:root {
    --primary-color: #1e3a5f;
    --secondary-color: #2c5282;
    --accent-color: #ed8936;
    --success-color: #38a169;
    --danger-color: #e53e3e;
    --warning-color: #dd6b20;
    --info-color: #3182ce;
    --light-bg: #f7fafc;
    --dark-text: #2d3748;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--light-bg);
    color: var(--dark-text);
}

.navbar {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.navbar-brand {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    font-weight: 700;
    font-size: 1.5rem;
}

.app-logo-navbar {
    width: 40px;
    height: 40px;
    object-fit: contain;
}

.sidebar {
    min-height: calc(100vh - 56px);
    background: white;
    border-right: 1px solid #e2e8f0;
}

.sidebar .nav-link {
    color: var(--dark-text);
    padding: 12px 20px;
    border-radius: 0;
    transition: all 0.2s;
}

.sidebar .nav-link:hover {
    background-color: #edf2f7;
    color: var(--primary-color);
}

.sidebar .nav-link.active {
    background-color: var(--primary-color);
    color: white;
}

.card {
    border: none;
    border-radius: 12px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
    transition: transform 0.2s, box-shadow 0.2s;
}

.card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.12);
}

.card-header {
    background: transparent;
    border-bottom: 1px solid #e2e8f0;
    font-weight: 600;
}

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

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

.badge-status {
    padding: 6px 12px;
    border-radius: 20px;
    font-weight: 500;
    font-size: 0.85rem;
}

.badge-aberta { background-color: #c6f6d5; color: #22543d; }
.badge-em-andamento { background-color: #bee3f8; color: #2a4365; }
.badge-concluida { background-color: #e2e8f0; color: #4a5568; }
.badge-cancelada { background-color: #fed7d7; color: #822727; }

.turma-card { cursor: pointer; height: 100%; }
.turma-card .card-body { display: flex; flex-direction: column; }

.table thead { background-color: var(--primary-color); color: white; }
.table th, .table td { vertical-align: middle; }

.user-avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    object-fit: cover;
}

.stats-card { text-align: center; padding: 20px; }
.stats-card .stats-number { font-size: 2.5rem; font-weight: 700; color: var(--primary-color); }
.stats-card .stats-label { color: #718096; font-size: 0.9rem; }

.modal-header {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
}

.modal-header .btn-close { filter: invert(1); }

.alert { border-radius: 8px; }

.form-control:focus, .form-select:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 0.2rem rgba(30, 58, 95, 0.25);
}

.footer {
    background-color: white;
    border-top: 1px solid #e2e8f0;
    padding: 20px 0;
    margin-top: 40px;
}

.empty-icon-xl {
    font-size: 4rem;
}

.instructor-avatar {
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.profile-card {
    background: linear-gradient(135deg, #1e3a5f, #2c5282);
    border-radius: 12px;
    padding: 30px;
}

.profile-avatar {
    width: 120px;
    height: 120px;
    object-fit: cover;
    border: 4px solid white;
}

.profile-avatar-placeholder {
    width: 120px;
    height: 120px;
    background: rgba(255, 255, 255, 0.2);
}

.profile-placeholder-icon {
    font-size: 3rem;
}

@media (max-width: 768px) {
    .sidebar {
        min-height: auto;
        border-right: none;
        border-bottom: 1px solid #e2e8f0;
    }
}