:root {
  --bg: #f8fafc;
  --surface: #ffffff;
  --surface-secondary: #f1f5f9;
  --border: #e2e8f0;
  --border-hover: #cbd5e1;
  --text: #1e293b;
  --text-secondary: #64748b;
  --text-tertiary: #94a3b8;
  --primary: #4f46e5;
  --primary-hover: #4338ca;
  --primary-soft: #eef2ff;
  --danger: #dc2626;
  --danger-soft: #fee2e2;
  --success: #16a34a;
  --success-soft: #dcfce7;
  --radius: 12px;
  --radius-sm: 8px;
  --shadow: 0 1px 3px rgba(15, 23, 42, 0.05), 0 1px 2px rgba(15, 23, 42, 0.03);
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  min-height: 100vh;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.55;
  font-size: 14px;
}

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 24px 20px 64px;
}

/* Navigation */
.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 0;
  margin-bottom: 28px;
  border-bottom: 1px solid var(--border);
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--text);
}

.nav-logo {
  width: 30px;
  height: 30px;
  border-radius: 8px;
  background: var(--primary-soft);
  color: var(--primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  font-size: 14px;
}

.nav-brand span {
  font-weight: 600;
  font-size: 15px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 24px;
  font-size: 14px;
}

.nav-links a {
  color: var(--text-secondary);
  text-decoration: none;
  padding: 4px 0;
  border-bottom: 2px solid transparent;
  transition: color 0.15s, border-color 0.15s;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--text);
  border-bottom-color: var(--primary);
}

.nav-user {
  display: flex;
  align-items: center;
  gap: 10px;
  padding-left: 20px;
  border-left: 1px solid var(--border);
}

.nav-avatar {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--surface-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 12px;
  font-weight: 600;
  color: var(--text-secondary);
}

.nav-username {
  color: var(--text-secondary);
  font-size: 13px;
}

.nav-logout {
  color: var(--text-tertiary);
  font-size: 13px;
  text-decoration: none;
}

.nav-logout:hover { color: var(--danger); }

/* Page header */
.page-header {
  margin-bottom: 20px;
}

.page-header h1 {
  font-size: 22px;
  font-weight: 600;
  margin: 0 0 4px 0;
  letter-spacing: -0.2px;
}

.page-header p {
  margin: 0;
  color: var(--text-secondary);
  font-size: 14px;
}

/* Cards */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
}

.card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 20px;
  background: var(--surface-secondary);
  border-bottom: 1px solid var(--border);
}

.card-title {
  font-size: 15px;
  font-weight: 600;
  margin: 0;
}

.card-body {
  padding: 0;
}

.card-footer {
  padding: 14px 20px;
  color: var(--text-secondary);
  font-size: 13px;
  border-top: 1px solid var(--border);
}

/* Lists / Tables */
.list {
  display: flex;
  flex-direction: column;
}

.list-row {
  display: grid;
  grid-template-columns: minmax(0, 2fr) 100px 140px 120px;
  gap: 16px;
  align-items: center;
  padding: 12px 20px;
  border-bottom: 1px solid var(--border);
  transition: background 0.1s;
}

.list-row:hover { background: rgba(248, 250, 252, 0.6); }

.list-row:last-child { border-bottom: none; }

.list-header {
  background: var(--surface-secondary);
  font-size: 12px;
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.3px;
  padding: 12px 20px;
}

.list-header .list-row { padding: 12px 20px; border-bottom: none; }

/* Sortable table headers */
.sortable {
  cursor: pointer;
  user-select: none;
  display: flex;
  align-items: center;
  gap: 4px;
}

.sortable:hover,
.sortable:focus-visible {
  color: var(--text);
}

.sortable.active {
  color: var(--text);
}

.sort-arrow {
  font-size: 10px;
  color: var(--primary);
  opacity: 0;
}

.sortable.active .sort-arrow {
  opacity: 1;
}

.cell-file {
  min-width: 0;
}

.name-row {
  display: flex;
  align-items: center;
  gap: 8px;
  min-width: 0;
}

.cell-file .name {
  font-weight: 500;
  font-size: 14px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  min-width: 0;
}

.cell-file .meta {
  font-size: 12px;
  color: var(--text-secondary);
  margin-top: 2px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.cell-secondary {
  font-size: 13px;
  color: var(--text-secondary);
}

.cell-actions {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 8px;
  text-align: right;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 7px 14px;
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  text-decoration: none;
  transition: background 0.15s, border-color 0.15s, color 0.15s;
  background: var(--primary);
  color: #fff;
}

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

.btn:focus-visible {
  outline: 2px solid var(--primary);
  outline-offset: 2px;
}

.btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

.btn-primary-soft {
  background: var(--primary-soft);
  color: var(--primary);
  border-color: transparent;
}

.btn-primary-soft:hover {
  background: var(--primary);
  color: #fff;
}

.btn-sm {
  padding: 5px 10px;
  font-size: 12px;
}

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

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

.btn-danger {
  background: var(--danger-soft);
  color: var(--danger);
  border-color: transparent;
}

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

.btn-pin {
  flex: 0 0 auto;
  width: 28px;
  height: 28px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 1.5px solid transparent;
  border-radius: 8px;
  background: transparent;
  cursor: pointer;
  font-size: 14px;
  line-height: 1;
  color: var(--text-tertiary);
  transition: color 0.2s, background 0.2s, transform 0.2s;
}

.btn-pin:hover,
.btn-pin:focus-visible {
  color: var(--primary);
  background: var(--primary-soft);
}

.btn-pin:focus-visible {
  outline: 2px solid var(--primary);
  outline-offset: 2px;
}

.btn-pin.pinned {
  color: var(--primary);
}

.btn-pin.pinned .pin-icon {
  transform: rotate(-15deg);
  animation: pin-pop 0.25s ease-out;
}

.btn-pin:disabled {
  cursor: wait;
  opacity: 0.5;
}

.pin-icon {
  display: block;
  pointer-events: none;
}

@keyframes pin-pop {
  0% { transform: rotate(-15deg) scale(1); }
  40% { transform: rotate(-25deg) scale(1.2); }
  100% { transform: rotate(-15deg) scale(1); }
}

@media (prefers-reduced-motion: reduce) {
  .btn-pin .pin-icon {
    animation: none !important;
  }
}

.row-pinned {
  background: var(--primary-soft) !important;
  box-shadow: inset 3px 0 0 0 var(--primary);
}

.row-pinned:hover {
  background: rgba(79, 70, 229, 0.10) !important;
}

/* Badges */
.badge {
  display: inline-flex;
  align-items: center;
  padding: 3px 8px;
  border-radius: 6px;
  font-size: 12px;
  font-weight: 600;
}

.badge-success {
  background: var(--success-soft);
  color: var(--success);
}

.badge-muted {
  background: var(--surface-secondary);
  color: var(--text-secondary);
}

/* Forms */
.form-group {
  margin-bottom: 16px;
}

.form-group label {
  display: block;
  font-size: 13px;
  font-weight: 500;
  color: var(--text-secondary);
  margin-bottom: 6px;
}

.form-control {
  width: 100%;
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--surface);
  color: var(--text);
  font-size: 14px;
  outline: none;
  transition: border-color 0.15s, box-shadow 0.15s;
}

.form-control:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.08);
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.checkbox-row {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  color: var(--text-secondary);
}

.checkbox-row input[type="checkbox"] {
  width: 16px;
  height: 16px;
  accent-color: var(--primary);
}

/* Alerts */
.alert {
  padding: 12px 16px;
  border-radius: var(--radius-sm);
  margin-bottom: 20px;
  font-size: 14px;
}

.alert-error {
  background: var(--danger-soft);
  color: var(--danger);
  border: 1px solid rgba(220, 38, 38, 0.15);
}

.alert-success {
  background: var(--success-soft);
  color: var(--success);
  border: 1px solid rgba(22, 163, 74, 0.15);
}

/* Login */
.login-container {
  max-width: 400px;
  margin: 100px auto 0;
}

.login-logo {
  text-align: center;
  margin-bottom: 24px;
}

.login-logo .nav-logo {
  margin: 0 auto 12px;
  width: 48px;
  height: 48px;
  font-size: 20px;
  border-radius: 14px;
}

.login-logo h1 {
  font-size: 20px;
  font-weight: 600;
  margin: 0;
}

.login-logo p {
  color: var(--text-secondary);
  font-size: 14px;
  margin: 4px 0 0 0;
}

/* Error */
.error-container {
  max-width: 460px;
  margin: 120px auto 0;
  text-align: center;
}

.error-code {
  font-size: 48px;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 8px;
}

.error-message {
  font-size: 16px;
  color: var(--text-secondary);
  margin-bottom: 24px;
}

.empty-state {
  text-align: center;
  padding: 48px 20px;
  color: var(--text-secondary);
  font-size: 14px;
}

/* Toast */
.toast {
  position: fixed;
  top: 20px;
  right: 20px;
  background: var(--surface);
  border: 1px solid var(--success);
  border-radius: var(--radius-sm);
  padding: 12px 16px;
  display: flex;
  align-items: center;
  gap: 10px;
  box-shadow: 0 4px 12px rgba(15, 23, 42, 0.08);
  z-index: 1000;
  transform: translateY(-20px);
  opacity: 0;
  transition: transform 0.25s, opacity 0.25s;
}

.toast.show {
  transform: translateY(0);
  opacity: 1;
}

.toast-icon {
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--success-soft);
  color: var(--success);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 12px;
  font-weight: 600;
}

.toast-text {
  font-size: 14px;
  color: var(--success);
  font-weight: 500;
}

/* Mobile */
@media (max-width: 700px) {
  .container { padding: 16px 16px 48px; }
  .nav { flex-wrap: wrap; gap: 12px; }
  .nav-links { gap: 16px; font-size: 13px; }
  .nav-user { padding-left: 0; border-left: none; }

  .list-row {
    grid-template-columns: 1fr auto;
    gap: 12px;
    padding: 12px 16px;
  }

  .list-header { display: none; }

  .cell-file .name { white-space: normal; word-break: break-all; }
  .cell-secondary { display: none; }
  .cell-actions { grid-column: 2; grid-row: 1; align-self: center; }

  .btn-sm {
    min-height: 40px;
    min-width: 44px;
    padding: 8px 12px;
  }

  .btn-pin {
    width: 36px;
    height: 36px;
  }

  .toast {
    left: 16px;
    right: 16px;
    top: auto;
    bottom: 20px;
  }

  .form-row { grid-template-columns: 1fr; }
}