@import url('https://fonts.googleapis.com/css2?family=Plus+Jakarta+Sans:wght@400;500;600;700;800&display=swap');

:root {
  --font-main: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, sans-serif;
  
  --bg-gradient: linear-gradient(135deg, #0f172a 0%, #1e1b4b 50%, #0f172a 100%);
  --surface-bg: rgba(255, 255, 255, 0.95);
  --surface-card: #ffffff;
  --text-main: #0f172a;
  --text-muted: #64748b;
  --text-light: #94a3b8;
  
  --primary: #4f46e5;
  --primary-hover: #4338ca;
  --primary-light: #e0e7ff;
  --secondary: #06b6d4;
  --success: #10b981;
  --success-light: #d1fae5;
  --danger: #ef4444;
  --danger-light: #fee2e2;
  --warning: #f59e0b;
  --warning-light: #fef3c7;
  
  --border-color: #e2e8f0;
  --border-focus: #818cf8;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.05);
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
}

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

body {
  font-family: var(--font-main);
  background: #f8fafc;
  color: var(--text-main);
  min-height: 100vh;
  line-height: 1.5;
}

/* Header Navbar */
.navbar {
  background: var(--bg-gradient);
  color: white;
  padding: 1.25rem 2rem;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.15);
  position: sticky;
  top: 0;
  z-index: 100;
}

.navbar-container {
  max-width: 1300px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.brand {
  display: flex;
  flex-direction: column;
}

.brand-title {
  font-size: 1.25rem;
  font-weight: 800;
  letter-spacing: -0.02em;
}

.brand-subtitle {
  font-size: 0.8rem;
  color: #94a3b8;
  font-weight: 500;
}

.quick-sample-btn {
  background: rgba(255, 255, 255, 0.15);
  backdrop-filter: blur(8px);
  color: white;
  border: 1px solid rgba(255, 255, 255, 0.25);
  padding: 0.5rem 1rem;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 0.875rem;
  cursor: pointer;
  transition: all 0.2s ease;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.quick-sample-btn:hover {
  background: rgba(255, 255, 255, 0.25);
  transform: translateY(-1px);
}

/* Main Container */
.container {
  max-width: 1300px;
  margin: 2rem auto;
  padding: 0 1.5rem;
}

/* Setup Form Section */
.upload-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 1.5rem;
  margin-bottom: 2rem;
}

.card {
  background: var(--surface-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  box-shadow: var(--shadow-sm);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.card:hover {
  box-shadow: var(--shadow-md);
}

.card-title {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 1rem;
  color: var(--text-main);
}

.file-dropzone {
  border: 2px dashed var(--border-color);
  border-radius: var(--radius-sm);
  padding: 1.5rem 1rem;
  text-align: center;
  background: #fafafa;
  cursor: pointer;
  transition: all 0.2s ease;
  position: relative;
}

.file-dropzone:hover, .file-dropzone.dragover {
  border-color: var(--primary);
  background: var(--primary-light);
}

.file-dropzone input[type="file"] {
  position: absolute;
  top: 0; left: 0; width: 100%; height: 100%;
  opacity: 0;
  cursor: pointer;
}

.file-dropzone-icon {
  font-size: 2rem;
  color: var(--text-muted);
  margin-bottom: 0.5rem;
}

.file-name {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--primary);
  margin-top: 0.5rem;
  word-break: break-all;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  font-weight: 600;
  font-size: 0.95rem;
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius-sm);
  border: none;
  cursor: pointer;
  transition: all 0.2s ease;
  width: 100%;
}

.btn-primary {
  background: var(--primary);
  color: white;
  box-shadow: 0 4px 12px rgba(79, 70, 229, 0.3);
}

.btn-primary:hover {
  background: var(--primary-hover);
  transform: translateY(-1px);
  box-shadow: 0 6px 16px rgba(79, 70, 229, 0.4);
}

.btn-success {
  background: var(--success);
  color: white;
  box-shadow: 0 4px 12px rgba(16, 185, 129, 0.3);
}

.btn-success:hover {
  background: #059669;
  transform: translateY(-1px);
}

.btn-secondary {
  background: #e2e8f0;
  color: #334155;
}

.btn-secondary:hover {
  background: #cbd5e1;
}

/* Alert Notification */
.alert {
  padding: 1rem 1.25rem;
  border-radius: var(--radius-sm);
  margin-bottom: 1.5rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 0.9rem;
}

.alert-danger {
  background: var(--danger-light);
  color: #991b1b;
  border: 1px solid #fecaca;
}

.alert-success {
  background: var(--success-light);
  color: #065f46;
  border: 1px solid #a7f3d0;
}

/* Stats Overview */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1.25rem;
  margin-bottom: 2rem;
}

.stat-card {
  background: var(--surface-card);
  border-radius: var(--radius-md);
  padding: 1.25rem;
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
}

.stat-label {
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
  margin-bottom: 0.5rem;
}

.stat-value {
  font-size: 1.85rem;
  font-weight: 800;
  color: var(--text-main);
}

.stat-sub {
  font-size: 0.8rem;
  color: var(--text-light);
  margin-top: 0.25rem;
}

/* Tabs */
.tabs-header {
  display: flex;
  gap: 0.5rem;
  border-bottom: 2px solid var(--border-color);
  margin-bottom: 1.5rem;
}

.tab-btn {
  padding: 0.75rem 1.25rem;
  font-weight: 600;
  font-size: 0.9rem;
  background: none;
  border: none;
  border-bottom: 3px solid transparent;
  color: var(--text-muted);
  cursor: pointer;
  transition: all 0.2s ease;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

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

.tab-btn.active {
  color: var(--primary);
  border-bottom-color: var(--primary);
}

.tab-content {
  display: none;
}

.tab-content.active {
  display: block;
}

/* Table Controls */
.table-controls {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
  margin-bottom: 1rem;
}

.search-input {
  padding: 0.6rem 1rem;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  font-family: inherit;
  font-size: 0.875rem;
  width: 280px;
  outline: none;
  transition: border-color 0.2s ease;
}

.search-input:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.15);
}

.export-actions {
  display: flex;
  gap: 0.5rem;
}

/* Results Table */
.table-responsive {
  overflow-x: auto;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  background: white;
  box-shadow: var(--shadow-sm);
}

table.data-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.875rem;
}

table.data-table th, table.data-table td {
  padding: 0.875rem 1rem;
  border-bottom: 1px solid var(--border-color);
}

table.data-table th {
  background: #f8fafc;
  font-weight: 700;
  color: #334155;
  white-space: nowrap;
}

table.data-table tbody tr:hover {
  background: #f1f5f9;
}

.pill {
  display: inline-flex;
  align-items: center;
  padding: 0.25rem 0.6rem;
  border-radius: 999px;
  font-size: 0.75rem;
  font-weight: 700;
}

.pill-score {
  background: #ecfdf5;
  color: #047857;
  font-size: 0.9rem;
}

.pill-pass {
  background: var(--success-light);
  color: #065f46;
}

.pill-fail {
  background: var(--danger-light);
  color: #991b1b;
}

.btn-detail {
  padding: 0.35rem 0.75rem;
  font-size: 0.75rem;
  font-weight: 600;
  border-radius: 6px;
  border: 1px solid var(--primary);
  color: var(--primary);
  background: transparent;
  cursor: pointer;
  transition: all 0.15s ease;
}

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

/* Modal */
.modal-overlay {
  position: fixed;
  top: 0; left: 0; width: 100%; height: 100%;
  background: rgba(15, 23, 42, 0.6);
  backdrop-filter: blur(4px);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  padding: 1.5rem;
}

.modal-overlay.active {
  display: flex;
}

.modal-card {
  background: white;
  border-radius: var(--radius-md);
  max-width: 800px;
  width: 100%;
  max-height: 85vh;
  display: flex;
  flex-direction: column;
  box-shadow: var(--shadow-lg);
  overflow: hidden;
}

.modal-header {
  padding: 1.25rem 1.5rem;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: #f8fafc;
}

.modal-title {
  font-size: 1.1rem;
  font-weight: 700;
}

.modal-close {
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: var(--text-muted);
}

.modal-body {
  padding: 1.5rem;
  overflow-y: auto;
}

.student-info-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 1rem;
  background: #f8fafc;
  padding: 1rem;
  border-radius: var(--radius-sm);
  margin-bottom: 1.5rem;
}

.item-matrix {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(90px, 1fr));
  gap: 0.5rem;
}

.matrix-item {
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 0.5rem;
  text-align: center;
  font-size: 0.75rem;
}

.matrix-item.correct {
  background: #ecfdf5;
  border-color: #a7f3d0;
  color: #065f46;
}

.matrix-item.wrong {
  background: #fef2f2;
  border-color: #fecaca;
  color: #991b1b;
}

.matrix-item.blank {
  background: #f1f5f9;
  border-color: #cbd5e1;
  color: #475569;
}

/* Spinner */
.spinner {
  width: 20px;
  height: 20px;
  border: 3px solid rgba(255, 255, 255, 0.3);
  border-top-color: white;
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  display: inline-block;
}

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

@media (max-width: 768px) {
  .navbar-container {
    flex-direction: column;
    gap: 1rem;
    align-items: flex-start;
  }
  .table-controls {
    flex-direction: column;
    align-items: stretch;
  }
  .search-input {
    width: 100%;
  }
}