/* instead of *, use html and body to avoid the 'slow' warning */
html, body {
  gap: 15px;
      background-color: black;
    color: red;
    font-family: monospace;
    text-transform: lowercase;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100vh;
    margin: 0;
    border: 9px solid red;
    box-sizing: border-box;
}
input {
    background-color: black;
    color: red;
    border: 2px solid red;
    padding: 10px;
    margin-top: 20px;
    text-align: center;
    font-family: monospace;
    outline: none; 
    caret-color: red;
}

input:focus {
    box-shadow: 0 0 10px red;
}

input {
    background-color: black;
    color: red;
    border: 2px solid red;
    padding: 10px;
    margin-top: 20px;
    outline: none;
    text-align: center;
    font-family: monospace;
}

body {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    /* the thick red frame from killerfishGD's profile */
    border: 8px solid red;
    box-sizing: border-box;
}

/* this creates the inner "floating" look from your screenshots */
.menu-container {
    border: 2px solid red;
    border-radius: 20px;
    padding: 40px;
    background: black;
    box-shadow: 0 0 15px rgba(255, 0, 0, 0.5);
    text-align: center;
}