:root {
    --bg: #ffffff;
    --surface: #f7f6f3;
    --card: #ffffff;
    --border: #e3e2de;
    --text: #37352f;
    --text2: #9b9a97;
    --blue: #2383e2;
    --sidebar-w: 240px;
  }
  * { margin: 0; padding: 0; box-sizing: border-box; }

  body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Microsoft JhengHei", sans-serif;
    background: var(--bg);
    color: var(--text);
    height: 100vh;
    display: flex;
    overflow: hidden;
  }

  /* ── Sidebar ── */
  .sidebar {
    width: var(--sidebar-w);
    min-width: var(--sidebar-w);
    background: var(--surface);
    border-right: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    transition: margin-left .25s ease, opacity .25s ease;
    overflow: hidden;
    z-index: 10;
  }
  .sidebar.collapsed {
    margin-left: calc(var(--sidebar-w) * -1);
    opacity: 0;
    pointer-events: none;
  }
  .sidebar-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 16px 14px 12px;
    border-bottom: 1px solid var(--border);
  }
  .sidebar-header h2 {
    font-size: 14px;
    font-weight: 700;
    color: var(--text2);
    text-transform: uppercase;
    letter-spacing: .5px;
  }
  .sidebar-header .btn-collapse {
    background: none;
    border: none;
    color: var(--text2);
    cursor: pointer;
    font-size: 18px;
    padding: 2px 4px;
    border-radius: 4px;
    line-height: 1;
    transition: color .1s, background .1s;
  }
  .sidebar-header .btn-collapse:hover { color: var(--text); background: var(--border); }

  .sidebar-list {
    flex: 1;
    overflow-y: auto;
    padding: 8px 8px;
  }
  .sidebar-item {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 8px 10px;
    border-radius: 6px;
    cursor: pointer;
    font-size: 14px;
    transition: background .1s;
    user-select: none;
  }
  .sidebar-item:hover { background: var(--border); }
  .sidebar-item.active { background: rgba(35,131,226,.08); color: var(--blue); font-weight: 600; }
  .sidebar-item .board-icon {
    font-size: 16px;
    flex-shrink: 0;
    width: 20px;
    text-align: center;
  }
  .sidebar-item .board-name {
    flex: 1;
    min-width: 0;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
  }
  .sidebar-item .btn-del-board {
    background: none;
    border: none;
    color: transparent;
    cursor: pointer;
    font-size: 12px;
    padding: 2px 4px;
    border-radius: 4px;
    transition: color .1s;
    flex-shrink: 0;
  }
  .sidebar-item:hover .btn-del-board { color: var(--text2); }
  .sidebar-item .btn-del-board:hover { color: #d44c47; }

  .sidebar-list .sortable-ghost {
    background: rgba(35,131,226,.08) !important;
    border: 1px dashed var(--blue) !important;
    border-radius: 6px !important;
  }
  .sidebar-list .sortable-ghost * { visibility: hidden; }
  .sidebar-list .sortable-drag {
    background: var(--surface) !important;
    box-shadow: 0 2px 8px rgba(0,0,0,.1) !important;
    border-radius: 6px !important;
  }

  .sidebar-add {
    padding: 6px 8px 2px;
  }
  .sidebar-add button {
    width: 100%;
    padding: 7px 10px;
    border: none;
    border-radius: 6px;
    background: transparent;
    color: var(--text2);
    font-size: 13px;
    font-weight: 600;
    cursor: pointer;
    text-align: left;
    transition: background .1s, color .1s;
  }
  .sidebar-add button:hover { background: var(--border); color: var(--text); }

  /* ── Sidebar User Profile ── */
  .sidebar-user {
    padding: 12px;
    border-top: 1px solid var(--border);
    display: flex;
    align-items: center;
    gap: 10px;
    cursor: pointer;
    transition: background .1s;
  }
  .sidebar-user:hover { background: var(--border); }
  .sidebar-user .avatar {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    background: var(--border);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 14px;
    color: var(--text2);
    flex-shrink: 0;
    overflow: hidden;
  }
  .sidebar-user .avatar img {
    width: 100%;
    height: 100%;
    object-fit: cover;
  }
  .sidebar-user .user-info {
    flex: 1;
    min-width: 0;
  }
  .sidebar-user .user-name {
    font-size: 13px;
    font-weight: 600;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
  }
  .sidebar-user .user-plan {
    font-size: 11px;
    color: var(--text2);
    margin-top: 1px;
  }
  .sidebar-user .user-plan .plan-badge {
    display: inline-block;
    padding: 1px 6px;
    border-radius: 3px;
    font-weight: 600;
    font-size: 10px;
  }
  .sidebar-user .plan-free {
    background: rgba(155,154,151,.15);
    color: var(--text2);
  }
  .sidebar-user .plan-pro {
    background: rgba(35,131,226,.1);
    color: var(--blue);
  }

  /* ── Main Content ── */
  .main {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    min-width: 0;
  }

  /* ── Header ── */
  header {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 20px 32px 12px;
  }
  .btn-toggle-sidebar {
    background: none;
    border: none;
    color: var(--text2);
    cursor: pointer;
    font-size: 20px;
    padding: 4px 6px;
    border-radius: 4px;
    line-height: 1;
    transition: color .1s, background .1s;
    flex-shrink: 0;
  }
  .btn-toggle-sidebar:hover { color: var(--text); background: var(--surface); }
  header h1 {
    font-size: 24px;
    font-weight: 700;
    flex: 1;
    min-width: 0;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    cursor: pointer;
    border-radius: 4px;
    padding: 2px 6px;
    margin: -2px -6px;
    transition: background .1s;
  }
  header h1:hover { background: var(--surface); }
  header .stats { font-size: 14px; color: var(--text2); flex-shrink: 0; }

  /* ── Quick Add ── */
  .quick-add {
    display: flex;
    gap: 10px;
    padding: 0 32px 16px;
  }
  .quick-add input {
    flex: 1;
    padding: 10px 14px;
    border: 1px solid var(--border);
    border-radius: 6px;
    background: var(--bg);
    color: var(--text);
    font-size: 15px;
    outline: none;
    transition: border-color .15s, box-shadow .15s;
  }
  .quick-add input:focus {
    border-color: var(--blue);
    box-shadow: 0 0 0 2px rgba(35,131,226,.15);
  }
  .quick-add input::placeholder { color: var(--text2); }
  .quick-add button {
    padding: 10px 20px;
    border: none;
    border-radius: 6px;
    background: var(--blue);
    color: #fff;
    font-size: 15px;
    font-weight: 600;
    cursor: pointer;
    transition: opacity .15s;
    white-space: nowrap;
  }
  .quick-add button:hover { opacity: .85; }

  /* ── Board ── */
  .board {
    flex: 1;
    display: flex;
    gap: 12px;
    padding: 0 32px 16px;
    overflow-x: auto;
    overflow-y: hidden;
  }
  .column {
    flex: 0 0 auto;
    width: 300px;
    min-width: 280px;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 0 4px 6px;
  }
  .column-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 8px 8px 10px;
    font-weight: 600;
    font-size: 15px;
    cursor: grab;
  }
  .column-header:active { cursor: grabbing; }
  .column-header .label {
    padding: 2px 8px;
    border-radius: 4px;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
  }
  .column-header .label:hover { opacity: .8; }
  .column-header .count {
    font-size: 13px;
    color: var(--text2);
    font-weight: 400;
  }
  .column-header .col-actions {
    display: flex;
    align-items: center;
    gap: 4px;
  }
  .column-header .btn-del-col {
    background: none;
    border: none;
    color: var(--border);
    cursor: pointer;
    font-size: 13px;
    padding: 2px 5px;
    border-radius: 4px;
    transition: color .1s;
  }
  .column-header .btn-del-col:hover { color: #d44c47; }

  .column-body {
    flex: 1;
    padding: 0 4px;
    overflow-x: hidden;
    overflow-y: auto;
    min-height: 60px;
    scroll-behavior: smooth;
  }

  /* ── Add Column ── */
  .add-column {
    flex: 0 0 auto;
    width: 280px;
    min-width: 280px;
    display: flex;
    align-items: flex-start;
    padding-top: 6px;
  }
  .add-column button {
    width: 100%;
    padding: 10px;
    border: 2px dashed var(--border);
    border-radius: 8px;
    background: transparent;
    color: var(--text2);
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: border-color .15s, color .15s;
  }
  .add-column button:hover {
    border-color: var(--blue);
    color: var(--blue);
  }

  /* ── Cards ── */
  .card {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: 4px;
    padding: 9px 10px;
    margin-bottom: 6px;
    display: flex;
    align-items: center;
    gap: 8px;
    transition: background .1s;
    user-select: none;
    cursor: grab;
  }
  .card:hover { background: var(--surface); }
  .board.is-dragging .card:hover { background: var(--card); }
  .card:active { cursor: grabbing; }

  .card-title {
    font-size: 16px;
    font-weight: 600;
    line-height: 1.5;
    flex: 1;
    min-width: 0;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
  }

  .card .btn-delete {
    background: none;
    border: none;
    color: var(--border);
    cursor: pointer;
    font-size: 14px;
    padding: 3px 5px;
    border-radius: 4px;
    flex-shrink: 0;
    transition: color .1s;
  }
  .card .btn-delete:hover { color: #d44c47; }

  /* SortableJS - Cards */
  .sortable-ghost {
    opacity: 1;
    background: rgba(35,131,226,.06) !important;
    border: 2px dashed var(--blue) !important;
    transition: none !important;
  }
  .sortable-ghost * { visibility: hidden; }
  .sortable-chosen {
    background: var(--card) !important;
    box-shadow: 0 2px 8px rgba(0,0,0,.12) !important;
    cursor: grabbing !important;
  }
  .sortable-drag {
    opacity: 0.95;
    background: var(--card) !important;
    box-shadow: 0 4px 16px rgba(0,0,0,.15) !important;
    border: 1px solid var(--border) !important;
  }

  /* SortableJS - Columns */
  .board > .sortable-ghost {
    background: rgba(35,131,226,.04) !important;
    border: 2px dashed var(--blue) !important;
    border-radius: 8px !important;
    opacity: 1;
  }
  .board > .sortable-ghost * { visibility: hidden; }
  .board > .sortable-chosen {
    background: var(--surface) !important;
    box-shadow: none !important;
  }
  .board > .sortable-drag {
    background: var(--surface) !important;
    box-shadow: 0 4px 20px rgba(0,0,0,.12) !important;
    border-radius: 8px !important;
    border: 1px solid var(--border) !important;
    opacity: 0.95;
  }

  /* ── Animations ── */
  @keyframes cardIn {
    from { opacity: 0; transform: translateY(-6px); }
    to   { opacity: 1; transform: translateY(0); }
  }
  .card.new-card { animation: cardIn .2s ease-out; }

  /* ── Modal ── */
  .modal-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,.3);
    z-index: 100;
    align-items: center;
    justify-content: center;
  }
  .modal-overlay.active { display: flex; }
  .modal {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 28px;
    width: 640px;
    max-width: 90vw;
    box-shadow: 0 8px 32px rgba(0,0,0,.12);
    animation: cardIn .2s ease-out;
  }
  .modal h3 { margin-bottom: 24px; font-size: 20px; font-weight: 700; }
  .modal-field { margin-bottom: 16px; }
  .modal-field label {
    display: block;
    margin-bottom: 6px;
    font-size: 13px;
    color: var(--text2);
    font-weight: 600;
  }
  .modal-field input,
  .modal-field textarea,
  .modal-field select {
    width: 100%;
    padding: 10px 12px;
    border: 1px solid var(--border);
    border-radius: 6px;
    background: var(--bg);
    color: var(--text);
    font-size: 16px;
    outline: none;
    font-family: inherit;
    transition: border-color .15s, box-shadow .15s;
  }
  .modal-field input:focus,
  .modal-field textarea:focus {
    border-color: var(--blue);
    box-shadow: 0 0 0 2px rgba(35,131,226,.15);
  }
  .modal-field textarea {
    resize: none;
    height: 200px;
  }
  .modal-buttons {
    display: flex;
    justify-content: flex-end;
    gap: 8px;
    margin-top: 20px;
  }
  .modal-buttons button {
    padding: 8px 20px;
    border: none;
    border-radius: 6px;
    font-size: 14px;
    cursor: pointer;
    font-weight: 600;
    transition: opacity .15s;
  }
  .btn-cancel { background: var(--surface); color: var(--text2); border: 1px solid var(--border); }
  .btn-cancel:hover { color: var(--text); }
  .btn-save { background: var(--blue); color: #fff; }
  .btn-save:hover { opacity: .85; }

  /* ── Column Name Modal ── */
  .col-modal-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,.3);
    z-index: 100;
    align-items: center;
    justify-content: center;
  }
  .col-modal-overlay.active { display: flex; }
  .col-modal {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 24px;
    width: 400px;
    max-width: 90vw;
    box-shadow: 0 8px 32px rgba(0,0,0,.12);
    animation: cardIn .2s ease-out;
  }
  .col-modal h3 { margin-bottom: 20px; font-size: 18px; font-weight: 700; }
  .color-picker {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    margin-top: 8px;
  }
  .color-swatch {
    width: 28px;
    height: 28px;
    border-radius: 50%;
    border: 2px solid transparent;
    cursor: pointer;
    transition: transform .1s, border-color .1s;
  }
  .color-swatch:hover { transform: scale(1.15); }
  .color-swatch.selected { border-color: var(--text); transform: scale(1.15); }

  /* ── Scrollbar ── */
  ::-webkit-scrollbar { width: 6px; height: 6px; }
  ::-webkit-scrollbar-track { background: transparent; }
  ::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }

  /* ── Footer ── */
  .keyboard-hint {
    text-align: center;
    padding: 6px;
    font-size: 12px;
    color: var(--text2);
    border-top: 1px solid var(--border);
  }