/* ===== CSS Variables ===== */
:root {
    --primary: #4f46e5;
    --primary-light: #6366f1;
    --primary-dark: #3730a3;
    --primary-bg: #eef2ff;
    --success: #059669;
    --success-bg: #ecfdf5;
    --warning: #d97706;
    --warning-bg: #fffbeb;
    --danger: #dc2626;
    --danger-bg: #fef2f2;
    --info: #0891b2;
    --info-bg: #ecfeff;
    --surface: #ffffff;
    --surface-hover: #f8fafc;
    --bg: #f1f5f9;
    --bg-alt: #e2e8f0;
    --text: #1e293b;
    --text-muted: #64748b;
    --text-light: #94a3b8;
    --border: #e2e8f0;
    --border-light: #f1f5f9;
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
    --shadow: 0 1px 3px rgba(0,0,0,0.08), 0 1px 2px rgba(0,0,0,0.04);
    --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.08), 0 2px 4px -2px rgba(0,0,0,0.04);
    --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.08), 0 4px 6px -4px rgba(0,0,0,0.04);
    --radius: 0.625rem;
    --radius-lg: 0.875rem;
    --radius-xl: 1rem;
    --transition: 0.2s ease;
}

/* ===== Base ===== */
body {
    background-color: var(--bg);
    color: var(--text);
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
}

a { color: var(--primary); transition: color var(--transition); }
a:hover { color: var(--primary-dark); }

::selection {
    background: var(--primary-bg);
    color: var(--primary-dark);
}

/* ===== Navbar ===== */
.navbar {
    background: linear-gradient(135deg, #1e1b4b 0%, #312e81 100%) !important;
    box-shadow: var(--shadow-md);
    padding: 0.5rem 1rem;
    border-bottom: none;
}

.navbar-brand {
    font-weight: 700;
    font-size: 1.15rem;
    letter-spacing: -0.02em;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.navbar-brand i {
    font-size: 1.4rem;
    background: linear-gradient(135deg, #818cf8, #c084fc);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.navbar .nav-link {
    font-size: 0.875rem;
    font-weight: 500;
    color: rgba(255,255,255,0.7) !important;
    padding: 0.6rem 0.85rem !important;
    border-radius: var(--radius);
    transition: all var(--transition);
    display: flex;
    align-items: center;
    gap: 0.4rem;
}

.navbar .nav-link:hover,
.navbar .nav-link.active {
    color: #fff !important;
    background: rgba(255,255,255,0.1);
}

.navbar .nav-link i { font-size: 1rem; }

.navbar .badge {
    font-size: 0.65rem;
    font-weight: 600;
    padding: 0.2em 0.5em;
    border-radius: 999px;
}

.navbar-toggler {
    border: 1px solid rgba(255,255,255,0.2);
    padding: 0.35rem 0.6rem;
}

/* ===== Cards ===== */
.card {
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    transition: box-shadow var(--transition), transform var(--transition);
    background: var(--surface);
    overflow: hidden;
}

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

.card-header {
    background: var(--surface);
    border-bottom: 1px solid var(--border-light);
    font-weight: 600;
    font-size: 0.9rem;
    padding: 0.75rem 1.25rem;
    color: var(--text);
}

.card-body { padding: 1.25rem; }
.card-footer { background: var(--surface-hover); border-top: 1px solid var(--border-light); }

/* Stat cards on dashboard */
.stat-card {
    border: none;
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.stat-card::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0;
    height: 4px;
}

.stat-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.stat-card.primary::before { background: linear-gradient(90deg, #4f46e5, #818cf8); }
.stat-card.success::before { background: linear-gradient(90deg, #059669, #34d399); }
.stat-card.info::before { background: linear-gradient(90deg, #0891b2, #22d3ee); }
.stat-card.warning::before { background: linear-gradient(90deg, #d97706, #fbbf24); }

.stat-card .stat-icon {
    width: 56px;
    height: 56px;
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
}

.stat-card.primary .stat-icon { background: var(--primary-bg); color: var(--primary); }
.stat-card.success .stat-icon { background: var(--success-bg); color: var(--success); }
.stat-card.info .stat-icon { background: var(--info-bg); color: var(--info); }
.stat-card.warning .stat-icon { background: var(--warning-bg); color: var(--warning); }

/* ===== Tables ===== */
.table {
    --bs-table-bg: transparent;
    font-size: 0.875rem;
}

.table th {
    font-weight: 600;
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--text-muted);
    border-bottom: 2px solid var(--border);
    padding: 0.75rem 1rem;
    white-space: nowrap;
}

.table td {
    padding: 0.75rem 1rem;
    vertical-align: middle;
    border-bottom: 1px solid var(--border-light);
    color: var(--text);
}

.table tbody tr {
    transition: background var(--transition);
}

.table-hover tbody tr:hover {
    background-color: var(--primary-bg) !important;
}

/* ===== Buttons ===== */
.btn {
    font-size: 0.875rem;
    font-weight: 500;
    border-radius: var(--radius);
    padding: 0.45rem 1rem;
    transition: all var(--transition);
    letter-spacing: -0.01em;
}

.btn-sm {
    padding: 0.3rem 0.6rem;
    font-size: 0.8rem;
    border-radius: 0.5rem;
}

.btn-lg {
    padding: 0.65rem 1.5rem;
    font-size: 1rem;
    border-radius: var(--radius-lg);
}

.btn-primary {
    background: var(--primary);
    border-color: var(--primary);
}
.btn-primary:hover { background: var(--primary-dark); border-color: var(--primary-dark); transform: translateY(-1px); box-shadow: var(--shadow); }

.btn-outline-primary { color: var(--primary); border-color: var(--primary); }
.btn-outline-primary:hover { background: var(--primary); border-color: var(--primary); }

.btn-outline-secondary { color: var(--text-muted); border-color: var(--border); }
.btn-outline-secondary:hover { background: var(--bg); border-color: var(--bg-alt); color: var(--text); }

.btn-group .btn { border-radius: 0; }
.btn-group .btn:first-child { border-radius: var(--radius) 0 0 var(--radius); }
.btn-group .btn:last-child, .btn-group form:last-child .btn { border-radius: 0 var(--radius) var(--radius) 0; }

/* ===== Badges ===== */
.badge {
    font-weight: 600;
    font-size: 0.72rem;
    letter-spacing: 0.02em;
    padding: 0.35em 0.65em;
    border-radius: 999px;
}

.badge.bg-primary { background: var(--primary) !important; }
.badge.bg-success { background: var(--success) !important; }
.badge.bg-warning { background: var(--warning) !important; }
.badge.bg-danger { background: var(--danger) !important; }
.badge.bg-info { background: var(--info) !important; }

/* ===== Forms ===== */
.form-control, .form-select {
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 0.5rem 0.85rem;
    font-size: 0.875rem;
    transition: border-color var(--transition), box-shadow var(--transition);
    color: var(--text);
}

.form-control:focus, .form-select:focus {
    border-color: var(--primary-light);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.12);
}

.form-label {
    font-weight: 500;
    font-size: 0.85rem;
    color: var(--text);
    margin-bottom: 0.35rem;
}

/* ===== Breadcrumbs ===== */
.breadcrumb {
    font-size: 0.85rem;
    margin-bottom: 0.5rem;
    background: none;
    padding: 0;
}

.breadcrumb-item a { color: var(--primary); text-decoration: none; }
.breadcrumb-item.active { color: var(--text-muted); }

/* ===== Page Headers ===== */
h3, .page-title {
    font-weight: 700;
    font-size: 1.5rem;
    color: var(--text);
    letter-spacing: -0.02em;
}

h5 { font-weight: 600; letter-spacing: -0.01em; }
h6 { font-weight: 600; font-size: 0.85rem; text-transform: uppercase; letter-spacing: 0.04em; color: var(--text-muted); }

/* ===== Modals ===== */
.modal-content {
    border: none;
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-lg);
}

.modal-header { padding: 1.25rem 1.5rem 0.5rem; }
.modal-body { padding: 0.75rem 1.5rem; font-size: 0.9rem; line-height: 1.7; }
.modal-footer { padding: 0.5rem 1.5rem 1.25rem; }

.modal-title {
    font-weight: 600;
    font-size: 1.1rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.modal-backdrop.show { opacity: 0.4; backdrop-filter: blur(4px); }

/* ===== Category Cards ===== */
.category-card {
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    background: var(--surface);
    box-shadow: var(--shadow-sm);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.category-card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
    border-color: var(--primary-light);
}

.category-card .card-body { padding: 1.25rem; }

.category-card .cat-icon {
    width: 44px;
    height: 44px;
    border-radius: var(--radius);
    background: var(--primary-bg);
    color: var(--primary);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    margin-bottom: 0.75rem;
}

/* ===== Empty States ===== */
.empty-state {
    text-align: center;
    padding: 3rem 1rem;
    color: var(--text-muted);
}

.empty-state i {
    font-size: 3rem;
    color: var(--text-light);
    margin-bottom: 1rem;
    display: block;
}

.empty-state p {
    font-size: 0.95rem;
    max-width: 400px;
    margin: 0 auto;
}

/* ===== Login Page ===== */
.login-card {
    border: none;
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-lg);
    overflow: hidden;
}

.login-card .login-header {
    background: linear-gradient(135deg, #1e1b4b, #312e81);
    padding: 2rem 1.5rem;
    text-align: center;
    color: white;
}

.login-card .login-header i {
    font-size: 2.5rem;
    background: linear-gradient(135deg, #818cf8, #c084fc);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.login-card .login-header h4 {
    font-weight: 700;
    margin-top: 0.75rem;
    margin-bottom: 0.25rem;
}

.login-card .login-header p {
    opacity: 0.7;
    font-size: 0.9rem;
    margin: 0;
}

/* ===== Report Detail ===== */
.score-card {
    text-align: center;
    padding: 1rem;
    border-radius: var(--radius-lg);
    background: var(--bg);
}

.score-card .score-value {
    font-size: 1.75rem;
    font-weight: 700;
    line-height: 1.2;
}

.score-card .score-label {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-muted);
    font-weight: 600;
    margin-top: 0.25rem;
}

/* ===== Answer Sheet ===== */
.answer-category-header {
    background: var(--bg);
    padding: 0.65rem 1rem;
    font-weight: 600;
    font-size: 0.9rem;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: background var(--transition);
    border-bottom: 1px solid var(--border-light);
}

.answer-category-header:hover { background: var(--bg-alt); }

.answer-item { padding: 1rem 1.25rem; border-bottom: 1px solid var(--border-light); }
.answer-item:last-child { border-bottom: none; }
.answer-item:nth-child(odd) { background: rgba(241, 245, 249, 0.5); }

.option-box {
    border: 1.5px solid var(--border);
    border-radius: var(--radius);
    padding: 0.5rem 0.85rem;
    font-size: 0.875rem;
    transition: all var(--transition);
}

.option-box.correct { border-color: var(--success); background: var(--success-bg); }
.option-box.wrong { border-color: var(--danger); background: var(--danger-bg); }

/* ===== Question Bank Table ===== */
.q-deactivated { opacity: 0.55; }
.q-deactivated:hover { opacity: 0.8; }

/* ===== Exam Taking ===== */
.exam-sidebar { background: linear-gradient(180deg, #f8fafc, #f1f5f9); }

/* ===== Scrollbar ===== */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--bg-alt); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-light); }

/* ===== Utilities ===== */
.text-gradient {
    background: linear-gradient(135deg, var(--primary), #818cf8);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hover-lift { transition: transform 0.3s ease, box-shadow 0.3s ease; }
.hover-lift:hover { transform: translateY(-3px); box-shadow: var(--shadow-md); }

/* ===== Responsive ===== */
@media (max-width: 768px) {
    .container-fluid { padding: 0.75rem; }
    .btn-group { flex-wrap: wrap; }
    h3, .page-title { font-size: 1.25rem; }
}