header {
        background-color: black;
        display: flex;
        justify-content: center;       
    }
    footer {
        display: flex;
        justify-content: center; 
    } 
    body {
        background-color: black;
    }
    
    .Aufgabe {
        display: flex;
        flex-direction: column;
        align-items: center;
    }
    input[type="checkbox"] {
        width: 20px;
        height: 20px;
    }
    
    .Abfrage {
        height: 25px; 
        color: thistle;
    }
    
    .counter {
        margin: 8px 0 18px;
        padding: 8px 12px;
        border: 1px solid black;
        border-radius: 8px;
        background: #f7f7f7;
        color: #000;
        text-align: center;
        width: fit-content;
    }
    
    .Notesystem.hard {
        display: flex;
        font-display:center ;
        align-items: center;;
        border: 1px solid rgb(218, 13, 13);
        padding: 10px;
    }
        @media (max-width: 600px) {
            .Notesystem.hard {
                max-width: 90vw;
            }
        }
    
    #boo {
        background-color: thistle;
        border: 1px solid rgb(58, 36, 119);
    }
    #Notenabfrage {
        color: rgb(199, 42, 42);
        text-align: center;
        font-size: 20px;
        min-width: 250px;
    }

    
    /* Klavier */
    .klavier {
        position: relative;
        display: flex;
        width: 1120px;
        margin-bottom: 20px;
        border: 1px solid rgb(204, 13, 13);
        box-shadow: 0 0 20px rgba(194, 12, 12, 0.87);
    }
        @media (max-width: 900px) {
            .klavier {
                transform: scale(0.6);
            }
         }
        @media (max-width: 750px) {
            .klavier {
                display:none;
            }
        }
   
    .white {
        width: 40px;
        height: 150px;
        border: 1px solid black;
        border-radius: 2px;
        background: white;
        cursor: pointer;
        font-size: 30px;
    }
        @media (max-width: (900px)) {
            .klavier .white .black {
                width: calc(40px*0.6);
                height: calc(150px*0.6);
            }
        }
    
    .white.correct {
        background: rgb(19, 216, 19);
        border: 1px solid rgb(0, 128, 0);
        box-shadow: 0 0 10px rgb(19, 216, 19);
    }
    
    .white.wrong {
        background: rgb(255, 0, 0);
        border: 1px solid rgb(128, 0, 0);
        box-shadow: 0 0 10px rgb(255, 0, 0);
    }
    
    .white:hover {
       border: 1px solid rgb(128, 0, 38);
       box-shadow: 0 0 10px rgb(23, 31, 150);
    }

    .black {
        position: absolute;
        width: 25px;
        height: 90px;
        background: black;
        color: white;
        border-color: black;
        border-style: solid;
        border-width: 1px;
        top: 0;
        z-index: 2;
        cursor: pointer;
    }
    
    .black.correct {
        background: rgb(19, 216, 19);
        border: 1px solid rgb(0, 128, 0);
        box-shadow: 0 0 10px rgb(19, 216, 19);
    }
    
    .black.wrong {
        background: rgb(255, 0, 0);
        border: 1px solid rgb(128, 0, 0);
        box-shadow: 0 0 10px rgb(255, 0, 0);
    }
    
    .black:hover {
        border-color: #00ffff;
        box-shadow: 0 0 10px #00ffff;
    }
   
    /* Schriftern und Buttons */
    h1 {
        color: rgb(199, 42, 42);
        
    }
         @media (max-width: 600px) {
        h1 {
            font-size: 24px;
        }   
        }
    
    h2 {
        color: rgb(199, 42, 42);
        text-align: center;
    }
    
    p {
        color: rgb(199, 42, 42);
        text-align: center;
    }
    
    button {     
        background-color: white;
        color: black;
        font-size: 16px;
        margin: 5px;
        padding: 10px 20px;              
        border: solid 2px black;
        border-radius: 5px;
        cursor: pointer;
    }
    
    button:hover {
        background-color: black;
        color: white;
    }