chore: initialize monorepo with project scaffolding, configs, and CI setup

apps/explorer-web/public/css/base.css

@@ -0,0 +1,82 @@
+:root {
+  color-scheme: dark;
+  font-family: var(--font-base);
+  font-size: 16px;
+  line-height: 1.5;
+}
+
+* {
+  box-sizing: border-box;
+}
+
+body {
+  margin: 0;
+  background-color: var(--color-bg);
+  color: var(--color-text-primary);
+}
+
+a {
+  color: var(--color-primary);
+  text-decoration: none;
+}
+
+a:hover,
+a:focus {
+  text-decoration: underline;
+}
+
+p {
+  margin: 0 0 1rem;
+}
+
+h1,
+h2,
+h3,
+h4,
+h5,
+h6 {
+  margin: 0 0 0.75rem;
+  line-height: 1.2;
+}
+
+code {
+  font-family: var(--font-mono);
+  font-size: 0.95em;
+  background: var(--color-table-head);
+  padding: 0.125rem 0.375rem;
+  border-radius: var(--radius-sm);
+}
+
+.table {
+  width: 100%;
+  border-collapse: collapse;
+  margin: 1rem 0;
+}
+
+.table thead {
+  background: var(--color-table-head);
+}
+
+.table th,
+.table td {
+  padding: 0.75rem;
+  text-align: left;
+}
+
+.table tbody tr:nth-child(even) {
+  background: var(--color-table-even);
+}
+
+.table tbody tr:hover {
+  background: var(--color-primary-hover);
+}
+
+.placeholder {
+  color: var(--color-placeholder);
+  font-style: italic;
+}
+
+.lead {
+  font-size: 1.05rem;
+  color: var(--color-text-secondary);
+}