Fixed

• CSS !important removed — removed all !important declarations from task.css (.drop-zone-active, .batch-selected), replaced with higher-specificity selectors.

• Inline style="display:none" removed — replaced 10 instances in index.html with class="hidden".

• JS style.display toggling replaced — converted ~42 style.display toggles to classList.add/remove("hidden") across 11 JS modules. Added :not(.hidden) CSS rules for elements requiring display: flex when visible.

• Inline styles extracted to CSS — moved hardcoded layout, color, and spacing styles from index.html and JS modules into CSS classes: color swatches use [data-color] selectors, modals use --sm/--md/--lg size modifiers, sidenav meta rows use .sidenav-meta-row, form grids use .form-grid-2col, board.js drop zones use .drop-zone classes, milestones card view uses .milestones-card classes.