:root {
  --bg: #f4f6f8;
  --surface: #ffffff;
  --primary: #1a5276;
  --primary-light: #2980b9;
  --accent: #2ecc71;
  --danger: #e74c3c;
  --warn: #f39c12;
  --text: #2c3e50;
  --text-muted: #7f8c8d;
  --border: #dce1e6;
  --radius: 8px;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}

header {
  background: var(--primary);
  color: #fff;
  padding: 1.5rem 2rem;
}

header h1 {
  font-size: 1.5rem;
  font-weight: 600;
  letter-spacing: 0.02em;
}

.subtitle {
  color: rgba(255, 255, 255, 0.7);
  font-size: 0.9rem;
  margin-top: 0.25rem;
}

main {
  max-width: 1200px;
  margin: 0 auto;
  padding: 2rem 1.5rem;
}

/* Drop zone */
#drop-zone {
  border: 2px dashed var(--border);
  border-radius: var(--radius);
  padding: 3rem 2rem;
  text-align: center;
  cursor: pointer;
  transition: border-color 0.2s, background 0.2s;
  background: var(--surface);
}

#drop-zone:hover, #drop-zone.dragover {
  border-color: var(--primary-light);
  background: rgba(41, 128, 185, 0.04);
}

.drop-content svg { color: var(--text-muted); margin-bottom: 0.75rem; }
.drop-content p { color: var(--text); font-size: 1rem; }
.drop-content .hint { color: var(--text-muted); font-size: 0.85rem; margin-top: 0.25rem; }

/* File list */
#file-list {
  margin-top: 1rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.file-tag {
  background: var(--primary);
  color: #fff;
  padding: 0.3rem 0.75rem;
  border-radius: 999px;
  font-size: 0.85rem;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
}

.file-tag .remove {
  cursor: pointer;
  opacity: 0.7;
  font-weight: bold;
}

.file-tag .remove:hover { opacity: 1; }

/* Upload button */
#upload-btn {
  margin-top: 1rem;
  padding: 0.6rem 2rem;
  background: var(--primary);
  color: #fff;
  border: none;
  border-radius: var(--radius);
  font-size: 1rem;
  cursor: pointer;
  transition: background 0.2s;
}

#upload-btn:hover:not(:disabled) { background: var(--primary-light); }
#upload-btn:disabled { opacity: 0.5; cursor: not-allowed; }

/* Spinner */
#status-section {
  text-align: center;
  padding: 3rem 0;
}

.spinner {
  width: 40px;
  height: 40px;
  border: 4px solid var(--border);
  border-top-color: var(--primary);
  border-radius: 50%;
  margin: 0 auto 1rem;
  animation: spin 0.8s linear infinite;
}

@keyframes spin { to { transform: rotate(360deg); } }

/* Results */
.file-result {
  background: var(--surface);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin-bottom: 1.5rem;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
}

.file-result h2 {
  font-size: 1.2rem;
  color: var(--primary);
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--border);
}

.file-result .error {
  color: var(--danger);
  font-weight: 600;
}

/* SPC table */
.spc-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.85rem;
  margin-bottom: 1.5rem;
  overflow-x: auto;
  display: block;
}

.spc-table th, .spc-table td {
  padding: 0.5rem 0.75rem;
  text-align: right;
  border-bottom: 1px solid var(--border);
  white-space: nowrap;
}

.spc-table th {
  background: var(--bg);
  font-weight: 600;
  text-align: right;
  position: sticky;
  top: 0;
}

.spc-table th:first-child, .spc-table td:first-child { text-align: left; }

.spc-table tr:hover td { background: rgba(41, 128, 185, 0.04); }

.cpk-good { color: var(--accent); font-weight: 600; }
.cpk-warn { color: var(--warn); font-weight: 600; }
.cpk-bad { color: var(--danger); font-weight: 600; }

/* Summary */
.summary {
  background: var(--bg);
  border-left: 4px solid var(--primary);
  padding: 1rem 1.25rem;
  margin-bottom: 1.5rem;
  border-radius: 0 var(--radius) var(--radius) 0;
  white-space: pre-wrap;
  font-size: 0.9rem;
  line-height: 1.7;
}

/* Charts */
.charts-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin-bottom: 1.5rem;
}

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

.chart-full { grid-column: 1 / -1; }

/* Measurements table */
.meas-toggle {
  background: none;
  border: 1px solid var(--border);
  padding: 0.4rem 1rem;
  border-radius: var(--radius);
  cursor: pointer;
  font-size: 0.85rem;
  color: var(--primary);
  margin-bottom: 1rem;
}

.meas-toggle:hover { background: var(--bg); }

.meas-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.8rem;
}

.meas-table th, .meas-table td {
  padding: 0.4rem 0.6rem;
  border-bottom: 1px solid var(--border);
  text-align: right;
}

.meas-table th { background: var(--bg); font-weight: 600; }
.meas-table th:first-child, .meas-table td:first-child { text-align: left; }

.meas-table .oot { background: rgba(231, 76, 60, 0.08); color: var(--danger); }

@media (max-width: 768px) {
  .charts-grid { grid-template-columns: 1fr; }
  main { padding: 1rem; }
}