content-body h1,
 .reader-content-body h2,
-.reader-content-body h3 {
+.reader-content-body h3,
+.reader-content-body h4,
+.reader-content-body h5,
+.reader-content-body h6 {
     font-family: var(--font-family);
     margin: 28px 0 16px;
     color: var(--text-main);
+    text-indent: 0;
 }
 
+.reader-content-body h4 { font-size: 1.15em; }
+.reader-content-body h5 { font-size: 1.05em; }
+
 .reader-content-body p {
     margin-bottom: 20px;
     text-indent: 1.2em;
 }
 
+/* Fenced Code Block */
+.reader-code-block {
+    margin: 24px 0;
+    border-radius: var(--radius-md);
+    background: #141820;
+    border: 1px solid var(--border-color);
+    overflow: hidden;
+    box-shadow: 0 4px 14px rgba(0, 0, 0, 0.3);
+}
+
+.reader-code-header {
+    display: flex;
+    justify-content: space-between;
+    align-items: center;
+    padding: 8px 14px;
+    background: rgba(255, 255, 255, 0.04);
+    border-bottom: 1px solid var(--border-color);
+    font-family: monospace;
+    font-size: 12px;
+    color: var(--text-muted);
+    text-transform: uppercase;
+    letter-spacing: 0.5px;
+}
+
+.reader-code-lang {
+    font-weight: 600;
+}
+
+.reader-copy-code-btn {
+    background: transparent;
+    border: 1px solid var(--border-color);
+    color: var(--text-muted);
+    border-radius: 4px;
+    padding: 3px 8px;
+    font-size: 11px;
+    cursor: pointer;
+    transition: all 0.15s ease;
+    display: inline-flex;
+    align-items: center;
+    gap: 4px;
+}
+
+.reader-copy-code-btn:hover {
+    background: rgba(255, 255, 255, 0.08);
+    color: var(--text-main);
+    border-color: var(--primary);
+}
+
+.reader-content-body pre {
+    margin: 0;
+    padding: 16px;
+    overflow-x: auto;
+    background: transparent;
+    border: none;
+    border-radius: 0;
+    font-family: 'JetBrains Mono', 'Fira Code', 'Consolas', monospace;
+    font-size: 14.5px;
+    line-height: 1.6;
+    text-indent: 0 !important;
+    white-space: pre;
+    tab-size: 4;
+}
+
+.reader-content-body pre code {
+    font-family: inherit;
+    font-size: inherit;
+    color: #e6edf3;
+    background: transparent;
+    padding: 0;
+    border: none;
+    white-space: pre;
+    display: block;
+    text-indent: 0;
+}
+
+/* Inline Code Badge */
+.reader-inline-code {
+    font-family: 'JetBrains Mono', 'Consolas', monospace;
+    font-size: 0.88em;
+    background: rgba(255, 255, 255, 0.08);
+    color: var(--primary);
+    padding: 2px 6px;
+    border-radius: 4px;
+    border: 1px solid rgba(255, 255, 255, 0.12);
+    white-space: pre-wrap;
+    word-break: break-all;
+}
+
+/* Blockquote */
+.reader-content-body blockquote {
+    margin: 20px 0;
+    padding: 12px 20px;
+    border-left: 4px solid var(--primary);
+    background: rgba(56, 189, 248, 0.06);
+    border-radius: 0 var(--radius-md) var(--radius-md) 0;
+    font-style: italic;
+    color: var(--text-main);
+    text-indent: 0;
+}
+
+.reader-content-body blockquote p {
+    margin: 0;
+    text-indent: 0;
+}
+
+/* Lists */
+.reader-content-body ul,
+.reader-content-body ol {
+    margin: 16px 0 20px 24px;
+    padding-left: 12px;
+    text-indent: 0;
+}
+
+.reader-content-body li {
+    margin-bottom: 8px;
+    line-height: 1.7;
+    text-indent: 0;
+}
+
+.reader-content-body hr {
+    border: 0;
+    height: 1px;
+    background: var(--border-color);
+    margin: 32px 0;
+}
+
 /* Interactive Words */
 .reader-word {
     cursor: pointer;