* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: sans-serif;
}
body {
    background: #0f1115; 
    color: #e5e7eb; 
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: space-between;
    height: 100vh;
    padding: 2rem;
}
.btn {
    display: block;
    width: 100%;
    margin: 1rem 0;
    padding: 1rem;
    background: #2b2b2b;
    color: #fff;
    border: none;
    text-align: center;
    font-size: 1.2rem;
    cursor: pointer;
    text-decoration: none;
}
.stack {
    width: 100%;
    max-width: 700px;
}