:root {
  --primary: #0f766e;
  --primary-hover: #0d655e;
  --primary-light: rgba(15, 118, 110, 0.1);
  --primary-glow: rgba(15, 118, 110, 0.25);
  --accent: #f59e0b;
  --accent-light: rgba(245, 158, 11, 0.15);
  --bg: #f8fafc;
  --surface: #ffffff;
  --surface-alt: #f1f5f9;
  --text: #0f172a;
  --text-muted: #64748b;
  --line: #e2e8f0;
  --line-strong: #cbd5e1;
  --success: #16a34a;
  --success-light: rgba(22, 163, 74, 0.12);
  --danger: #dc2626;
  --danger-light: rgba(220, 38, 38, 0.12);
  --warning: #d97706;
  --radius: 12px;
  --radius-lg: 18px;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
  --shadow-lg: 0 12px 32px rgba(15, 23, 42, 0.12);
  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, "Open Sans", "Helvetica Neue", sans-serif;
}

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

body {
  font-family: var(--font-family);
  background-color: var(--bg);
  color: var(--text);
  min-height: 100vh;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

button, input, select, textarea {
  font: inherit;
  color: inherit;
}

/* App Shell Layout */
.app-container {
  display: flex;
  min-height: 100vh;
}

/* Sidebar */
.app-sidebar {
  width: 260px;
  background: var(--surface);
  border-right: 1px solid var(--line);
  display: flex;
  flex-direction: column;
  position: fixed;
  top: 0;
  bottom: 0;
  left: 0;
  z-index: 50;
  transition: transform 0.25s ease-in-out;
}

.brand-header {
  padding: 1.25rem 1.5rem;
  display: flex;
  align-items: center;
  gap: 0.85rem;
  border-bottom: 1px solid var(--line);
}

.brand-logo {
  width: 40px;
  height: 40px;
  border-radius: 10px;
  object-fit: cover;
  background: var(--primary-light);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--primary);
  font-weight: 700;
  font-size: 1.2rem;
  flex-shrink: 0;
}

.brand-info {
  overflow: hidden;
}

.brand-name {
  font-weight: 700;
  font-size: 1rem;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  color: var(--text);
}

.brand-session {
  font-size: 0.75rem;
  color: var(--text-muted);
}

.sidebar-nav {
  flex: 1;
  overflow-y: auto;
  padding: 1rem 0.75rem;
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.nav-item {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.7rem 0.9rem;
  border-radius: var(--radius);
  color: var(--text-muted);
  text-decoration: none;
  font-weight: 500;
  font-size: 0.92rem;
  transition: all 0.15s ease;
  cursor: pointer;
  border: none;
  background: transparent;
  width: 100%;
  text-align: left;
}

.nav-item:hover {
  background: var(--surface-alt);
  color: var(--text);
}

.nav-item.active {
  background: var(--primary-light);
  color: var(--primary);
  font-weight: 600;
}

.nav-item svg {
  width: 20px;
  height: 20px;
  flex-shrink: 0;
}

.sidebar-footer {
  padding: 1rem 1.25rem;
  border-top: 1px solid var(--line);
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.user-badge {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.user-avatar {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--primary-light);
  color: var(--primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.9rem;
}

.user-details {
  flex: 1;
  min-width: 0;
}

.user-name {
  font-weight: 600;
  font-size: 0.85rem;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.user-role-badge {
  display: inline-block;
  font-size: 0.7rem;
  padding: 0.1rem 0.45rem;
  border-radius: 999px;
  text-transform: capitalize;
  font-weight: 600;
  background: var(--surface-alt);
  color: var(--text-muted);
}

/* Main Content Area */
.app-main {
  flex: 1;
  margin-left: 260px;
  display: flex;
  flex-direction: column;
  min-width: 0;
  min-height: 100vh;
}

/* Top App Bar */
.app-topbar {
  height: 64px;
  background: var(--surface);
  border-bottom: 1px solid var(--line);
  padding: 0 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  position: sticky;
  top: 0;
  z-index: 40;
}

.topbar-left {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  padding: 0.4rem;
  cursor: pointer;
  color: var(--text);
  border-radius: 6px;
}

.page-title-wrap h1 {
  font-size: 1.25rem;
  font-weight: 700;
}

.topbar-right {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.status-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.35rem 0.75rem;
  border-radius: 999px;
  font-size: 0.75rem;
  font-weight: 600;
  background: var(--surface-alt);
  color: var(--text-muted);
}

.status-chip.online {
  background: var(--success-light);
  color: var(--success);
}

.status-chip.offline {
  background: var(--accent-light);
  color: var(--warning);
}

.status-dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: currentColor;
}

/* Main Content Body */
.content-area {
  flex: 1;
  padding: 1.75rem 2rem 3rem;
  max-width: 1440px;
  width: 100%;
  margin: 0 auto;
}

/* Banner */
.banner {
  padding: 0.85rem 1.25rem;
  border-radius: var(--radius);
  margin-bottom: 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.9rem;
}

.banner-warning {
  background: var(--accent-light);
  color: #92400e;
  border: 1px solid rgba(245, 158, 11, 0.3);
}

.banner-info {
  background: var(--primary-light);
  color: var(--primary-hover);
  border: 1px solid var(--primary-glow);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.6rem 1.1rem;
  border-radius: var(--radius);
  font-weight: 600;
  font-size: 0.88rem;
  cursor: pointer;
  transition: all 0.15s ease;
  border: 1px solid transparent;
  text-decoration: none;
}

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

.btn-primary:hover {
  background: var(--primary-hover);
  transform: translateY(-1px);
}

.btn-secondary {
  background: var(--surface-alt);
  color: var(--text);
  border-color: var(--line);
}

.btn-secondary:hover {
  background: var(--line);
}

.btn-danger {
  background: var(--danger-light);
  color: var(--danger);
  border-color: rgba(220, 38, 38, 0.2);
}

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

.btn-sm {
  padding: 0.35rem 0.7rem;
  font-size: 0.8rem;
  border-radius: 8px;
}

.btn-icon {
  padding: 0.5rem;
  border-radius: 8px;
}

/* Cards & Panels */
.card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  padding: 1.5rem;
  margin-bottom: 1.5rem;
}

.card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 1.25rem;
  gap: 1rem;
  flex-wrap: wrap;
}

.card-title {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text);
}

.card-subtitle {
  font-size: 0.82rem;
  color: var(--text-muted);
  margin-top: 0.2rem;
}

/* Stats Grid */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1.25rem;
  margin-bottom: 1.75rem;
}

.stat-card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 1.25rem;
  box-shadow: var(--shadow-sm);
}

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

.stat-value {
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--text);
  margin-top: 0.25rem;
}

.stat-trend {
  font-size: 0.78rem;
  color: var(--success);
  margin-top: 0.35rem;
  display: flex;
  align-items: center;
  gap: 0.25rem;
}

/* Forms & Controls */
.form-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1.2rem;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.form-group.full-width {
  grid-column: 1 / -1;
}

label {
  font-size: 0.84rem;
  font-weight: 600;
  color: var(--text);
}

.form-control {
  padding: 0.65rem 0.85rem;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  background: var(--surface);
  font-size: 0.9rem;
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

.form-control:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px var(--primary-glow);
}

textarea.form-control {
  min-height: 90px;
  resize: vertical;
}

.input-hint {
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* Toolbar & Filters */
.toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1.25rem;
  flex-wrap: wrap;
}

.toolbar-group {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.search-bar {
  position: relative;
  min-width: 240px;
}

.search-bar input {
  padding-left: 2.2rem;
  width: 100%;
}

.search-bar svg {
  position: absolute;
  left: 0.75rem;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-muted);
  width: 16px;
  height: 16px;
}

/* Tables */
.table-responsive {
  width: 100%;
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
}

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.88rem;
  text-align: left;
}

th, td {
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--line);
}

th {
  background: var(--surface-alt);
  font-weight: 600;
  color: var(--text-muted);
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  white-space: nowrap;
}

tbody tr:hover {
  background: rgba(241, 245, 249, 0.6);
}

/* Broadsheet Specialized Table */
.broadsheet-table-wrap {
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fff;
  max-height: 75vh;
}

.broadsheet-table {
  border-collapse: collapse;
  font-size: 0.82rem;
  white-space: nowrap;
}

.broadsheet-table th, .broadsheet-table td {
  padding: 0.5rem 0.65rem;
  border: 1px solid #cbd5e1;
  text-align: center;
}

.broadsheet-table th.col-student, .broadsheet-table td.col-student {
  text-align: left;
  position: sticky;
  left: 38px;
  background: #fff;
  z-index: 10;
  font-weight: 600;
  min-width: 190px;
}

.broadsheet-table th.col-sn, .broadsheet-table td.col-sn {
  position: sticky;
  left: 0;
  background: #fff;
  z-index: 10;
  width: 38px;
}

.broadsheet-table th.subject-group-header {
  background: #f6be1e !important;
  color: #1a1a1a;
  font-weight: 700;
}

.broadsheet-table th.student-group-header {
  background: #f79a57 !important;
  color: #1a1a1a;
  font-weight: 700;
}

.broadsheet-table th.summary-group-header {
  background: #e2e8f0 !important;
  color: #1a1a1a;
  font-weight: 700;
}

/* Status Badges */
.badge {
  display: inline-flex;
  align-items: center;
  padding: 0.2rem 0.55rem;
  border-radius: 999px;
  font-size: 0.75rem;
  font-weight: 600;
}

.badge-success { background: var(--success-light); color: var(--success); }
.badge-warning { background: var(--accent-light); color: var(--warning); }
.badge-danger { background: var(--danger-light); color: var(--danger); }
.badge-neutral { background: var(--surface-alt); color: var(--text-muted); }

/* Modal Dialogs */
.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, 0.55);
  backdrop-filter: blur(4px);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1rem;
  z-index: 100;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s ease;
}

.modal-backdrop.active {
  opacity: 1;
  pointer-events: auto;
}

.modal-card {
  background: var(--surface);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  width: 100%;
  max-width: 580px;
  max-height: 90vh;
  display: flex;
  flex-direction: column;
  transform: scale(0.96);
  transition: transform 0.2s ease;
}

.modal-backdrop.active .modal-card {
  transform: scale(1);
}

.modal-card.modal-lg {
  max-width: 840px;
}

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

.modal-title {
  font-size: 1.15rem;
  font-weight: 700;
}

.modal-close-btn {
  background: transparent;
  border: none;
  font-size: 1.5rem;
  line-height: 1;
  color: var(--text-muted);
  cursor: pointer;
  padding: 0.25rem;
}

.modal-body {
  padding: 1.5rem;
  overflow-y: auto;
  flex: 1;
}

.modal-footer {
  padding: 1rem 1.5rem;
  border-top: 1px solid var(--line);
  display: flex;
  justify-content: flex-end;
  gap: 0.75rem;
  background: var(--surface-alt);
  border-bottom-left-radius: var(--radius-lg);
  border-bottom-right-radius: var(--radius-lg);
}

/* Toast Notifications */
.toast-container {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  z-index: 200;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  pointer-events: none;
}

.toast {
  pointer-events: auto;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 0.85rem 1.25rem;
  box-shadow: var(--shadow-lg);
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-size: 0.88rem;
  min-width: 280px;
  animation: slideInToast 0.25s ease forwards;
}

.toast-success { border-left: 4px solid var(--success); }
.toast-error { border-left: 4px solid var(--danger); }
.toast-info { border-left: 4px solid var(--primary); }

@keyframes slideInToast {
  from { transform: translateX(100%); opacity: 0; }
  to { transform: translateX(0); opacity: 1; }
}

/* Score Input Highlight Card */
.score-summary-box {
  background: var(--surface-alt);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1rem;
  display: flex;
  align-items: center;
  justify-content: space-around;
  margin-top: 0.5rem;
}

.score-stat {
  text-align: center;
}

.score-stat-val {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--primary);
}

.score-stat-lbl {
  font-size: 0.75rem;
  color: var(--text-muted);
  text-transform: uppercase;
}

/* Mobile Responsive */
@media (max-width: 960px) {
  .app-sidebar {
    transform: translateX(-100%);
  }

  .app-sidebar.open {
    transform: translateX(0);
  }

  .app-main {
    margin-left: 0;
  }

  .mobile-menu-btn {
    display: block;
  }

  .content-area {
    padding: 1rem 1rem 2rem;
  }
}

@media (max-width: 640px) {
  .toolbar {
    flex-direction: column;
    align-items: stretch;
  }
  .search-bar {
    min-width: 100%;
  }
  .stats-grid {
    grid-template-columns: 1fr;
  }
}