Change leadership graph to line and add linear best fit

app/static/css/style.css

@@ -814,6 +814,94 @@ tr:hover td {
     box-shadow: 0 0 0 3px var(--accent-glow);
 }
 
+/* ========== CHART FILTERS ========== */
+.chart-filters {
+    display: flex;
+    flex-wrap: wrap;
+    gap: 1rem;
+    align-items: flex-start;
+    padding: 0 0 1rem;
+}
+
+.filter-group {
+    display: flex;
+    flex-direction: column;
+    gap: 0.35rem;
+}
+
+.filter-group label {
+    font-size: 0.75rem;
+    font-weight: 500;
+    text-transform: uppercase;
+    letter-spacing: 0.05em;
+    color: var(--text-muted);
+}
+
+.filter-group input[type="date"] {
+    width: 160px;
+    padding: 0.5rem 0.75rem;
+    background: var(--bg-input);
+    border: 1px solid var(--border);
+    border-radius: var(--radius-sm);
+    color: var(--text-primary);
+    font-family: inherit;
+    font-size: 0.85rem;
+    outline: none;
+    transition: all 0.2s ease;
+}
+
+.filter-group input[type="date"]:focus {
+    border-color: var(--border-focus);
+    box-shadow: 0 0 0 3px var(--accent-glow);
+}
+
+.filter-group-people {
+    flex: 1;
+    min-width: 200px;
+}
+
+.person-filter-list {
+    display: flex;
+    flex-wrap: wrap;
+    gap: 0.5rem;
+    max-height: 72px;
+    overflow-y: auto;
+    padding: 0.25rem 0;
+}
+
+.person-checkbox {
+    display: inline-flex;
+    align-items: center;
+    gap: 0.35rem;
+    padding: 0.3rem 0.65rem;
+    background: var(--bg-secondary);
+    border: 1px solid var(--border);
+    border-radius: 100px;
+    font-size: 0.8rem;
+    color: var(--text-secondary);
+    cursor: pointer;
+    transition: all 0.2s ease;
+    user-select: none;
+}
+
+.person-checkbox:hover {
+    border-color: var(--accent);
+    color: var(--text-primary);
+}
+
+.person-checkbox input[type="checkbox"] {
+    accent-color: var(--accent);
+    width: 14px;
+    height: 14px;
+    cursor: pointer;
+}
+
+.person-checkbox:has(input:checked) {
+    background: var(--accent-glow);
+    border-color: rgba(59, 130, 246, 0.3);
+    color: var(--accent);
+}
+
 /* ========== RESPONSIVE ========== */
 @media (max-width: 768px) {
     .navbar {