diff --git a/backend/internal/web/ui/app.css b/backend/internal/web/ui/app.css
index e326167..e043484 100644
--- a/backend/internal/web/ui/app.css
+++ b/backend/internal/web/ui/app.css
@@ -448,3 +448,243 @@
   gap: 0.5rem;
   margin-bottom: 1rem;
 }
+
+/* ============================================================
+   Section 19 — Tasks section (kanban column container)
+   ============================================================ */
+
+.tasks-section {
+  background: var(--color-surface-default);
+  border: 1px solid var(--color-border-subtle);
+  border-radius: 1rem;
+  overflow: hidden;
+}
+
+.tasks-section-header {
+  align-items: center;
+  border-bottom: 1px solid var(--color-border-muted);
+  display: flex;
+  justify-content: space-between;
+  padding: 1.2rem 1rem;
+}
+
+.tasks-add-button {
+  align-items: center;
+  background: var(--color-surface-default);
+  border: 1px solid var(--color-border-muted);
+  border-radius: 0.7rem;
+  color: var(--color-text-secondary);
+  cursor: pointer;
+  display: inline-flex;
+  font-weight: 500;
+  gap: 0.5rem;
+  min-height: 2.75rem;
+  padding: 0.7rem 1rem;
+}
+
+.task-list {
+  display: flex;
+  flex-direction: column;
+}
+
+.task-row {
+  align-items: center;
+  border-bottom: 1px solid var(--color-border-muted);
+  cursor: pointer;
+  display: flex;
+  gap: 0.75rem;
+  padding: 0.9rem 1rem;
+  transition: background-color 0.2s ease;
+}
+
+.task-row:hover {
+  background: var(--color-surface-neutral-hover);
+}
+
+.task-check {
+  align-items: center;
+  background: var(--color-surface-default);
+  border: 2px solid var(--color-border-strong);
+  border-radius: 999px;
+  color: var(--color-text-inverse);
+  cursor: pointer;
+  display: inline-flex;
+  flex-shrink: 0;
+  height: 2rem;
+  justify-content: center;
+  width: 2rem;
+}
+
+.task-check.is-complete {
+  background: var(--color-text-brand-strong);
+  border-color: var(--color-text-brand-strong);
+}
+
+.task-body {
+  flex: 1;
+  min-width: 0;
+}
+
+.task-body p {
+  color: var(--color-surface-muted-inverse);
+  font-size: 0.95rem;
+  font-weight: 500;
+  margin: 0;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
+.task-row.is-complete .task-body p {
+  color: var(--color-text-faint);
+  text-decoration: line-through;
+}
+
+.task-meta {
+  align-items: center;
+  color: var(--color-text-muted);
+  display: flex;
+  flex-wrap: wrap;
+  font-size: 0.75rem;
+  gap: 0.45rem;
+  margin-top: 0.3rem;
+}
+
+/* ============================================================
+   Section 20 — Progress track and bar
+   ============================================================ */
+
+.project-progress-track {
+  background: var(--color-surface-muted);
+  border-radius: 999px;
+  height: 0.5rem;
+  overflow: hidden;
+}
+
+.project-progress-bar {
+  background: var(--project-color, var(--color-project-fallback));
+  border-radius: 999px;
+  height: 100%;
+}
+
+/* ============================================================
+   Section 21 — Tab nav (tablo detail tab bar)
+   ============================================================ */
+
+.tab-nav {
+  align-items: center;
+  border-bottom: 1px solid var(--color-border-muted);
+  display: flex;
+  gap: 1.5rem;
+  margin-bottom: 1.5rem;
+  overflow-x: auto;
+}
+
+.tab-nav-item {
+  align-items: center;
+  border-bottom: 2px solid transparent;
+  color: var(--color-text-muted);
+  display: flex;
+  font-size: 0.875rem;
+  font-weight: 400;
+  gap: 0.5rem;
+  min-height: 44px;
+  padding-bottom: 0.75rem;
+  padding-inline: 0.25rem;
+  transition: color 0.15s ease, border-color 0.15s ease;
+}
+
+.tab-nav-item.is-active {
+  border-bottom-color: var(--color-brand-primary);
+  color: var(--color-text-brand);
+  font-weight: 600;
+}
+
+.tab-nav-item:hover:not(.is-active) {
+  color: var(--color-text-primary);
+}
+
+/* ============================================================
+   Section 22 — Tablo detail metadata row
+   ============================================================ */
+
+.tablo-metadata-row {
+  align-items: center;
+  border-bottom: 1px solid var(--color-border-muted);
+  display: flex;
+  flex-wrap: wrap;
+  gap: 1rem;
+  margin-bottom: 1rem;
+  padding-bottom: 1rem;
+}
+
+.tablo-metadata-date {
+  align-items: center;
+  color: var(--color-text-muted);
+  display: flex;
+  font-size: 0.875rem;
+  gap: 0.5rem;
+}
+
+.tablo-metadata-date svg {
+  height: 1rem;
+  width: 1rem;
+}
+
+/* ============================================================
+   Section 23 — Kanban column wrapper
+   ============================================================ */
+
+.kanban-column {
+  flex-shrink: 0;
+  width: 18rem;
+}
+
+/* Scope column h3 to 1rem — base rule is 1.6rem (full-width views).
+   18rem columns overflow at 1.6rem. Base rule left unchanged. */
+.kanban-column .tasks-section-header h3 {
+  font-size: 1rem;
+}
+
+/* ============================================================
+   Section 24 — Etape group sub-headings inside kanban columns
+   ============================================================ */
+
+.etape-group-header {
+  align-items: center;
+  background: var(--color-surface-muted);
+  border-bottom: 1px solid var(--color-border-muted);
+  display: flex;
+  gap: 0.5rem;
+  padding: 0.5rem 1rem;
+}
+
+.etape-group-color-dot {
+  background: var(--project-color, var(--color-project-fallback));
+  border-radius: 999px;
+  flex-shrink: 0;
+  height: 0.5rem;
+  width: 0.5rem;
+}
+
+.etape-group-label {
+  color: var(--color-text-secondary);
+  font-size: 0.875rem;
+  font-weight: 600;
+}
+
+.etape-group-label.is-unassigned {
+  color: var(--color-text-muted);
+  font-weight: 400;
+}
+
+/* ============================================================
+   Section 25 — Empty task list placeholder
+   ============================================================ */
+
+.task-list-empty {
+  color: var(--color-text-faint);
+  font-size: 0.875rem;
+  font-style: italic;
+  padding: 0.75rem 1rem;
+}