init: DPDK → DPU learning blog (VitePress)

- VitePress static site for rendering all markdown documents
- Auto-discovers .md files from dpdk-roadmap-v3 and dpdk-study-kb
- Features: full-text search, dark mode, responsive design
- Pages: roadmap, notes (Phase 0-3), product docs, knowledge base

Co-Authored-By: Claude <noreply@anthropic.com>

.vitepress/theme/custom.css

@@ -0,0 +1,97 @@
+/* Custom styles for DPDK → DPU Blog */
+
+:root {
+  --vp-c-brand-1: #2563eb;
+  --vp-c-brand-2: #3b82f6;
+  --vp-c-brand-3: #1d4ed8;
+  --vp-c-brand-soft: rgba(37, 99, 235, 0.14);
+
+  --vp-font-family-base: 'Inter', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, sans-serif;
+  --vp-font-family-mono: 'JetBrains Mono', 'Fira Code', 'Cascadia Code', monospace;
+}
+
+/* Hero section tweaks */
+.VPHero .name {
+  background: linear-gradient(135deg, #2563eb, #06b6d4);
+  -webkit-background-clip: text;
+  -webkit-text-fill-color: transparent;
+  background-clip: text;
+}
+
+.VPHero .text {
+  font-size: 2.5rem;
+}
+
+/* Blog-like content */
+.vp-doc h1 {
+  font-size: 2rem;
+  font-weight: 700;
+  letter-spacing: -0.02em;
+}
+
+.vp-doc h2 {
+  font-size: 1.5rem;
+  font-weight: 600;
+  border-bottom: 1px solid var(--vp-c-divider);
+  padding-bottom: 0.3em;
+  margin-top: 2em;
+}
+
+/* Code blocks */
+.vp-doc div[class*='language-'] {
+  border-radius: 8px;
+  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
+}
+
+.vp-doc code {
+  font-size: 0.9em;
+}
+
+/* Inline code */
+.vp-doc :not(pre) > code {
+  background: var(--vp-c-bg-soft);
+  border-radius: 4px;
+  padding: 0.15em 0.4em;
+  color: var(--vp-c-brand-1);
+}
+
+/* Tables */
+.vp-doc table {
+  width: 100%;
+  border-collapse: collapse;
+  margin: 1.5em 0;
+}
+
+.vp-doc th {
+  background: var(--vp-c-bg-soft);
+  font-weight: 600;
+}
+
+.vp-doc tr:nth-child(even) {
+  background: var(--vp-c-bg-soft);
+}
+
+/* Timeline-style for notes */
+.vp-doc ul:has(li input[type="checkbox"]) {
+  list-style: none;
+  padding-left: 0;
+}
+
+/* Print-friendly */
+@media print {
+  .VPNav, .VPSidebar, .VPFooter {
+    display: none;
+  }
+}
+
+/* Dark mode tweaks */
+.dark .VPHero .name {
+  background: linear-gradient(135deg, #60a5fa, #22d3ee);
+  -webkit-background-clip: text;
+  -webkit-text-fill-color: transparent;
+  background-clip: text;
+}
+
+.dark .vp-doc div[class*='language-'] {
+  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
+}