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

body {
    font-family: "Segoe UI", Tahoma, sans-serif;
    background: 
        linear-gradient(rgba(0, 0, 0, 0.4), rgba(0, 0, 0, 0.4)),
        url("https://img.freepik.com/premium-vector/human-connection-social-network-digital-communication-technology-concept-background_618588-965.jpg") 
        no-repeat center center fixed;
    background-size: cover;
    text-align: center;
    padding: 20px;
    color: #333;
}

h1 {
    font-size: 2rem;
    margin-bottom: 10px;
    color: #fff;
    text-shadow: 1px 1px 3px rgba(0,0,0,0.5);
}

p.subtitle {
    color: #ddd;
    margin-bottom: 20px;
}

/* ===== User Container ===== */
.user-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 20px;
    margin-top: 20px;
    padding: 0 10px;
}

/* ===== User Card ===== */
.user-card {
    background: rgba(255, 255, 255, 0.9);
    border-radius: 12px;
    padding: 20px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.15);
    text-align: left;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}
.user-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 20px rgba(0,0,0,0.2);
}
.user-card h3 {
    font-size: 1.2rem;
    color: #0077cc;
    margin-bottom: 10px;
}
.user-card p {
    font-size: 0.95rem;
    color: #444;
    margin: 5px 0;
}

/* ===== Button ===== */
button {
    margin-top: 25px;
    padding: 12px 18px;
    border: none;
    background: #0077cc;
    color: white;
    font-size: 1rem;
    font-weight: bold;
    cursor: pointer;
    border-radius: 6px;
    transition: background 0.2s ease, transform 0.2s ease;
}
button:hover {
    background: #005fa3;
    transform: scale(1.05);
}
button:disabled {
    background: #ccc;
    cursor: not-allowed;
}

/* ===== Loader ===== */
.loader {
    border: 4px solid #f3f3f3;
    border-top: 4px solid #0077cc;
    border-radius: 50%;
    width: 40px;
    height: 40px;
    margin: 30px auto;
    animation: spin 1s linear infinite;
}
@keyframes spin {
    to { transform: rotate(360deg); }
}