:root {
  --bg: #f4f5f7;
  --panel: #ffffff;
  --border: #d8dce1;
  --text: #1f2430;
  --text-dim: #5b6472;
  --accent: #1f5fa8;
  --accent-dim: #eaf1fb;
  --radius: 10px;
  --brand-yellow: #f4b400;
  --brand-black: #1a1a1a;
  --danger: #c0392b;
}
* { box-sizing: border-box; }
[hidden] { display: none !important; }
body {
  margin: 0;
  font-family: -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.4;
}
button { font-family: inherit; cursor: pointer; }

/* ---- login ---- */
.login-screen {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--brand-black);
}
.login-box {
  background: var(--panel);
  padding: 32px 28px;
  border-radius: var(--radius);
  width: 320px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  box-shadow: 0 12px 40px rgba(0,0,0,0.35);
}
.login-box h1 { margin: 0; font-size: 1.3em; }
.login-sub { margin: 0 0 8px; color: var(--text-dim); font-size: 0.9em; }
.login-box input {
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: 6px;
  font-size: 1em;
}
.login-box button[type="submit"] {
  background: var(--brand-yellow);
  color: var(--brand-black);
  border: none;
  padding: 10px 12px;
  border-radius: 6px;
  font-weight: 700;
  margin-top: 4px;
}
.login-error { color: var(--danger); font-size: 0.85em; margin: 0; }

/* ---- app shell ---- */
.app { height: 100vh; display: flex; flex-direction: column; }
.topbar {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 10px 20px;
  background: var(--brand-black);
  color: white;
  flex: none;
}
.topbar .logo { height: 28px; }
.topbar h1 { font-size: 1.1em; margin: 0; white-space: nowrap; }
.topbar .hint { flex: 1; color: #b7bcc4; font-size: 0.82em; text-align: center; }
.search-wrap { flex: 1; display: flex; align-items: center; gap: 6px; }
.search-scope { display: flex; align-items: center; gap: 4px; font-size: 0.82em; color: var(--text-dim); white-space: nowrap; cursor: pointer; }
.search-wrap input {
  flex: 1;
  min-width: 0;
  padding: 7px 10px;
  border-radius: 6px;
  border: 1px solid var(--border);
}
.search-wrap button, .user-wrap button {
  background: var(--accent);
  color: white;
  border: none;
  padding: 7px 12px;
  border-radius: 6px;
}
.user-wrap { display: flex; align-items: center; gap: 10px; white-space: nowrap; }
.user-wrap button { background: transparent; border: 1px solid #4a4f5a; }

/* ---- three-column layout ---- */
.columns { flex: 1; display: flex; min-height: 0; }
.col { min-width: 0; display: flex; flex-direction: column; border-right: 1px solid var(--border); }
.col:last-child { border-right: none; }
.col-root { flex: 0 0 220px; }
.col-work { flex: 1 1 0; }
.col-preview { flex: 1 1 0; }
.col-header {
  display: flex; align-items: center; justify-content: space-between; gap: 8px;
  padding: 10px 12px; background: var(--panel); border-bottom: 1px solid var(--border);
}
.col-header h2 { margin: 0; font-size: 0.95em; }
.col-header button {
  background: var(--panel); border: 1px solid var(--border); border-radius: 6px;
  padding: 5px 10px; font-size: 0.85em; white-space: nowrap;
}
.col-header button:hover { background: var(--accent-dim); }
.col-toolbar {
  display: flex; align-items: center; justify-content: space-between; gap: 8px; flex-wrap: wrap;
  padding: 8px 12px; background: var(--panel); border-bottom: 1px solid var(--border);
}
.toolbar { display: flex; gap: 8px; flex: none; }
.toolbar button {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 6px 12px;
  font-size: 0.88em;
  white-space: nowrap;
}
.toolbar button:hover { background: var(--accent-dim); }

.breadcrumbs {
  padding: 8px 12px;
  background: var(--panel);
  border-bottom: 1px solid var(--border);
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  font-size: 0.9em;
}
.breadcrumbs a { color: var(--accent); cursor: pointer; text-decoration: none; }
.breadcrumbs a:hover { text-decoration: underline; }
.breadcrumbs .sep { color: var(--text-dim); }

.col-content { flex: 1; overflow: auto; padding: 0 12px 20px; position: relative; }
.col-content.drag-over { outline: 2px dashed var(--accent); outline-offset: -2px; background: var(--accent-dim); }
.file-table { width: 100%; border-collapse: collapse; background: var(--panel); }
.file-table th {
  text-align: left;
  padding: 8px 10px;
  border-bottom: 2px solid var(--border);
  color: var(--text-dim);
  font-size: 0.82em;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  position: sticky;
  top: 0;
  background: var(--panel);
}
.file-table th.sortable { cursor: pointer; user-select: none; }
.file-table th.sortable:hover { color: var(--text); }
.file-table th.sort-asc::after { content: " \25B2"; }
.file-table th.sort-desc::after { content: " \25BC"; }
.file-table td { padding: 7px 10px; border-bottom: 1px solid var(--border); font-size: 0.94em; }
.file-table tr.row:hover { background: var(--accent-dim); }
.file-table tr.row { cursor: pointer; user-select: none; }
.file-table tr.row.selected { background: var(--accent-dim); box-shadow: inset 3px 0 0 var(--accent); }
.col-size, .col-modified { white-space: nowrap; color: var(--text-dim); width: 140px; }
.name-cell { display: flex; align-items: center; gap: 8px; }
.content-match-badge {
  background: var(--accent-dim); color: var(--accent); border-radius: 4px;
  padding: 1px 6px; font-size: 0.72em; font-weight: 600; text-transform: uppercase; letter-spacing: 0.03em;
}
.icon { width: 18px; text-align: center; }
.empty-state { padding: 40px; text-align: center; color: var(--text-dim); }

/* ---- context menu ---- */
.context-menu {
  position: fixed;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 8px;
  box-shadow: 0 8px 24px rgba(0,0,0,0.18);
  padding: 6px;
  min-width: 220px;
  z-index: 1000;
}
.context-menu .item {
  padding: 8px 12px;
  border-radius: 5px;
  font-size: 0.92em;
  white-space: nowrap;
}
.context-menu .item:hover { background: var(--accent-dim); }
.context-menu .sep { height: 1px; background: var(--border); margin: 5px 2px; }
.context-menu .item.disabled { color: var(--text-dim); cursor: default; }
.context-menu .item.disabled:hover { background: none; }

/* ---- modals ---- */
.modal-backdrop {
  position: fixed; inset: 0; background: rgba(0,0,0,0.4);
  display: flex; align-items: center; justify-content: center; z-index: 2000;
}
.modal {
  background: var(--panel); border-radius: var(--radius); width: 420px; max-width: 92vw;
  max-height: 88vh; display: flex; flex-direction: column; overflow: hidden;
}
.modal-header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 12px 16px; border-bottom: 1px solid var(--border); font-weight: 600;
}
.modal-close { background: none; border: none; font-size: 1.3em; color: var(--text-dim); }
.modal-body { padding: 16px; overflow: auto; display: flex; flex-direction: column; gap: 12px; }
.modal-body label { display: flex; flex-direction: column; gap: 4px; font-size: 0.88em; color: var(--text-dim); }
.modal-body input, .modal-body select, .modal-body textarea {
  padding: 8px 10px; border: 1px solid var(--border); border-radius: 6px; font-size: 0.95em; font-family: inherit; color: var(--text);
}
.modal-footer { display: flex; justify-content: flex-end; gap: 8px; padding: 12px 16px; border-top: 1px solid var(--border); }
.btn-primary { background: var(--brand-yellow); color: var(--brand-black); border: none; padding: 8px 16px; border-radius: 6px; font-weight: 700; }
.btn-secondary { background: transparent; border: 1px solid var(--border); padding: 8px 16px; border-radius: 6px; }
.form-error { color: var(--danger); font-size: 0.85em; margin: 0; }
#preview-body img, #preview-body iframe { max-width: 100%; }
#preview-body iframe { width: 100%; height: calc(100vh - 160px); border: none; }
#preview-download-btn { background: var(--accent); color: white; border: none; }

/* ---- office document preview ---- */
.doc-preview { padding: 4px 2px; }
.doc-preview img { max-width: 100%; }
.doc-preview table { border-collapse: collapse; margin: 8px 0; }
.doc-preview table td, .doc-preview table th { border: 1px solid var(--border); padding: 4px 8px; }

.sheet-tabs { display: flex; gap: 4px; flex-wrap: wrap; border-bottom: 1px solid var(--border); padding-bottom: 8px; }
.sheet-tab { background: var(--panel); border: 1px solid var(--border); border-radius: 6px; padding: 5px 10px; font-size: 0.85em; }
.sheet-tab.active { background: var(--accent); color: white; border-color: var(--accent); }
.sheet-table-wrap { margin-top: 8px; overflow-x: auto; }
.sheet-table-wrap table { border-collapse: collapse; font-size: 0.85em; }
.sheet-table-wrap table td, .sheet-table-wrap table th { border: 1px solid var(--border); padding: 4px 8px; white-space: nowrap; }

.slide-preview { border: 1px solid var(--border); border-radius: 8px; padding: 12px 14px; margin-bottom: 10px; }
.slide-num { font-weight: 700; color: var(--text-dim); font-size: 0.8em; text-transform: uppercase; margin-bottom: 6px; }
.slide-text { white-space: pre-wrap; }

/* ---- task editor ---- */
.task-editor-modal { width: min(780px, 94vw); }
.task-table-wrap { display: flex; flex-direction: column; gap: 8px; }
.task-table { width: 100%; border-collapse: collapse; font-size: 0.85em; }
.task-table th { text-align: left; padding: 4px 6px; color: var(--text-dim); font-weight: 600; }
.task-table td { padding: 3px 4px; }
.task-table input, .task-table select { width: 100%; padding: 5px 6px; font-size: 0.95em; }
.task-table .task-name { min-width: 130px; }
.task-table .task-remove { background: none; border: none; color: var(--danger); font-size: 1.1em; cursor: pointer; }

/* ---- activity log ---- */
.activity-modal { width: min(560px, 92vw); height: 70vh; }
.activity-list { display: flex; flex-direction: column; gap: 2px; }
.activity-row { padding: 8px 10px; border-bottom: 1px solid var(--border); font-size: 0.88em; }
.activity-row .activity-meta { color: var(--text-dim); font-size: 0.82em; }
.activity-row .activity-action { font-weight: 600; text-transform: capitalize; }
.activity-empty { padding: 24px; text-align: center; color: var(--text-dim); }

/* ---- move modal ---- */
.move-modal { width: min(520px, 92vw); height: 70vh; }
.mv-breadcrumbs { padding: 6px 0; border-bottom: 1px solid var(--border); margin-bottom: 8px; }
.mv-list { flex: 1; overflow: auto; border: 1px solid var(--border); border-radius: 6px; }
.mv-item { padding: 8px 10px; cursor: pointer; font-size: 0.92em; }
.mv-item:hover { background: var(--accent-dim); }
.mv-empty { padding: 16px; color: var(--text-dim); font-size: 0.88em; }

/* ---- viewer accounts: hide every write action ---- */
body.viewer-mode #root-new-folder-btn,
body.viewer-mode #work-new-folder-btn,
body.viewer-mode #work-upload-btn,
body.viewer-mode #work-photo-btn { display: none; }

@media (max-width: 1000px) {
  .columns { flex-direction: column; }
  .col, .col-root { flex: none; border-right: none; border-bottom: 1px solid var(--border); min-height: 220px; }
  .col:last-child { border-bottom: none; }
  .topbar .hint { display: none; }
}

/* ---- toast ---- */
.toast {
  position: fixed; bottom: 24px; left: 50%; transform: translateX(-50%);
  background: var(--brand-black); color: white; padding: 10px 18px; border-radius: 8px;
  font-size: 0.9em; z-index: 3000; box-shadow: 0 6px 20px rgba(0,0,0,0.3);
}
.toast.error { background: var(--danger); }