:root {
  --color-bg: #f4f6f9;
  --color-panel: #ffffff;
  --color-primary: #2563eb;
  --color-primary-dark: #1d4ed8;
  --color-success: #16a34a;
  --color-error: #dc2626;
  --color-warning: #d97706;
  --color-border: #e2e8f0;
  --color-text: #1e293b;
  --color-text-muted: #64748b;
  --radius: 10px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  background: var(--color-bg);
  color: var(--color-text);
}

.app {
  max-width: 1100px;
  margin: 0 auto;
  padding: 32px 20px 60px;
}

.app-header h1 {
  font-size: 26px;
  margin-bottom: 4px;
}

.subtitle {
  color: var(--color-text-muted);
  margin-top: 0;
  margin-bottom: 28px;
}

.app-main {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}

@media (max-width: 860px) {
  .app-main { grid-template-columns: 1fr; }
}

.panel {
  background: var(--color-panel);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 22px;
  box-shadow: 0 1px 2px rgba(0,0,0,0.03);
}

.panel h2 {
  font-size: 16px;
  margin-top: 0;
  margin-bottom: 14px;
}

.panel-hint {
  font-size: 13px;
  color: var(--color-text-muted);
  margin-top: -8px;
  margin-bottom: 16px;
}

/* Dropzone */
.dropzone {
  border: 2px dashed var(--color-border);
  border-radius: var(--radius);
  padding: 32px 20px;
  text-align: center;
  transition: border-color .15s, background .15s;
  cursor: pointer;
}

.dropzone.dragover {
  border-color: var(--color-primary);
  background: #eff6ff;
}

.dropzone-icon { font-size: 34px; margin-bottom: 6px; }
.dropzone-text { margin: 4px 0; font-weight: 500; }
.dropzone-or { color: var(--color-text-muted); font-size: 12px; margin: 6px 0; }

/* Buttons */
.btn {
  border: none;
  border-radius: 8px;
  padding: 10px 18px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: background .15s, opacity .15s;
}

.btn-primary {
  background: var(--color-primary);
  color: #fff;
  width: 100%;
  margin-top: 16px;
  padding: 12px 18px;
}
.btn-primary:hover:not(:disabled) { background: var(--color-primary-dark); }
.btn-primary:disabled { opacity: 0.5; cursor: not-allowed; }

.btn-secondary {
  background: #eef2ff;
  color: var(--color-primary-dark);
}
.btn-secondary:hover { background: #e0e7ff; }

.btn-outline {
  background: transparent;
  border: 1px solid var(--color-border);
  color: var(--color-text);
  font-size: 13px;
  padding: 8px 12px;
}
.btn-outline:hover { background: #f8fafc; }

.btn-link {
  background: none;
  border: none;
  color: var(--color-text-muted);
  font-size: 12px;
  text-decoration: underline;
  cursor: pointer;
  padding: 0;
}

/* File info */
.file-info {
  margin-top: 14px;
  padding: 12px 14px;
  background: #f0fdf4;
  border: 1px solid #bbf7d0;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.file-info-row { display: flex; align-items: center; gap: 10px; }
.file-info-icon { color: var(--color-success); font-size: 18px; }
.file-name { margin: 0; font-weight: 600; font-size: 14px; }
.file-meta { margin: 2px 0 0; font-size: 12px; color: var(--color-text-muted); }

.hidden { display: none !important; }

.error-box {
  margin-top: 14px;
  padding: 10px 14px;
  background: #fef2f2;
  border: 1px solid #fecaca;
  color: var(--color-error);
  border-radius: 8px;
  font-size: 13px;
}

.result-box {
  margin-top: 18px;
  padding: 14px;
  background: #f0fdf4;
  border: 1px solid #bbf7d0;
  border-radius: 8px;
  font-size: 14px;
}
.result-success { color: var(--color-success); font-weight: 600; margin-top: 0; }
.result-secondary { color: var(--color-text-muted); font-size: 12px; }
.result-warning { color: var(--color-warning); font-size: 12px; }

/* Layout form */
.form-row { margin-bottom: 14px; }
.form-row label { display: block; font-size: 13px; font-weight: 600; margin-bottom: 6px; }
.form-row-checkbox label { display: flex; align-items: center; gap: 8px; font-weight: 500; }
select {
  width: 100%;
  padding: 8px 10px;
  border-radius: 6px;
  border: 1px solid var(--color-border);
  font-size: 14px;
}

.columns-list { list-style: none; padding: 0; margin: 0; }
.columns-list li {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 8px 10px;
  border: 1px solid var(--color-border);
  border-radius: 6px;
  margin-bottom: 6px;
  font-size: 13px;
  background: #fafafa;
}
.columns-list li .col-label { flex: 1; }
.columns-list li button {
  border: none;
  background: #fff;
  border: 1px solid var(--color-border);
  border-radius: 4px;
  cursor: pointer;
  width: 24px;
  height: 24px;
  font-size: 12px;
}

.layout-actions {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
  margin-top: 18px;
}

/* Preview table */
.panel-preview { margin-top: 20px; }
.table-wrapper { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; font-size: 13px; }
thead th {
  text-align: left;
  background: #f8fafc;
  padding: 10px;
  border-bottom: 2px solid var(--color-border);
  white-space: nowrap;
}
tbody td {
  padding: 8px 10px;
  border-bottom: 1px solid var(--color-border);
  white-space: nowrap;
}
.empty-state { color: var(--color-text-muted); text-align: center; padding: 24px; }

.app-footer {
  text-align: center;
  color: var(--color-text-muted);
  font-size: 12px;
  margin-top: 30px;
}