body {
    background-color: #f4f6f9;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

.header-portal {
    background: #ffffff;
    border-bottom: 3px solid #198754;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}

.logo-img {
    max-height: 60px;
    width: auto;
}

.category-card {
    border: none;
    border-radius: 12px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.05);
    background: #ffffff;
    margin-bottom: 24px;
}

.category-header {
    background-color: #f8f9fa;
    border-bottom: 2px solid #e9ecef;
    border-top-left-radius: 12px !important;
    border-top-right-radius: 12px !important;
    font-weight: 700;
    color: #2c3e50;
}

.app-btn {
    border: none;
    border-radius: 8px;
    padding: 12px 16px;
    font-weight: 600;
    text-decoration: none;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: transform 0.15s ease-in-out, box-shadow 0.15s ease-in-out;
    box-shadow: 0 2px 4px rgba(0,0,0,0.08);
}

.app-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0,0,0,0.15);
    opacity: 0.95;
}

#clock {
    font-size: 0.95rem;
    font-weight: 600;
}