:root {
  --radius: 10px;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.12);
  --transition: 0.2s ease;

  /* Light theme (default) */
  --bg: #f3f4f6;
  --panel: #ffffff;
  --text: #111827;
  --text-secondary: #4b5563;
  --muted: #6b7280;
  --border: #e5e7eb;
  --border-strong: #d1d5db;
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --primary-soft: #dbeafe;
  --danger: #dc2626;
  --danger-hover: #b91c1c;
  --danger-soft: #fee2e2;
  --secondary: #f3f4f6;
  --secondary-hover: #e5e7eb;
  --success: #16a34a;
  --icon-folder: #f59e0b;
  --icon-file: #6b7280;
}

[data-theme="dark"] {
  --bg: #0f172a;
  --panel: #1e293b;
  --text: #f8fafc;
  --text-secondary: #cbd5e1;
  --muted: #94a3b8;
  --border: #334155;
  --border-strong: #475569;
  --primary: #60a5fa;
  --primary-hover: #3b82f6;
  --primary-soft: rgba(96, 165, 250, 0.15);
  --danger: #f87171;
  --danger-hover: #ef4444;
  --danger-soft: rgba(248, 113, 113, 0.15);
  --secondary: #334155;
  --secondary-hover: #475569;
  --success: #4ade80;
  --icon-folder: #fbbf24;
  --icon-file: #94a3b8;
}

@media (prefers-color-scheme: dark) {
  [data-theme="system"] {
    --bg: #0f172a;
    --panel: #1e293b;
    --text: #f8fafc;
    --text-secondary: #cbd5e1;
    --muted: #94a3b8;
    --border: #334155;
    --border-strong: #475569;
    --primary: #60a5fa;
    --primary-hover: #3b82f6;
    --primary-soft: rgba(96, 165, 250, 0.15);
    --danger: #f87171;
    --danger-hover: #ef4444;
    --danger-soft: rgba(248, 113, 113, 0.15);
    --secondary: #334155;
    --secondary-hover: #475569;
    --success: #4ade80;
    --icon-folder: #fbbf24;
    --icon-file: #94a3b8;
  }
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  height: 100%;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  transition: background var(--transition), color var(--transition);
}

.icon {
  width: 20px;
  height: 20px;
  display: inline-block;
  vertical-align: middle;
  flex-shrink: 0;
}

.icon-sm { width: 16px; height: 16px; }
.icon-lg { width: 48px; height: 48px; }
.icon-xl { width: 64px; height: 64px; }

.screen.hidden { display: none !important; }

/* Browser warning */
.browser-warning {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.75rem 1rem;
  background: var(--danger-soft);
  color: var(--danger);
  border-bottom: 1px solid var(--danger);
  font-size: 0.95rem;
}

.browser-warning.hidden { display: none !important; }

.browser-warning .icon { color: currentColor; }

.browser-warning span { flex: 1; }

.browser-warning .btn-close {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  padding: 0;
  border: none;
  border-radius: 6px;
  background: transparent;
  color: currentColor;
  cursor: pointer;
}

.browser-warning .btn-close:hover { background: rgba(0, 0, 0, 0.08); }

/* Tooltip */
[data-tooltip] {
  position: relative;
}

[data-tooltip]::after {
  content: attr(data-tooltip);
  position: absolute;
  bottom: 120%;
  left: 50%;
  transform: translateX(-50%) translateY(4px);
  padding: 0.35rem 0.6rem;
  background: var(--text);
  color: var(--bg);
  font-size: 0.75rem;
  white-space: nowrap;
  border-radius: 6px;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition), transform var(--transition);
  z-index: 1000;
}

[data-tooltip]:hover::after {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  padding: 0.55rem 0.9rem;
  border: 1px solid transparent;
  border-radius: var(--radius);
  cursor: pointer;
  font-weight: 500;
  font-size: 0.9rem;
  background: var(--secondary);
  color: var(--text);
  transition: background var(--transition), transform 0.1s ease;
}

.btn:hover { background: var(--secondary-hover); }
.btn:active { transform: translateY(1px); }

.btn-primary { background: var(--primary); color: white; }
.btn-primary:hover { background: var(--primary-hover); }

.btn-danger { background: var(--danger); color: white; }
.btn-danger:hover { background: var(--danger-hover); }

.btn-secondary { background: var(--secondary); color: var(--text); border-color: var(--border); }
.btn-secondary:hover { background: var(--secondary-hover); }

.icon-btn {
  padding: 0.55rem;
  width: 38px;
  height: 38px;
}

/* Login */
#login-screen {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1rem;
}

.login-card {
  background: var(--panel);
  padding: 2.5rem;
  border-radius: var(--radius);
  box-shadow: var(--shadow-lg);
  width: 100%;
  max-width: 380px;
  text-align: center;
  border: 1px solid var(--border);
}

.login-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 80px;
  height: 80px;
  border-radius: 50%;
  background: var(--primary-soft);
  color: var(--primary);
  margin-bottom: 1rem;
}

.login-card h1 { margin: 0 0 1.5rem; font-size: 1.5rem; }

.login-card label {
  display: block;
  margin-bottom: 1rem;
  font-weight: 500;
  text-align: left;
  color: var(--text-secondary);
}

.login-card input {
  width: 100%;
  margin-top: 0.35rem;
  padding: 0.65rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg);
  color: var(--text);
}

.login-card button {
  width: 100%;
  padding: 0.75rem;
  background: var(--primary);
  color: white;
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  font-weight: 600;
  font-size: 1rem;
}

.login-card button:hover { background: var(--primary-hover); }

.error { color: var(--danger); margin: 0.75rem 0 0; font-size: 0.9rem; }

/* Manager */
#manager-screen {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem 1.25rem;
  background: var(--panel);
  border-bottom: 1px solid var(--border);
  gap: 1rem;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 700;
  font-size: 1.2rem;
  color: var(--text);
}

.brand .icon { color: var(--primary); }

.toolbar {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.search-box {
  position: relative;
  display: flex;
  align-items: center;
}

.search-box .icon {
  position: absolute;
  left: 0.7rem;
  color: var(--muted);
  pointer-events: none;
}

.search-box input[type="search"] {
  padding: 0.55rem 0.75rem 0.55rem 2.2rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  min-width: 220px;
  background: var(--bg);
  color: var(--text);
}

.theme-switcher {
  display: inline-flex;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.15rem;
  gap: 0.15rem;
}

.theme-switcher .btn {
  width: 32px;
  height: 32px;
  border-radius: 6px;
  background: transparent;
  color: var(--muted);
}

.theme-switcher .btn:hover { background: var(--secondary-hover); color: var(--text); }
.theme-switcher .btn.active { background: var(--panel); color: var(--primary); box-shadow: var(--shadow); }

.main-layout {
  display: flex;
  flex: 1;
  overflow: hidden;
}

.sidebar {
  width: 220px;
  background: var(--panel);
  border-right: 1px solid var(--border);
  padding: 1rem 0.75rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.sidebar-title {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--muted);
  padding: 0 0.75rem;
  margin-bottom: 0.25rem;
}

.sidebar ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

.sidebar li { margin-bottom: 0.15rem; }

.sidebar a {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.55rem 0.75rem;
  color: var(--text-secondary);
  text-decoration: none;
  border-radius: var(--radius);
  transition: background var(--transition), color var(--transition);
}

.sidebar a:hover { background: var(--bg); color: var(--text); }
.sidebar a.active { background: var(--primary-soft); color: var(--primary); font-weight: 600; }
.sidebar a .icon { color: var(--icon-folder); }
.sidebar a.active .icon { color: var(--primary); }

.content {
  flex: 1;
  padding: 1.25rem;
  overflow: auto;
}

/* Breadcrumbs */
.breadcrumbs {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  margin-bottom: 1rem;
  padding: 0.5rem 0.75rem;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 0.95rem;
  box-shadow: var(--shadow);
}

.breadcrumbs a {
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  padding: 0.25rem 0.4rem;
  color: var(--text-secondary);
  text-decoration: none;
  border-radius: 6px;
}

.breadcrumbs a:hover { background: var(--bg); color: var(--primary); }

.breadcrumbs a.root { color: var(--primary); font-weight: 600; }

.breadcrumbs .sep {
  color: var(--muted);
  display: inline-flex;
  align-items: center;
}

.breadcrumbs .sep svg { width: 14px; height: 14px; }

/* File list */
.file-list {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
}

.file-list-header, .tree-row {
  display: grid;
  grid-template-columns: minmax(0, 2.5fr) 1fr 1fr 1.5fr;
  gap: 1rem;
  padding: 0.75rem 1rem;
  align-items: center;
}

.file-list-header {
  font-weight: 600;
  background: var(--bg);
  color: var(--text-secondary);
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  border-bottom: 1px solid var(--border);
}

.tree-node { border-bottom: 1px solid var(--border); }
.tree-node:last-child { border-bottom: none; }
.tree-node[data-type="directory"] > .tree-row:hover { background: var(--bg); }
.tree-node[data-type="file"] > .tree-row:hover { background: var(--bg); }

.tree-row { transition: background var(--transition); }

.tree-children {
  border-left: 2px solid var(--border);
  margin-left: 1.25rem;
  background: var(--panel);
}

.tree-children.hidden { display: none !important; }

.tree-empty {
  padding: 0.75rem 1rem;
  color: var(--muted);
  font-size: 0.9rem;
  font-style: italic;
}

.tree-name {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  min-width: 0;
}

.tree-name .icon {
  color: var(--icon-file);
  flex-shrink: 0;
}

.tree-name.directory .icon { color: var(--icon-folder); }

.tree-name span {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.tree-name.directory {
  font-weight: 600;
  cursor: pointer;
}

.tree-name.directory:hover { color: var(--primary); }

.tree-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 22px;
  height: 22px;
  padding: 0;
  border: none;
  background: transparent;
  color: var(--muted);
  cursor: pointer;
  border-radius: 4px;
  transition: background var(--transition), transform var(--transition);
}

.tree-toggle:hover { background: var(--secondary); color: var(--text); }

.tree-toggle.expanded { transform: rotate(90deg); }

.tree-cell { color: var(--text-secondary); font-size: 0.9rem; }

.actions {
  display: flex;
  gap: 0.35rem;
  justify-content: flex-end;
}

.actions button {
  padding: 0.4rem;
  width: 34px;
  height: 34px;
  border: 1px solid var(--border);
  background: var(--panel);
  color: var(--text-secondary);
  border-radius: var(--radius);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: background var(--transition), color var(--transition), border-color var(--transition);
}

.actions button:hover { background: var(--bg); color: var(--text); border-color: var(--border-strong); }
.actions button.btn-copy:hover { color: var(--primary); border-color: var(--primary); }
.actions button.btn-download:hover { color: var(--primary); border-color: var(--primary); }
.actions button.btn-rename:hover { color: var(--primary); border-color: var(--primary); }
.actions button.btn-move:hover { color: var(--primary); border-color: var(--primary); }
.actions button.btn-delete:hover { color: var(--danger); border-color: var(--danger); background: var(--danger-soft); }

.empty-state {
  grid-column: 1 / -1;
  padding: 3rem;
  text-align: center;
  color: var(--muted);
}

/* Modal */
.modal {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.5);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
  padding: 1rem;
}

.modal.hidden { display: none !important; }

.modal-body {
  background: var(--panel);
  padding: 1.5rem;
  border-radius: var(--radius);
  width: 100%;
  max-width: 520px;
  box-shadow: var(--shadow-lg);
  border: 1px solid var(--border);
}

.modal-body h2 { margin-top: 0; }

.drop-zone {
  border: 2px dashed var(--border-strong);
  border-radius: var(--radius);
  padding: 2.5rem 2rem;
  text-align: center;
  color: var(--muted);
  cursor: pointer;
  margin-bottom: 1rem;
  transition: border-color var(--transition), background var(--transition);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.75rem;
}

.drop-zone .icon { color: var(--primary); }

.drop-zone.dragover { border-color: var(--primary); background: var(--primary-soft); }

.drop-zone input[type="file"] { display: none; }

.upload-queue {
  list-style: none;
  margin: 0 0 1rem;
  padding: 0;
  max-height: 220px;
  overflow: auto;
}

.upload-queue li {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.5rem 0;
  border-bottom: 1px solid var(--border);
  font-size: 0.9rem;
}

.upload-queue li button {
  padding: 0.25rem 0.5rem;
  font-size: 0.8rem;
  border: 1px solid var(--border);
  background: var(--panel);
  color: var(--danger);
  border-radius: 6px;
  cursor: pointer;
}

.upload-queue li button:hover { background: var(--danger-soft); }

.modal-actions {
  display: flex;
  justify-content: flex-end;
  gap: 0.5rem;
}

/* Toasts */
.toast-container {
  position: fixed;
  top: 1rem;
  right: 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  z-index: 200;
}

.toast {
  padding: 0.85rem 1rem;
  border-radius: var(--radius);
  color: white;
  box-shadow: var(--shadow-lg);
  min-width: 260px;
  background: var(--text);
  animation: slideIn 0.2s ease;
}

.toast.success { background: var(--success); }
.toast.error { background: var(--danger); }

@keyframes slideIn {
  from { opacity: 0; transform: translateX(20px); }
  to { opacity: 1; transform: translateX(0); }
}

/* Responsive */
@media (max-width: 768px) {
  .sidebar { display: none; }
  .file-list-header, .tree-row {
    grid-template-columns: minmax(0, 2fr) 1fr 1.2fr;
  }
  .file-list-header > div:nth-child(3),
  .tree-row > div:nth-child(3) { display: none; }
}