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

body {
    font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
    background: #f8f9fa;
    color: #333;
}

/* Section Styles */
.header, .sidebar, .content, .footer {
    border-radius: 12px;
    padding: 20px;
}

/* Header */
.header {
    background: linear-gradient(135deg, #007bff, #0056b3);
    color: white;
    text-align: center;
    font-size: 1.8rem;
    font-weight: bold;
    box-shadow: 0px 4px 8px rgba(0,0,0,0.2);
}

/* Sidebar */
.sidebar {
    background: white;
    box-shadow: 0px 2px 5px rgba(0,0,0,0.1);
}

.sidebar ul {
    list-style: none;
}

.sidebar li {
    margin: 12px 0;
}

.sidebar a {
    text-decoration: none;
    color: #007bff;
    font-size: 1.1rem;
    font-weight: 600;
    display: block;
    padding: 8px 10px;
    border-radius: 6px;
    transition: background 0.3s ease, transform 0.2s ease;
}

.sidebar a:hover {
    background: #007bff;
    color: white;
    transform: translateX(5px);
}

/* Content */
.content {
    background: white;
    box-shadow: 0px 2px 5px rgba(0,0,0,0.1);
    line-height: 1.6;
    font-size: 1.1rem;
}

/* Footer */
.footer {
    background: #333;
    color: white;
    text-align: center;
    font-size: 0.9rem;
    box-shadow: 0px -2px 5px rgba(0,0,0,0.1);
}

/* Desktop Layout (Grid) */
@media (min-width: 768px) {
    body {
        display: grid;
        grid-template-areas:
            "header header"
            "sidebar content"
            "footer footer";
        grid-template-columns: 250px 1fr;
        grid-template-rows: auto 1fr auto;
        gap: 20px;
        padding: 20px;
    }

    .header { grid-area: header; }
    .sidebar { grid-area: sidebar; }
    .content { grid-area: content; }
    .footer { grid-area: footer; }
}

/* Mobile Layout (Stacked) */
@media (max-width: 767px) {
    body {
        display: flex;
        flex-direction: column;
        gap: 15px;
        padding: 10px;
    }
}