:root {
  --gt-sidebar-bg: #101d3d;
  --gt-sidebar-hover: #1a2b57;
  --gt-navbar-bg: #2554e8;
  --gt-primary: #2554e8;
  --gt-content-bg: #f3f5f9;
  --gt-card-radius: 0.6rem;
  --gt-sidebar-width: 250px;
}

body {
  background-color: var(--gt-content-bg);
  font-family: "Segoe UI", Roboto, -apple-system, BlinkMacSystemFont, sans-serif;
}

/* ---------- Layout shell ---------- */
.gt-app {
  display: flex;
  min-height: 100vh;
}

.gt-sidebar {
  width: var(--gt-sidebar-width);
  background-color: var(--gt-sidebar-bg);
  flex-shrink: 0;
  transition: margin-left 0.2s ease;
  position: fixed;
  top: 0;
  bottom: 0;
  left: 0;
  z-index: 1030;
  overflow-y: auto;
}

.gt-sidebar.collapsed {
  margin-left: calc(var(--gt-sidebar-width) * -1);
}

.gt-sidebar-brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 1.1rem 1.25rem;
  color: #fff;
  font-weight: 700;
  font-size: 1.05rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.gt-sidebar-brand i {
  color: #ffb020;
}

.gt-sidebar-logo {
  height: 34px;
  width: 34px;
  object-fit: contain;
  background: #fff;
  border-radius: 50%;
  padding: 2px;
  flex-shrink: 0;
}

.gt-nav {
  list-style: none;
  margin: 0.5rem 0;
  padding: 0;
}

.gt-nav-link {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.65rem 1.25rem;
  color: rgba(255, 255, 255, 0.75);
  text-decoration: none;
  font-size: 0.92rem;
  border-left: 3px solid transparent;
}

.gt-nav-link i {
  width: 1.1rem;
  text-align: center;
}

.gt-nav-link:hover {
  background-color: var(--gt-sidebar-hover);
  color: #fff;
}

.gt-nav-link.active {
  background-color: var(--gt-sidebar-hover);
  color: #fff;
  border-left-color: #ffb020;
}

/* ---------- Menu / submenu accordion ---------- */
.gt-nav-parent > .gt-nav-link {
  cursor: pointer;
  justify-content: space-between;
}

.gt-nav-parent > .gt-nav-link .gt-nav-label {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-grow: 1;
}

.gt-nav-caret {
  font-size: 0.7rem;
  color: rgba(255, 255, 255, 0.5);
  transition: transform 0.15s ease;
  width: auto !important;
}

.gt-nav-parent > .gt-nav-link[aria-expanded="true"] .gt-nav-caret {
  color: #ffb020;
}

.gt-nav-submenu {
  list-style: none;
  margin: 0;
  padding: 0;
  background-color: rgba(0, 0, 0, 0.15);
}

.gt-nav-sublink {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  padding: 0.55rem 1.25rem 0.55rem 2.35rem;
  color: rgba(255, 255, 255, 0.65);
  text-decoration: none;
  font-size: 0.86rem;
  border-left: 3px solid transparent;
}

.gt-nav-sublink i {
  width: 1rem;
  text-align: center;
  font-size: 0.8rem;
}

.gt-nav-sublink:hover {
  background-color: var(--gt-sidebar-hover);
  color: #fff;
}

.gt-nav-sublink.active {
  background-color: var(--gt-sidebar-hover);
  color: #fff;
  border-left-color: #ffb020;
}

.gt-main {
  flex-grow: 1;
  margin-left: var(--gt-sidebar-width);
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  transition: margin-left 0.2s ease;
}

.gt-main.expanded {
  margin-left: 0;
}

.gt-topbar {
  background-color: var(--gt-navbar-bg);
  color: #fff;
  padding: 0.75rem 1.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  position: sticky;
  top: 0;
  z-index: 1020;
}

.gt-topbar h1 {
  font-size: 1.15rem;
  font-weight: 600;
  margin: 0;
  color: #fff;
}

.gt-topbar-toggle {
  background: transparent;
  border: none;
  color: #fff;
  font-size: 1.2rem;
  cursor: pointer;
}

.gt-topbar .dropdown-toggle {
  color: #fff;
  text-decoration: none;
}

.gt-content {
  padding: 1.5rem;
  flex-grow: 1;
}

/* ---------- Cards ---------- */
.gt-card {
  background: #fff;
  border-radius: var(--gt-card-radius);
  box-shadow: 0 1px 3px rgba(15, 23, 42, 0.08);
  border: 1px solid rgba(15, 23, 42, 0.06);
}

.gt-kpi-card {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1.1rem 1.25rem;
}

.gt-kpi-icon {
  width: 3rem;
  height: 3rem;
  border-radius: 0.6rem;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.3rem;
  color: #fff;
  flex-shrink: 0;
}

.gt-kpi-icon.bg-books { background-color: #2554e8; }
.gt-kpi-icon.bg-students { background-color: #7c3aed; }
.gt-kpi-icon.bg-issued { background-color: #f97316; }
.gt-kpi-icon.bg-returned { background-color: #8b5cf6; }
.gt-kpi-icon.bg-available { background-color: #16a34a; }
.gt-kpi-icon.bg-overdue { background-color: #dc2626; }
.gt-kpi-icon.bg-fine { background-color: #0891b2; }

.gt-kpi-value {
  font-size: 1.4rem;
  font-weight: 700;
  color: #0f172a;
}

.gt-kpi-label {
  font-size: 0.82rem;
  color: #64748b;
}

/* ---------- Tables ---------- */
.gt-card table thead th {
  background-color: #f8fafc;
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  color: #64748b;
  border-bottom-width: 1px;
}

.table > :not(caption) > * > * {
  vertical-align: middle;
}

/* ---------- Login screens ---------- */
.gt-login-wrap {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, #101d3d 0%, #2554e8 100%);
  padding: 1.5rem;
}

.gt-login-card {
  background: #fff;
  border-radius: 1rem;
  overflow: hidden;
  max-width: 900px;
  width: 100%;
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.25);
}

.gt-login-illustration {
  background: #eef2ff;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 2.5rem;
}

.gt-login-illustration i {
  font-size: 6rem;
  color: var(--gt-primary);
}

.gt-login-logo {
  width: 300px;
  height: 300px;
  object-fit: contain;
}

.gt-login-logo-sm {
  width: 64px;
  height: 64px;
  object-fit: contain;
}

.gt-badge-status-active { background-color: #16a34a; }
.gt-badge-status-inactive { background-color: #94a3b8; }

/* Bootstrap 5.1 (bundled here) has no bg-*-subtle / text-*-emphasis utilities
   (those only exist from 5.3+) — a plain .badge with neither falls back to
   white-on-white and disappears, so subject badges get their own class. */
.gt-badge-subject { background-color: #e2e8f0; color: #334155; }

/* ---------- Tabbed forms (Student registration, etc.) ---------- */
.gt-form-tabs {
  border-bottom: 2px solid #e2e8f0;
  gap: 0.25rem;
  flex-wrap: wrap;
}

.gt-form-tabs .nav-link {
  border: none;
  border-bottom: 3px solid transparent;
  border-radius: 0;
  color: #64748b;
  font-weight: 600;
  font-size: 0.88rem;
  padding: 0.65rem 1rem;
}

.gt-form-tabs .nav-link:hover {
  color: var(--gt-primary);
  border-bottom-color: #c7d2fe;
}

.gt-form-tabs .nav-link.active {
  color: var(--gt-primary);
  background: transparent;
  border-bottom-color: var(--gt-primary);
}

.gt-form-tab-content {
  background: #fff;
  border: 1px solid #e2e8f0;
  border-top: none;
  border-radius: 0 0 0.6rem 0.6rem;
  padding: 1.5rem;
}

.gt-form-side-card {
  background: #f8fafc;
  border: 1px solid #e2e8f0;
  border-radius: 0.6rem;
  padding: 1.25rem;
  position: sticky;
  top: 1rem;
}

.gt-signature-preview {
  width: 100%;
  max-width: 220px;
  height: 80px;
  object-fit: contain;
  border: 1px solid #e2e8f0;
  border-radius: 0.4rem;
  background: #fff;
}

.gt-signature-placeholder {
  margin: 0 auto;
}

.gt-doc-table td {
  vertical-align: middle;
}

@media (max-width: 991.98px) {
  .gt-sidebar {
    margin-left: calc(var(--gt-sidebar-width) * -1);
  }
  .gt-sidebar.mobile-open {
    margin-left: 0;
  }
  .gt-main {
    margin-left: 0;
  }
}