*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --bg: #f5f6fa;
  --surface: #ffffff;
  --border: #e2e5ec;
  --text: #2c3e50;
  --text-secondary: #7f8c9b;
  --primary: #3498db;
  --primary-hover: #2980b9;
  --danger: #e74c3c;
  --danger-hover: #c0392b;
  --success: #27ae60;
  --radius: 8px;
  --shadow: 0 1px 3px rgba(0,0,0,.08);
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Noto Sans SC", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
  min-height: 100vh;
}

#app {
  max-width: 960px;
  margin: 0 auto;
  padding: 24px 16px;
}

.header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 20px;
}

.logo {
  font-size: 22px;
  font-weight: 700;
}

.file-count {
  color: var(--text-secondary);
  font-size: 14px;
}

.toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 16px;
  flex-wrap: wrap;
}

.toolbar-left {
  display: flex;
  align-items: center;
  gap: 8px;
}

.toolbar-right {
  flex: 1;
  max-width: 320px;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 16px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--surface);
  color: var(--text);
  font-size: 14px;
  cursor: pointer;
  transition: all .15s;
  white-space: nowrap;
}

.btn:hover {
  background: #f0f2f7;
}

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

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

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

.btn-danger:hover {
  background: #fdf0ef;
  border-color: var(--danger);
}

.search-input {
  width: 100%;
  padding: 8px 12px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 14px;
  background: var(--surface);
  color: var(--text);
  outline: none;
  transition: border-color .15s;
}

.search-input:focus {
  border-color: var(--primary);
}

.upload-progress {
  margin-bottom: 16px;
  padding: 12px 16px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  gap: 12px;
}

.progress-bar {
  flex: 1;
  height: 6px;
  background: var(--border);
  border-radius: 3px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  width: 0%;
  background: var(--primary);
  border-radius: 3px;
  transition: width .3s;
}

.progress-text {
  font-size: 13px;
  color: var(--text-secondary);
  white-space: nowrap;
}

.breadcrumb {
  display: flex;
  align-items: center;
  gap: 6px;
  margin-bottom: 12px;
  padding: 8px 12px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 13px;
  flex-wrap: wrap;
}

.breadcrumb a {
  color: var(--primary);
  text-decoration: none;
  cursor: pointer;
}

.breadcrumb a:hover {
  text-decoration: underline;
}

.breadcrumb .sep {
  color: var(--text-secondary);
  user-select: none;
}

.breadcrumb .current {
  color: var(--text-secondary);
}

.drop-zone {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}

.drop-zone.drag-over {
  border-color: var(--primary);
  background: #ebf5fb;
}

.file-table-header {
  display: grid;
  grid-template-columns: 1fr 100px 160px 80px;
  gap: 8px;
  padding: 10px 16px;
  background: #f8f9fb;
  border-bottom: 1px solid var(--border);
  font-size: 12px;
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: .5px;
}

.file-list {
  min-height: 200px;
}

.file-item {
  display: grid;
  grid-template-columns: 1fr 100px 160px 80px;
  gap: 8px;
  padding: 10px 16px;
  align-items: center;
  border-bottom: 1px solid var(--border);
  transition: background .1s;
  cursor: default;
}

.file-item:last-child {
  border-bottom: none;
}

.file-item:hover {
  background: #f8f9fb;
}

.file-item.folder-item {
  cursor: pointer;
}

.file-item.folder-item:hover {
  background: #eef4fb;
}

.col-name {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

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

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

.col-actions {
  display: flex;
  gap: 4px;
}

.action-btn {
  padding: 4px 8px;
  border: 1px solid transparent;
  border-radius: 4px;
  background: none;
  cursor: pointer;
  font-size: 14px;
  transition: all .1s;
}

.action-btn:hover {
  background: var(--bg);
  border-color: var(--border);
}

.action-btn.download:hover {
  background: #e8f4fd;
  color: var(--primary);
}

.action-btn.delete:hover {
  background: #fdf0ef;
  color: var(--danger);
}

.empty-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 60px 20px;
  color: var(--text-secondary);
}

.empty-state .icon {
  font-size: 48px;
  margin-bottom: 12px;
  opacity: .4;
}

.empty-state .text {
  font-size: 15px;
}

.toast {
  position: fixed;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%);
  padding: 10px 20px;
  border-radius: var(--radius);
  font-size: 14px;
  color: #fff;
  z-index: 1000;
  animation: toastIn .3s ease;
  box-shadow: 0 4px 12px rgba(0,0,0,.15);
}

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

@keyframes toastIn {
  from { opacity: 0; transform: translateX(-50%) translateY(10px); }
  to { opacity: 1; transform: translateX(-50%) translateY(0); }
}

@media (max-width: 640px) {
  .file-table-header { display: none; }

  .file-item {
    grid-template-columns: 1fr auto;
    gap: 4px 12px;
    padding: 12px 16px;
  }

  .col-name { grid-column: 1; }
  .col-size { grid-column: 1; font-size: 12px; }
  .col-date { display: none; }
  .col-actions { grid-column: 2; grid-row: 1 / 3; display: flex; align-items: center; }

  .toolbar-right { max-width: 100%; }
}