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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: #f0f2f5;
  color: #1a1a2e;
  min-height: 100vh;
}

header {
  background: #1a1a2e;
  color: #fff;
  padding: 16px 32px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

header h1 { font-size: 22px; font-weight: 600; }

.status { font-size: 13px; opacity: 0.7; }
.status.loaded { color: #4ade80; }

main { max-width: 1200px; margin: 0 auto; padding: 24px; }

.upload-section {
  background: #fff;
  border-radius: 12px;
  padding: 24px;
  margin-bottom: 20px;
  box-shadow: 0 1px 3px rgba(0,0,0,0.08);
}

.upload-section form {
  display: flex;
  gap: 16px;
  align-items: center;
}

.drop-zone {
  flex: 1;
  border: 2px dashed #c0c0d0;
  border-radius: 10px;
  padding: 28px 20px;
  text-align: center;
  cursor: pointer;
  transition: all 0.2s;
  display: block;
}
.drop-zone:hover, .drop-zone.drag-over {
  border-color: #4f46e5;
  background: #f5f3ff;
}
.drop-text { display: block; font-size: 15px; color: #555; margin-bottom: 4px; }
.drop-hint { font-size: 12px; color: #999; }

button {
  background: #4f46e5;
  color: #fff;
  border: none;
  padding: 12px 28px;
  border-radius: 8px;
  font-size: 15px;
  cursor: pointer;
  transition: background 0.15s;
  white-space: nowrap;
}
button:hover:not(:disabled) { background: #4338ca; }
button:disabled { opacity: 0.5; cursor: not-allowed; }

#uploadStatus {
  font-size: 13px;
  color: #666;
  min-width: 200px;
}
#uploadStatus.success { color: #16a34a; }
#uploadStatus.error { color: #dc2626; }

.tabs {
  display: flex;
  gap: 0;
  background: #fff;
  border-radius: 12px 12px 0 0;
  overflow: hidden;
  box-shadow: 0 1px 3px rgba(0,0,0,0.08);
}
.tab {
  padding: 12px 24px;
  border: none;
  background: #fff;
  color: #666;
  font-size: 14px;
  cursor: pointer;
  border-bottom: 3px solid transparent;
  transition: all 0.15s;
  border-radius: 0;
}
.tab:hover { color: #4f46e5; background: #f9f9fb; }
.tab.active { color: #4f46e5; border-bottom-color: #4f46e5; font-weight: 600; }

.tab-content {
  display: none;
  background: #fff;
  padding: 24px;
  border-radius: 0 0 12px 12px;
  box-shadow: 0 1px 3px rgba(0,0,0,0.08);
}
.tab-content.active { display: block; }

.summary-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 16px;
  margin-bottom: 24px;
}
.card {
  background: #f8f9fc;
  border-radius: 10px;
  padding: 20px;
  text-align: center;
  border: 1px solid #e5e7eb;
}
.card .value { font-size: 28px; font-weight: 700; color: #4f46e5; }
.card .label { font-size: 13px; color: #666; margin-top: 4px; }

.alerts { display: flex; flex-direction: column; gap: 8px; }
.alert {
  padding: 12px 16px;
  border-radius: 8px;
  font-size: 14px;
  display: flex;
  align-items: center;
  gap: 8px;
}
.alert.warning { background: #fef3c7; color: #92400e; border: 1px solid #fcd34d; }
.alert.danger { background: #fee2e2; color: #991b1b; border: 1px solid #fca5a5; }
.alert.info { background: #e0f2fe; color: #075985; border: 1px solid #7dd3fc; }

.table-wrapper { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; font-size: 14px; }
th, td { padding: 10px 12px; text-align: left; border-bottom: 1px solid #f0f0f0; }
th { background: #f8f9fc; font-weight: 600; color: #555; font-size: 13px; white-space: nowrap; }
tr:hover td { background: #f9f9fb; }
td.num { text-align: center; font-variant-numeric: tabular-nums; }

.low-grades { color: #dc2626; font-weight: 600; }
.no-grades { color: #d97706; font-weight: 600; }

h2 { font-size: 18px; margin-bottom: 16px; color: #1a1a2e; }

.empty-state {
  text-align: center;
  padding: 40px;
  color: #999;
}

.filters {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 16px;
  align-items: center;
}
.filters input {
  padding: 6px 10px;
  border: 1px solid #d0d0d0;
  border-radius: 6px;
  font-size: 13px;
  width: 140px;
}
.filters input:focus {
  outline: none;
  border-color: #4f46e5;
}

.global-filters {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  align-items: center;
  background: #fff;
  border-radius: 12px;
  padding: 14px 20px;
  margin-bottom: 16px;
  box-shadow: 0 1px 3px rgba(0,0,0,0.08);
}
.global-filters input {
  padding: 7px 10px;
  border: 1px solid #d0d0d0;
  border-radius: 6px;
  font-size: 13px;
  width: 140px;
}
.global-filters input[type="date"] {
  width: 145px;
}
.global-filters .btn-reset {
  background: transparent;
  color: #666;
  border: 1px solid #d0d0d0;
  margin-left: auto;
}
.global-filters .btn-reset:hover {
  background: #f5f5f5;
  color: #333;
}

.upload-progress {
  width: 100%;
  margin-top: 10px;
}
.upload-progress.hidden { display: none; }
.progress-bar {
  width: 100%;
  height: 6px;
  background: #e5e5e5;
  border-radius: 3px;
  overflow: hidden;
}
.progress-fill {
  height: 100%;
  width: 0%;
  background: #4f46e5;
  border-radius: 3px;
  transition: width 0.3s ease;
}
.progress-fill:not(.determinate) {
  animation: progress-indeterminate 1.5s ease-in-out infinite;
}
@keyframes progress-indeterminate {
  0% { width: 0%; margin-left: 0%; }
  50% { width: 60%; margin-left: 20%; }
  100% { width: 0%; margin-left: 100%; }
}
.progress-text {
  display: block;
  text-align: center;
  font-size: 12px;
  color: #888;
  margin-top: 6px;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}
.spinner {
  display: inline-block;
  width: 16px;
  height: 16px;
  border: 2px solid #d0d0d0;
  border-top-color: #4f46e5;
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
  vertical-align: middle;
  margin-right: 6px;
}
.btn-danger {
  background: #dc2626;
}
.btn-danger:hover:not(:disabled) {
  background: #b91c1c;
}

.modal-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.4);
  z-index: 1000;
  align-items: center;
  justify-content: center;
}
.modal-overlay.open {
  display: flex;
}
.modal {
  background: #fff;
  border-radius: 14px;
  width: 480px;
  max-width: 95vw;
  max-height: 90vh;
  overflow-y: auto;
  box-shadow: 0 8px 30px rgba(0,0,0,0.18);
}
.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 18px 22px 12px;
}
.modal-header h3 { font-size: 17px; }
.modal-close {
  background: none;
  border: none;
  font-size: 22px;
  cursor: pointer;
  color: #999;
  padding: 0 4px;
}
.modal-close:hover { color: #333; }
.modal-body {
  padding: 0 22px 20px;
}
.modal-option {
  padding: 12px 0;
}
.modal-option strong {
  display: block;
  margin-bottom: 8px;
  font-size: 14px;
}
.modal-option input {
  padding: 7px 10px;
  border: 1px solid #d0d0d0;
  border-radius: 6px;
  font-size: 13px;
  width: 160px;
  margin-right: 8px;
}
.modal-option input:focus {
  outline: none;
  border-color: #4f46e5;
}
.modal-option hr {
  border: none;
  border-top: 1px solid #eee;
  margin: 12px 0;
}
.modal-option p {
  font-size: 12px;
  color: #999;
  margin: 6px 0 10px;
}
.danger-zone {
  background: #fef2f2;
  border-radius: 8px;
  padding: 14px;
  margin-top: 4px;
}
.modal-option span {
  font-size: 12px;
  margin-left: 8px;
}
.modal-option span.success { color: #16a34a; }
.modal-option span.error { color: #dc2626; }

.period-selector {
  display: flex;
  gap: 6px;
  align-items: center;
  margin-bottom: 14px;
}
.per-btn {
  padding: 6px 16px;
  border: 1px solid #d0d0d0;
  background: #fff;
  border-radius: 6px;
  font-size: 13px;
  cursor: pointer;
  color: #555;
}
.per-btn.active {
  background: #4f46e5;
  color: #fff;
  border-color: #4f46e5;
}
.per-info {
  margin-left: auto;
  font-size: 13px;
  color: #888;
}

.pivot-scroll {
  overflow-x: auto;
  max-width: 100%;
}
#pivotTable {
  border-collapse: collapse;
  font-size: 13px;
  min-width: 100%;
}
#pivotTable th, #pivotTable td {
  padding: 6px 8px;
  border: 1px solid #e5e5e5;
  white-space: nowrap;
  vertical-align: middle;
}
#pivotTable th {
  background: #f0f2f5;
  font-weight: 600;
  color: #444;
  position: sticky;
  top: 0;
  z-index: 1;
}
#pivotTable thead th:first-child {
  position: sticky;
  left: 0;
  z-index: 2;
  background: #f0f2f5;
}
#pivotTable td:first-child {
  position: sticky;
  left: 0;
  background: #fff;
  font-weight: 500;
  z-index: 0;
  min-width: 160px;
  border-right: 2px solid #d0d0d0;
}
#pivotTable tr:hover td {
  background: #f8f9fc;
}
#pivotTable tr:hover td:first-child {
  background: #f0f2f5;
}
.pivot-subject {
  cursor: pointer;
  font-weight: 700;
  color: #1a1a2e;
}
.pivot-subject .toggle {
  display: inline-block;
  width: 16px;
  font-size: 11px;
  transition: transform 0.15s;
}
.pivot-subject .toggle.open {
  transform: rotate(90deg);
}
.pivot-teacher {
  padding-left: 20px !important;
  color: #555;
}
.pivot-student {
  padding-left: 36px !important;
  font-size: 12px;
  color: #666;
}
.pivot-cell {
  text-align: center;
  font-variant-numeric: tabular-nums;
  color: #333;
}
.pivot-hidden { display: none; }

.control-tabs {
  display: flex;
  gap: 0;
  margin-bottom: 12px;
}
.ctrl-tab {
  padding: 7px 18px;
  border: 1px solid #d0d0d0;
  background: #fff;
  font-size: 13px;
  cursor: pointer;
  color: #555;
}
.ctrl-tab:first-child { border-radius: 6px 0 0 6px; }
.ctrl-tab:last-child { border-radius: 0 6px 6px 0; }
.ctrl-tab.active {
  background: #4f46e5;
  color: #fff;
  border-color: #4f46e5;
}
.control-filters {
  display: flex;
  gap: 16px;
  align-items: center;
  margin-bottom: 12px;
  font-size: 13px;
}
.control-filters label {
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 4px;
}
.control-filters input[type="checkbox"] {
  cursor: pointer;
}
.control-filters input[type="number"] {
  padding: 4px 6px;
  border: 1px solid #d0d0d0;
  border-radius: 4px;
  font-size: 13px;
}

#controlTable td.missing {
  background: #fee2e2;
  color: #991b1b;
  font-style: italic;
}
#controlTable tr.red-row td {
  background: #fee2e2;
}
#controlTable td.grades-cell {
  max-width: 300px;
  white-space: normal;
  word-break: break-all;
  font-size: 12px;
}
#controlTable tr.red-row td {
  background: #fee2e2;
}
#controlTable tr.green-row td {
  background: #dcfce7;
}
.chain-mini {
  border-collapse: collapse;
  display: inline-table;
  vertical-align: middle;
}
.chain-mini td {
  padding: 2px 5px;
  border: 1px solid #e5e5e5;
  font-size: 12px;
  text-align: center;
  background: #fff;
}
.cm-date {
  color: #888;
  font-size: 11px !important;
}
.cm-grade {
  font-weight: 600;
  min-width: 22px;
}
.cm-bad {
  color: #dc2626;
}

.control-filters select {
  padding: 4px 8px;
  border: 1px solid #d0d0d0;
  border-radius: 4px;
  font-size: 13px;
  cursor: pointer;
}

.dvoiki-pills {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
}
.pill {
  padding: 7px 16px;
  border: 1px solid #d0d0d0;
  background: #fff;
  border-radius: 20px;
  font-size: 13px;
  cursor: pointer;
  transition: all 0.15s;
  color: #555;
}
.pill:hover {
  border-color: #4f46e5;
  color: #4f46e5;
}
.pill.active {
  background: #4f46e5;
  color: #fff;
  border-color: #4f46e5;
}
.pill-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 18px;
  height: 18px;
  border-radius: 9px;
  background: #dc2626;
  color: #fff;
  font-size: 11px;
  font-weight: 700;
  padding: 0 5px;
  margin-left: 4px;
}

.dvoiki-cards {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(420px, 1fr));
  gap: 14px;
  margin-top: 14px;
}

.d-card {
  background: #fff;
  border-radius: 12px;
  padding: 16px 18px;
  border: 1px solid #e5e5e5;
  box-shadow: 0 1px 4px rgba(0,0,0,0.04);
}
.d-card.unresolved {
  border-left: 4px solid #dc2626;
}
.d-card.resolved {
  border-left: 4px solid #16a34a;
}

.d-card-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 8px;
}
.d-card-status {
  font-size: 12px;
  color: #888;
}
.d-card-steps {
  font-size: 11px;
  color: #aaa;
}
.d-card-student {
  font-size: 15px;
  font-weight: 600;
  color: #1a1a2e;
  margin-bottom: 3px;
}
.d-card-subject {
  font-size: 13px;
  color: #666;
  margin-bottom: 12px;
}

.step-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
}
.step {
  display: flex;
  flex-direction: column;
  align-items: center;
  min-width: 42px;
}
.step-date {
  font-size: 10px;
  color: #999;
  margin-bottom: 3px;
}
.step-grade {
  width: 28px;
  height: 28px;
  border-radius: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 13px;
  font-weight: 700;
  color: #fff;
}
.s-2 { background: #dc2626; }
.s-3 { background: #f59e0b; }
.s-45 { background: #16a34a; }
.s-sym { background: #e5e5e5; color: #888; }
.s-stop {
  background: #fff;
  color: #dc2626;
  border: 2px solid #dc2626;
  font-weight: 900;
}
.s-empty {
  background: #fff;
  color: #999;
  border: 1px dashed #ccc;
  font-weight: 400;
}
.pagination {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 12px;
  margin-top: 16px;
  font-size: 14px;
}
.pagination button {
  padding: 6px 14px;
  font-size: 13px;
}

@media (max-width: 640px) {
  .upload-section form { flex-direction: column; }
  button { width: 100%; }
  .tabs { overflow-x: auto; }
  .tab { padding: 10px 14px; font-size: 13px; }
}