app/main.css

* {
    margin: 0;
    padding: 0;
}

body {
    margin: 0;
    padding: 0;
    padding-top: 30px;
    overflow-x: hidden;
    width: 100vw;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    background-color: rgb(0, 0, 0);
    color: white;
    font-family: Verdana, Geneva, Tahoma, sans-serif;
}

h1 {
    text-align: center;
    margin-bottom: 20px;
}

p {
    text-align: center;
    margin-bottom: 20px;
}

span {
    font-size: xx-large;
    font-weight: bold;
}

img {
    border-radius: 20%;
}

.contador {
    width: 100px;
    text-align: center;
    padding: 20px;
    background-color: rgb(10, 185, 225);
    font-size: xx-large;
    font-family: Impact, Haettenschweiler, 'Arial Narrow Bold', sans-serif;
    margin-bottom: 20px;
}

.numero {}

.botones {
    text-align: center;
    margin-bottom: 20px;
}

button {
    padding: 15px;
    border: none;
    font-family: Verdana, Geneva, Tahoma, sans-serif;
    color: white;
    border: 2px solid;
    background-color: rgba(0, 0, 0, 0);
    border-radius: 5px;
}

.up {
    border-color: rgb(12, 195, 120);
}

.down {
    border-color: rgb(200, 120, 120);
}

.parrafo {
    display: flex;
    flex-direction: column;
    justify-content: center;
}